Image forming optical system and electronic image pickup apparatus using image forming optical system

Abstract

An image forming optical system according to the present invention is characterized in that, in an image forming optical system having a positive lens group, a negative lens group, and an aperture stop, the positive lens group is disposed at an object side of the aperture stop, the positive lens group has a cemented lens which is formed by cementing a plurality of lenses,in a rectangular coordinate system in which a horizontal axis is let to be Nd and a vertical axis is let to be νd, when a straight line indicated by Nd=α×νd+β (where, α=−0.017) is set,Nd and νd of at least one lens forming the cemented lens is included in both of areas namely, an area which is determined by a line when a lower limit value is in a range of a following conditional expression (1a), and a line when an upper limit value is in a range of the following conditional expression (1a), and of an area determined by following conditional expressions (2a) and (3a). 1.45<β<2.15  (1a)1.30

Description

CROSS-REFERENCE TO RELATED APPLICATION

The present application is based upon and claims the benefit of priority from the prior Japanese Patent Application Nos. 2005-264529 filed on Sep. 13, 2005, 2005-264533 filed on Sep. 13, 2005, 2006-241747 filed on Sep. 6, 2006, and 2006-241771 filed on Sep. 6, 2006, the entire contents of which are incorporated herein by reference.

TECHNICAL FIELD

The present invention relates to an image forming optical system which is used in an extremely small image pickup module, and an electronic image pickup apparatus which includes the image forming optical system.

BACKGROUND ART

In recent years, a digital camera has been widely used as a next generation camera replacing a silver salt 35 mm film camera. Recently, there has been increasing reduction in size, and thinning of a digital camera. Moreover, a camera function (hereinafter called as ‘image pickup module’) has been provided even in a portable telephone, the use of which has also been increasing widely. For mounting this image pickup module in the portable telephone, an optical system has to be smaller and thinner than an optical system of the digital camera. Particularly, in a zoom lens, the reduction in size, and thinning has been sought. However, a zoom lens having a size reduced so as to mount in the portable telephone has not been known much.

As a typical means for reducing the size and thinning of the zoom lens, the following two means can be taken into consideration. In other words,

A. To use a collapsible lens barrel, and to accommodate the optical system in a thickness (depth) of a casing. This collapsible lens barrel is a lens barrel having a structure in which the optical system protrudes from a camera casing, and is accommodated in the camera casing while carrying.

B. To accommodate the optical system in a direction of width or in a direction of height by adopting a dioptric system. This dioptric system is an optical system having a structure in which an optical path (optical axis) of the optical system is folded by a reflecting optical element such as a mirror or a prism.

However, in the structure in which the abovementioned means A is used, the number of lenses forming the optical system or the number of movable lens group is more, and it is difficult to carry out the reduction in size, and the thinning.

Moreover, in the structure in which the abovementioned means B is used, it is easy to make the casing thin as compared to a case in which the means in the abovementioned A is used, but an amount of movement of the movable lens group at the time of varying the power, and the number of lenses forming the optical system tend to increase. Therefore, volumetrically, it is not at all suitable for the reduction in size.

DISCLOSURE OF THE INVENTION

An image forming optical system according to the present invention is characterized in that, in an image forming optical system having a positive lens group, a negative lens group, and an aperture stop,

the positive lens group is disposed at an object side of the aperture stop,

the positive lens group has a cemented lens which is formed by cementing a plurality of lenses,

in a rectangular coordinate system in which a horizontal axis is let to be Nd and a vertical axis is let to be νd, when a straight line indicated by Nd=α×νd+β (where, α=−0.017) is set,

Nd and νd of at least one lens forming the cemented lens are included in both areas namely, an area which is determined by a line when a lower limit value is in a range of a following conditional expression (1a), and a line when an upper limit value is in a range of the following conditional expression (1a), and of an area determined by following conditionals expressions (2a) and (3a).1.45<β<2.15  (1a)1.30<Nd<2.20  (2a)3<νd<12  (3a)

Here, Nd denotes a refractive index, and νd denotes an Abbe's number.

Moreover, an image forming optical system according to the present invention is characterized in that, in an image forming optical system having a positive lens group, a negative lens group, and an aperture stop,

the positive lens group is disposed at an object side of the aperture stop,

the positive lens group has a cemented lens in which a plurality of lenses are cemented,

in a rectangular coordinate system in which, a horizontal axis is let to be Nd and a vertical axis is let to be νd, when a straight line indicated by Nd=α×νd+β (where, α=−0.017) is set,

Nd and νd of at least one lens forming the cemented lens are included in both areas namely, an area which is determined by a line when a lower limit value is in a range of a following conditional expression (1b), and a line when an upper limit value is in a range of the following conditional expression (1b), and of an area determined by following conditional expressions (2b) and (3b).1.45<β<2.15  (1b)1.58<Nd<2.20  (2b)3<νd<40  (3b)

Here, Nd denotes a refractive index, and νd denotes an Abbe's number.

Moreover, an electronic image pickup apparatus of the present invention is characterized in that the electronic image pickup apparatus includes an image forming optical system mentioned in any one above, an electronic image pickup element, and an image processing means which is capable of processing image data obtained by image pickup by the electronic image pickup element an image which is formed through the image forming optical system, and outputting as image data in which a shape is changed upon processing, and in which the image forming optical system is a zoom lens, and the zoom lens satisfies a following conditional expression at a time of infinite object point focusing.0.7<y₀₇/(fw·tan ω_07w)<0.96

where, y₀₇ is indicated as y₀₇=0.7 y₁₀ when, in an effective image pickup surface (surface in which, image pickup is possible), a distance from a center up to a farthest point (maximum image height) is let to be y₁₀. Moreover, ω_07w is an angle with respect to an optical axis in a direction of an object point corresponding to an image point connecting from a center on the image pickup surface in a wide angle end up to a position of y₀₇.

According to the present invention, it is possible to achieve a thinning and a size reduction of a volume of the image forming optical system, and further to have both of a widening of an angle and a favorable correction of various aberrations in the electronic image pickup apparatus of the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross-sectional view along an optical axis showing an optical arrangement at the time of an infinite object point focusing at a wide angle end of a zoom lens according to a first embodiment of the present invention;

FIG. 2A, FIG. 2B, and FIG. 2C are diagrams showing a spherical aberration, an astigmatism, a distortion, and a chromatic aberration of magnification at the time of the infinite object point focusing of the zoom lens according to the first embodiment of the present invention, where, FIG. 2A shows a state at the wide angle end, FIG. 2B shows an intermediate state, and FIG. 2C shows a state at a telephoto end;

FIG. 3 is a cross-sectional view along the optical axis showing an optical arrangement at the time of the infinite object point focusing at the wide angle end of a zoom lens according to a second embodiment of the present invention;

FIG. 4A, FIG. 4B, and FIG. 4C are diagrams showing the spherical aberration, the astigmatism, the distortion, and the chromatic aberration of magnification at the time of the infinite object point focusing of the zoom lens according to the second embodiment of the present invention, where, FIG. 4A shows the state at the wide angle end, FIG. 4B shows the intermediate state, and FIG. 4C shows the state at the telephoto end;

FIG. 5 is a cross-sectional view along the optical axis showing an optical arrangement at the time of the infinite object point focusing at the wide angle end of a zoom lens according to a third embodiment of the present invention;

FIG. 6A, FIG. 6B, and FIG. 6C are diagrams showing the spherical aberration, the astigmatism, the distortion, and the chromatic aberration of magnification at the time of the infinite object point focusing of the zoom lens according to the third embodiment of the present invention, where, FIG. 6A shows the state at the wide angle end, FIG. 6B shows the intermediate state, and FIG. 6C shows the state at the telephoto end;

FIG. 7 is a cross-sectional view along the optical axis showing an optical arrangement at the time of the infinite object point focusing at the wide angle end of a zoom lens according to a fourth embodiment of the present invention;

FIG. 8A, FIG. 8B, and FIG. 8C are diagrams showing the spherical aberration, the astigmatism, the distortion, and the chromatic aberration of magnification at the time of the infinite object point focusing of the zoom lens according to the fourth embodiment of the present invention, where, FIG. 8A shows the state at the wide angle end, FIG. 8B shows the intermediate state, and FIG. 8C shows the state at the telephoto end;

FIG. 9 is a cross-sectional view along the optical axis showing an optical arrangement at the time of the infinite object point focusing at the wide angle end of a zoom lens according to a fifth embodiment of the present invention;

FIG. 10A, FIG. 10B, and FIG. 10C are diagrams showing the spherical aberration, the astigmatism, the distortion, and the chromatic aberration of magnification at the time of the infinite object point focusing of the zoom lens according to the fifth embodiment of the present invention, where, FIG. 10A shows the state at the wide angle end, FIG. 10B shows the intermediate state, and FIG. 10C shows the state at the telephoto end;

FIG. 11 is a cross-sectional view along the optical axis showing an optical arrangement at the time of the infinite object point focusing at the wide angle end of a zoom lens according to a sixth embodiment of the present invention;

FIG. 12A, FIG. 12B, and FIG. 12C are diagrams showing the spherical aberration, the astigmatism, the distortion, and the chromatic aberration of magnification at the time of the infinite object point focusing of the zoom lens according to the sixth embodiment of the present invention, where, FIG. 12A shows the state at the wide angle end, FIG. 12B shows the intermediate state, and FIG. 12C shows the state at the telephoto end;

FIG. 13 is a cross-sectional view along the optical axis showing an optical arrangement at the time of the infinite object point focusing at the wide angle end of a zoom lens according to a seventh embodiment of the present invention;

FIG. 14A, FIG. 14B, and FIG. 14C are diagrams showing the spherical aberration, the astigmatism, the distortion, and the chromatic aberration of magnification at the time of the infinite object point focusing of the zoom lens according to the seventh embodiment of the present invention, where, FIG. 14A shows the state at the wide angle end, FIG. 14B shows the intermediate state, and FIG. 14C shows the state at the telephoto end;

FIG. 15 is a cross-sectional view along the optical axis showing an optical arrangement at the time of the infinite object point focusing at the wide angle end of a zoom lens according to an eighth embodiment of the present invention;

FIG. 16A, FIG. 16B, and FIG. 16C are diagrams showing the spherical aberration, the astigmatism, the distortion, and the chromatic aberration of magnification at the time of the infinite object point focusing of the zoom lens according to the eighth embodiment of the present invention, where, FIG. 16A shows the state at the wide angle end, FIG. 16B shows the intermediate state, and FIG. 16C shows the state at the telephoto end;

FIG. 17 is a cross-sectional view along the optical axis showing an optical arrangement at the time of the infinite object point focusing at the wide angle end of a zoom lens according to a ninth embodiment of the present invention;

FIG. 18A, FIG. 18B, and FIG. 18C are diagrams showing the spherical aberration, the astigmatism, the distortion, and the chromatic aberration of magnification at the time of the infinite object point focusing of the zoom lens according to the ninth embodiment of the present invention, where, FIG. 18A shows the state at the wide angle end, FIG. 18B shows the intermediate state, and FIG. 18C shows the state at the telephoto end;

FIG. 19 is a cross-sectional view along the optical axis showing an optical arrangement at the time of the infinite object point focusing at the wide angle end of a zoom lens according to a tenth embodiment of the present invention;

FIG. 20A, FIG. 20B, and FIG. 20C are diagrams showing the spherical aberration, the astigmatism, the distortion, and the chromatic aberration of magnification at the time of the infinite object point focusing of the zoom lens according to the tenth embodiment of the present invention, where, FIG. 20A shows the state at the wide angle end, FIG. 20B shows the intermediate state, and FIG. 20C shows the state at the telephoto end;

FIG. 21 is a cross-sectional view along the optical axis showing an optical arrangement at the time of the infinite object point focusing at the wide angle end of a zoom lens according to an eleventh embodiment of the present invention;

FIG. 22A, FIG. 22B, and FIG. 22C are diagrams showing the spherical aberration, the astigmatism, the distortion, and the chromatic aberration of magnification at the time of the infinite object point focusing of the zoom lens according to the eleventh embodiment of the present invention, where, FIG. 22A shows the state at the wide angle end, FIG. 22B shows the intermediate state, and FIG. 22C shows the state at the telephoto end;

FIG. 23 is a cross-sectional view along the optical axis showing an optical arrangement at the time of the infinite object point focusing at the wide angle end of a zoom lens according to a twelfth embodiment of the present invention;

FIG. 24A, FIG. 24B, and FIG. 24C are diagrams showing the spherical aberration, the astigmatism, the distortion, and the chromatic aberration of magnification at the time of the infinite object point focusing of the zoom lens according to the twelfth embodiment of the present invention, where, FIG. 24A shows the state at the wide angle end, FIG. 24B shows the intermediate state, and FIG. 24C shows the state at the telephoto end;

FIG. 25 is a cross-sectional view along the optical axis showing an optical arrangement at the time of the infinite object point focusing at the wide angle end of a zoom lens according to a thirteenth embodiment of the present invention;

FIG. 26A, FIG. 26B, FIG. 26C are diagrams showing the spherical aberration, the astigmatism, the distortion, and the chromatic aberration of magnification at the time of the infinite object point focusing of the zoom lens according to the thirteenth embodiment of the present invention, where, FIG. 26A shows the state at the wide angle end, FIG. 26B shows the intermediate state, and FIG. 26C shows the state at the telephoto end;

FIG. 27 is a cross-sectional view along the optical axis showing an optical arrangement at the time of the infinite object point focusing at the wide angle end of a zoom lens according to a fourteenth embodiment of the present invention;

FIG. 28A, FIG. 28B, and FIG. 28C are diagrams showing the spherical aberration, the astigmatism, the distortion, and the chromatic aberration of magnification at the time of the infinite object point focusing of the zoom lens according to the fourteenth embodiment of the present invention, where, FIG. 28A shows the state at the wide angle end, FIG. 28B shows the intermediate state, and FIG. 28C shows the state at the telephoto end;

FIG. 29 is a cross-sectional view along the optical axis showing an optical arrangement at the time of the infinite object point focusing at the wide angle end of a zoom lens according to a fifteenth embodiment of the present invention;

FIG. 30A, FIG. 30B, and FIG. 30C are diagrams showing the spherical aberration, the astigmatism, the distortion, and the chromatic aberration of magnification at the time of the infinite object point focusing of the zoom lens according to the fifteenth embodiment of the present invention, where, FIG. 30A shows the state at the wide angle end, FIG. 30B shows the intermediate state, and FIG. 30C shows the state at the telephoto end;

FIG. 31 is a cross-sectional view along the optical axis showing an optical arrangement at the time of the infinite object point focusing at the wide angle end of a zoom lens according to a sixteenth embodiment of the present invention;

FIG. 32A, FIG. 32B, and FIG. 32C are diagrams showing the spherical aberration, the astigmatism, the distortion, and the chromatic aberration of magnification at the time of the infinite object point focusing of the zoom lens according to the sixteenth embodiment of the present invention, where, FIG. 32A shows the state at the wide angle end, FIG. 32B shows the intermediate state, and FIG. 32C shows the state at the telephoto end;

FIG. 33 is a cross-sectional view along the optical axis showing an optical arrangement at the time of the infinite object point focusing at the wide angle end of a zoom lens according to a seventeenth embodiment of the present invention;

FIG. 34A, FIG. 34B, and FIG. 34C are diagrams showing the spherical aberration, the astigmatism, the distortion, and the chromatic aberration of magnification at the time of the infinite object point focusing of the zoom lens according to the seventeenth embodiment of the present invention, where, FIG. 34A shows the state at the wide angle end, FIG. 34B shows the intermediate state, and FIG. 34C shows the state at the telephoto end;

FIG. 35 is a cross-sectional view along the optical axis showing an optical arrangement at the time of the infinite object point focusing at the wide angle end of a zoom lens according to an eighteenth embodiment of the present invention;

FIG. 36A, FIG. 36B, and FIG. 36C are diagrams showing the spherical aberration, the astigmatism, the distortion, and the chromatic aberration of magnification at the time of the infinite object point focusing of the zoom lens according to the eighteenth embodiment of the present invention, where, FIG. 36A shows the state at the wide angle end, FIG. 36B shows the intermediate state, and FIG. 36C shows the state at the telephoto end;

FIG. 37 is a cross-sectional view along the optical axis showing an optical arrangement at the time of the infinite object point focusing at the wide angle end of a zoom lens according to a nineteenth embodiment of the present invention;

FIG. 38A, FIG. 38B, and FIG. 38C are diagrams showing the spherical aberration, the astigmatism, the distortion, and the chromatic aberration of magnification at the time of the infinite object point focusing of the zoom lens according to the nineteenth embodiment of the present invention, where, FIG. 38A shows the state at the wide angle end, FIG. 38B shows the intermediate state, and FIG. 38C shows the state at the telephoto end;

FIG. 39 is a cross-sectional view along the optical axis showing an optical arrangement at the time of the infinite object point focusing at the wide angle end of a zoom lens according to a twentieth embodiment of the present invention;

FIG. 40A, FIG. 40B, and FIG. 40C are diagrams showing the spherical aberration, the astigmatism, the distortion, and the chromatic aberration of magnification at the time of the infinite object point focusing of the zoom lens according to the twentieth embodiment of the present invention, where, FIG. 40A shows the state at the wide angle end, FIG. 40B shows the intermediate state, and FIG. 40C shows the state at the telephoto end;

FIG. 41 is a cross-sectional view along the optical axis showing an optical arrangement at the time of the infinite object point focusing at the wide angle end of a zoom lens according to a twenty first embodiment of the present invention;

FIG. 42A, FIG. 42B, and FIG. 42C are diagrams showing the spherical aberration, the astigmatism, the distortion, and the chromatic aberration of magnification at the time of the infinite object point focusing of the zoom lens according to the twenty first embodiment of the present invention, where, FIG. 42A shows the state at the wide angle end, FIG. 42B shows the intermediate state, and FIG. 42C shows the state at the telephoto end;

FIG. 43 is a cross-sectional view along the optical axis showing an optical arrangement at the time of the infinite object point focusing at the wide angle end of a zoom lens according to a twenty second embodiment of the present invention;

FIG. 44A, FIG. 44B, and FIG. 44C are diagrams showing the spherical aberration, the astigmatism, the distortion, and the chromatic aberration of magnification at the time of the infinite object point focusing of the zoom lens according to the twenty second embodiment of the present invention, where, FIG. 44A shows the state at the wide angle and, FIG. 44B shows the intermediate state, and FIG. 44C shows the state at the telephoto end;

FIG. 45 is a cross-sectional view along the optical axis showing an optical arrangement at the time of the infinite object point focusing at the wide angle end of a zoom lens according to a twenty third embodiment of the present invention;

FIG. 46A, FIG. 46B, and FIG. 46C are diagrams showing the spherical aberration, the astigmatism, the distortion, and the chromatic aberration of magnification at the time of the infinite object point focusing of the zoom lens according to the twenty third embodiment of the present invention, where, FIG. 46A shows the state at the wide angle end, FIG. 46B shows the intermediate state, and FIG. 46C shows the state at the telephoto end;

FIG. 47 is a cross-sectional view along the optical axis showing an optical arrangement at the time of the infinite object point focusing at the wide angle end of a zoom lens according to a twenty fourth embodiment of the present invention;

FIG. 48A, FIG. 48B, and FIG. 48C are diagrams showing the spherical aberration, the astigmatism, the distortion, and the chromatic aberration of magnification at the time of the infinite object point focusing of the zoom lens according to the twenty fourth embodiment of the present invention, where, FIG. 48A shows the state at the wide angle end, FIG. 48B shows the intermediate state, and FIG. 48C shows the state at the telephoto end;

FIG. 49 is a cross-sectional view along the optical axis showing an optical arrangement at the time of the infinite object point focusing at the wide angle end of a zoom lens according to a twenty fifth embodiment of the present invention;

FIG. 50A, FIG. 50B, and FIG. 50C are diagrams showing the spherical aberration, the astigmatism, the distortion, and the chromatic aberration of magnification at the time of the infinite object point focusing of the zoom lens according to the twenty fifth embodiment of the present invention, where, FIG. 50A shows the state at the wide angle end, FIG. 50B shows the intermediate state, and FIG. 50C shows the state at the telephoto end;

FIG. 51 is a cross-sectional view along the optical axis showing an optical arrangement at the time of the infinite object point focusing at the wide angle end of a zoom lens according to a twenty sixth embodiment of the present invention;

FIG. 52A, FIG. 52B, and FIG. 52C are diagrams showing the spherical aberration, the astigmatism, the distortion, and the chromatic aberration of magnification at the time of the infinite object point focusing of the zoom lens according to the twenty sixth embodiment of the present invention, where, FIG. 52A shows the state at the wide angle end, FIG. 52B shows the intermediate state, and FIG. 52C shows the state at the telephoto end;

FIG. 53 is a cross-sectional view along the optical axis showing an optical arrangement at the time of the infinite object point focusing at the wide angle end of a zoom lens according to a twenty seventh embodiment of the present invention;

FIG. 54A, FIG. 54B, and FIG. 54C are diagrams showing the spherical aberration, the astigmatism, the distortion, and the chromatic aberration of magnification at the time of the infinite object point focusing of the zoom lens according to the twenty seventh embodiment of the present invention, where, FIG. 54A shows the state at the wide angle end, FIG. 54B shows the intermediate state, and FIG. 54C shows the state at the telephoto end;

FIG. 55 is a cross-sectional view along the optical axis showing an optical arrangement at the time of the infinite object point focusing at the wide angle end of a zoom lens according to a twenty eighth embodiment of the present invention;

FIG. 56A, FIG. 56B, and FIG. 56C are diagrams showing the spherical aberration, the astigmatism, the distortion, and the chromatic aberration of magnification at the time of the infinite object point focusing of the zoom lens according to the twenty eighth embodiment of the present invention, where, FIG. 56A shows the state at the wide angle end, FIG. 56B shows the intermediate state, and FIG. 56C shows the state at the telephoto end;

FIG. 57 is a cross-sectional view along the optical axis showing an optical arrangement at the time of the infinite object point focusing at the wide angle end of a zoom lens according to a twenty ninth embodiment of the present invention;

FIG. 58A, FIG. 58B, and FIG. 58C are diagrams showing the spherical aberration, the astigmatism, the distortion, and the chromatic aberration of magnification at the time of the infinite object point focusing of the zoom lens according to the twenty ninth embodiment of the present invention, where, FIG. 58A shows the state at the wide angle end, FIG. 58B shows the intermediate state, and FIG. 58C shows the state at the telephoto end;

FIG. 59 is a cross-sectional view along the optical axis showing an optical arrangement at the time of the infinite object point focusing at the wide angle end of a zoom lens according to a thirtieth embodiment of the present invention;

FIG. 60A, FIG. 60B, and FIG. 60C are diagrams showing the spherical aberration, the astigmatism, the distortion, and the chromatic aberration of magnification at the time of the infinite object point focusing of the zoom lens according to the thirtieth embodiment of the present invention, where, FIG. 60A shows the state at the wide angle end, FIG. 60B shows the intermediate state, and FIG. 60C shows the state at the telephoto end;

FIG. 61 is a cross-sectional view along the optical axis showing an optical arrangement at the time of the infinite object point focusing at the wide angle end of a zoom lens according to a thirty first embodiment of the present invention;

FIG. 62A, FIG. 62B, and FIG. 62C are diagrams showing the spherical aberration, the astigmatism, the distortion, and the chromatic aberration of magnification at the time of the infinite object point focusing of the zoom lens according to the thirty first embodiment of the present invention, where, FIG. 62A shows the state at the wide angle end, FIG. 62B shows the intermediate state, and FIG. 62C shows the state at the telephoto end;

FIG. 63 is a cross-sectional view along the optical axis showing an optical arrangement at the time of the infinite object point focusing at the wide angle end of a zoom lens according to a thirty second embodiment of the present invention;

FIG. 64A, FIG. 64B, and FIG. 64C are diagrams showing the spherical aberration, the astigmatism, the distortion, and the chromatic aberration of magnification at the time of the infinite object point focusing of the zoom lens according to the thirty second embodiment of the present invention, where, FIG. 64A shows the state at the wide angle end, FIG. 64B shows the intermediate state, and FIG. 64C shows the state at the telephoto end;

FIG. 65 is a cross-sectional view along the optical axis showing an optical arrangement at the time of the infinite object point focusing at the wide angle end of a zoom lens according to a thirty third embodiment of the present invention;

FIG. 66A, FIG. 66B, and FIG. 66C are diagrams showing the spherical aberration, the astigmatism, the distortion, and the chromatic aberration of magnification at the time of the infinite object point focusing of the zoom lens according to the thirty third embodiment of the present invention, where, FIG. 66A shows the state at the wide angle end, FIG. 66B shows the intermediate state, and FIG. 66C shows the state at the telephoto end;

FIG. 67 is a cross-sectional view along the optical axis showing an optical arrangement at the time of the infinite object point focusing at the wide angle end of a zoom lens according to a thirty fourth embodiment of the present invention;

FIG. 68A, FIG. 68B, and FIG. 68C are diagrams showing the spherical aberration, the astigmatism, the distortion, and the chromatic aberration of magnification at the time of the infinite object point focusing of the zoom lens according to the thirty fourth embodiment of the present invention, where, FIG. 68A shows the state at the wide angle end, FIG. 68B shows the intermediate state, and FIG. 68C shows the state at the telephoto end;

FIG. 69 is a cross-sectional view along the optical axis showing an optical arrangement at the time of the infinite object point focusing at the wide angle end of a zoom lens according to a thirty fifth embodiment of the present invention;

FIG. 70A, FIG. 70B, FIG. 70C are diagrams showing the spherical aberration, the astigmatism, the distortion, and the chromatic aberration of magnification at the time of the infinite object point focusing of the zoom lens according to the thirty fifth embodiment of the present invention, where, FIG. 70A shows the state at the wide angle end, FIG. 70B shows the intermediate state, and FIG. 70C shows the state at the telephoto end;

FIG. 71 is a cross-sectional view along the optical axis showing an optical arrangement at the time of the infinite object point focusing at the wide angle end of a zoom lens according to a thirty sixth embodiment of the present invention;

FIG. 72A, FIG. 72B, and FIG. 72C are diagrams showing the spherical aberration, the astigmatism, the distortion, and the chromatic aberration of magnification at the time of the infinite object point focusing of the zoom lens according to the thirty sixth embodiment of the present invention, where, FIG. 72A shows the state at the wide angle end, FIG. 72B shows the intermediate state, and FIG. 72C shows the state at the telephoto end;

FIG. 73 is a cross-sectional view along the optical axis showing an optical arrangement at the wide angle end of a zoom lens according to a thirty seventh embodiment of the present invention;

FIG. 74A, FIG. 74B, and FIG. 74C are diagrams showing the spherical aberration, the astigmatism, the distortion, and the chromatic aberration of magnification at the time of the infinite object point focusing of the zoom lens according to the thirty seventh embodiment of the present invention, where, FIG. 74A shows the state at the wide angle end, FIG. 74B shows the intermediate state, and FIG. 74C shows the state at the telephoto end;

FIG. 75 is a cross-sectional view along the optical axis showing an optical arrangement at the time of the infinite object point focusing at the wide angle end of a zoom lens according to a thirty eighth embodiment of the present invention;

FIG. 76A, FIG. 76B, and FIG. 76C are diagrams showing the spherical aberration, the astigmatism, the distortion, and the chromatic aberration of magnification at the time of the infinite object point focusing of the zoom lens according to the thirty eighth embodiment of the present invention, where, FIG. 76A shows the state at the wide angle end, FIG. 76B shows the intermediate state, and FIG. 76C shows the state at the telephoto end;

FIG. 77 is a frontward perspective view showing an appearance of a digital camera 40 in which a zoom optical system according to the present invention is incorporated;

FIG. 78 is a rearward perspective view of the digital camera 40;

FIG. 79 is a cross-sectional view showing an optical arrangement of the digital camera 40;

FIG. 80 is a frontward perspective view of a personal computer 300 with its cover opened, which is an example of an information processing apparatus with the built-in zoom optical system of the present invention, as an objective optical system;

FIG. 81 is a cross-sectional view of a photographic optical system 303 of the personal computer 300;

FIG. 82 is a side view of the personal computer 300; and

FIG. 83A, FIG. 83B, and FIG. 83C are diagrams showing a portable telephone which is an example of the information processing apparatus in which the zoom optical system of the present invention is built in as the photographing optical system, where, FIG. 83A is a front view of a portable telephone 400, FIG. 83B is a side view of the portable telephone 400, and FIG. 83C is a cross-sectional view of a photographic optical system 405.

BEST MODE FOR CARRYING OUT THE INVENTION

Prior to a description of embodiments, an action and an effect of the present invention will be described below.

An image forming optical system of the present invention, where the image forming optical system includes a positive lens group, a negative lens group, and an aperture stop, has a basic structure in which the positive lens group is disposed at an object side of the aperture stop, and the positive lens group includes a cemented lens which is formed by cementing a plurality of lenses.

In this manner, in the basic structure, since the cemented lens is used in the positive lens group disposed at on the object side of the aperture stop, a fluctuation in a chromatic aberration of magnification particularly in a zoom lens, at the time of varying a power is easily suppressed. Moreover, with a fewer number of lenses, it is possible to suppress sufficiently an occurrence of a color blur over an entire zooming area. Moreover, since it is possible to make thin the positive lens group (positive lens group disposed at the object side of the aperture stop) which tends to be thick, it is possible to make shallow (short) a distance from a vertex of a lens surface at a farthest side of the object, up to an entrance pupil. As a result of this, it is possible to make thin a lens group other than the lens group disposed at the object side of the aperture stop.

Moreover, in the abovementioned basic structure, it is preferable that at least one lens forming the cemented lens has the following characteristics. In other words, in a rectangular coordinate system in which a horizontal axis is let to be Nd and a vertical axis is let to be νd, when a straight line indicated by Nd=α×νd+β (where, α=−0.017) is set, it is desirable that Nd and νd of at least one lens forming the cemented lens are included in both areas namely, an area which is determined by a line when a lower limit value is in a range of a following conditional expression (1a), and a line when an upper limit value is in a range of the following conditional expression (1a), and an area determined by following conditional expressions (2a) and (3a).1.45<β<2.15  (1a)1.30<Nd<2.20  (2a)3<νd<12  (3a)

Here, Nd denotes a refractive index, and νd denotes an Abbe's number.

Here, a glass means a lens material such as a glass and a resin. Moreover, as a cemented lens, a lens in which a plurality of lenses made of a glass selected appropriately is cemented, is selected.

When value is lower than the lower limit value in the conditional expression (1a), since a refractive index is low, an effect when an aspheric surface is provided on a side which is in contact with air is small, and a correction of a spherical aberration, a coma aberration, and a distortion becomes difficult. Or, since the Abbe's number is low, a correction of a chromatic aberration, as an extremely thin cemented lens is possible, but when the side in contact with air is made to be an aspheric surface, a chromatic coma and a chromatic aberration of magnification of high order is susceptible to occur, and a degree of freedom of an aberration correction is decreased.

When a value is higher than the upper limit value in the conditional expression (1a), since a power and a thickness of the cemented lens is required to be more than a certain magnitude for the correction of the chromatic aberration, it become susceptible to be effected by optical characteristics which depend on an environment of the material.

When a value is lower than the lower limit value in the conditional expression (2a), the effect when the aspheric surface is provided on the side which is in contact with air is small, and the correction of the spherical aberration, the comatic aberration, and the distortion becomes difficult.

When a value is higher than the upper limit value in the conditional expression (2a), in a case of a material which includes organic properties, when the refractive index is excessively high, a temperature variance becomes excessively high, and optical characteristics which depend on the environment are susceptible to become unstable. Moreover, a reflectivity becomes excessively high, and a ghost is susceptible to occur even when coating is optimized.

When a value is lower than the lower limit value in the conditional expression (3a), the correction of the chromatic aberration, as an extremely thin cemented lens is possible, but when the side in contact with air is made to be an aspheric surface, the chromatic coma and the chromatic aberration of magnification of high order are susceptible to occur, and the degree of freedom of the aberration correction is decreased.

When a value is higher than the upper limit value in the conditional expression (3a), it is necessary to enhance a refracting power of the cemented lens for correcting the chromatic aberration, and it is advantageous for a correction of a Petzval's sum, but it becomes susceptible to be effected by the optical characteristics which depend on the environment of the material.

It is more preferable when a following conditional expression (1a′) is satisfied.1.48<β<2.04  (1a′)

Furthermore, it is even more preferable when a following conditional expression (1a″) is satisfied.1.50<β<2.00  (1a″)

Moreover, it is more preferable when a following conditional expression (2a′) is satisfied.1.58<Nd<2.10  (2a′)

Furthermore, it is even more preferable when a following conditional expression (2a″) is satisfied.1.63<Nd<1.95  (2a″)

Moreover, it is more preferable when a following conditional expression (3a′) is satisfied.5<νd<10  (3a′)

Furthermore, it is more preferable when a following conditional expression (3a″) is satisfied.6<νd<9  (3a″)

Or, in the abovementioned basic structure, it is preferable that at least one lens forming the cemented lens has the following characteristics. In other words, in a rectangular coordinate system in which a horizontal axis is let to be Nd and a vertical axis is let to be νd, when a straight line indicated by Nd=α×νd+β (where, α=−0.017) is set, it is desirable that Nd and νd of at least one lens forming the cemented lens is included in both areas namely, an area which is determined by a line when a lower limit value is in a range of a following conditional expression (1b), and a line when an upper limit value is in a range of the following conditional expression (1b), and of an area determined by following conditional expressions (2b) and (3b).1.45<β<2.15  (1b)1.58<Nd<2.20  (2b)3<νd<40  (3b)

Here, Nd denotes the refractive index, and νd denotes the Abbe's number.

When a value is lower than the lower limit value in the conditional expression (1b), since the refractive index is low, the effect when the aspheric surface is provided on the side which is in contact with air is small, and the correction of the spherical aberration, the coma aberration, and the distortion becomes difficult. Or, since the Abbe's number is low, the correction of the chromatic aberration, as an extremely thin cemented lens is possible, but when the side in contact with air is made to be an aspheric surface, the chromatic coma and the chromatic aberration of magnification of high order are susceptible to occur, and the degree of freedom of the aberration correction is decreased.

When a value is higher than the upper limit value in the conditional expression (1b), a correction level of the chromatic aberration and the Petzval's sum become same as of a general optical glass lens, and characteristics of the present invention are not achieved.

When a value is lower than the lower limit value in the conditional expression (2b), the effect when the aspheric surface is provided on the side which is in contact with air is small, and the correction of the spherical aberration, the coma aberration, and the distortion becomes difficult.

When a value is higher than the upper limit value in the conditional expression (2b), in the case of a material which includes organic properties, when the refractive index is excessively high, the temperature variance becomes excessively high, and the optical characteristics which depend on the environment are susceptible to become unstable. Moreover, the reflectivity becomes excessively high, and a ghost is susceptible to occur even when the coating is optimized.

When a value is lower than the lower limit value in the conditional expression (3b), the correction of the chromatic aberration, as an extremely thin cemented lens is possible, but when the side in contact with air is made to be an aspheric surface, the chromatic coma and the chromatic aberration of magnification of high order are susceptible to occur, and the degree of freedom of the aberration correction is decreased.

When a value is higher than the upper limit value in the conditional expression (3b), it is necessary to enhance the refracting power of the cemented lens for correcting the chromatic aberration, and it is advantageous for the correction of the Petzval's sum, but it becomes susceptible to be effected by the optical characteristics which depend on the environment of the material.

It is more preferable when a following conditional expression (1b′) is satisfied.1.48<β<2.04  (1b′)

Furthermore, it is even more preferable when a following conditional expression (1b″) is satisfied.1.50<β<2.00  (1b″)

Moreover, it is more preferable when a following conditional expression (2b′) is satisfied.1.60<Nd<2.10  (2b′)

Furthermore, it is more preferable when a following conditional expression (2b″) is satisfied.1.63<Nd<1.95  (2b″)

Moreover, it is more preferable when a following conditional expression (3b′) is satisfied.5<νd<30  (3b′)

Furthermore, it is more preferable when a following conditional expression (3b″) is satisfied.6<νd<25  (3b″)

Moreover, it is preferable that the cemented lens is formed by a lens having the values of Nd and νd which are included in both the areas mentioned above (hereinafter, called as a ‘predetermined lens’), and a lens other than the predetermined lens, and a center thickness along an optical axis of the predetermined lens is less than a center thickness along an optical axis of the other lens. By making such an arrangement, it is possible to realize a more favorable correction of each aberration mentioned above, and thinning of the lens group.

Furthermore, the cemented lens may be a compound lens which is formed by closely adhering and hardening a resin on a lens surface (lens surface of the other lens), in order to improve a manufacturing accuracy. Here, the resin which is adhered and hardened corresponds to the predetermined lens.

Moreover, the cemented lens may be a compound lens which is formed by closely adhering and hardening a glass on the lens surface (lens surface of the other lens), as it is advantageous for resistance such as a light resistance and a chemical resistance. Here, the glass which is adhered and hardened corresponds to the predetermined lens.

Furthermore, in the cemented lens, a center thickness t1 along the optical axis of the predetermined lens (one lens in which Nd and νd are included in both the areas mentioned above) may satisfy a following conditional expression (4), in order to make a size small and to carry out molding stably.0.22<t1<2.0  (4)

It is more preferable that a following conditional expression (4′) is satisfied.0.3<t1<1.5  (4′)

Furthermore, it is even more preferable that a following conditional expression (4″) is satisfied.0.32<t1<1.0  (4″)

Moreover, the image forming optical system may be a zoom lens in which the closest side of an object is a positive group, from a viewpoint of having a high magnification of the zoom, and improving a brightness of the lens.

Furthermore, the image forming optical system may be a zoom lens in which the closest side of an object is a negative group, for making the size small.

Moreover, the image forming optical system may have a prism for folding, and for facilitating thinning of an optical system with respect to a direction of photography.

Furthermore, in the image forming optical system, the prism may be in a group on the closest side of an object, for facilitating the thinning.

Incidentally, when a pixel size of the electronic image pickup element becomes smaller than a certain size, a component of a frequency higher than a Nyquist frequency is eliminated due to an effect of diffraction. Therefore, when this is used, it is possible to omit an optical low-pass filter. This is preferable from a point of making the entire optical system extremely thin.

For this, it is preferable that a following conditional expression (6) is satisfied.Fw≧a (μm)  (6)

where, Fw is a full-aperture F value at wide angle end, and “a” is a distance between pixels in a horizontal direction of the electronic image pickup element (unit: μm).

When the conditional expression (6) is satisfied, the optical low-pass filter is not required to be disposed in an optical path. Accordingly it is possible to make the optical system small.

In a case of satisfying the conditional expression (6), it is preferable that the aperture stop is let to be open only. This means that the optical system in this case is an optical system with a constant diameter of the aperture stop all the time. Moreover, in the optical system in this case, since an operation of narrowing is not necessary, it is possible to omit a narrowing mechanism. Accordingly, the size can be made small saving that much space. When the conditional expression (6) is not satisfied, the optical low-pass filter is necessary.

Moreover, it is more preferable that a conditional expression (6′) is satisfied.Fw≧1.2a (μm)  (6′)

Furthermore, it is even more preferable that a conditional expression (6″) is satisfied.Fw≧1.4a (μm)  (6″)

Finally, an electronic image pickup apparatus will be described below. As the electronic image pickup apparatus, an electronic image pickup apparatus in which both a thinning of depth and a widening of image angle are realized is preferable.

Here, an infinite object is let to be imaged by an optical system which has no distortion. In this case, since the image which is formed has no distortion,f=y/tan ωholds.

Here, y is a height of an image point from an optical axis, f is a focal length of the image forming system, and ω is an angle with respect to an optical axis in a direction of an object point corresponding to the image point connecting from a center on an image pickup surface up to a position of y.

On the other hand, when the optical system has a barrel distortion,f>y/tan ωholds. In other words, when f and y are let to be constant values, ω becomes a substantial value.

Therefore, in the electronic image pickup apparatus, it is preferable to use a zoom lens as the image forming optical system. As a zoom lens, particularly in a focal length near a wide-angle end, an optical system having a substantial barrel distortion may be used intentionally. In this case, since a purpose is served without correcting the distortion, it is possible to achieve the widening of the image angle of the optical system. However, an image of the object is formed on the electronic image pickup element, in a state of having the barrel distortion. Therefore, in the electronic image pickup apparatus, image data obtained by the electronic image pickup element is processed by an image processing. In this process, the image data (a shape of the image) is changed such that the barrel distortion is corrected. By changing the image data, image data takes a shape almost similar to the object. Accordingly, based on this image data, the image of the object may be output to a CRT or a printer.

Here, as the image pickup optical system, an image pickup optical system which satisfies a following conditional expression (7) at the time of infinite object point focusing, may be adopted.0.7<y₀₇/(fw·tan ω_07w)<0.96  (7)

where, y₀₇ is indicated as y₀₇=0.7y₁₀ when, in an effective image pickup surface (surface in which image pickup is possible), a distance from a center up to a farthest point (maximum image height) is let to be y₁₀. Moreover, ω_07w is an angle with respect to an optical axis in a direction of an object point corresponding to an image point connecting from a center on the image pickup surface in a wide angle end up to a position of y₀₇.

The conditional expression (7) mentioned above is an expression in which an amount of the barrel distortion in a zoom wide-angle end is regulated. When the conditional expression (7) is satisfied, it is possible to fetch information of the wide image angle without making the optical system enlarged. An image which is distorted to barrel shape is subjected to photoelectric conversion, and becomes image data which is distorted to barrel shape. However, on the image data which is distorted to the barrel shape, a process equivalent to a shape change of the image is carried out electrically by the image processing means which is a signal processing system of the electronic image pickup apparatus. When this process is carried out, even when the image data output from the image processing means is reproduced finally by a display apparatus (unit), the distortion is corrected, and an image almost similar to a shape of an object to be photographed is obtained.

Here, when a value is higher than the upper limit value in the conditional expression (7), particularly when a value close to 1 is to be taken, it is possible to carry out by the image processing means a correction equivalent to a correction in which the distortion is corrected favorably optically, but it is difficult to fetch an image over a wide angle of visibility. On the other hand, a value is lower than the lower limit value in the conditional expression (7), rate of enlarging in a direction of radiating in a portion around an image angle when the image distortion due to the distortion of the optical system is corrected by the image processing means, becomes excessively high. As a result of this, a decline in a sharpness of the area around the image becomes remarkable.

On the other hand, by satisfying the conditional expression (7), it is possible to widen the angle (make an image angle in a vertical direction in the distortion to be 38° or more) and to make small the optical system.

Moreover, it is more preferable when a following conditional expression (7′) is satisfied.0.75<y₀₇/(fw·tan ω_07w)<0.94  (7′)

Furthermore, it is even more preferable when a following conditional expression (7″) is satisfied.0.80<y₀₇/(fw·tan ω_07w)<0.92  (7″)

The image forming optical system of the present invention, even when an electronic image pickup element of a large number of pixels is used, is capable of achieving thinning and reduction in size of a volume of the image forming optical system, by satisfying or providing each of conditional expressional and structural characteristics mentioned above, and realizing a favorable correction of aberration. Moreover, the image forming optical system of the present invention is capable of providing (satisfying) in combination the conditional expressional and structural characteristics mentioned above. In this case, it is possible to achieve further reduction in size and thinning, or the favorable aberration correction. Moreover, in the electronic image pick up apparatus having the image forming optical system of the present invention, it is possible to achieve the thinning and reduction is size of the volume of the image forming optical system, and further, to have both of the favorable correction of various aberrations, and widening of the angle.

Embodiments of the present invention will be described below by using diagrams.

As a zoom lens of the present invention, a five-groups structure or a four-groups structure can be taken into consideration. In a zoom lens of the five-group structure, it is preferable to dispose each lens group in an order of a first lens group having a positive refracting power, a second lens group having a negative refracting power, a third lens group having a positive refracting power, a fourth lens group having a negative refracting power, and a fifth lens group having a positive refracting power, from an object side.

Here, it is preferable that the first lens group includes a negative lens, a prism, and a cemented lens. At this time, it is preferable to dispose these in an order of the negative lens, the prism, and the cemented lens, from the object side. Moreover, it is preferable to form the cemented lens by a positive lens and a negative lens, and to dispose the cemented lens such that the negative lens is positioned toward the object side. The first lens group may be formed by one negative lens, one prism, and one cemented lens. In this case, the cemented lens is formed by one positive lens and one negative lens.

Moreover, it is preferable that the second lens group includes a positive lens and a negative lens. At this time, it is preferable to dispose these in an order of the negative lens and the positive lens from the object side. The second lens group may include only one positive lens and one negative lens.

Furthermore, it is preferable that the third lens group includes a positive lens and a negative lens. At this time, it is preferable to form a cemented lens by the positive lens and the negative lens, and to dispose the cemented lens such that the positive lens is positioned at the object side. The third lens group may be formed by only one cemented lens. In this case, the cemented lens is formed by one positive lens and one negative lens.

Moreover, it is preferable that the fourth lens group includes a negative lens. At this time, it is preferable to form the fourth lens group by only one negative lens.

Furthermore, it is preferable that the fifth lens group includes a positive lens. At this time, it is preferable to form the fifth lens group by only one positive lens.

Moreover, in a zoom lens of the four-groups structure, it is preferable to dispose each lens group in an order of a first lens group having a negative refracting power, a second lens group having a positive refracting power, a third lens group having a negative refracting power, and a fourth lens group having a positive refracting power, from the object side.

Here, it is preferable that the first lens group includes a negative lens, a prism, and a cemented lens. At this time, it is preferable to dispose these in an order of the negative lens, the prism, and the cemented lens from the object side. Moreover, it is preferable to form the cemented lens by a positive lens and a negative lens, and to dispose the cemented lens such that the positive lens is positioned at the object side. The first lens group may be formed by only one negative lens, one prism, and one cemented lens. In this case, the cemented lens is formed by one positive lens and one negative lens.

Moreover, it is preferable that the second lens group includes a positive lens and a negative lens. At this time, it is preferable to form a cemented lens by the positive lens and the negative lens, and to dispose the cemented lens such that the positive lens is positioned at the object side. The second lens group may be formed by only one cemented lens. In this case, the cemented lens is formed by one positive lens and one negative lens.

Furthermore, it is preferable that the third lens group includes a positive lens and a negative lens. At this time, it is preferable to form a cemented lens by the positive lens and the negative lens, and to dispose the cemented lens such that the negative lens is positioned at the object side. The third lens group may include only one cemented lens. In this case, the cemented lens is formed by one positive lens and one negative lens.

Moreover, it is preferable that the fourth lens group includes a positive lens and a negative lens. At this time, it is preferable to form a cemented lens by the positive lens and the negative lens, and to dispose the cemented lens such that the positive lens is positioned at the object side. The fourth lens group may be formed by only one cemented lens. In this case, the cemented lens includes one positive lens and one negative lens.

It is possible to distribute a refracting power of one lens into two lenses. Accordingly, in each of the lens groups mentioned above, it is possible to substitute one lens by two lenses. However, from a point of view of the reduction in size and thinning, it is desirable to let the number of lenses to be substituted by two lenses in each group to be one.

FIRST EMBODIMENT

FIG. 1 is a cross-sectional view along an optical axis showing an optical arrangement at the time of an infinite object point focusing at a wide angle end of a zoom lens according to a first embodiment.

FIG. 2A, FIG. 2B, and FIG. 2C are diagrams showing a spherical aberration, an astigmatism, a distortion, and a chromatic aberration of magnification at the time of the infinite object point focusing of the zoom lens according to the first embodiment of the present invention, where, FIG. 2A shows a state at the wide angle end, FIG. 2B shows an intermediate state, and FIG. 2C shows a state at a telephoto end.

The zoom lens of the first embodiment, as shown in FIG. 1, has a first lens group G1, a second lens group G2, an aperture stop S, a third lens group G3, a fourth lens group G4, and a fifth lens group G5, in this order from the object side. In the diagram, LPF is a low-pass filter, CG is a cover glass, and I is an image pickup surface of a electronic image pickup element.

The first lens group G1 includes a negative meniscus lens L111 having a convex surface directed toward the object side, a prism L112, and a cemented lens which is formed by a negative meniscus lens L113 having a convex surface directed toward the object side, and a biconvex lens L114, and has a positive refracting power as a whole.

The second lens group G2 includes a biconcave lens L121, and a positive meniscus lens L122 having a convex surface directed toward the object side, and has a negative refracting power as a whole.

The third lens group G3 includes a cemented lens which is formed by a biconvex lens L131 and a biconcave lens L132, and has a positive refracting power as a whole.

The fourth lens group G4 includes a negative meniscus lens L141 having a convex surface directed toward the object side, and has a negative refracting power as a whole.

The fifth lens group G5 includes a biconvex lens L142, and has a positive refracting power as a whole.

At the time of zooming from the wide-angle end to the telephoto end, the first lens group G1 is fixed, the second lens group G2 moves toward an image side, the aperture stop S is fixed, the third lens group G3 moves toward the object side, the fourth lens group G4 moves once toward the image side, and then moves toward the object side, and the fifth lens group G5 moves toward the image side.

Aspheric surfaces are provided on a surface toward the object side, of the negative meniscus lens L113 having the convex surface directed toward the object in the first lens group G1, both surfaces of the biconcave lens L121 in the second lens group G2, a surface toward the object side, of the biconvex lens L131, and a surface toward the image side of the biconcave lens L132 in the third lens group G3, and a surface toward the object side, of the biconvex lens L142 in the fifth lens group G5.

Next, numerical data of optical members forming the zoom lens of the first embodiment will be enumerated.

In the numerical data of the first embodiment, r1, r2, . . . denote a radius of curvature of each lens surface, d1, d2, . . . denote a thickness or an air space of each lens, nd1, nd2, . . . denote a refractive index at d line of each lens, νd1, νd2, . . . denote the Abbe's number for each lens, Fno. denotes an F number, f denotes a focal length of an overall system, and D0 denotes a distance from the object to a first surface.

An aspheric surface shape is expressed by a following expression when a direction of an optical axis is let to be z, a direction orthogonal to the optical axis is let to be y, a conical coefficient is let to be K, and an aspheric coefficient is let to be A4, A6, A8, and A10.z=(y²/r)/[1+{1−(1+K)(y/r)²}^1/2]+A4y⁴+A6y⁶+A8y⁸+A10y¹⁰

Moreover, E denotes a power of 10. These symbols of data values are common even in numerical data of embodiments which will be described later. The conical coefficient may also be denoted by k.

Next, numerical data of the first embodiment will be enumerated.

Numerical data 1
r1 = 29.769	d1 = 1	Nd1 = 1.8061	νd1 = 40.92
r2 = 9.996	d2 = 2.9
r3 = ∞	d3 = 12	Nd3 = 1.8061	νd3 = 40.92
r4 = ∞	d4 = 0.3
r5 = 20.456	d5 = 0.1	Nd5 = 1.41244	νd5 = 12.42
(Aspheric surface)
r6 = 17.047	d6 = 3.54	Nd6 = 1.741	νd6 = 52.64
r7 = −40.493	d7 = D7
r8 = −78.921	d8 = 0.8	Nd8 = 1.8061	νd8 = 40.92
(Aspheric surface)
r9 = 5.100	d9 = 0.7
(Aspheric surface)
r10 = 6.857	d10 = 2.2	Nd10 = 1.7552	νd10 = 27.51
r11 = 101.37	d11 = D11
r12 = Aperture stop	d12 = D12
r13 = 8.626	d13 = 6.74	Nd13 = 1.6935	νd13 = 53.21
(Aspheric surface)
r14 = −9.767	d14 = 1	Nd14 = 1.84666	νd14 = 23.78
r15 = 48.970	d15 = D15
(Aspheric surface)
r16 = 23.269	d16 = 0.6	Nd16 = 1.48749	νd16 = 70.23
r17 = 9.679	d17 = D17
r18 = 10.881	d18 = 1.8	Nd18 = 1.7432	νd18 = 49.34
(Aspheric surface)
r19 = −248.017	d19 = D19
r20 = ∞	d20 = 1.9	Nd20 = 1.54771	νd20 = 62.84
r21 = ∞	d21 = 0.8
r22 = ∞	d22 = 0.75	Nd22 = 1.51633	νd22 = 64.14
r23 = ∞	d23 = D23
Aspherical coefficients
	5th surface
	k = 0
	A4 = 7.03408E−06
	A6 = 1.07494E−07
	A8 = 0
	8th surface
	k = 0
	A4 = 5.78353E−04
	A6 = −2.76230E−05
	A8 = 4.54522E−07
	9th surface
	k = 0
	A4 = 1.19342E−04
	A6 = −3.10809E−05
	A8 = −1.06052E−06
	13th surface
	k = 0
	A4 = 6.44238E−05
	A6 = 1.52064E−06
	A8 = −2.73314E−08
	15th surface
	k = 0
	A4 = 4.61191E−04
	A6 = 1.41022E−05
	A8 = −1.40537E−07
	18th surface
	k = 0
	A4 = −6.80311E−05
	A6 = 7.56313E−06
	A8 = −2.12005E−07
Zoom data
When D0 (distance from object up to 1st surface) is ∞
	wide-angle end	intermediate	telephoto end
Focal length	6	13.699	18.001
FNO.	2.86	4.73	5.67
D7	0.8	8.09	9.84
D11	10.43	3.15	1.4
D12	10.04	3.3	1.2
D15	1.2	10.47	12.94
D17	1.24	1.79	2.81
D19	4.97	1.89	0.5
D23	1.36	1.36	1.36

SECOND EMBODIMENT

FIG. 3 is a cross-sectional view along the optical axis showing an optical arrangement at the time of the infinite object point focusing at the wide angle end of a zoom lens according to a second embodiment of the present invention.

FIG. 4A, FIG. 4B, and FIG. 4C are diagrams showing spherical aberration, the astigmatism, the distortion, and the chromatic aberration of magnification at the time of the infinite object point focusing of the zoom lens according to the second embodiment of the present invention, where, FIG. 4A shows the state at the wide angle end, FIG. 4B shows the intermediate state, and FIG. C shows the state at the telephoto end.

The zoom lens of the second embodiment, as shown in FIG. 3, has a first lens group G1, a second lens group G2, an aperture stop S, a third lens group G3, a fourth lens group G4, and a fifth lens group G5 in this order from the object side. In the diagram, LPF is a low-pass filter, CG is a cover glass, and I is an image pickup surface of an electronic image pickup element. The first lens group G1 includes a negative meniscus lens L111 having a convex surface directed toward the object side, a prism L112, and a cemented lens which is formed by a negative meniscus lens L113 having a convex surface directed toward the object side, and a biconvex lens L114, and has a positive refracting power as a whole.

The second lens group G2 includes a biconcave lens L121, and a positive meniscus lens L122 having a convex surface directed toward the object side, and has a negative refracting power as a whole. The third lens group G3 includes a cemented lens which is formed by a biconvex lens L131 and a biconcave lens L132, and has a positive refracting power as a whole.

The fourth lens group G4 includes a negative meniscus lens L141 having a convex surface directed toward the object side, and has a negative refracting power as a whole.

The fifth lens group G5 includes a biconvex lens L142, and has a positive refracting power as a whole.

At the time of zooming from the wide-angle end to the telephoto end, the first lens group G1 is fixed, the second lens group G2 moves toward the image side, the aperture stop S is fixed, the third lens group G3 moves toward the object side, the fourth lens group G4 moves once toward the image side, and then moves toward the object side, and the fifth lens group G5 moves toward the image side.

An aspheric surface is provided on the surface toward the object side, of the negative meniscus lens 113 having the convex surface directed toward the object side in the first lens group G1, both surfaces of the biconcave lens L121 in the second lens group G2, the surface toward the object side, of the biconvex lens L131, and the surface toward the image side of the biconcave lens L132 in the third lens group G3, and the surface toward the object side, of the biconvex lens L142 in the fifth lens group G5.

Next, numerical data of the second embodiment will be enumerated.

Numerical data 2
r1 = 26.407	d1 = 1	Nd1 = 1.8061	νd1 = 40.92
r2 = 10.001	d2 = 2.9
r3 = ∞	d3 = 12	Nd3 = 1.8061	νd3 = 40.92
r4 = ∞	d4 = 0.3
r5 = 20.270	d5 = 0.1	Nd5 = 1.42001	νd5 = 6.55
(Aspheric surface)
r6 = 16.892	d6 = 3.54	Nd6 = 1.7495	νd6 = 35.28
r7 = −44.948	d7 = D7
r8 = −73.431	d8 = 0.8	Nd8 = 1.8061	νd8 = 40.92
(Aspheric surface)
r9 = 5.401	d9 = 0.7
(Aspheric surface)
r10 = 7.514	d10 = 2.2	Nd10 = 1.7552	νd10 = 27.51
r11 = 96.185	d11 = D11
r12 = Aperture stop	d12 = D12
r13 = 8.347	d13 = 6.32	Nd13 = 1.6935	νd13 = 53.21
(Aspheric surface)
r14 = −9.655	d14 = 1	Nd14 = 1.84666	νd14 = 23.78
r15 = 48.501	d15 = D15
(Aspheric surface)
r16 = 24.743	d16 = 0.6	Nd16 = 1.48749	νd16 = 70.23
r17 = 9.363	d17 = D17
r18 = 10.583	d18 = 1.8	Nd18 = 1.7432	νd18 = 49.34
(Aspheric surface)
r19 = −192.596	d19 = D19
r20 = ∞	d20 = 1.9	Nd20 = 1.54771	νd20 = 62.84
r21 = ∞	d21 = 0.8
r22 = ∞	d22 = 0.75	Nd22 = 1.51633	νd22 = 64.14
r23 = ∞	d23 = D23
Aspherical coefficients
	5th surface
	k = 0
	A4 = 1.03451E−05
	A6 = 1.59102E−07
	A8 = 0
	8th surface
	k = 0
	A4 = 1.43925E−04
	A6 = −4.39610E−06
	A8 = 1.83409E−07
	9th surface
	k = 0
	A4 = −3.47884E−04
	A6 = −1.24823E−05
	A8 = −1.16714E−07
	13th surface
	k = 0
	A4 = 7.96498E−05
	A6 = 1.77836E−06
	A8 = 2.35088E−08
	15th surface
	k = 0
	A4 = 5.27749E−04
	A6 = 1.10798E−05
	A8 = 3.25369E−07
	18th surface
	k = 0
	A4 = −8.84149E−05
	A6 = 9.05232E−06
	A8 = −2.49918E−07
Zoom data
When D0 (distance from object up to 1st surface) is ∞
	wide-angle end	intermediate	telephoto end
Focal length	6.001	13.7	17.999
FNO.	2.86	4.73	5.67
D7	0.8	6.41	7.83
D11	8.43	2.82	1.4
D12	11.22	3.58	1.2
D15	1.2	11.62	14.83
D17	1.19	1.64	2.05
D19	4.98	1.74	0.5
D23	1.36	1.36	1.36

THIRD EMBODIMENT

FIG. 5 is a cross-sectional view along the optical axis showing an optical arrangement at the time of the infinite object point focusing at the wide angle end of a zoom lens according to a third embodiment.

FIG. 6A, FIG. 6B, and FIG. 6C are diagrams showing the spherical aberration, the astigmatism, the distortion, and the chromatic aberration of magnification at the time of the infinite object point focusing of the zoom lens according to the third embodiment, where, FIG. 6A shows the state at the wide angle end, FIG. 6B shows the intermediate state, and FIG. 6C shows the state at the telephoto end.

The zoom lens of the third embodiment, as shown in FIG. 5, has a first lens group G1, a second lens group G2, an aperture stop S, a third lens group G3, a fourth lens group G4, and a fifth lens group G5 in this order from the object side. In the diagram, LPF is a low-pass filter, CG is a cover glass, and I is an image pickup surface of an electronic image pickup element.

The first lens group G1 includes a negative meniscus lens L111 having a convex surface directed toward an object side, a prism 112, and a cemented lens which is formed by a negative meniscus lens L113 having a convex surface directed toward the object side, and a biconvex lens L114, and has a positive refracting power as a whole.

The second lens group G2 includes a biconcave lens L121, and a positive meniscus lens L122 having a convex surface directed toward the object side, and has a negative refracting power as a whole.

The third lens group G3 includes a cemented lens which is formed by a biconvex lens L131 and a biconcave lens L132, and has a positive refracting power as a whole.

The fourth lens group G4 includes a negative meniscus lens L141 having a convex surface directed toward the object side, and has a negative refracting power as a whole.

The fifth lens group G5 includes a biconvex lens L142, and has a positive refracting power as a whole.

At the time of zooming from the wide-angle end to the telephoto end, the first lens group G1 is fixed, the second lens group G2 moves toward the image side, the aperture stop S is fixed, the third lens group G3 moves toward the object side, the fourth lens group G4 moves once toward the image side, and then moves toward the object side, and the fifth lens group G5 moves toward the image side.

An aspheric surface is provided on the surface toward the object side, of the negative meniscus lens L113 having the convex surface directed toward the object side in the first lens group G1, both surfaces of the biconcave lens L121 in the second lens group G2, the surface toward the object side, of the biconvex lens L131, and the surface toward the image side of the biconcave lens L132 in the third lens group G3, and the surface toward the object side, of the biconvex lens L142 in the fifth lens group G5.

Next, numerical data of the third embodiment will be enumerated.

Numerical data 3
r1 = 27.82	d1 = 1	Nd1 = 1.8061	νd1 = 40.92
r2 = 10.002	d2 = 2.9
r3 = ∞	d3 = 12	Nd3 = 1.8061	νd3 = 40.92
r4 = ∞	d4 = 0.3
r5 = 23.480	d5 = 0.1	Nd5 = 1.51824	νd5 = 12.85
(Aspheric surface)
r6 = 19.567	d6 = 3.54	Nd6 = 1.741	νd6 = 52.64
r7 = −28.65	d7 = D7
r8 = −61.821	d8 = 0.8	Nd8 = 1.8061	νd8 = 40.92
(Aspheric surface)
r9 = 4.913	d9 = 0.7
(Aspheric surface)
r10 = 6.827	d10 = 2.2	Nd10 = 1.7552	νd10 = 27.51
r11 = 132.993	d11 = D11
r12 = Aperture stop	d12 = D12
r13 = 8.583	d13 = 8.63	Nd13 = 1.6935	νd13 = 53.21
(Aspheric surface)
r14 = −8.089	d14 = 1	Nd14 = 1.84666	νd14 = 23.78
r15 = 48.417	d15 = D15
(Aspheric surface)
r16 = 35.107	d16 = 0.6	Nd16 = 1.48749	νd16 = 70.23
r17 = 10.292	d17 = D17
r18 = 9.475	d18 = 1.8	Nd18 = 1.7432	νd18 = 49.34
(Aspheric surface)
r19 = −233.568	d19 = D19
r20 = ∞	d20 = 1.9	Nd20 = 1.54771	νd20 = 62.84
r21 = ∞	d21 = 0.8
r22 = ∞	d22 = 0.75	Nd22 = 1.51633	νd22 = 64.14
r23 = ∞	d23 = D23
Aspherical coefficients
	5th surface
	k = 0
	A4 = 2.38481E−06
	A6 = 1.42255E−07
	A8 = 0
	8th surface
	k = 0
	A4 = 2.60205E−04
	A6 = −1.86315E−05
	A8 = 3.96540E−07
	9th surface
	k = 0
	A4 = −3.29150E−04
	A6 = −3.05243E−05
	A8 = −1.10959E−06
	13th surface
	k = 0
	A4 = 3.14928E−05
	A6 = −1.15481E−06
	A8 = 2.01049E−08
	15th surface
	k = 0
	A4 = 4.73717E−04
	A6 = 1.67097E−05
	A8 = −3.53306E−07
	18th surface
	k = 0
	A4 = −9.35376E−05
	A6 = 5.96154E−06
	A8 = −1.74283E−07
Zoom data
When D0 (distance from object up to 1st surface) is ∞
	wide-angle end	intermediate	telephoto end
Focal length	6	13.7	17.998
FNO.	2.86	4.73	5.67
D7	0.8	7.81	9.62
D11	10.22	3.22	1.4
D12	9.02	3.17	1.2
D15	1.2	10.49	12.72
D17	1.68	0.85	1.59
D19	4.1	1.51	0.49
D23	1.36	1.36	1.36

FOURTH EMBODIMENT

FIG. 7 is a cross-sectional view along the optical axis showing an optical arrangement at the time of the infinite object point focusing at the wide angle end of a zoom lens according to a fourth embodiment of the present invention.

FIG. 8A, FIG. 8B, and FIG. 8C are diagrams showing the spherical aberration, the astigmatism, the distortion, and the chromatic aberration of magnification at the time of the infinite object point focusing of the zoom lens according to the fourth embodiment, where, FIG. 8A shows the state at the wide angle end, FIG. 8B shows the intermediate state, and FIG. 8C shows the state at the telephoto end.

The zoom lens of the fourth embodiment, as shown in FIG. 7, has a first lens group G1, a second lens group G2, an aperture stop S, a third lens group G3, a fourth lens group G4, and a fifth lens group G5 in this order from an object side. In the diagram, LPF is a low-pas filter, CG is a cover glass, and I is an image pickup surface of an electronic image pickup element.

The first lens group G1 includes a negative meniscus lens L111 having a convex surface directed toward the object side, a prism L112, and a cemented lens which is formed by a negative meniscus lens L113 having a convex surface directed toward the object side, and a biconvex lens L114, and has a positive refracting power as a whole.

The second lens group G2 includes a biconcave lens L121, and a positive meniscus lens L122 having a convex surface directed toward the object side, and has a negative refracting power as a whole.

The third lens group G3 includes a cemented lens which is formed by a biconvex lens L131 and a biconcave lens L132, and has a positive refracting power as a whole.

The fourth lens group G4 includes a negative meniscus lens L141 having a convex surface directed toward the object side, and has a negative refracting power as a whole.

The fifth lens group G5 includes a biconvex lens L142, and has a positive refracting power as a whole.

At the time of zooming from the wide angle end to the telephoto end, the first lens group G1 is fixed, the second lens group G2 moves toward the image side, the aperture stop S is fixed, the third lens group G3 moves toward the object side, the fourth lens group G4 moves once toward the image side, and then moves toward the object side, and the fifth lens group G5 moves toward the image side.

An aspheric surface is provided on the surface toward the object side, of the negative meniscus lens L113 having the convex surface directed toward the object side in the first lens group G1, both surfaces of the biconcave lens L121 in the second lens group G2, the surface toward the object side of the biconvex lens L131, and the surface toward the image side of the biconcave lens L132 in the third lens group G3, and the surface toward the object side, of the biconvex lens L142 in the fifth lens group G5.

Next, numerical data of the fourth embodiment will be enumerated.

Numerical data 4
r1 = 27.694	d1 = 1	Nd1 = 1.8061	νd1 = 40.92
r2 = 10.006	d2 = 2.9
r3 = ∞	d3 = 12	Nd3 = 1.8061	νd3 = 40.92
r4 = ∞	d4 = 0.3
r5 = 19.683	d5 = 0.1	Nd5 = 1.54856	νd5 = 7.04
(Aspheric surface)
r6 = 17.419	d6 = 3.54	Nd6 = 1.883	νd6 = 40.76
r7 = −93.913	d7 = D7
r8 = −71.447	d8 = 0.8	Nd8 = 1.8061	νd8 = 40.92
(Aspheric surface)
r9 = 5.388	d9 = 0.7
(Aspheric surface)
r10 = 7.37	d10 = 2.2	Nd10 = 1.7552	νd10 = 27.51
r11 = 95.844	d11 = D11
r12 = Aperture stop	d12 = D12
r13 = 8.478	d13 = 6.45	Nd13 = 1.6935	νd13 = 53.21
(Aspheric surface)
r14 = −10.197	d14 = 1	Nd14 = 1.84666	νd14 = 23.78
r15 = 51.863	d15 = D15
(Aspheric surface)
r16 = 24.22	d16 = 0.6	Nd16 = 1.48749	νd16 = 70.23
r17 = 9.369	d17 = D17
r18 = 10.688	d18 = 1.8	Nd18 = 1.7432	νd18 = 49.34
(Aspheric surface)
r19 = −170.684	d19 = D19
r20 = ∞	d20 = 1.9	Nd20 = 1.54771	νd20 = 62.84
r21 = ∞	d21 = 0.8
r22 = ∞	d22 = 0.75	Nd22 = 1.51633	νd22 = 64.14
r23 = ∞	d23 = D23
Aspherical coefficients
	5th surface
	k = 0
	A4 = 1.89634E−05
	A6 = 2.52746E−08
	A8 = 0.00000E+00
	8th surface
	k = 0
	A4 = 4.32026E−04
	A6 = −1.73558E−05
	A8 = 2.97589E−07
	9th surface
	k = 0
	A4 = 2.83249E−05
	A6 = −2.70770E−05
	A8 = −3.90203E−07
	13th surface
	k = 0
	A4 = 6.36673E−05
	A6 = 2.41615E−06
	A8 = −1.70207E−08
	15th surface
	k = 0
	A4 = 4.36864E−04
	A6 = 1.97436E−05
	A8 = −1.21544E−07
	18th surface
	k = 0
	A4 = −1.13296E−04
	A6 = 1.04349E−05
	A8 = −2.67157E−07
Zoom data
When D0 (distance from object up to 1st surface) is ∞
	wide-angle end	intermediate	telephoto end
Focal length	6.004	13.7	17.999
FNO.	2.84	4.7	5.63
D7	0.8	6.81	8.42
D11	9.02	3.01	1.4
D12	10.81	3.55	1.2
D15	1.2	11.71	13.72
D17	1.39	1.6	2.82
D19	4.84	1.38	0.5
D23	1.36	1.36	1.36

FIFTH EMBODIMENT

FIG. 9 is a cross-sectional view along the optical axis showing an optical arrangement at the time of the infinite object point focusing at the wide angle end of a zoom lens according to a fifth embodiment of the present invention.

FIG. 10A, FIG. 10B, and FIG. 10C are diagrams showing the spherical aberration, the astigmatism, the distortion, and the chromatic aberration of magnification at the time of the infinite object point focusing of the zoom lens according to the fifth embodiment, where, FIG. 10A shows the state at the wide angle end, FIG. 10B shows the intermediate state, and FIG. 10C shows the state at the telephoto end.

The zoom lens of the fifth embodiment, as shown in FIG. 9, has a first lens group G1, a second lens group G2, an aperture stop S, a third lens group G3, a fourth lens group G4, and a fifth lens group G5, in this order from an object side. In the diagram, LPF is a low-pass filter, CG is a cover glass, and I is an image pickup surface of an electronic image pickup element.

The first lens group G1 includes a negative meniscus lens L111 having a convex surface directed toward the object side, a prism L112, and cemented lens which is formed by a negative meniscus lens L113 having a convex surface directed toward the object side, and a biconvex lens L114, and has a positive refracting power as a whole.

The second lens group G2 includes a biconcave lens L121, and a positive meniscus lens L122 having a convex surface directed toward the object side, and has a negative refracting power as a whole.

The third lens group G3 includes a cemented lens which is formed by a biconvex lens L131 and a biconcave lens L132, and has a positive refracting power as a whole.

The fourth lens group G4 includes a negative meniscus lens L141 having a convex surface directed toward the object side, and has a negative refracting power as a whole.

The fifth lens group G5 includes a biconvex lens L142, and has a positive refracting power as a whole.

At the time of zooming from the wide angle end to the telephoto end, the first lens group G1 is fixed, the second lens group G2 moves toward the image side, the aperture stop S is fixed, the third lens group G3 moves toward the object side, the fourth lens group G4 moves once toward the image side, and then moves toward the object side, and the fifth lens group G5 moves toward the image side.

An aspheric surface is provided on a surface toward the object side, of the negative meniscus lens L113 having the convex surface directed toward the object side in the first lens group G1, both surfaces of the biconcave lens L121 in the second lens group G2, the surface toward the object side of the biconvex lens L131, and the surface toward the image side of the biconcave lens L132 in the third lens group G3, and the surface toward the object side, of the biconvex lens L142 in the fifth lens group G5.

Next, numerical data of the fifth embodiment will be enumerated.

Numerical data 5
r1 = 26.268	d1 = 1	Nd1 = 1.8061	νd1 = 40.92
r2 = 9.767	d2 = 2.9
r3 = ∞	d3 = 12	Nd3 = 1.8061	νd3 = 40.92
r4 = ∞	d4 = 0.3
r5 = 18.845	d5 = 0.1	Nd5 = 1.65228	νd5 = 12.75
(Aspheric surface)
r6 = 17.425	d6 = 3.54	Nd6 = 1.741	νd6 = 52.64
r7 = −46.982	d7 = D7
r8 = −47.767	d8 = 0.8	Nd8 = 1.8061	νd8 = 40.92
(Aspheric surface)
r9 = 5.610	d9 = 0.7
(Aspheric surface)
r10 = 7.861	d10 = 2.2	Nd10 = 1.7552	νd10 = 27.51
r11 = 651.723	d11 = D11
r12 = Aperture stop	d12 = D12
r13 = 8.372	d13 = 6.59	Nd13 = 1.6935	νd13 = 53.21
(Aspheric surface)
r14 = −10.413	d14 = 1	Nd14 = 1.84666	νd14 = 23.78
r15 = 47.183	d15 = D15
(Aspheric surface)
r16 = 19.829	d16 = 0.6	Nd16 = 1.48749	νd16 = 70.23
r17 = 9.344	d17 = D17
r18 = 11.290	d18 = 1.8	Nd18 = 1.7432	νd18 = 49.34
(Aspheric surface)
r19 = −3235.664	d19 = D19
r20 = ∞	d20 = 1.9	Nd20 = 1.54771	νd20 = 62.84
r21 = ∞	d21 = 0.8
r22 = ∞	d22 = 0.75	Nd22 = 1.51633	νd22 = 64.14
r23 = ∞	d23 = D23
Aspherical coefficients
	5th surface
	k = 0
	A4 = 1.29265E−05
	A6 = 2.25482E−08
	A8 = 0
	8th surface
	k = 0
	A4 = 3.13232E−04
	A6 = −1.10497E−05
	A8 = 2.00754E−07
	9th surface
	k = 0
	A4 = −1.49920E−04
	A6 = −1.69745E−05
	A8 = −3.47629E−07
	13th surface
	k = 0
	A4 = 6.03004E−05
	A6 = 1.94139E−06
	A8 = 1.57565E−08
	15th surface
	k = 0
	A4 = 5.14589E−04
	A6 = 9.41419E−06
	A8 = 4.95331E−07
	18th surface
	k = 0
	A4 = −8.99715E−05
	A6 = 8.05337E−06
	A8 = −1.55937E−07
Zoom data
When D0 (distance from object up to 1st surface) is ∞
	wide-angle end	intermediate	telephoto end
Focal length	6.1	13.42	17.995
FNO.	3.15	4.79	5.87
D7	1.44	7.29	8.68
D11	12.19	3.52	1.54
D12	7.82	3.25	0.84
D15	1.21	11.41	13.88
D17	1.42	1.6	2.93
D19	4.82	1.38	0.4
D23	1.36	1.36	1.36

SIXTH EMBODIMENT

FIG. 11 is a cross-sectional view along the optical axis showing an optical arrangement at the time of the infinite object point focusing at the wide angle end of a zoom lens according to a sixth embodiment of the present invention.

FIG. 12A, FIG. 12B, and FIG. 12C are diagrams showing the spherical aberration, the astigmatism, the distortion, and the chromatic aberration of magnification at the time of the infinite object point focusing of the zoom lens according to the sixth embodiment, where, FIG. 12A shows the state at the wide angle end, FIG. 12B shows the intermediate state, and FIG. 12C shows the state at the telephoto end.

The zoom lens of the sixth embodiment, as shown in FIG. 11, has a first lens group G1, a second lens group G2, an aperture stop S, a third lens group G3, a fourth lens group G4, and a fifth lens group G5, in this order from an object side. In the diagram, LPF is a low-pass filter, CG is a cover glass, and I is an image pickup surface of an electronic image pickup element.

The first lens group G1 includes a negative meniscus lens L111 having a convex surface directed toward the object side, a prism L112, and a cemented lens which is formed by a negative meniscus lens L113 having a convex surface directed toward the object side, and a biconvex lens L114, and has a positive refracting power as a whole.

The second lens group G2 includes a biconcave lens L121, and a positive meniscus lens L122 having a convex surface directed toward the object side, and has a negative refracting power as a whole.

The third lens group G3 includes a cemented lens which is formed by a biconvex lens L131 and a biconcave lens L132, and has a positive refracting power as a whole.

The fourth lens group G4 includes a negative meniscus lens L141 having a convex surface directed toward the object side, and has a negative refracting power as a whole.

The fifth lens group G5 includes a positive meniscus lens L142 having a convex surface directed toward the object side, and has positive refracting power as a whole.

At the time of zooming from the wide angle end to the telephoto end, the first lens group G1 is fixed, the second lens group G2 moves toward the image side, the aperture stop S is fixed, the third lens group G3 moves toward the object side, the fourth lens group G4 moves once toward the image side, and then moves toward the object side, and the fifth lens group G5 moves toward the image side.

An aspheric surface is provided on the surface toward the object side, of the negative meniscus lens L113 having the convex surface directed toward the object side in the first lens group G1, both surfaces of the biconcave lens L121 in the second lens group G2, the surface toward the object side of the biconvex lens L131, and the surface toward the image side of the biconcave lens L132 in the third lens group G3, and the surface toward the object side, of the positive meniscus lens L142 having the convex surface directed toward the object side in the fifth lens group G5.

Next, numerical data of the sixth embodiment will be enumerated.

Numerical data 6
r1 = 23.104	d1 = 1	Nd1 = 1.8061	νd1 = 40.92
r2 = 9.993	d2 = 2.9
r3 = ∞	d3 = 12	Nd3 = 1.8061	νd3 = 40.92
r4 = ∞	d4 = 0.3
r5 = 144.417	d5 = 0.1	Nd5 = 1.59885	νd5 = 6.52
(Aspheric surface)
r6 = 120.347	d6 = 3.54	Nd6 = 1.741	νd6 = 52.64
r7 = −15.632	d7 = D7
r8 = −67.973	d8 = 0.8	Nd8 = 1.8061	νd8 = 40.92
(Aspheric surface)
r9 = 5.079	d9 = 0.7
(Aspheric surface)
r10 = 7.029	d10 = 2.2	Nd10 = 1.7552	νd10 = 27.51
r11 = 101.993	d11 = D11
r12 = Aperture stop	d12 = D12
r13 = 7.719	d13 = 6.28	Nd13 = 1.6935	νd13 = 53.21
(Aspheric surface)
r14 = −9.571	d14 = 1	Nd14 = 1.84666	νd14 = 23.78
r15 = 34.509	d15 = D15
(Aspheric surface)
r16 = 39.476	d16 = 0.6	Nd16 = 1.48749	νd16 = 70.23
r17 = 9.117	d17 = D17
r18 = 7.840	d18 = 1.8	Nd18 = 1.7432	νd18 = 49.34
(Aspheric surface)
r19 = 34.132	d19 = D19
r20 = ∞	d20 = 1.9	Nd20 = 1.54771	νd20 = 62.84
r21 = ∞	d21 = 0.8
r22 = ∞	d22 = 0.75	Nd22 = 1.51633	νd22 = 64.14
r23 = ∞	d23 = D23
Aspherical coefficients
	5th surface
	k = 0
	A4 = −4.37427E−05
	A6 = 4.88599E−07
	A8 = 0
	8th surface
	k = 0
	A4 = −4.24746E−04
	A6 = 1.70408E−05
	A8 = −5.77793E−07
	9th surface
	k = 0
	A4 = −1.15464E−03
	A6 = 3.78562E−05
	A8 = −3.07050E−06
	13th surface
	k = 0
	A4 = 1.41938E−04
	A6 = −5.92299E−07
	A8 = 7.51323E−08
	15th surface
	k = 0
	A4 = 9.41257E−04
	A6 = −6.26116E−06
	A8 = 1.51062E−06
	18th surface
	k = 0
	A4 = −7.24351E−05
	A6 = −2.74136E−07
	A8 = −7.56639E−08
Zoom data
When D0 (distance from object up to 1st surface) is ∞
	wide-angle end	intermediate	telephoto end
Focal length	6.005	13.7	17.999
FNO.	3.01	4.93	5.95
D7	0.8	6.91	8.38
D11	8.98	2.86	1.4
D12	10.51	3.71	1.2
D15	1.2	11.56	13.88
D17	1.59	1.78	2.67
D19	4.97	1.21	0.5
D23	1.36	1.36	1.36

SEVENTH EMBODIMENT

FIG. 13 is a cross-sectional view along the optical axis showing an optical arrangement at the time of the infinite object point focusing at the wide angle end of a zoom lens according to a seventh embodiment of the present invention.

FIG. 14A, FIG. 14B, and FIG. 14C are diagrams showing the spherical aberration, the astigmatism, the distortion, and the chromatic aberration of magnification at the time of the infinite object point focusing of the zoom lens according to the seventh embodiment, where, FIG. 14A shows the state at the wide angle end, FIG. 14B shows the intermediate state, and FIG. 14C shows the state at the telephoto end.

The zoom lens of the seventh embodiment, as shown in FIG. 13, has a first lens group G1, a second lens group G2, an aperture stop S, a third lens group G3, a fourth lens group G4, and a fifth lens group G5 in this order from an object side. In the diagram, LPF is a low-pass filter, CG is a cover glass, and I is an image pickup surface of an electronic image pickup element.

The first lens group G1 includes a negative meniscus lens L111 having a convex surface directed toward the object side, a prism L112, and a cemented lens which is formed by a negative meniscus lens L113 having a convex surface directed toward the object side, and a biconvex lens L114, and has a positive refracting power as a whole.

The second lens group G2 includes a biconcave lens L121, and a positive meniscus lens L122 having a convex surface directed toward the object side, and has a negative refracting power as a whole.

The third lens group G3 includes a cemented lens which is formed by a biconvex lens L131 and a biconcave lens L132, and has a positive refracting power as a whole.

The fourth lens group G4 includes a negative meniscus lens L141 having a convex surface directed toward the object side, and has a negative refracting power as a whole.

The fifth lens group G5 includes a positive meniscus lens L142 having a convex surface directed toward the object side, and has a positive refracting power as a whole.

At the time of zooming from the wide angle end to the telephoto end, the first lens group G1 is fixed, the second lens group G2 moves toward the image side, the aperture stop S is fixed, the third lens group G3 moves toward the object side, the fourth lens group G4 moves once toward the image side, and then moves toward the object side, and the fifth lens group G5 moves toward the image side.

An aspheric surface is provided on the surface toward the object side, of the negative meniscus lens L113 having the convex surface directed toward the object side in the first lens group G1, both surfaces of the biconcave lens L121 in the second lens group G2, the surface toward the object side of the biconvex lens L131, and the surface toward the image side of the biconcave lens L132 in the third lens group G3, and the surface toward the object side, of the positive meniscus lens L142 having the convex surface directed toward the object side in the fifth lens group G5.

Next, numerical data of the seventh embodiment will be enumerated.

Numerical data 7
r1 = 23.339	d1 = 1	Nd1 = 1.8061	νd1 = 40.92
r2 = 9.998	d2 = 2.9
r3 = ∞	d3 = 12	Nd3 = 1.8061	νd3 = 40.92
r4 = ∞	d4 = 0.3
r5 = 100.200	d5 = 0.1	Nd5 = 1.79525	νd5 = 9.95
(Aspheric surface)
r6 = 83.501	d6 = 3.54	Nd6 = 1.741	νd6 = 52.64
r7 = −16.063	d7 = D7
r8 = −45.653	d8 = 0.8	Nd8 = 1.8061	νd8 = 40.92
(Aspheric surface)
r9 = 5.378	d9 = 0.7
(Aspheric surface)
r10 = 7.441	d10 = 2.2	Nd10 = 1.7552	νd10 = 27.51
r11 = 202.84	d11 = D11
r12 = Aperture stop	d12 = D12
r13 = 7.519	d13 = 6.32	Nd13 = 1.6935	νd13 = 53.21
(Aspheric surface)
r14 = −10.334	d14 = 1	Nd14 = 1.84666	νd14 = 23.78
r15 = 26.284	d15 = D15
(Aspheric surface)
r16 = 28.574	d16 = 0.6	Nd16 = 1.48749	νd16 = 70.23
r17 = 8.89	d17 = D17
r18 = 7.764	d18 = 1.8	Nd18 = 1.7432	νd18 = 49.34
(Aspheric surface)
r19 = 32.431	d19 = D19
r20 = ∞	d20 = 1.9	Nd20 = 1.54771	νd20 = 62.84
r21 = ∞	d21 = 0.8
r22 = ∞	d22 = 0.75	Nd22 = 1.51633	νd22 = 64.14
r23 = ∞	d23 = D23
Aspherical coefficients
	5th surface
	k = 0
	A4 = −2.65536E−05
	A6 = 3.17647E−07
	A8 = 0
	8th surface
	k = 0
	A4 = −3.26054E−04
	A6 = 1.26273E−05
	A8 = −4.63097E−07
	9th surface
	k = 0
	A4 = −9.57291E−04
	A6 = 2.85872E−05
	A8 = −2.27299E−06
	13th surface
	k = 0
	A4 = 1.05906E−04
	A6 = 3.76011E−07
	A8 = 3.75282E−08
	15th surface
	k = 0
	A4 = 9.47239E−04
	A6 = −1.75798E−06
	A8 = 1.62992E−06
	18th surface
	k = 0
	A4 = −8.98935E−05
	A6 = 9.26013E−07
	A8 = −9.48654E−08
Zoom data
When D0 (distance from object up to 1st surface) is ∞
	wide-angle end	intermediate	telephoto end
Focal length	6.001	13.7	18
FNO.	3.01	4.93	5.92
D7	0.8	6.87	8.47
D11	9.07	3	1.4
D12	10.55	3.61	1.2
D15	1.2	11.39	13.85
D17	1.66	1.82	2.52
D19	4.66	1.26	0.5
D23	1.36	1.36	1.36

EIGHTH EMBODIMENT

FIG. 15 is a cross-sectional view along the optical axis showing an optical arrangement at the time of the infinite object point focusing at the wide angle end of a zoom lens according to an eighth embodiment of the present invention.

FIG. 16A, FIG. 16B, and FIG. 16C are diagrams showing the spherical aberration, the astigmatism, the distortion, and the chromatic aberration of magnification at the time of the infinite object point focusing of the zoom lens according to the eighth embodiment, where, FIG. 16A shows the state at the wide angle end, FIG. 16B shows the intermediate state, and FIG. 16C shows the state at the telephoto end.

The zoom lens of the eighth embodiment, as shown in FIG. 15, has a first lens group G1, a second lens group G2, an aperture stop S, a third lens group G3, a fourth lens group G4, and a fifth lens group G5 in this order from an object side. In the diagram, LPF is a low-pas filter, CG is a cover glass, and I is an image pickup surface of an electronic image pickup element.

The first lens group G1 includes a negative meniscus lens L111 having a convex surface directed toward the object side, a prism L112, and a cemented lens which is formed by a negative meniscus lens L113 having a convex surface directed toward the object side, and a biconvex lens L114, and has a positive refracting power as a whole.

The second lens group G2 includes a biconcave lens L121, and a positive meniscus lens L122 having a convex surface directed toward the object side, and has a negative refracting power as a whole.

The third lens group G3 includes a cemented lens which is formed by a biconvex lens L131 and a biconcave lens L132, and has a positive refracting power as a whole.

The fourth lens group G4 includes a negative meniscus lens L141 having a convex surface directed toward the object side, and has a negative refracting power as a whole.

The fifth lens group G5 includes a positive meniscus lens L142 having a convex surface directed toward the object side, and has the positive refracting power as a whole.

At the time of zooming from the wide angle end to the telephoto end, the first lens group G1 is fixed, the second lens group G2 moves toward an image side, the aperture stop S is fixed, the third lens group G3 moves toward the object side, the fourth lens group G4 moves once toward the image side, and then moves toward the object side, and the fifth lens group G5 moves toward the image side.

An aspheric surface is provided on the surface toward the object side, of the negative meniscus lens L113 having the convex surface directed toward the object side in the first lens group G1, both surfaces of the biconcave lens L121 in the second lens group G2, a surface toward the object side of the biconvex lens L131, and a surface toward the image side of the biconcave lens L132 in the third lens group G3, and the surface toward the object side, of the positive meniscus lens L142 having the convex surface directed toward the object side in the fifth lens group G5.

Next, numerical data of the eighth embodiment will be enumerated.

Numerical data 8
r1 = 23.412	d1 = 1	Nd1 = 1.8061	νd1 = 40.92
r2 = 9.999	d2 = 2.9
r3 = ∞	d3 = 12	Nd3 = 1.8061	νd3 = 40.92
r4 = ∞	d4 = 0.3
r5 = 71.727	d5 = 0.1	Nd5 = 1.9712	νd5 = 12.88
(Aspheric surface)
r6 = 59.773	d6 = 3.54	Nd6 = 1.741	νd6 = 52.64
r7 = −16.653	d7 = D7
r8 = −36.331	d8 = 0.8	Nd8 = 1.8061	νd8 = 40.92
(Aspheric surface)
r9 = 5.425	d9 = 0.7
(Aspheric surface)
r10 = 7.528	d10 = 2.2	Nd10 = 1.7552	νd10 = 27.51
r11 = 1523.438	d11 = D11
r12 = Aperture stop	d12 = D12
r13 = 7.312	d13 = 6.35	Nd13 = 1.6935	νd13 = 53.21
(Aspheric surface)
r14 = −10.511	d14 = 1	Nd14 = 1.84666	νd14 = 23.78
r15 = 22.264	d15 = D15
(Aspheric surface)
r16 = 31.087	d16 = 0.6	Nd16 = 1.48749	νd16 = 70.23
r17 = 9.171	d17 = D17
r18 = 7.719	d18 = 1.8	Nd18 = 1.7432	νd18 = 49.34
(Aspheric surface)
r19 = 34.976	d19 = D19
r20 = ∞	d20 = 1.9	Nd20 = 1.54771	νd20 = 62.84
r21 = ∞	d21 = 0.8
r22 = ∞	d22 = 0.75	Nd22 = 1.51633	νd22 = 64.14
r23 = ∞	d23 = D23
Aspherical coefficients
	5th surface
	k = 0
	A4 = −1.63140E−05
	A6 = 2.12684E−07
	A8 = 0
	8th surface
	k = 0
	A4 = −1.88552E−04
	A6 = 7.75646E−06
	A8 = −3.54924E−07
	9th surface
	k = 0
	A4 = −8.03970E−04
	A6 = 2.18772E−05
	A8 = −2.04118E−06
	13th surface
	k = 0
	A4 = 8.46048E−05
	A6 = 8.81547E−07
	A8 = 1.40013E−08
	15th surface
	k = 0
	A4 = 9.97088E−04
	A6 = 1.26510E−06
	A8 = 1.91272E−06
	18th surface
	k = 0
	A4 = −1.04269E−04
	A6 = 9.09683E−07
	A8 = −9.18645E−08
Zoom data
When D0 (distance from object up to 1st surface) is ∞
	wide-angle end	intermediate	telephoto end
Focal length	6.001	13.7	18
FNO.	3.02	4.95	5.89
D7	0.8	6.83	8.53
D11	9.13	3.11	1.4
D12	10.31	3.47	1.2
D15	1.2	11.21	13.79
D17	1.84	1.82	2.3
D19	4.44	1.28	0.5
D23	1.36	1.36	1.36

NINTH EMBODIMENT

FIG. 17 is a cross-sectional view along the optical axis showing an optical arrangement at the time of the infinite object point focusing at the wide angle end of a zoom lens according to a ninth embodiment of the present invention.

FIG. 18A, FIG. 18B, and FIG. 18C are diagrams showing the spherical aberration, the astigmatism, the distortion, and the chromatic aberration of magnification at the time of the infinite object point focusing of the zoom lens according to the ninth embodiment, where, FIG. 18A shows the state at the wide angle end, FIG. 18B shows the intermediate state, and FIG. 18C shows the state at the telephoto end.

The zoom lens of the ninth embodiment, as shown in FIG. 17, has a first lens group G1, a second lens group G2, an aperture stop S, a third lens group G3, a fourth lens group G4, and a fifth lens group G5, in this order from the object side. In the diagram, LPF is a low-pass filter, CG is a cover glass, and I is an image pickup surface of an electronic image pickup element.

The first lens group G1 includes negative meniscus lens L111 having a convex surface directed toward the object side, a prism L112, and a cemented lens which is formed by a negative meniscus lens L113 having a convex surface directed toward the object side, and a biconvex lens L114, and has a positive refracting power as a whole.

The second lens group G2 includes a biconcave lens L121, and a positive meniscus lens L122 having a convex surface directed toward the object side, and has a negative refracting power as a whole.

The third lens group G3 includes a cemented lens which is formed by a biconvex lens L131 and a biconcave lens L132, and has a positive refracting power as a whole.

The fourth lens group G4 includes a negative meniscus lens L141 having a convex surface directed toward the object side, and has a negative refracting power as a whole.

The fifth lens group. G5 includes a positive meniscus lens L142 having a convex surface directed toward the object side, and has a positive refracting power as a whole.

At the time of zooming from the wide angle end to the telephoto end, the first lens group G1 is fixed, the second lens group G2 moves toward an image side, the aperture stop S is fixed, the third lens group G3 moves toward the object side, the fourth lens group G4 moves once toward the image side, and then moves toward the object side, and the fifth lens group G5 moves toward the image side.

An aspheric surface is provided on the surface toward the object side, of the negative meniscus lens L113 having the convex surface directed toward the object side in the first lens group G1, both surfaces of the biconcave lens L121 in the second lens group G2, a surface toward the object side of the biconvex lens L131, and a surface toward the image side of the biconcave lens L132 in the third lens group G3, and the surface toward the object side of the positive meniscus lens L142 having the convex surface directed toward the object side in the fifth lens group G5.

Next, numerical data of the ninth embodiment will be enumerated.

Numerical data 9
r1 = 22.766	d1 = 1	Nd1 = 1.8061	νd1 = 40.92
r2 = 9.996	d2 = 2.9
r3 = ∞	d3 = 12	Nd3 = 1.8061	νd3 = 40.92
r4 = ∞	d4 = 0.3
r5 = 201.902	d5 = 0.1	Nd5 = 2.05122	νd5 = 6.28
(Aspheric surface)
r6 = 168.251	d6 = 3.54	Nd6 = 1.741	νd6 = 52.64
r7 = −15.092	d7 = D7
r8 = −33.130	d8 = 0.8	Nd8 = 1.8061	νd8 = 40.92
(Aspheric surface)
r9 = 5.469	d9 = 0.7
(Aspheric surface)
r10 = 7.619	d10 = 2.2	Nd10 = 1.7552	νd10 = 27.51
r11 = −366.416	d11 = D11
r12 = Aperture stop	d12 = D12
r13 = 7.087	d13 = 6.41	Nd13 = 1.6935	νd13 = 53.21
(Aspheric surface)
r14 = −10.191	d14 = 1	Nd14 = 1.84666	νd14 = 23.78
r15 = 19.545	d15 = D15
(Aspheric surface)
r16 = 53.254	d16 = 0.6	Nd16 = 1.48749	νd16 = 70.23
r17 = 9.799	d17 = D17
r18 = 7.635	d18 = 1.8	Nd18 = 1.7432	νd18 = 49.34
(Aspheric surface)
r19 = 39.242	d19 = D19
r20 = ∞	d20 = 1.9	Nd20 = 1.54771	νd20 = 62.84
r21 = ∞	d21 = 0.8
r22 = ∞	d22 = 0.75	Nd22 = 1.51633	νd22 = 64.14
r23 = ∞	d23 = D23
Aspherical coefficients
	5th surface
	k = 0
	A4 = −2.29550E−05
	A6 = 1.93244E−07
	A8 = 0
	8th surface
	k = 0
	A4 = −2.64173E−04
	A6 = 1.12898E−05
	A8 = −4.80203E−07
	9th surface
	k = 0
	A4 = −8.96070E−04
	A6 = 2.86426E−05
	A8 = −2.27403E−06
	13th surface
	k = 0
	A4 = 8.06718E−05
	A6 = 3.66237E−07
	A8 = 1.49391E−08
	15th surface
	k = 0
	A4 = 1.14232E−03
	A6 = −2.15240E−06
	A8 = 2.64820E−06
	18th surface
	k = 0
	A4 = −1.11897E−04
	A6 = −1.49140E−07
	A8 = −8.03112E−08
Zoom data
When D0 (distance from object up to 1st surface) is ∞
	wide-angle end	intermediate	telephoto end
Focal length	6.004	13.7	17.999
FNO.	3.05	5.03	5.99
D7	0.8	6.83	8.58
D11	9.18	3.14	1.4
D12	10.28	3.48	1.2
D15	1.2	11.15	13.77
D17	1.8	1.81	2.19
D19	4.37	1.22	0.5
D23	1.36	1.36	1.36

TENTH EMBODIMENT

FIG. 19 is a cross-sectional view along the optical axis showing an optical arrangement at the time of the infinite object point focusing at the wide angle end of a zoom lens according to a tenth embodiment of the present invention.

FIG. 20A, FIG. 20B, and FIG. 20C are diagrams showing the spherical aberration, the astigmatism, the distortion, and the chromatic aberration of magnification at the time of the infinite object point focusing of the zoom lens according to the tenth embodiment, where, FIG. 20A shows the state at the wide angle end, FIG. 20B shows the intermediate state, and FIG. 20C shows the state at the telephoto end.

The zoom lens of the tenth embodiment, as shown in FIG. 19, has a first lens group G1, a second lens group G2, an aperture stop S, a third lens group G3, and a fourth lens group G4 in this order from the object side. In the diagram, LPF is a low-pass filter, CG is a cover glass, and I is an image pickup surface of an electronic image pickup element.

The first lens group G1 includes a negative meniscus lens L211 having a convex surface directed toward the object side, a prism L212, and a cemented lens which is formed by a positive meniscus lens L213 having a convex surface directed toward an image side and a biconcave lens L214, and has a negative refracting power as a whole.

The second lens group G2 includes a cemented lens which is formed by a biconvex lens L221 and a negative meniscus lens L222 having a convex surface directed toward the image side, and has a positive refracting power as a whole.

The third lens group G3 includes a cemented lens which is formed by a biconcave lens L231 and a positive meniscus lens L232 having a convex side directed toward the object side, and has a negative refracting power as a whole.

The fourth lens group G4 includes a cemented lens which is formed by a biconvex lens L241 and a negative meniscus lens L242 having a concave surface directed toward the object side, and has a positive refracting power as a whole.

At the time of zooming from the wide angle end to the telephoto end, the first lens group G1 is fixed, the second lens group G2 moves toward the object side, the aperture stop S is fixed, the third lens group G3 moves toward the image side, and the fourth lens group G4 moves toward the image side.

An aspheric surface is provided on a surface toward the object side, of the positive meniscus lens L213 having the convex surface directed toward the image side in the first lens group G1, a surface on the object side of the biconvex lens L221, and a surface on the image side of the negative meniscus lens having the convex surface directed toward the image side in the second lens group G2, and a surface on the object side of the biconvex lens L241 in the fourth lens group G4.

Next, numerical data of the tenth embodiment will be enumerated.

Numerical data 10
r1 = 16.18	d1 = 1.1	Nd1 = 1.741	νd1 = 52.64
r2 = 8.095	d2 = 3.7
r3 = ∞	d3 = 12.5	Nd3 = 1.801	νd3 = 34.97
r4 = ∞	d4 = 0.55
r5 = −31.723	d5 = 2.2	Nd5 = 1.8061	νd5 = 40.92
(Aspheric surface)
r6 = −8.755	d6 = 0.7	Nd6 = 1.51633	νd6 = 64.14
r7 = 18.545	d7 = D7
r8 = 9.850	d8 = 4	Nd8 = 1.43875	νd8 = 94.93
(Aspheric surface)
r9 = −12	d9 = 0.35	Nd9 = 1.41244	νd9 = 12.42
r10 = −15.504	d10 = D10
(Aspheric surface)
r11 = Aperture stop	d11 = D11
r12 = −16.407	d12 = 0.7	Nd12 = 1.497	νd12 = 81.54
r13 = 18.799	d13 = 1.6	Nd13 = 1.84666	νd13 = 23.78
r14 = 30.356	d14 = D14
r15 = 15.129	d15 = 3.5	Nd15 = 1.7432	νd15 = 49.34
(Aspheric surface)
r16 = −6	d16 = 0.7	Nd16 = 1.80518	νd16 = 25.42
r17 = −17.077	d17 = D17
r18 = ∞	d18 = 1.44	Nd18 = 1.54771	νd18 = 62.84
r19 = ∞	d19 = 0.8
r20 = ∞	d20 = 0.6	Nd20 = 1.51633	νd20 = 64.14
r21 = ∞	d21 = D21
Aspherical coefficients
	5th surface
	k = 0
	A4 = 4.47180E−05
	A6 = −2.1758E−07
	A8 = 0
	8th surface
	k = 0
	A4 = −2.23159E−04
	A6 = −1.95685E−06
	A8 = 0.00000E+00
	10th surface
	k = 0
	A4 = 5.19411E−05
	A6 = −1.17193E−06
	A8 = 0.00000E+00
	15th surface
	k = 0
	A4 = −1.16950E−04
	A6 = −4.73116E−07
	A8 = 0.00000E+00
Zoom data
When D0 (distance from object up to 1st surface) is ∞
	wide-angle end	intermediate	telephoto end
Focal length	6.077	13.7	17.98
FNO.	2.85	3.41	3.73
D7	12.35	4.54	0.8
D10	1.59	9.4	13.14
D11	1.4	6.41	10.76
D14	8.19	7.01	2.99
D17	5.4	1.58	1.25
D21	1.36	1.36	1.36

ELEVENTH EMBODIMENT

FIG. 21 is a cross-sectional view along the optical axis showing an optical arrangement at the time of the infinite object point focusing at the wide angle end of a zoom lens according to an eleventh embodiment of the present invention.

FIG. 22A, FIG. 22B, and FIG. 22C are diagrams showing the spherical aberration, the astigmatism, the distortion, and the chromatic aberration of magnification at the time of the infinite object point focusing of the zoom lens according to the eleventh embodiment, where, FIG. 22A shows the state at the wide angle end, FIG. 22B shows the intermediate state, and FIG. 22C shows the state at the telephoto end.

The zoom lens of the eleventh embodiment, as shown in FIG. 21, has a first lens group G1, a second lens group G2, an aperture stop S, a third lens group G3, and a fourth lens group G4 in this order from the object side. In the diagram, LPF is a low-pass filter, CG is a cover glass, and I is an image pickup surface of an electronic image pickup element.

The first lens group G1 includes a negative meniscus lens L211 having a convex surface directed toward the object side, a prism L212, and a cemented lens which is formed by a biconvex lens L213 and a biconcave lens L214, and has a negative refracting power as a whole.

The second lens group G2 includes a cemented lens which is formed by a biconvex lens L221 and a negative meniscus lens L222 having a convex surface directed toward an image side, and has a positive refracting power as a whole.

The third lens group G3 includes a cemented lens which is formed by a biconcave lens L231 and a positive meniscus lens L232 having a convex surface directed toward the object side, and has a negative refracting power as a whole.

The fourth lens group G4 includes a cemented lens which is formed by a biconvex lens L241 and a negative meniscus lens L242 having a concave surface directed toward the object side, and has a positive refracting power as a whole.

At the time of zooming from the wide angle end to the telephoto end, the first lens group G1 is fixed, the second lens group G2 moves toward the object side, the aperture stop S is fixed, the third lens group G3 moves toward the image side, and the fourth lens group G4 moves toward the image side.

An aspheric surface is provided on a surface toward the object side, of the biconvex lens L213 in the first lens group G1, a surface on the object side of the biconvex lens L221, and a surface on the image side of the negative meniscus lens L222 having the convex surface directed toward the image side in the second lens group G2, and a surface on the object side of the biconvex lens L241 in the fourth lens group G4.

Next, numerical data of the eleventh embodiment will be enumerated.

Numerical data 11
r1 = 48.381	d1 = 1.1	Nd1 = 1.7432	νd1 = 49.34
r2 = 10.569	d2 = 3
r3 = ∞	d3 = 12.5	Nd3 = 1.801	νd3 = 34.97
r4 = ∞	d4 = 0.4
r5 = 94.633	d5 = 1.97	Nd5 = 1.8061	νd5 = 40.92
(Aspheric surface)
r6 = −12.45	d6 = 0.7	Nd6 = 1.52	νd6 = 57
r7 = 19.015	d7 = D7
r8 = 12.682	d8 = 6.23	Nd8 = 1.497	νd8 = 81.54
(Aspheric surface)
r9 = −24.282	d9 = 0.35	Nd9 = 1.42001	νd9 = 6.55
r10 = −30.780	d10 = D10
(Aspheric surface)
r11 = Aperture stop	d11 = D11
r12 = −13.223	d12 = 0.7	Nd12 = 1.48749	νd12 = 70.23
r13 = 8.748	d13 = 1.6	Nd13 = 1.83481	νd13 = 40.7
r14 = 19.455	d14 = D14
r15 = 12.231	d15 = 3.5	Nd15 = 1.7432	νd15 = 49.34
(Aspheric surface)
r16 = −6	d16 = 0.7	Nd16 = 1.84666	νd16 = 23.78
r17 = −16.336	d17 = D17
r18 = ∞	d18 = 1.44	Nd18 = 1.54771	νd18 = 62.84
r19 = ∞	d19 = 0.8
r20 = ∞	d20 = 0.6	Nd20 = 1.51633	νd20 = 64.14
r21 = ∞	d21 = D21
Aspherical coefficients
	5th surface
	k = 0
	A4 = 1.92293E−05
	A6 = −3.35070E−08
	A8 = 0
	8th surface
	k = 0
	A4 = −7.14678E−05
	A6 = −1.27432E−07
	A8 = 0.00000E+00
	10th surface
	k = 0
	A4 = 1.08454E−05
	A6 = 1.53862E−07
	A8 = 0.00000E+00
	15th surface
	k = 0
	A4 = −1.71178E−04
	A6 = 5.29534E−07
	A8 = 0.00000E+00
Zoom data
When D0 (distance from object up to 1st surface) is ∞
	wide-angle end	intermediate	telephoto end
Focal length	5.99	13.7	17.997
FNO.	2.85	3.49	3.73
D7	15.36	4.85	0.8
D10	1.6	12.11	16.16
D11	1.4	7.07	9.13
D14	6.31	4.18	3
D17	5.62	2.08	1.21
D21	1.36	1.36	1.36

TWELFTH EMBODIMENT

FIG. 23 is a cross-sectional view along the optical axis showing an optical arrangement at the time of the infinite object point focusing at the wide angle end of a zoom lens according to a twelfth embodiment of the present invention.

FIG. 24A, FIG. 24B, and FIG. 24C are diagrams showing the spherical aberration, the astigmatism, the distortion, and the chromatic aberration of magnification at the time of the infinite object point focusing of the zoom lens according to the twelfth embodiment, where, FIG. 24A shows the state at the wide angle end, FIG. 24B shows the intermediate state, and FIG. 24C shows the state at the telephoto end.

The zoom lens of the twelfth embodiment, as shown in FIG. 23, has a first lens group G1, a second lens group G2, an aperture stop S, a third lens group G3, and a fourth lens group G4, in this order from an object side. In the diagram, LPF is a low-pass filter, CG is a cover glass, and I is an image pickup surface of an electronic image pickup element.

The first lens group G1 includes a negative meniscus lens L211 having a convex surface directed toward the object side, a prism L212, and a cemented lens which is formed by a positive meniscus lens L213 having a convex surface directed toward an image side, and a biconcave lens L214, and has a negative refracting power as a whole.

The second lens group G2 includes a cemented lens which is formed by a biconvex lens L221 and a negative meniscus lens L222 having a convex surface directed toward the image side, and has a positive refracting power as a whole.

The third lens group G3 includes a cemented lens which is formed by a biconcave lens L231 and a positive meniscus lens L232 having a convex surface directed toward the object side, and has a negative refracting power as a whole.

The fourth lens group G4 includes a cemented lens which is formed by a biconvex lens L241 and a negative meniscus lens L242 having a concave surface directed toward the object side, and has a positive refracting power as a whole.

At the time of zooming from the wide angle end to the telephoto end, the first lens group G1 is fixed, the second lens group G2 moves toward the object side, the aperture stop S is fixed, the third lens group G3 moves toward the image side, and the fourth lens group G4 moves toward the image side.

An aspheric surface is provided on a surface toward the object side, of the positive meniscus lens L213 having the convex surface directed toward the image side in the first lens group G1, a surface on the object side of the biconvex lens L221, and a surface on the image side of the negative meniscus lens L222 having the convex surface directed toward the image side in the second lens group G2, and a surface on the object side of the biconvex lens L241 in the fourth lens group G4.

Next, numerical data of the twelfth embodiment will be enumerated.

Numerical data 12
r1 = 15.958	d1 = 1.1	Nd1 = 1.741	νd1 = 52.64
r2 = 8.095	d2 = 3.7
r3 = ∞	d3 = 12.5	Nd3 = 1.801	νd3 = 34.97
r4 = ∞	d4 = 0.55
r5 = −29.717	d5 = 2.2	Nd5 = 1.8061	νd5 = 40.92
(Aspheric surface)
r6 = −8.846	d6 = 0.7	Nd6 = 1.51633	νd6 = 64.14
r7 = 18.475	d7 = D7
r8 = 9.653	d8 = 4	Nd8 = 1.43875	νd8 = 94.93
(Aspheric surface)
r9 = −12	d9 = 0.35	Nd9 = 1.51824	νd9 = 12.85
r10 = −14.260	d10 = D10
(Aspheric surface)
r11 = Aperture stop	d11 = D11
r12 = −16.685	d12 = 0.7	Nd12 = 1.48749	νd12 = 70.23
r13 = 11.863	d13 = 1.6	Nd13 = 1.83481	νd13 = 42.71
r14 = 20.917	d14 = D14
r15 = 15.028	d15 = 3.5	Nd15 = 1.7432	νd15 = 49.34
(Aspheric surface)
r16 = −6	d16 = 0.7	Nd16 = 1.84666	νd16 = 23.78
r17 = −16.013	d17 = D17
r18 = ∞	d18 = 1.44	Nd18 = 1.54771	νd18 = 62.84
r19 = ∞	d19 = 0.8
r20 = ∞	d20 = 0.6	Nd20 = 1.51633	νd20 = 64.14
r21 = ∞	d21 = D21
Aspherical coefficients
	5th surface
	k = 0
	A4 = 4.58748E−05
	A6 = 2.00925E−08
	A8 = 0
	8th surface
	k = 0
	A4 = −2.22174E−04
	A6 = −2.10655E−06
	A8 = 0.00000E+00
	10th surface
	k = 0
	A4 = 5.76382E−05
	A6 = −8.00870E−07
	A8 = 0.00000E+00
	15th surface
	k = 0
	A4 = −1.01844E−04
	A6 = −3.50190E−07
	A8 = 0.00000E+00
Zoom data
When D0 (distance from object up to 1st surface) is ∞
	wide-angle end	intermediate	telephoto end
Focal length	6.079	13.784	18.095
FNO.	2.85	3.41	3.73
D7	12.58	4.57	0.8
D10	1.59	9.6	13.37
D11	1.42	5.65	10.43
D14	8.13	7.54	2.99
D17	5.12	1.48	1.25
D21	1.33	1.2	1.09

THIRTEENTH EMBODIMENT

FIG. 25 is a cross-sectional view along the optical axis showing an optical arrangement at the time of the infinite object point focusing at the wide angle end of a zoom lens according to a thirteenth embodiment of the present invention.

FIG. 26A, FIG. 26B, and FIG. 26C are diagrams showing the spherical aberration, the astigmatism, the distortion, and the chromatic aberration of magnification at the time of the infinite object point focusing of the zoom lens according to the thirteenth embodiment, where, FIG. 26A shows the state at the wide angle end, FIG. 26B shows the intermediate state, and FIG. 26C shows the state at the telephoto end.

The zoom lens of the thirteenth embodiment, as shown in FIG. 25, has a first lens group G1, a second lens group G2, an aperture stop S, a third lens group G3, and a fourth lens group G4 in this order from the object side. In the diagram, LPF is a low-pass filter, CG is a cover glass, and I is an image pickup surface of an electronic image pickup element.

The first lens group G1 includes a negative meniscus lens L211 having a convex surface directed toward the object side, a prism L212, and a cemented lens which is formed by a biconvex lens L213 and a biconcave lens L214, and has a negative refracting power as a whole.

The second lens group G2 includes a cemented lens which is formed by a biconvex lens L221 and a negative meniscus lens L222 having a convex surface directed toward an image side, and has a positive refracting power as a whole.

The third lens group G3 includes a cemented lens which is formed by a biconcave lens L231 and the positive meniscus lens L232 having a convex surface directed toward the object side, and has a negative refracting power as a whole.

The fourth lens group G4 includes a cemented lens which is formed by a biconvex lens L241 and a negative meniscus lens L242 having a concave surface directed toward the object side, and has a positive refracting power as a whole.

At the time of zooming from the wide angle end to the telephoto end, the first lens group G1 is fixed, the second lens group G2 moves toward the object side, the aperture stop S is fixed, the third lens group G3 moves toward the image side, and the fourth lens group G4 moves toward the image side.

An aspheric surface is provided on a surface toward the object of the biconvex lens L213 in the first lens group, a surface on the object side of the biconvex lens L221 and a surface on the image side of the negative meniscus lens L222 having the convex surface directed toward the image side in the second lens group G2, and a surface on the object side of the biconvex lens in the fourth lens group G4.

Next, numerical data of the thirteenth embodiment will be enumerated.

Numerical data 13
r1 = 33.982	d1 = 1.1	Nd1 = 1.7432	νd1 = 49.34
r2 = 10.473	d2 = 3
r3 = ∞	d3 = 12.5	Nd3 = 1.801	νd3 = 34.97
r4 = ∞	d4 = 0.4
r5 = 420.903	d5 = 2.2	Nd5 = 1.8061	νd5 = 40.92
(Aspheric surface)
r6 = −12.739	d6 = 0.7	Nd6 = 1.51823	νd6 = 58.9
r7 = 18.9	d7 = D7
r8 = 11.769	d8 = 4	Nd8 = 1.497	νd8 = 81.54
(Aspheric surface)
r9 = −21.158	d9 = 0.35	Nd9 = 1.54856	νd9 = 7.04
r10 = −25.172	d10 = D10
(Aspheric surface)
r11 = Aperture stop	d11 = D11
r12 = −12.515	d12 = 0.7	Nd12 = 1.48749	νd12 = 70.23
r13 = 10.408	d13 = 1.6	Nd13 = 1.83481	νd13 = 42.71
r14 = 24.37	d14 = D14
r15 = 13.942	d15 = 3.5	Nd15 = 1.7432	νd15 = 49.34
(Aspheric surface)
r16 = −6	d16 = 0.7	Nd16 = 1.84666	νd16 = 23.78
r17 = −14.625	d17 = D17
r18 = ∞	d18 = 1.44	Nd18 = 1.54771	νd18 = 62.84
r19 = ∞	d19 = 0.8
r20 = ∞	d20 = 0.6	Nd20 = 1.51633	νd20 = 64.14
r21 = ∞	d21 = D21
Aspherical coefficients
	5th surface
	k = 0
	A4 = 1.74566E−05
	A6 = 6.67000E−08
	A8 = 0.00000E+00
	8th surface
	k = 0
	A4 = −1.19200E−04
	A6 = −2.02183E−07
	A8 = −4.21441E−07
	10th surface
	k = 0
	A4 = −2.32245E−05
	A6 = 3.20470E−07
	A8 = −1.28129E−06
	15th surface
	k = 0
	A4 = −1.55574E−04
	A6 = −1.65793E−07
	A8 = 5.27383E−08
Zoom data
When D0 (distance from object up to 1st surface) is ∞
	wide-angle end	intermediate	telephoto end
Focal length	6.013	13.699	17.991
FNO.	2.89	3.48	3.83
D7	13.94	4	0.8
D10	1.6	11.55	14.74
D11	1.4	6.02	9.19
D14	6.37	4.95	3
D17	5.62	2.41	1.2
D21	1.36	1.36	1.36

FOURTEENTH EMBODIMENT

FIG. 27 is a cross-sectional view along the optical axis showing an optical arrangement at the time of the infinite object point focusing at the wide angle end of a zoom lens according to a fourteenth embodiment of the present invention.

FIG. 28A, FIG. 28B, and FIG. 28C are diagrams showing the spherical aberration, the astigmatism, the distortion, and the chromatic aberration of magnification at the time of the infinite object point focusing of the zoom lens according to the fourteenth embodiment of the present invention, where, FIG. 28A shows the state at the wide angle end, FIG. 28B shows the intermediate state, and FIG. 28C shows the state at the telephoto end.

The zoom lens of the fourteenth embodiment, as shown in FIG. 27, has a first lens group G1, a second lens group G2, an aperture stop S, a third lens group G3, and a fourth lens group G4 in this order from an object side. In the diagram, LPF is a low-pass filter, CG is a cover glass, and I is an image pickup surface of an electronic image pickup element.

The first lens group G1 includes a negative meniscus lens L211 having a convex surface directed toward the object side, a prism L212, and a cemented lens which is formed by a positive meniscus lens L213 having a convex surface directed toward an image side and a biconcave lens L214, and has a negative refracting power as a whole.

The second lens group G2 includes a cemented lens which is formed by a biconvex lens L221 and a negative meniscus lens L222 having a convex surface directed toward the image side, and has a positive refracting power as a whole.

The third lens group G3 includes a cemented lens which is formed by a biconcave lens L231 and a positive meniscus lens L232 having a convex surface directed toward the object side, and has a negative refracting power as a whole.

The fourth lens group G4 includes a cemented lens which is formed by a biconvex lens L241 and a negative meniscus lens L242 having a concave surface directed toward the object side, and has a positive refracting power as a whole.

At the time of zooming from the wide angle end to the telephoto end, the first lens group G1 is fixed, the second lens group G2 moves toward the object side, the aperture stop S is fixed, the third lens group G3 moves toward the image side, and the fourth lens group G4 moves toward the image side.

An aspheric surface is provided on a surface toward the object, of the positive meniscus lens L213 having the convex surface directed toward the image side in the first lens group G1, a surface on the object side of the biconvex lens L221 and a surface on the image side of the negative meniscus lens L222 having the convex surface directed toward the image side in the second lens group G2, and a surface on the object side, of the biconvex lens L241 in the fourth lens group G4.

Next, numerical data of the fourteenth embodiment will be enumerated.

Numerical data 14
r1 = 21.697	d1 = 1.1	Nd1 = 1.7432	νd1 = 49.34
r2 = 8.621	d2 = 3
r3 = ∞	d3 = 12.5	Nd3 = 1.94891	νd3 = 23.05
r4 = ∞	d4 = 0.4
r5 = −61.481	d5 = 2.2	Nd5 = 1.82367	νd5 = 32.14
(Aspheric surface)
r6 = −12.879	d6 = 0.7	Nd6 = 1.55419	νd6 = 58.44
r7 = 30.673	d7 = D7
r8 = 15.245	d8 = 4	Nd8 = 1.50278	νd8 = 78.82
(Aspheric surface)
r9 = −12	d9 = 0.35	Nd9 = 1.65228	νd9 = 12.75
r10 = −14.968	d10 = D10
(Aspheric surface)
r11 = Aperture stop	d11 = D11
r12 = −19.694	d12 = 0.7	Nd12 = 1.55228	νd12 = 49.08
r13 = 7.159	d13 = 1.6	Nd13 = 1.85942	νd13 = 42.23
r14 = 24.86	d14 = D14
r15 = 15.192	d15 = 3.5	Nd15 = 1.7501	νd15 = 51.93
(Aspheric surface)
r16 = −6	d16 = 0.7	Nd16 = 1.80849	νd16 = 35.3
r17 = −39.907	d17 = D17
r18 = ∞	d18 = 1.44	Nd18 = 1.54771	νd18 = 62.84
r19 = ∞	d19 = 0.8
r20 = ∞	d20 = 0.6	Nd20 = 1.51633	νd20 = 64.14
r21 = ∞	d21 = D21
Aspherical coefficients
	5th surface
	k = 0
	A4 = 4.46958E−05
	A6 = 4.51820E−07
	A8 = 0
	8th surface
	k = 0
	A4 = −1.07884E−04
	A6 = −2.45135E−06
	A8 = 0.00000E+00
	10th surface
	k = 0
	A4 = 2.92065E−06
	A6 = −1.30323E−06
	A8 = 0.00000E+00
	15th surface
	k = 0
	A4 = −1.69708E−04
	A6 = 4.01584E−07
	A8 = 0.00000E+00
Zoom data
When D0 (distance from object up to 1st surface) is ∞
	wide-angle end	intermediate	telephoto end
Focal length	6.1	13.42	17.995
FNO.	3.45	3.91	4.55
D7	18.29	3.07	0.58
D10	2.88	11.62	14.96
D11	0.85	5.17	12
D14	7.15	5.14	2.53
D17	4.47	4.43	2.92
D21	1.36	1.36	1.36

FIFTEENTH EMBODIMENT

FIG. 29 is a cross-sectional view along the optical axis showing an optical arrangement at the time of the infinite object point focusing at the wide angle end of a zoom lens according to a fifteenth embodiment of the present invention.

FIG. 30A, FIG. 30B, and FIG. 30C are diagrams showing the spherical aberration, the astigmatism, the distortion, and the chromatic aberration of magnification at the time of the infinite object point focusing of the zoom lens according to the fifteenth embodiment, where, FIG. 30A shows the state at the wide angle end, FIG. 30B shows the intermediate state, and FIG. 30C shows the state at the telephoto end.

The zoom lens of the fifteenth embodiment, as shown in FIG. 29, has a first lens group G1, a second lens group G2, an aperture stop S, a third lens group G3, and a fourth lens group G4 in this order from an object side. In the diagram, LPF is a low-pass filter, CG is a cover glass, and I is an image pickup surface of an electronic image pickup element.

The first lens group G1 includes a negative meniscus lens L211 having the convex surface directed toward the object side, the prism L212, and a cemented lens which is formed by a biconvex lens L213 and a biconcave lens L214, and has a negative refracting power as a whole.

The second lens group G2 includes a cemented lens which is formed by a biconvex lens L221 and a negative meniscus lens L222 having a convex surface directed toward an image side, and has a positive refracting power as a whole.

The third lens group G3 includes a cemented lens which is formed by a biconcave lens L231 and a positive meniscus lens L232 having a convex surface directed toward the object side, and has a negative refracting power as a whole.

The fourth lens group G4 includes a cemented lens which is formed by a biconvex lens L241 and a negative meniscus lens L242 having a concave surface directed toward the object side, and has a positive refracting power as a whole.

At the time of zooming from the wide angle end to the telephoto end, the first lens group G1 is fixed, the second lens group G2 moves toward the object side, the aperture stop S is fixed, the third lens group G3 moves toward the image side, and the fourth lens group G4 moves toward the image side.

An aspheric surface is provided on a surface on the object side, of the biconvex lens L213 in the first lens group G1, a surface on the object side of the biconvex lens L221 and a surface on the image side of the negative meniscus lens L222 having the convex surface directed toward the image side in the second lens group G2, and a surface on the object side, of the biconvex lens L241 in the fourth lens group G4.

Next, numerical data of the fifteenth embodiment will be enumerated.

Numerical data 15
r1 = 39.511	d1 = 1.1	Nd1 = 1.7432	νd1 = 49.34
r2 = 9.954	d2 = 3
r3 = ∞	d3 = 12.5	Nd3 = 1.801	νd3 = 34.97
r4 = ∞	d4 = 0.4
r5 = 50.212	d5 = 2.14	Nd5 = 1.8061	νd5 = 40.92
(Aspheric surface)
r6 = −12.508	d6 = 0.7	Nd6 = 1.52	νd6 = 57
r7 = 15.872	d7 = D7
r8 = 11.955	d8 = 4.86	Nd8 = 1.497	νd8 = 81.54
(Aspheric surface)
r9 = −29.183	d9 = 0.35	Nd9 = 1.59885	νd9 = 6.52
r10 = −36.717	d10 = D10
(Aspheric surface)
r11 = Aperture stop	d11 = D11
r12 = −13.687	d12 = 0.7	Nd12 = 1.48749	νd12 = 70.23
r13 = 8.399	d13 = 1.6	Nd13 = 1.83481	νd13 = 40.7
r14 = 18.182	d14 = D14
r15 = 12.005	d15 = 3.5	Nd15 = 1.7432	νd15 = 49.34
(Aspheric surface)
r16 = −6	d16 = 0.7	Nd16 = 1.84666	νd16 = 23.78
r17 = −16.33	d17 = D17
r18 = ∞	d18 = 1.44	Nd18 = 1.54771	νd18 = 62.84
r19 = ∞	d19 = 0.8
r20 = ∞	d20 = 0.6	Nd20 = 1.51633	νd20 = 64.14
r21 = ∞	d21 = D21
Aspherical coefficients
	5th surface
	k = 0
	A4 = 1.86622E−05
	A6 = −1.24351E−08
	A8 = 0
	8th surface
	k = 0
	A4 = −5.16885E−05
	A6 = 3.34589E−07
	A8 = 0.00000E+00
	10th surface
	k = 0
	A4 = 2.45844E−05
	A6 = 6.28246E−07
	A8 = 0.00000E+00
	15th surface
	k = 0
	A4 = −1.76798E−04
	A6 = 4.99749E−07
	A8 = 0.00000E+00
Zoom data
When D0 (distance from object up to 1st surface) is ∞
	wide-angle end	intermediate	telephoto end
Focal length	6	13.7	17.999
FNO.	2.85	3.49	3.73
D7	15.39	4.68	0.8
D10	1.6	12.31	16.2
D11	1.4	7.01	9.12
D14	6.3	4.1	3
D17	5.63	2.21	1.21
D21	1.36	1.36	1.36

SIXTEENTH EMBODIMENT

FIG. 31 is a cross-sectional view along the optical axis showing an optical arrangement at the time of the infinite object point focusing at the wide angle end of a zoom lens according to a sixteenth embodiment of the present invention.

FIG. 32A, FIG. 32B, and FIG. 32C are diagrams showing the spherical aberration, the astigmatism, the distortion, and the chromatic aberration of magnification at the time of the infinite object point focusing of the zoom lens according to the sixteenth embodiment of the present invention, where, FIG. 32A shows the state at the wide angle end, FIG. 32B shows the intermediate state, and FIG. 32C shows the state at the telephoto end.

The zoom lens of the sixteenth embodiment, as shown in FIG. 31, has a first lens group G1, a second lens group G2, an aperture stop S, a third lens group G3, and a fourth lens group G4 in this order from the object side. In the diagram, LPF is a low-pass filter, CG is a cover glass, and I is an image pickup surface of an electronic image pickup element.

The first lens group G1 includes a negative meniscus lens L211 having a convex surface directed toward the object side, the prism L212, and a cemented lens which is formed by a biconvex lens L213 and a biconcave lens L214, and has a negative refracting power as a whole.

The second lens group G2 includes a cemented lens which is formed by a biconvex lens L221 and a negative meniscus lens L222 having a convex surface directed toward an image side, and has a positive refracting power as a whole.

The third lens group G3 includes a cemented lens which is formed by a biconcave lens L231 and a positive meniscus lens L232 having a convex surface directed toward the object side, and has a negative refracting power as a whole.

The fourth lens group G4 includes a cemented lens which is formed by a biconvex lens L241 and a negative meniscus lens L242 having a concave surface directed toward the object side, and has a positive refracting power as a whole.

At the time of zooming from the wide angle end to the telephoto end, the first lens group G1 is fixed, the second lens group G2 moves toward the object side, the aperture stop S is fixed, the third lens group G3 moves toward the image side, and the fourth lens group G4 moves toward the image side.

An aspheric surface is provided on a surface on the object side, of the biconvex lens L213 in the first lens group G1, a surface on the object side of the biconvex lens L221 and a surface on the image side of the negative meniscus lens L222 having the convex surface directed toward the image side in the second lens group G2, and a surface on the object side, of the biconvex lens L241 in the fourth lens group G4.

Next, numerical data of the sixteenth embodiment will be enumerated.

Numerical data 16
r1 = 38.962	d1 = 1.1	Nd1 = 1.7432	νd1 = 49.34
r2 = 9.911	d2 = 3
r3 = ∞	d3 = 12.5	Nd3 = 1.801	νd3 = 34.97
r4 = ∞	d4 = 0.4
r5 = 47.772	d5 = 2.11	Nd5 = 1.8061	νd5 = 40.92
(Aspheric surface)
r6 = −12.757	d6 = 0.7	Nd6 = 1.52	νd6 = 57
r7 = 15.478	d7 = D7
r8 = 11.780	d8 = 5.1	Nd8 = 1.497	νd8 = 81.54
(Aspheric surface)
r9 = −23.99	d9 = 0.35	Nd9 = 1.79525	νd9 = 9.95
r10 = −31.574	d10 = D10
(Aspheric surface)
r11 = Aperture stop	d11 = D11
r12 = −13.748	d12 = 0.7	Nd12 = 1.48749	νd12 = 70.23
r13 = 8.46	d13 = 1.6	Nd13 = 1.83481	νd13 = 40.7
r14 = 18.241	d14 = D14
r15 = 12.049	d15 = 3.5	Nd15 = 1.7432	νd15 = 49.34
(Aspheric surface)
r16 = −6	d16 = 0.7	Nd16 = 1.84666	νd16 = 23.78
r17 = −16.277	d17 = D17
r18 = ∞	d18 = 1.44	Nd18 = 1.54771	νd18 = 62.84
r19 = ∞	d19 = 0.8
r20 = ∞	d20 = 0.6	Nd20 = 1.51633	νd20 = 64.14
r21 = ∞	d21 = D21
Aspherical coefficients
	5th surface
	k = 0
	A4 = 2.09655E−05
	A6 = 1.33197E−08
	A8 = 0
	8th surface
	k = 0
	A4 = −5.05955E−05
	A6 = 3.02697E−07
	A8 = 0.00000E+00
	10th surface
	k = 0
	A4 = 2.20076E−05
	A6 = 4.81649E−07
	A8 = 0.00000E+00
	15th surface
	k = 0
	A4 = −1.74494E−04
	A6 = 4.58302E−07
	A8 = 0.00000E+00
Zoom data
When D0 (distance from object up to 1st surface) is ∞
	wide-angle end	intermediate	telephoto end
Focal length	5.999	10.399	17.999
FNO.	2.85	3.32	3.72
D7	15.36	8.57	0.8
D10	1.6	8.39	16.16
D11	1.4	5.88	9.07
D14	6.29	4.21	3
D17	5.58	3.18	1.21
D21	1.36	1.36	1.36

SEVENTEENTH EMBODIMENT

FIG. 33 is a cross-sectional view along the optical axis showing an optical arrangement at the time of the infinite object point focusing at the wide angle end of a zoom lens according to a seventeenth embodiment of the present invention.

FIG. 34A, FIG. 34B, and FIG. 34C are diagrams showing the spherical aberration, the astigmatism, the distortion, and the chromatic aberration of magnification at the time of the infinite object point focusing of the zoom lens according to the seventeenth embodiment, where, FIG. 34A shows the state at the wide angle end, FIG. 34B shows the intermediate state, and FIG. 34C shows the state at the telephoto end.

The zoom lens of the seventeenth embodiment, as shown in FIG. 33, has a first lens group G1, a second lens group G2, an aperture stop S, a third lens group G3, and a fourth lens group G4 in this order from an object side. In the diagram, LPF is a low-pass filter, CG is a cover glass, and I is an image pickup surface of an electronic image pickup element.

The first lens group G1 includes a negative meniscus lens L211 having a convex surface directed toward the object side, a prism L212, and a cemented lens which is formed by a biconvex lens L213 and a biconcave lens L214, and has a negative refracting power as a whole.

The second lens group G2 includes a cemented lens which is formed by a biconvex lens L221 and a negative meniscus lens L222 having a convex surface directed toward an image side, and has a positive refracting power as a whole.

The third lens group G3 includes a cemented lens which is formed by a biconcave lens L231 and a positive meniscus lens L232 having a convex surface directed toward the object side, and has a positive refracting power as a whole.

The fourth lens group G4 includes a cemented lens which is formed by a biconvex lens L241 and the negative meniscus lens L242 having a concave surface directed toward the object side, and has a positive refracting power as a whole.

At the time of zooming from the wide angle end to the telephoto end, the first lens group G1 is fixed, the second lens group G2 moves toward the object side, the aperture stop S is fixed, the third lens group G3 moves toward the image side, and the fourth lens group G4 moves toward the image side.

An aspheric surface is provided on a surface on the object side, of the biconvex lens L213 in the first lens group G1, a surface on the object side of the biconvex lens L221 and a surface on the image side of the negative meniscus lens L222 having the convex surface directed toward the image side in the second lens group G2, and a surface on the object side, of the biconvex lens in the fourth lens group G4.

Next, numerical data of the seventeenth embodiment will be enumerated.

Numerical data 17
r1 = 39.372	d1 = 1.1	Nd1 = 1.7432	νd1 = 49.34
r2 = 9.927	d2 = 3
r3 = ∞	d3 = 12.5	Nd3 = 1.801	νd3 = 34.97
r4 = ∞	d4 = 0.4
r5 = 45.949	d5 = 2.12	Nd5 = 1.8061	νd5 = 40.92
(Aspheric surface)
r6 = −12.875	d6 = 0.7	Nd6 = 1.52	νd6 = 57
r7 = 15.221	d7 = D7
r8 = 11.744	d8 = 5.22	Nd8 = 1.497	νd8 = 81.54
(Aspheric surface)
r9 = −20.824	d9 = 0.35	Nd9 = 1.9712	νd9 = 12.88
r10 = −27.330	d10 = D10
(Aspheric surface)
r11 = Aperture stop	d11 = D11
r12 = −13.73	d12 = 0.7	Nd12 = 1.48749	νd12 = 70.23
r13 = 8.492	d13 = 1.6	Nd13 = 1.83481	νd13 = 40.7
r14 = 18.325	d14 = D14
r15 = 12.076	d15 = 3.5	Nd15 = 1.7432	νd15 = 49.34
(Aspheric surface)
r16 = −6	d16 = 0.7	Nd16 = 1.84666	νd16 = 23.78
r17 = −16.273	d17 = D17
r18 = ∞	d18 = 1.44	Nd18 = 1.54771	νd18 = 62.84
r19 = ∞	d19 = 0.8
r20 = ∞	d20 = 0.6	Nd20 = 1.51633	νd20 = 64.14
r21 = ∞	d21 = D21
Aspherical coefficients
	5th surface
	k = 0
	A4 = 2.17207E−05
	A6 = 1.35440E−08
	A8 = 0
	8th surface
	k = 0
	A4 = −5.21380E−05
	A6 = 2.41157E−07
	A8 = 0.00000E+00
	10th surface
	k = 0
	A4 = 1.71590E−05
	A6 = 3.51620E−07
	A8 = 0.00000E+00
	15th surface
	k = 0
	A4 = −1.73599E−04
	A6 = 4.60077E−07
	A8 = 0.00000E+00
Zoom data
When D0 (distance from object up to 1st surface) is ∞
	wide-angle end	intermediate	telephoto end
Focal length	5.999	10.399	17.999
FNO.	2.85	3.32	3.73
D7	15.34	8.57	0.8
D10	1.6	8.37	16.14
D11	1.4	5.88	9.07
D14	6.29	4.22	3
D17	5.58	3.17	1.21
D21	1.36	1.36	1.36

EIGHTEENTH EMBODIMENT

FIG. 35 is a cross-sectional view along the optical axis showing an optical arrangement at the time of the infinite object point focusing at the wide angle end of a zoom lens according to an eighteenth embodiment of the present invention.

FIG. 36A, FIG. 36B, and FIG. 36C are diagrams showing the spherical aberration; the astigmatism, the distortion, and the chromatic aberration of magnification a the time of the infinite object point focusing of the zoom lens according to the eighteenth embodiment, where, FIG. 36A shows the state at the wide angle end, the FIG. 36B shows the intermediate state, and FIG. 36C shows the state at the telephoto end.

The zoom lens of the eighteenth embodiment, as shown in FIG. 35, has a first lens group G1, a second lens group G2, an aperture stop S, a third lens group G3, and a fourth lens group G4, in this order from an object side. In the diagram, LPF is a low-pass filter, CG is a cover glass, and I is an image pickup surface of an electronic image pickup element.

The first lens group G1 includes a negative meniscus lens L211 having a convex surface directed toward the object side, a prism L212, and a cemented lens which is formed by a biconvex lens L213 and a biconcave lens L214, and has a negative refracting power as a whole.

The second lens group G2 includes a cemented lens which is formed by a biconvex lens L221 and a negative meniscus lens L222 having a convex surface directed toward an image side, and has a positive refracting power as a whole.

The third lens group G3 includes a cemented lens which is formed by a biconcave lens L231 and a positive meniscus lens L232 having a convex surface directed toward the object side, and has a negative refracting power as a whole.

The fourth lens group G4 includes a cemented lens which is formed by a biconvex lens L241, and a negative meniscus lens L242 having a concave surface directed toward the object side, and has a positive refracting power as a whole.

At the time of zooming from the wide angle end to the telephoto end, the first lens group G1 is fixed, the second lens group G2 moves toward the object side, the aperture stop S is fixed, the third lens group G3 moves toward the image side, and the fourth lens group G4 moves toward the image side.

An aspheric surface is provided on a surface on the object side, of the biconvex lens L214 in the first lens group G1, a surface on the object side of the biconvex lens L221 and a surface on the image side of the negative meniscus lens L222 having the convex surface directed toward the image side in the second lens group G2, and a surface on the object side, of the biconvex lens in the fourth lens group G4.

Next, numerical data of the eighteenth embodiment will be enumerated.

Numerical data 18
r1 = 39.906	d1 = 1.1	Nd1 = 1.7432	νd1 = 49.34
r2 = 9.964	d2 = 3
r3 = ∞	d3 = 12.5	Nd3 = 1.801	νd3 = 34.97
r4 = ∞	d4 = 0.4
r5 = 44.825	d5 = 2.13	Nd5 = 1.8061	νd5 = 40.92
(Aspheric surface)
r6 = −12.948	d6 = 0.7	Nd6 = 1.52	νd6 = 57
r7 = 15.168	d7 = D7
r8 = 11.641	d8 = 5.09	Nd8 = 1.497	νd8 = 81.54
(Aspheric surface)
r9 = −29.171	d9 = 0.35	Nd9 = 2.05122	νd9 = 6.28
r10 = −33.680	d10 = D10
(Aspheric surface)
r11 = Aperture stop	d11 = D11
r12 = −13.644	d12 = 0.7	Nd12 = 1.48749	νd12 = 70.23
r13 = 8.503	d13 = 1.6	Nd13 = 1.83481	νd13 = 40.7
r14 = 18.44	d14 = D14
r15 = 12.109	d15 = 3.5	Nd15 = 1.7432	νd15 = 49.34
(Aspheric surface)
r16 = −6	d16 = 0.7	Nd16 = 1.84666	νd16 = 23.78
r17 = −16.133	d17 = D17
r18 = ∞	d18 = 1.44	Nd18 = 1.54771	νd18 = 62.84
r19 = ∞	d19 = 0.8
r20 = ∞	d20 = 0.6	Nd20 = 1.51633	νd20 = 64.14
r21 = ∞	d21 = D21
Aspherical coefficients
	5th surface
	k = 0
	A4 = 2.13457E−05
	A6 = 1.64989E−08
	A8 = 0
	8th surface
	k = 0
	A4 = −4.96465E−05
	A6 = 3.28544E−07
	A8 = 0.00000E+00
	10th surface
	k = 0
	A4 = 1.83684E−05
	A6 = 4.02729E−07
	A8 = 0.00000E+00
	15th surface
	k = 0
	A4 = −1.75253E−04
	A6 = 4.15528E−07
	A8 = 0.00000E+00
Zoom data
When D0 (distance from object up to 1st surface) is ∞
	wide-angle end	intermediate	telephoto end
Focal length	6	10.399	17.999
FNO.	2.84	3.31	3.72
D7	15.34	8.56	0.8
D10	1.6	8.37	16.14
D11	1.4	5.89	9.04
D14	6.27	4.18	3
D17	5.57	3.17	1.21
D21	1.36	1.36	1.36

NINETEENTH EMBODIMENT

FIG. 37 is a cross-sectional view along the optical axis showing an optical arrangement at the time of the infinite object point focusing at the wide angle end of a zoom lens according to a nineteenth embodiment of the present invention.

FIG. 38A, FIG. 38B, and FIG. 38C are diagrams showing the spherical aberration, the astigmatism, the distortion, and the chromatic aberration of magnification at the time of the infinite object point focusing of the zoom lens according to the nineteenth embodiment of the present invention, where, FIG. 38A shows the state at the wide angle end, FIG. 38B shows the intermediate state, and FIG. 38C shows the state at the telephoto end.

The zoom lens of the nineteenth embodiment, as shown in FIG. 37, has a first lens group G1, a second lens group G2, an aperture stop S, a third lens group G3, a fourth lens group G4, and a fifth lens group G5, in this order from an object side. In the diagram, LPF is a low-pass filter, CG is a cover glass, and I is an image pickup surface of an electronic image pickup element.

The first lens group G1 includes a negative meniscus lens L111 having a convex surface directed toward the object side, a prism L212, and a cemented lens which is formed by a negative meniscus lens L113 having a convex surface directed toward the object side and a biconvex lens 114, and has a positive refracting power as a whole.

The second lens group G2 includes a biconcave lens L121 and a positive meniscus lens L122 having a convex surface directed toward the object side, and has a negative refracting power as a whole.

The third lens group G3 includes a cemented lens which is formed by a biconvex lens L131 and a biconcave lens L132, and has a positive refracting power as a whole.

The fourth lens group G4 includes a negative meniscus lens L141 having a convex surface directed toward the object side, and has a negative refracting power as a whole.

The fifth lens group G5 includes a biconvex lens L142, and has a positive refracting power as a whole.

At the time of zooming from the wide angle end to the telephoto end, the first lens group G1 is fixed, the second lens group G2 moves toward an image side, the aperture stop S is fixed, the third lens group G3 moves toward the object side, the fourth lens group moves once to the image side and then moves toward the object side, and the fifth lens group G5 moves toward the image side.

An aspheric surface is provided on a surface on the object side of the negative meniscus lens L113 having the convex surface directed toward the object side in the first lens group G1, both surfaces of the biconcave lens L121 in the second lens group G2, a surface on the object side of the biconvex lens L131, and a surface on the image side, of the biconcave lens L132 in the third lens group G3, and a surface on the object side of the biconvex lens L142 in the fifth lens group G5.

Next, numerical data of the nineteenth embodiment will be enumerated.

Numerical data 19
r1 = 27.528	d1 = 1	Nd1 = 1.8061	νd1 = 40.92
r2 = 10.01	d2 = 2.9
r3 = ∞	d3 = 12	Nd3 = 1.8061	νd3 = 40.92
r4 = ∞	d4 = 0.3
r5 = 19.259	d5 = 0.1	Nd5 = 1.60687	νd5 = 27.03
(Aspheric surface)
r6 = 16.049	d6 = 3.54	Nd6 = 1.741	νd6 = 52.64
r7 = −43.585	d7 = D7
r8 = −74.609	d8 = 0.8	Nd8 = 1.8061	νd8 = 40.92
(Aspheric surface)
r9 = 5.443	d9 = 0.7
(Aspheric surface)
r10 = 7.458	d10 = 2.2	Nd10 = 1.7552	νd10 = 27.51
r11 = 91.204	d11 = D11
r12 = Aperture stop	d12 = D12
r13 = 8.403	d13 = 6.46	Nd13 = 1.6935	νd13 = 53.21
(Aspheric surface)
r14 = −10.035	d14 = 1	Nd14 = 1.84666	νd14 = 23.78
r15 = 47.150	d15 = D15
(Aspheric surface)
r16 = 24.758	d16 = 0.6	Nd16 = 1.48749	νd16 = 70.23
r17 = 9.504	d17 = D17
r18 = 10.540	d18 = 1.8	Nd18 = 1.7432	νd18 = 49.34
(Aspheric surface)
r19 = −222.308	d19 = D19
r20 = ∞	d20 = 1.9	Nd20 = 1.54771	νd20 = 62.84
r21 = ∞	d21 = 0.8
r22 = ∞	d22 = 0.75	Nd22 = 1.51633	νd22 = 64.14
r23 = ∞	d23 = D23
Aspherical coefficients
	5th surface
	k = 0
	A4 = 7.49511E−06
	A6 = 6.72180E−08
	A8 = 0.00000E+00
	8th surface
	k = 0
	A4 = 2.74050E−04
	A6 = −1.05373E−05
	A8 = 1.91437E−07
	9th surface
	k = 0
	A4 = −1.49959E−04
	A6 = −1.84286E−05
	A8 = −4.07805E−07
	13th surface
	k = 0
	A4 = 6.78959E−05
	A6 = 2.28068E−06
	A8 = −1.02002E−08
	15th surface
	k = 0
	A4 = 4.73455E−04
	A6 = 1.84961E−05
	A8 = −3.16845E−08
	18th surface
	k = 0
	A4 = −1.04278E−04
	A6 = 9.79328E−06
	A8 = −2.57765E−07
Zoom data
When D0 (distance from object up to 1st surface) is ∞
	wide-angle end	intermediate	telephoto end
Focal length	6.002	13.7	17.996
FNO.	2.86	4.73	5.67
D7	0.8	6.8	8.42
D11	9.02	3.01	1.39
D12	10.8	3.53	1.19
D15	1.2	11.73	13.72
D17	1.4	1.59	2.83
D19	4.84	1.4	0.51
D23	1.36	1.36	1.36

TWENTIETH EMBODIMENT

FIG. 39 is a cross-sectional view along the optical axis showing an optical arrangement at the time of the infinite object point focusing at the wide angle end of a zoom lens according to a twentieth embodiment of the present invention.

FIG. 40A, FIG. 40B, and FIG. 40C are diagrams showing the spherical aberration, the astigmatism, the distortion, and the chromatic aberration of magnification at the time of the infinite object point focusing of the zoom lens according to the twentieth embodiment, where, FIG. 40A shows the state at the wide angle end, FIG. 40B shows the intermediate state, and FIG. 40C shows the state at the telephoto end.

The zoom lens of the twentieth embodiment, as shown in FIG. 39, has a first lens group G1, a second lens group G2, an aperture stop S, a third lens group G3, a fourth lens group G4, and a fifth lens group G5, in this order from an object side. In the diagram, LPF is a low-pass filter, CG is a cover glass, and I is an image pickup surface of an electronic image pickup element.

The first lens group G1 includes a negative meniscus lens L111 having a convex surface directed toward the object side, a prism L112, and a cemented lens which is formed by a negative meniscus lens L113 having a convex surface directed toward the object side and a biconvex lens L114, and has a positive refracting power as a whole.

The second lens group G2 includes a biconcave lens L121 and a positive meniscus lens L122 having a convex surface directed toward the object side, and has a negative refracting power as a whole.

The third lens group G3 includes a cemented lens which is formed by a biconvex lens L131 and a biconcave lens L132, and has a positive refracting power as a whole.

The fourth lens group G4 includes a negative meniscus lens L141 having a convex surface directed toward the object side, and has a negative refracting power as a whole.

The fifth lens group G5 includes a biconvex lens L142, and has a positive refracting power as a whole.

At the time of zooming from the wide angle end to the telephoto end, the first lens group G1 is fixed, the second lens group G2 moves toward an image side, the aperture stop S is fixed, the third lens group G3 moves toward the object side, the fourth lens group G4 moves once toward the image side, and then moves toward the object side, and the fifth lens group G5 moves toward the image side.

An aspheric surface is provided on a surface on the object side of the negative meniscus lens L113 having the convex surface directed toward the object side in the first lens group G1, both surfaces of the biconcave lens L121 in the second lens group G2, a surface on the object side of the biconvex lens L131, and a surface on the image side, of the biconcave lens L132 in the third lens group G3, and a surface on the object side of the biconvex lens L142 in the fifth lens group G5.

Next, numerical data of the twentieth embodiment will be enumerated.

Numerical data 20
r1 = 28.438	d1 = 1	Nd1 = 1.8061	νd1 = 40.92
r2 = 10.004	d2 = 2.9
r3 = ∞	d3 = 12	Nd3 = 1.8061	νd3 = 40.92
r4 = ∞	d4 = 0.3
r5 = 20.895	d5 = 0.1	Nd5 = 1.60258	νd5 = 18.58
(Aspheric surface)
r6 = 17.413	d6 = 3.06	Nd6 = 1.741	νd6 = 52.64
r7 = −37.246	d7 = D7
r8 = −78.978	d8 = 0.73	Nd8 = 1.8061	νd8 = 40.92
(Aspheric surface)
r9 = 5.188	d9 = 0.64
(Aspheric surface)
r10 = 7.149	d10 = 1.47	Nd10 = 1.7552	νd10 = 27.51
r11 = 121.309	d11 = D11
r12 = Aperture stop	d12 = D12
r13 = 8.146	d13 = 7.35	Nd13 = 1.6935	νd13 = 53.21
(Aspheric surface)
r14 = −8.498	d14 = 1	Nd14 = 1.84666	νd14 = 23.78
r15 = 50.867	d15 = D15
(Aspheric surface)
r16 = 38.968	d16 = 0.6	Nd16 = 1.48749	νd16 = 70.23
r17 = 9.515	d17 = D17
r18 = 9.852	d18 = 1.8	Nd18 = 1.7432	νd18 = 49.34
(Aspheric surface)
r19 = −328.893	d19 = D19
r20 = ∞	d20 = 1.9	Nd20 = 1.54771	νd20 = 62.84
r21 = ∞	d21 = 0.8
r22 = ∞	d22 = 0.75	Nd22 = 1.51633	νd22 = 64.14
r23 = ∞	d23 = D23
Aspherical coefficients
	5th surface
	k = 0
	A4 = 1.23119E−05
	A6 = 8.84042E−08
	A8 = 0
	8th surface
	k = 0
	A4 = 8.85570E−05
	A6 = −5.07500E−07
	A8 = −1.21145E−07
	9th surface
	k = 0
	A4 = −5.11299E−04
	A6 = 8.61810E−06
	A8 = −1.99402E−06
	13th surface
	k = 0
	A4 = −4.74670E−06
	A6 = 4.46373E−06
	A8 = −8.38829E−08
	15th surface
	k = 0
	A4 = 5.04643E−04
	A6 = 8.30882E−06
	A8 = 6.17273E−07
	18th surface
	k = 0
	A4 = −8.08479E−05
	A6 = 1.99506E−06
	A8 = −1.12576E−08
Zoom data
When D0 (distance from object up to 1st surface) is ∞
	wide-angle end	intermediate	telephoto end
Focal length	6	13.7	17.999
FNO.	2.86	3.93	5.06
D7	0.8	10.24	10.6
D11	11.2	1.76	1.4
D12	8.75	4.27	1.2
D15	1.2	7.9	10.53
D17	1.28	1.42	3.34
D19	4.33	1.98	0.5
D23	1.36	1.36	1.36

TWENTY FIRST EMBODIMENT

FIG. 41 is a cross-sectional view along the optical axis showing an optical arrangement at the time of the infinite object point focusing at the wide angle end of a zoom lens according to a twenty first embodiment of the present invention.

FIG. 42A, FIG. 42B, and FIG. 42C are diagrams showing the spherical aberration, the astigmatism, the distortion, and the chromatic aberration of magnification at the time of the infinite object point focusing of the zoom lens according to the twenty first embodiment, where, FIG. 42A shows the state at the wide angle end, FIG. 42B shows the intermediate state, and FIG. 42C shows the state at the telephoto end.

The zoom lens of the twenty first embodiment, as shown in FIG. 41, has a first lens group G1, a second lens group G2, an aperture stop S, a third lens group G3, a fourth lens group G4, and a fifth lens group G5, in this order from an object side. In the diagram, LPF is a low-pass filter, CG is a cover glass, and I is an image pickup surface of an electronic image pickup element.

The first lens group G1 includes a negative meniscus lens L111 having a convex surface directed toward the object side, a prism L112, and a cemented lens which is formed by a negative meniscus lens L113 having a convex surface directed toward the object side and a biconvex lens L114, and has a positive refracting power as a whole.

The second lens group G2 includes a biconcave lens L121 and a positive meniscus lens L122 having a convex surface directed toward the object side, and has a negative refracting power as a whole.

The third lens group G3 includes a cemented lens which is formed by a biconvex lens L131 and a biconcave lens L132, and has a positive refracting power as a whole.

The fourth lens group G4 includes a negative meniscus lens L141 having a convex surface directed toward the object side, and has a negative refracting power as a whole.

The fifth lens group G5 includes a biconvex lens L142, and has a positive refracting power as a whole.

At the time of zooming from the wide angle end to the telephoto end, the first lens group G1 is fixed, the second lens group G2 moves toward an image side, the aperture stop S is fixed, the third lens group G3 moves toward the object side, the fourth lens group G4 moves once toward the image side, and then moves toward the object side, and the fifth lens group G5 moves toward the image side.

An aspheric surface is provided on a surface on the object side of the negative meniscus lens L113 having the convex surface directed toward the object side in the first lens group G1, both surfaces of the biconcave lens L121 in the second lens group G2, a surface on the object side of the biconvex lens L131, and a surface on the image side of the biconcave lens L132 in the third lens group G3, and a surface on the object side of the biconvex lens L142 in the fifth lens group G5.

Next, numerical data of the twenty first embodiment will be enumerated.

Numerical data 21
r1 = 27.426	d1 = 1	Nd1 = 1.8061	νd1 = 40.92
r2 = 10.031	d2 = 2.9
r3 = ∞	d3 = 12	Nd3 = 1.8061	νd3 = 40.92
r4 = ∞	d4 = 0.3
r5 = 19.203	d5 = 0.1	Nd5 = 1.69556	νd5 = 25.02
(Aspheric surface)
r6 = 16.038	d6 = 3.54	Nd6 = 1.741	νd6 = 52.64
r7 = −43.264	d7 = D7
r8 = −75.475	d8 = 0.8	Nd8 = 1.8061	νd8 = 40.92
(Aspheric surface)
r9 = 5.450	d9 = 0.7
(Aspheric surface)
r10 = 7.448	d10 = 2.2	Nd10 = 1.7552	νd10 = 27.51
r11 = 92.147	d11 = D11
r12 = Aperture stop	d12 = D12
r13 = 8.392	d13 = 6.46	Nd13 = 1.6935	νd13 = 53.21
(Aspheric surface)
r14 = −10.047	d14 = 1	Nd14 = 1.84666	νd14 = 23.78
r15 = 47.431	d15 = D15
(Aspheric surface)
r16 = 24.831	d16 = 0.6	Nd16 = 1.48749	νd16 = 70.23
r17 = 9.493	d17 = D17
r18 = 10.557	d18 = 1.8	Nd18 = 1.7432	νd18 = 49.34
(Aspheric surface)
r19 = −230.141	d19 = D19
r20 = ∞	d20 = 1.9	Nd20 = 1.54771	νd20 = 62.84
r21 = ∞	d21 = 0.8
r22 = ∞	d22 = 0.75	Nd22 = 1.51633	νd22 = 64.14
r23 = ∞	d23 = D23
Aspherical coefficients
	5th surface
	k = 0
	A4 = 1.12705E−05
	A6 = −8.08778E−08
	A8 = 0
	7th surface
	k = 0
	A4 = 2.73216E−04
	A6 = −1.02234E−05
	A8 = 1.64643E−07
	k = 0
	9th surface
	k = 0
	A4 = −1.46628E−04
	A6 = −1.85741E−05
	A8 = −4.55787E−07
	13th surface
	k = 0
	A4 = 6.74961E−05
	A6 = 2.14113E−06
	A8 = −1.38046E−08
	15th surface
	A4 = 4.72765E−04
	A6 = 1.81729E−05
	A8 = −5.79597E−08
	18th surface
	k = 0
	A4 = −1.04231E−04
	A6 = 9.85834E−06
	A8 = −2.64507E−07
Zoom data
When D0 (distance from object up to 1st surface) is ∞
	wide-angle end	intermediate	telephoto end
Focal length	6.005	13.639	17.893
FNO.	2.86	4.73	5.67
D7	0.8	6.8	8.42
D11	9.02	3.01	1.39
D12	10.8	3.53	1.19
D15	1.2	11.73	13.72
D17	1.4	1.59	2.83
D19	4.84	1.4	0.51
D23	1.35	1.36	1.4

TWENTY SECOND EMBODIMENT

FIG. 43 is a cross-sectional view along the optical axis showing an optical arrangement at the time of the infinite object point focusing at the wide angle end of a zoom lens according to a twenty second embodiment of the present invention.

FIG. 44A, FIG. 44B, and FIG. 44C are diagrams showing the spherical aberration, the astigmatism, the distortion, and the chromatic aberration of magnification at the time of the infinite object point-focusing of the zoom lens according to the twenty second embodiment, where, FIG. 44A shows the state at the wide angle end, FIG. 44B shows the intermediate state, and FIG. 44C shows the state at the telephoto end.

The zoom lens of the twenty second embodiment, as shown in FIG. 43, has a first lens group G1, a second lens group G2, an aperture stop S, a third lens group G3, a fourth lens group G4, and a fifth lens group G5, in this order from an object side. In the diagram, LPF is a low-pass filter, CG is a cover glass, and I is an image pickup surface of an electronic image pickup element.

The first lens group G1 includes a negative meniscus lens L111 having a convex surface directed toward the object side, a prism L112, and a cemented lens which is formed by a negative meniscus lens L113 having a convex surface directed toward the object side and a biconvex lens L114, and has a positive refracting power as a whole.

The second lens group G2 includes a biconcave lens L121 and a positive meniscus lens L122 having a convex surface directed toward the object side, and has a negative refracting power as a whole.

The third lens group G3 includes a cemented lens which is formed by a biconvex lens L131 and a biconcave lens L132, and has a positive refracting power as a whole.

The fourth lens group G4 includes a negative meniscus lens L141 having a convex surface directed toward the object side, and has a negative refracting power as a whole.

The fifth lens group G5 includes a biconvex lens L142, and has a positive refracting power as a whole.

At the time of zooming from the wide angle end to the telephoto end, the first lens group G1 is fixed, the second lens group G2 moves toward an image side, the aperture stop S is fixed, the third lens group G3 moves toward the object side, the fourth lens group G4 moves once toward the image side, and then moves toward the object side, and the fifth lens group G5 moves toward the image side.

An aspheric surface is provided on a surface on the object side of the negative meniscus lens L113 having the convex surface directed toward the object side in the first lens group G1, both surfaces of the biconcave lens L121 in the second lens group G2, a surface on the object side of the biconvex lens L131, and a surface on the image side of the biconcave lens L132 in the third lens group G3, and a surface on the object side of the biconvex lens L142 in the fifth lens group G5.

Next, numerical data of the twenty second embodiment will be enumerated.

Numerical data 22
r1 = 28.32	d1 = 1	Nd1 = 1.8061	νd1 = 40.92
r2 = 10.005	d2 = 2.9
r3 = ∞	d3 = 12	Nd3 = 1.8061	νd3 = 40.92
r4 = ∞	d4 = 0.3
r5 = 20.841	d5 = 0.1	Nd5 = 1.72568	νd5 = 18.68
(Aspheric surface)
r6 = 17.368	d6 = 2.82	Nd6 = 1.741	νd6 = 52.64
r7 = −35.523	d7 = D7
r8 = −77.234	d8 = 0.61	Nd8 = 1.8061	νd8 = 40.92
(Aspheric surface)
r9 = 5.150	d9 = 0.64
(Aspheric surface)
r10 = 7.099	d10 = 1.79	Nd10 = 1.7552	νd10 = 27.51
r11 = 125.495	d11 = D11
r12 = Aperture stop	d12 = D12
r13 = 8.137	d13 = 7.8	Nd13 = 1.6935	νd13 = 53.21
(Aspheric surface)
r14 = −8.325	d14 = 1	Nd14 = 1.84666	νd14 = 23.78
r15 = 50.362	d15 = D15
(Aspheric surface)
r16 = 40.192	d16 = 0.6	Nd16 = 1.48749	νd16 = 70.23
r17 = 9.772	d17 = D17
r18 = 9.992	d18 = 1.8	Nd18 = 1.7432	νd18 = 49.34
(Aspheric surface)
r19 = −337.631	d19 = D19
r20 = ∞	d20 = 1.9	Nd20 = 1.54771	νd20 = 62.84
r21 = ∞	d21 = 0.8
r22 = ∞	d22 = 0.75	Nd22 = 1.51633	νd22 = 64.14
r23 = ∞	d23 = D23
Aspherical coefficients
	5th surface
	k = 0
	A4 = 1.00332E−05
	A6 = 7.42109E−08
	A8 = 0
	8th surface
	k = 0
	A4 = 1.02571E−04
	A6 = −5.01039E−06
	A8 = −2.49531E−09
	9th surface
	k = 0
	A4 = −4.89182E−04
	A6 = −1.89829E−07
	A8 = −1.78387E−06
	13th surface
	k = 0
	A4 = −2.76088E−06
	A6 = 2.53907E−06
	A8 = −5.24977E−08
	15th surface
	k = 0
	A4 = 5.14295E−04
	A6 = 1.03006E−05
	A8 = 4.35904E−07
	18th surface
	k = 0
	A4 = −8.37722E−05
	A6 = 3.59740E−06
	A8 = −5.85328E−08
Zoom data
When D0 (distance from object up to 1st surface) is ∞
	wide-angle end	intermediate	telephoto end
Focal length	6.005	13.7	17.999
FNO.	2.86	3.83	4.95
D7	0.8	10.69	10.96
D11	11.56	1.68	1.4
D12	8.42	4.29	1.2
D15	1.2	7.13	9.86
D17	1.31	1.55	3.48
D19	4.11	2.05	0.5
D23	1.36	1.36	1.36

TWENTY THIRD EMBODIMENT

FIG. 45 is a cross-sectional view along the optical axis showing an optical arrangement at the time of the infinite object point focusing at the wide angle end of a zoom lens according to a twenty third embodiment of the present invention.

FIG. 46A, FIG. 46B, and FIG. 46C are diagrams showing the spherical aberration, the astigmatism, the distortion, and the chromatic aberration of magnification at the time of the infinite object point focusing of the zoom lens according to the twenty third embodiment, where, FIG. 46A shows the state at the wide angle end, FIG. 46B shows the intermediate state, and FIG. 46C shows the state at the telephoto end.

The zoom lens of the twenty third embodiment, as shown in FIG. 45, has a first lens group G1, a second lens group G2, an aperture stop S, a third lens group G3, a fourth lens group G4, and a fifth lens group G5, in this order from an object side. In the diagram, LPF is a low-pass filter, CG is a cover glass, and I is an image pickup surface of an electronic image pickup element.

The first lens group G1 includes a negative meniscus lens L111 having a convex surface directed toward the object side, a prism L112, and a cemented lens which is formed by a negative meniscus lens L113 having a convex surface directed toward the object side, and a biconvex lens L114, and has a positive refracting power as a whole.

The second lens group G2 includes a biconcave lens L121 and a positive meniscus lens L122 having a convex surface directed toward the object side, and has a negative refracting power as a whole.

The third lens group G3 includes a cemented lens which is formed by a biconvex lens L131 and a biconcave lens L132, and has a positive refracting power as a whole.

The fourth lens group G4 includes a negative meniscus lens L141 having a convex surface directed toward the object side, and has a negative refracting power as a whole.

The fifth lens group G5 includes a biconvex lens L142, and has a positive refracting power as a whole.

At the time of zooming from the wide angle end to the telephoto end, the first lens group G1 is fixed, the second lens group G2 moves toward an image side, the aperture stop S is fixed, the third lens group G3 moves toward the object side, the fourth lens group G4 moves once toward the image side, and then moves toward the object side, and the fifth lens group G5 moves toward the image side.

An aspheric surface is provided on a surface on the object side of the negative meniscus lens L113 having the convex surface directed toward the object side in the first lens group G1, both surfaces of the biconcave lens L121 in the second lens group G2, a surface on the object side of the biconvex lens L131, and a surface on the image side of the biconcave lens L132 in the third lens group G3, and a surface on the object side of the biconvex lens L142 in the fifth lens group G5.

Next, numerical data of the twenty third embodiment will be enumerated.

Numerical data 23
r1 = 28.32	d1 = 1	Nd1 = 1.8061	νd1 = 40.92
r2 = 10.005	d2 = 2.9
r3 = ∞	d3 = 12	Nd3 = 1.8061	νd3 = 40.92
r4 = ∞	d4 = 0.3
r5 = 20.841	d5 = 0.1	Nd5 = 1.72568	νd5 = 18.68
(Aspheric surface)
r6 = 17.368	d6 = 2.82	Nd6 = 1.741	νd6 = 52.64
r7 = −35.523	d7 = D7
r8 = −77.234	d8 = 0.61	Nd8 = 1.8061	νd8 = 40.92
(Aspheric surface)
r9 = 5.150	d9 = 0.64
(Aspheric surface)
r10 = 7.099	d10 = 1.79	Nd10 = 1.7552	νd10 = 27.51
r11 = 125.495	d11 = D11
r12 = Aperture stop	d12 = D12
r13 = 8.137	d13 = 7.8	Nd13 = 1.6935	νd13 = 53.21
(Aspheric surface)
r14 = −8.325	d14 = 1	Nd14 = 1.84666	νd14 = 23.78
r15 = 50.362	d15 = D15
(Aspheric surface)
r16 = 40.192	d16 = 0.6	Nd16 = 1.48749	νd16 = 70.23
r17 = 9.772	d17 = D17
r18 = 9.992	d18 = 1.8	Nd18 = 1.7432	νd18 = 49.34
(Aspheric surface)
r19 = −337.631	d19 = D19
r20 = ∞	d20 = 1.9	Nd20 = 1.54771	νd20 = 62.84
r21 = ∞	d21 = 0.8
r22 = ∞	d22 = 0.75	Nd22 = 1.51633	νd22 = 64.14
r23 = ∞	d23 = D23
Aspherical coefficients
	5th surface
	k = 0
	A4 = 1.00332E−05
	A6 = 7.42109E−08
	A8 = 0
	8th surface
	k = 0
	A4 = 1.02571E−04
	A6 = −5.01039E−06
	A8 = −2.49531E−09
	9th surface
	k = 0
	A4 = −4.89182E−04
	A6 = −1.89829E−07
	A8 = −1.78387E−06
	13th surface
	k = 0
	A4 = −2.76088E−06
	A6 = 2.53907E−06
	A8 = −5.24977E−08
	15th surface
	k = 0
	A4 = 5.14295E−04
	A6 = 1.03006E−05
	A8 = 4.35904E−07
	18th surface
	k = 0
	A4 = −8.37722E−05
	A6 = 3.59740E−06
	A8 = −5.85328E−08
Zoom data
When D0 (distance from object up to 1st surface) is ∞
	wide-angle end	intermediate	telephoto end
Focal length	6.005	13.7	17.999
FNO.	2.86	3.83	4.95
D7	0.8	10.69	10.96
D11	11.56	1.68	1.4
D12	8.42	4.29	1.2
D15	1.2	7.13	9.86
D17	1.31	1.55	3.48
D19	4.11	2.05	0.5
D23	1.36	1.36	1.36

TWENTY FOURTH EMBODIMENT

FIG. 47 is a cross-sectional view along the optical axis showing an optical arrangement at the time of the infinite object point focusing at the wide angle end of a zoom lens according to a twenty fourth embodiment of the present invention.

FIG. 48A, FIG. 48B, and FIG. 48C are diagrams showing the spherical aberration, the astigmatism, the distortion, and the chromatic aberration of magnification at the time of the infinite object point focusing of the zoom lens according to the twenty fourth embodiment, where, FIG. 48A shows the state at the wide angle end, FIG. 48B shows the intermediate state, and FIG. 48C shows the state at the telephoto end.

The zoom lens of the twenty fourth embodiment, as shown in FIG. 47, has a first lens group G1, a second lens group G2, an aperture stop S, a third lens group G3, a fourth lens group G4, and a fifth lens group, G5 in this order from an object side. In the diagram, LPF is a low-pass filter, CG is a cover glass, and I is an image pickup surface of an electronic image pickup element.

The first lens group G1 includes a negative meniscus lens L111 having a convex surface directed toward the object side, a prism L112, and a cemented lens which is formed by a negative meniscus lens L113 having a convex surface directed toward the object side, and a biconvex lens L114, and has a positive refracting power as a whole.

The second lens group G2 includes a biconcave lens L121 and a positive meniscus lens L122 having a convex surface directed toward the object side, and has a negative refracting power as a whole.

The third lens group G3 includes a cemented lens which is formed by a biconvex lens L131 and a biconcave lens L132, and has a positive refracting power as a whole.

The fourth lens group G4 includes a negative meniscus lens L141 having a convex surface directed toward the object side, and has a negative refracting power as a whole.

The fifth lens group G5 includes a biconvex lens L142, and has a positive refracting power as a whole.

At the time of zooming from the wide angle end to the telephoto end, the first lens group G1 is fixed, the second lens group G2 moves toward an image side, the aperture stop S is fixed, the third lens group G3 moves toward the image side, the fourth lens group G4 moves once toward the image side, and then moves toward the object side, and the fifth lens group G5 moves toward the image side.

An aspheric surface is provided on a surface on the object side of the negative meniscus lens L113 having the convex surface directed toward the object side in the first lens group G1, both surfaces of the biconcave lens L121 in the second lens group G2, a surface on the object side of the biconvex lens L131, and a surface on the image side of the biconcave lens L132 in the third lens group G3, and a surface on the object side of the biconvex lens L142 in the fifth lens group G5.

Next, numerical data of the twenty fourth embodiment will be enumerated.

Numerical data 24
r1 = 26.268	d1 = 1	Nd1 = 1.8061	νd1 = 40.92
r2 = 9.767	d2 = 2.9
r3 = ∞	d3 = 12	Nd3 = 1.8061	νd3 = 40.92
r4 = ∞	d4 = 0.3
r5 = 18.845	d5 = 0.1	Nd5 = 1.65228	νd5 = 12.75
(Aspheric surface)
r6 = 17.425	d6 = 3.54	Nd6 = 1.741	νd6 = 52.64
r7 = −46.982	d7 = D7
r8 = −47.767	d8 = 0.8	Nd8 = 1.8061	νd8 = 40.92
(Aspheric surface)
r9 = 5.610	d9 = 0.7
(Aspheric surface)
r10 = 7.861	d10 = 2.2	Nd10 = 1.7552	νd10 = 27.51
r11 = 651.723	d11 = D11
r12 = Aperture stop	d12 = D12
r13 = 8.372	d13 = 6.59	Nd13 = 1.6935	νd13 = 53.21
(Aspheric surface)
r14 = −10.413	d14 = 1	Nd14 = 1.84666	νd14 = 23.78
r15 = 47.183	d15 = D15
(Aspheric surface)
r16 = 19.829	d16 = 0.6	Nd16 = 1.48749	νd16 = 70.23
r17 = 9.344	d17 = D17
r18 = 11.290	d18 = 1.8	Nd18 = 1.7432	νd18 = 49.34
(Aspheric surface)
r19 = −3235.664	d19 = D19
r20 = ∞	d20 = 1.9	Nd20 = 1.54771	νd20 = 62.84
r21 = ∞	d21 = 0.8
r22 = ∞	d22 = 0.75	Nd22 = 1.51633	νd22 = 64.14
r23 = ∞	d23 = D23
Aspherical coefficients
	5th surface
	k = 0
	A4 = 1.29265E−05
	A6 = 2.25482E−08
	A8 = 0
	8th surface
	k = 0
	A4 = 3.13232E−04
	A6 = −1.10497E−05
	A8 = 2.00754E−07
	9th surface
	k = 0
	A4 = −1.49920E−04
	A6 = −1.69745E−05
	A8 = −3.47629E−07
	13th surface
	k = 0
	A4 = 6.03004E−05
	A6 = 1.94139E−06
	A8 = 1.57565E−08
	15th surface
	k = 0
	A4 = 5.14589E−04
	A6 = 9.41419E−06
	A8 = 4.95331E−07
	18th surface
	k = 0
	A4 = −8.99715E−05
	A6 = 8.05337E−06
	A8 = −1.55937E−07
Zoom data
When D0 (distance from object up to 1st surface) is ∞
	wide-angle end	intermediate	telephoto end
Focal length	6.1	13.42	17.995
FNO.	3.15	4.79	5.87
D7	1.44	7.29	8.68
D11	12.19	3.52	1.54
D12	7.82	3.25	0.84
D15	1.21	11.41	13.88
D17	1.42	1.6	2.93
D19	4.82	1.38	0.4
D23	1.36	1.36	1.36

TWENTY FIFTH EMBODIMENT

FIG. 49 is a cross-sectional view along the optical axis showing an optical arrangement at the time of the infinite object point focusing at the wide angle end of a zoom lens according to a twenty fifth embodiment of the present invention.

FIG. 50A, FIG. 50B, and FIG. 50C are diagrams showing the spherical aberration, the astigmatism, the distortion, and the chromatic aberration of magnification at the time of the infinite object point focusing of the zoom lens according to the twenty fifth embodiment, where, FIG. 50A shows a state at the wide angle end, FIG. 50B shows the intermediate state, and FIG. 50C shows the state at the telephoto end.

The zoom lens of the twenty fifth embodiment, as shown in FIG. 49, has a first lens group G1, a second lens group G2, an aperture stop S, a third lens group G3, a fourth lens group G4, and a fifth lens group G5, in this order from an object side. In the diagram, LPF is a low-pass filter, CG is a cover glass, and I is an image pickup surface of an electronic image pickup element.

The first lens group G1 includes a negative meniscus lens L111 having a convex surface directed toward the object side, a prism L112, and a cemented lens which is formed by a negative meniscus lens L113 having a convex surface directed toward the object side, and a biconvex lens L114, and has a positive refracting power as a whole.

The second lens group G2 includes a biconcave lens L121 and a positive meniscus lens L122 having a convex surface directed toward the object side, and has a negative refracting power as a whole.

The third lens group G3 includes a cemented lens which is formed by a biconvex lens L131 and a biconcave lens L132, and has a positive refracting power as a whole.

The fourth lens group G4 includes a negative meniscus lens L141 having a convex surface directed toward the object side, and has a negative refracting power as a whole.

The fifth lens group G5 includes a positive meniscus lens L142 having a convex surface directed toward the object side, and has a positive refracting power as a whole.

At the time of zooming from the wide angle end to the telephoto end, the first lens group G1 is fixed, the second lens group G2 moves toward an image side, the aperture stop S is fixed, the third lens group G3 moves toward the object side, the fourth lens group G4 moves once toward the image side, and then moves toward the object side, and the fifth lens group G5 moves toward the image side.

An aspheric surface is provided on a surface of the object side of the negative meniscus lens L113 having the convex surface directed toward the object side in the first lens group G1, both surfaces of the biconcave lens L121 in the second lens group G2, a surface on the object side of the biconvex lens L131, and a surface on the image side of the biconcave lens L132 in the third lens group G3, and a surface on the object side of the positive meniscus lens L142 having the convex surface directed toward the object side in the fifth lens group G5.

Next, numerical data of the twenty fifth embodiment will be enumerated.

Numerical data 25
r1 = 23.104	d1 = 1	Nd1 = 1.8061	νd1 = 40.92
r2 = 9.993	d2 = 2.9
r3 = ∞	d3 = 12	Nd3 = 1.8061	νd3 = 40.92
r4 = ∞	d4 = 0.3
r5 = 144.417	d5 = 0.1	Nd5 = 1.59885	νd5 = 6.52
(Aspheric surface)
r6 = 120.347	d6 = 3.54	Nd6 = 1.741	νd6 = 52.64
r7 = −15.632	d7 = D7
r8 = −67.973	d8 = 0.8	Nd8 = 1.8061	νd8 = 40.92
(Aspheric surface)
r9 = 5.079	d9 = 0.7
(Aspheric surface)
r10 = 7.029	d10 = 2.2	Nd10 = 1.7552	νd10 = 27.51
r11 = 101.993	d11 = D11
r12 = Aperture stop	d12 = D12
r13 = 7.719	d13 = 6.28	Nd13 = 1.6935	νd13 = 53.21
(Aspheric surface)
r14 = −9.571	d14 = 1	Nd14 = 1.84666	νd14 = 23.78
r15 = 34.509	d15 = D15
(Aspheric surface)
r16 = 39.476	d16 = 0.6	Nd16 = 1.48749	νd16 = 70.23
r17 = 9.117	d17 = D17
r18 = 7.840	d18 = 1.8	Nd18 = 1.7432	νd18 = 49.34
(Aspheric surface)
r19 = 34.132	d19 = D19
r20 = ∞	d20 = 1.9	Nd20 = 1.54771	νd20 = 62.84
r21 = ∞	d21 = 0.8
r22 = ∞	d22 = 0.75	Nd22 = 1.51633	νd22 = 64.14
r23 = ∞	d23 = D23
Aspherical coefficients
	5th surface
	k = 0
	A4 = −4.37427E−05
	A6 = 4.88599E−07
	A8 = 0
	8th surface
	k = 0
	A4 = −4.24746E−04
	A6 = 1.70408E−05
	A8 = −5.77793E−07
	9th surface
	k = 0
	A4 = −1.15464E−03
	A6 = 3.78562E−05
	A8 = −3.07050E−06
	13th surface
	k = 0
	A4 = 1.41938E−04
	A6 = −5.92299E−07
	A8 = 7.51323E−08
	15th surface
	k = 0
	A4 = 9.41257E−04
	A6 = −6.26116E−06
	A8 = 1.51062E−06
	18th surface
	k = 0
	A4 = −7.24351E−05
	A6 = −2.74136E−07
	A8 = −7.56639E−08
Zoom data
When D0 (distance from object up to 1st surface) is ∞
	wide-angle end	intermediate	telephoto end
Focal length	6.005	13.7	17.999
FNO.	3.01	4.93	5.95
D7	0.8	6.91	8.38
D11	8.98	2.86	1.4
D12	10.51	3.71	1.2
D15	1.2	11.56	13.88
D17	1.59	1.78	2.67
D19	4.97	1.21	0.5
D23	1.36	1.36	1.36

TWENTY SIXTH EMBODIMENT

FIG. 51 is a cross-sectional view along the optical axis showing an optical arrangement at the time of the infinite object point focusing at the wide angle end of a zoom lens according to a twenty sixth embodiment of the present invention.

FIG. 52A, FIG. 52B, and FIG. 52C are diagrams showing the spherical aberration, the astigmatism, the distortion, and the chromatic aberration of magnification at the time of the infinite object point focusing of the zoom lens according to the twenty sixth embodiment, where, FIG. 52A shows the state at the wide angle end, FIG. 52B shows the intermediate state, and FIG. 52C shows the state at the telephoto end.

The zoom lens of the twenty sixth embodiment, as shown in FIG. 51, has a first lens group G1, a second lens group G2, an aperture stop S, a third lens group G3, a fourth lens group G4, and a fifth lens group G5 in this order from an object side. In the diagram, LPF is a low-pass filter, CG is a cover glass, and I is an image pickup surface of an electronic image pickup element.

The first lens group G1 includes a negative meniscus lens L111 having a convex surface directed toward the object side, a prism L112, and a cemented lens which is formed by a negative meniscus lens L113 having a convex surface directed toward the object side, and a biconvex lens L114, and has a positive refracting power as a whole.

The second lens group G2 includes a biconcave lens L121 and a positive meniscus lens L122 having a convex surface directed toward the object side, and has a negative refracting power as a whole.

The third lens group G3 includes a cemented lens which is formed by a biconvex lens L131 and a biconcave lens L132, and has a positive refracting power as a whole.

The fourth lens group G4 includes a negative meniscus lens L141 having a convex surface directed toward the object side, and has a negative refracting power as a whole.

The fifth lens group G5 includes a positive meniscus lens L142 having a convex surface directed toward the object side, and has a positive refracting power as a whole.

At the time of zooming from the wide angle end to the telephoto end, the first lens group G1 is fixed, the second lens group G2 moves toward an image side, the aperture stop S is fixed, the third lens group G3 moves toward the object side, the fourth lens group G4 moves once toward the image side, and then moves toward the object side, and the fifth lens group G5 moves toward the image side.

An aspheric surface is provided on a surface of the object side of the negative meniscus lens L113 having the convex surface directed toward the object side in the first lens group G1, both surfaces of the biconcave lens L121 in the second lens group G2, a surface on the object side of the biconvex lens L131, and a surface on the image side of the biconcave lens L132 in the third lens group G3, and a surface on the object side of the positive meniscus lens L142 having the convex surface directed toward the object side in the fifth lens group G5.

Next, numerical data of the twenty sixth embodiment will be enumerated.

Numerical data 26
r1 = 23.339	d1 = 1	Nd1 = 1.8061	νd1 = 40.92
r2 = 9.998	d2 = 2.9
r3 = ∞	d3 = 12	Nd3 = 1.8061	νd3 = 40.92
r4 = ∞	d4 = 0.3
r5 = 100.200	d5 = 0.1	Nd5 = 1.79525	νd5 = 9.95
(Aspheric surface)
r6 = 83.501	d6 = 3.54	Nd6 = 1.741	νd6 = 52.64
r7 = −16.063	d7 = D7
r8 = −45.653	d8 = 0.8	Nd8 = 1.8061	νd8 = 40.92
(Aspheric surface)
r9 = 5.378	d9 = 0.7
(Aspheric surface)
r10 = 7.441	d10 = 2.2	Nd10 = 1.7552	νd10 = 27.51
r11 = 202.84	d11 = D11
r12 = Aperture stop	d12 = D12
r13 = 7.519	d13 = 6.32	Nd13 = 1.6935	νd13 = 53.21
(Aspheric surface)
r14 = −10.334	d14 = 1	Nd14 = 1.84666	νd14 = 23.78
r15 = 26.284	d15 = D15
(Aspheric surface)
r16 = 28.574	d16 = 0.6	Nd16 = 1.48749	νd16 = 70.23
r17 = 8.89	d17 = D17
r18 = 7.764	d18 = 1.8	Nd18 = 1.7432	νd18 = 49.34
(Aspheric surface)
r19 = 32.431	d19 = D19
r20 = ∞	d20 = 1.9	Nd20 = 1.54771	νd20 = 62.84
r21 = ∞	d21 = 0.8
r22 = ∞	d22 = 0.75	Nd22 = 1.51633	νd22 = 64.14
r23 = ∞	d23 = D23
Aspherical coefficients
	5th surface
	k = 0
	A4 = −2.65536E−05
	A6 = 3.17647E−07
	A8 = 0
	8th surface
	k = 0
	A4 = −3.26054E−04
	A6 = 1.26273E−05
	A8 = −4.63097E−07
	9th surface
	k = 0
	A4 = −9.57291E−04
	A6 = 2.85872E−05
	A8 = −2.27299E−06
	13th surface
	k = 0
	A4 = 1.05906E−04
	A6 = 3.76011E−07
	A8 = 3.75282E−08
	15th surface
	k = 0
	A4 = 9.47239E−04
	A6 = −1.75798E−06
	A8 = 1.62992E−06
	18th surface
	k = 0
	A4 = −8.98935E−05
	A6 = 9.26013E−07
	A8 = −9.48654E−08
Zoom data
When D0 (distance from object up to 1st surface) is ∞
	wide-angle end	intermediate	telephoto end
Focal length	6.001	13.7	18
FNO.	3.01	4.93	5.92
D7	0.8	6.87	8.47
D11	9.07	3	1.4
D12	10.55	3.61	1.2
D15	1.2	11.39	13.85
D17	1.66	1.82	2.52
D19	4.66	1.26	0.5
D23	1.36	1.36	1.36

TWENTY SEVENTH EMBODIMENT

FIG. 53 is a cross-sectional view along the optical axis showing an optical arrangement at the time of the infinite object point focusing at the wide angle end of a zoom lens according to a twenty seventh embodiment of the present invention.

FIG. 54A, FIG. 54B, and FIG. 54C are diagrams showing the spherical aberration, the astigmatism, the distortion, and the chromatic aberration of magnification at the time of the infinite object point focusing of the zoom lens according to the twenty seventh embodiment, where, FIG. 54A shows the state at the wide angle end, FIG. 54B shows the intermediate state, and FIG. 54C shows the state at the telephoto end.

The zoom lens of the twenty seventh embodiment, as shown in FIG. 53, has a first lens group G1, a second lens group G2, an aperture stop S, a third lens group G3, a fourth lens group G4, and a fifth lens group G5, in this order from the object side. In the diagram, LPF is a low-pass filter, CG is a cover glass, and I is an image pickup surface of an electronic image pickup element.

The first lens group G1 includes a negative meniscus lens L111 having a convex surface directed toward the object side, a prism L112, and a cemented lens which is formed by a negative meniscus lens L113 having a convex surface directed toward the object side, and a biconvex lens L114, and has a positive refracting power as a whole.

The second lens group G2 includes a biconcave lens L121 and a positive meniscus lens L122 having a convex surface directed toward the object side, and has a negative refracting power as a whole.

The third lens group G3 includes a cemented lens which is formed by a biconvex lens L131 and a biconcave lens L132, and has a positive refracting power as a whole.

The fourth lens group G4 includes a negative meniscus lens L141 having a convex surface directed toward the object side, and has a negative refracting power as a whole.

The fifth lens group G5 includes a positive meniscus lens L142 having a convex surface directed toward the object side, and has a positive refracting power as a whole.

At the time of zooming from the wide angle end to the telephoto end, the first lens group G1 is fixed, the second lens group G2 moves toward an image side, the aperture stop S is fixed, the third lens group G3 moves toward the object side, the fourth lens group G4 moves once toward the image side, and then moves toward the object side, and the fifth lens group G5 moves toward the image side.

An aspheric surface is provided on a surface of the object side of the negative meniscus lens L113 having the convex surface directed toward the object side in the first lens group G1, both surfaces of the biconcave lens L121 in the second lens group G2, a surface on the object side of the biconvex lens L131, and a surface on the image side of the biconcave lens L132 in the third lens group G3, and a surface on the object side of the positive meniscus lens L142 having the convex surface directed toward the object side in the fifth lens group G5.

Next, numerical data of the twenty seventh embodiment will be enumerated.

Numerical data 27
r1 = 23.412	d1 = 1	Nd1 = 1.8061	νd1 = 40.92
r2 = 9.999	d2 = 2.9
r3 = ∞	d3 = 12	Nd3 = 1.8061	νd3 = 40.92
r4 = ∞	d4 = 0.3
r5 = 71.727	d5 = 0.1	Nd5 = 1.9712	νd5 = 12.88
(Aspheric surface)
r6 = 59.773	d6 = 3.54	Nd6 = 1.741	νd6 = 52.64
r7 = −16.653	d7 = D7
r8 = −36.331	d8 = 0.8	Nd8 = 1.8061	νd8 = 40.92
(Aspheric surface)
r9 = 5.425	d9 = 0.7
(Aspheric surface)
r10 = 7.528	d10 = 2.2	Nd10 = 1.7552	νd10 = 27.51
r11 = 1523.438	d11 = D11
r12 = Aperture stop	d12 = D12
r13 = 7.312	d13 = 6.35	Nd13 = 1.6935	νd13 = 53.21
(Aspheric surface)
r14 = −10.511	d14 = 1	Nd14 = 1.84666	νd14 = 23.78
r15 = 22.264	d15 = D15
(Aspheric surface)
r16 = 31.087	d16 = 0.6	Nd16 = 1.48749	νd16 = 70.23
r17 = 9.171	d17 = D17
r18 = 7.719	d18 = 1.8	Nd18 = 1.7432	νd18 = 49.34
(Aspheric surface)
r19 = 34.976	d19 = D19
r20 = ∞	D20 = 1.9	Nd20 = 1.54771	νd20 = 62.84
r21 = ∞	d21 = 0.8
r22 = ∞	d22 = 0.75	Nd22 = 1.51633	νd22 = 64.14
r23 = ∞	d23 = D23
Aspherical coefficients
	5th surface
	k = 0
	A4 = −1.63140E−05
	A6 = 2.12684E−07
	A8 = 0
	8th surface
	k = 0
	A4 = −1.88552E−04
	A6 = 7.75646E−06
	A8 = −3.54924E−07
	9th surface
	k = 0
	A4 = −8.03970E−04
	A6 = 2.18772E−05
	A8 = −2.04118E−06
	13th surface
	k = 0
	A4 = 8.46048E−05
	A6 = 8.81547E−07
	A8 = 1.40013E−08
	15th surface
	k = 0
	A4 = 9.97088E−04
	A6 = 1.26510E−06
	A8 = 1.91272E−06
	18th surface
	k = 0
	A4 = −1.04269E−04
	A6 = 9.09683E−07
	A8 = −9.18645E−08
Zoom data
When D0 (distance from object up to 1st surface) is ∞
	wide-angle end	intermediate	telephoto end
Focal length	6.001	13.7	18
FNO.	3.02	4.95	5.89
D7	0.8	6.83	8.53
D11	9.13	3.11	1.4
D12	10.31	3.47	1.2
D15	1.2	11.21	13.79
D17	1.84	1.82	2.3
D19	4.44	1.28	0.5
D23	1.36	1.36	1.36

Twenty Eighth Embodiment

FIG. 55 is a cross-sectional view along the optical axis showing an optical arrangement at the time of the infinite object point focusing at the wide angle end of a zoom lens according to a twenty eighth embodiment of the present invention.

FIG. 56A, FIG. 56B, and FIG. 56C are diagrams showing the spherical aberration, the astigmatism, the distortion, and the chromatic aberration of magnification at the time of the infinite object point focusing of the zoom lens according to the twenty eighth embodiment, where, FIG. 56A shows the state at the wide angle end, FIG. 56B shows the intermediate state, and FIG. 56C shows the state at the telephoto end.

The zoom lens of the twenty eighth embodiment, as shown in FIG. 55 has a first lens group G1, a second lens group G2, an aperture stop S, a third lens group G3, a fourth lens group G4, and a fifth lens group G5 in this order from an object side. In the diagram, LPF is a low-pass filter, CG is a cover glass, and I is an image pickup surface of an electronic image pickup element.

The first lens group G1 includes a negative meniscus lens L111 having a convex surface directed toward the object side, a prism L112, and a cemented lens which is formed by a negative meniscus lens L113 having a convex surface directed toward the object side, and a biconvex lens L114, and has a positive refracting power as a whole.

The second lens group G2 includes a biconcave lens L121 and a biconvex lens L122, and has a negative refracting power as a whole.

The third lens group G3 includes a cemented lens which is formed by a biconvex lens L131 and a biconcave lens L132, and has a positive refracting power as a whole.

The fourth lens group G4 includes a negative meniscus lens L141 having a convex surface directed toward the object side, and has a negative refracting power as a whole.

The fifth lens group G5 includes a positive meniscus lens L142 having a convex surface directed toward the object side, and has a positive refracting power as a whole.

At the time of zooming from the wide angle end to the telephoto end, the first lens group G1 is fixed, the second lens group G2 moves toward an image side, the aperture stop S is fixed, the third lens group G3 moves toward the object side, the fourth lens group G4 moves once toward the image side, and then moves toward the object side, and the fifth lens group G5 moves toward the image side.

An aspheric surface is provided on a surface of the object side of the negative meniscus lens L113 having the convex surface directed toward the object side in the first lens group G1, both surfaces of the biconcave lens L121 in the second lens group G2, a surface on the object side of the biconvex lens L131, and a surface on the image side of the biconcave lens L132 in the third lens group G3, and a surface on the object side of the positive meniscus lens L142 having the convex surface directed toward the object side in the fifth lens group G5.

Next, numerical data of the twenty eighth embodiment will be enumerated.

Numerical data 28
r1 = 22.766	d1 = 1	Nd1 = 1.8061	νd1 = 40.92
r2 = 9.996	d2 = 2.9
r3 = ∞	d3 = 12	Nd3 = 1.8061	νd3 = 40.92
r4 = ∞	d4 = 0.3
r5 = 201.902	d5 = 0.1	Nd5 = 2.05122	νd5 = 6.28
(Aspheric surface)
r6 = 168.251	d6 = 3.54	Nd6 = 1.741	νd6 = 52.64
r7 = −15.092	d7 = D7
r8 = −33.130	d8 = 0.8	Nd8 = 1.8061	νd8 = 40.92
(Aspheric surface)
r9 = 5.469	d9 = 0.7
(Aspheric surface)
r10 = 7.619	d10 = 2.2	Nd10 = 1.7552	νd10 = 27.51
r11 = −366.416	d11 = D11
r12 = Aperture stop	d12 = D12
r13 = 7.087	d13 = 6.41	Nd13 = 1.6935	νd13 = 53.21
(Aspheric surface)
r14 = −10.191	d14 = 1	Nd14 = 1.84666	νd14 = 23.78
r15 = 19.545	d15 = D15
(Aspheric surface)
r16 = 53.254	d16 = 0.6	Nd16 = 1.48749	νd16 = 70.23
r17 = 9.799	d17 = D17
r18 = 7.635	d18 = 1.8	Nd18 = 1.7432	νd18 = 49.34
(Aspheric surface)
r19 = 39.242	d19 = D19
r20 = ∞	d20 = 1.9	Nd20 = 1.54771	νd20 = 62.84
r21 = ∞	d21 = 0.8
r22 = ∞	d22 = 0.75	Nd22 = 1.51633	νd22 = 64.14
r23 = ∞	d23 = D23
Aspherical coefficients
	5th surface
	k = 0
	A4 = −2.29550E−05
	A6 = 1.93244E−07
	A8 = 0
	8th surface
	k = 0
	A4 = −2.64173E−04
	A6 = 1.12898E−05
	A8 = −4.80203E−07
	9th surface
	k = 0
	A4 = −8.96070E−04
	A6 = 2.86426E−05
	A8 = −2.27403E−06
	13th surface
	k = 0
	A4 = 8.06718E−05
	A6 = 3.66237E−07
	A8 = 1.49391E−08
	15th surface
	k = 0
	A4 = 1.14232E−03
	A6 = −2.15240E−06
	A8 = 2.64820E−06
	18th surface
	k = 0
	A4 = −1.11897E−04
	A6 = −1.49140E−07
	A8 = −8.03112E−08
Zoom data
When D0 (distance from object up to 1st surface) is ∞
	wide-angle end	intermediate	telephoto end
Focal length	6.004	13.7	17.999
FNO.	3.05	5.03	5.99
D7	0.8	6.83	8.58
D11	9.18	3.14	1.4
D12	10.28	3.48	1.2
D15	1.2	11.15	13.77
D17	1.8	1.81	2.19
D19	4.37	1.22	0.5
D23	1.36	1.36	1.36

Twenty Ninth Embodiment

FIG. 57 is a cross-sectional view along the optical axis showing an optical arrangement at the time of the infinite object point focusing at the wide angle end of a zoom lens according to a twenty ninth embodiment of the present invention.

FIG. 58A, FIG. 58B, and FIG. 58C are diagrams showing the spherical aberration, the astigmatism, the distortion, and the chromatic aberration of magnification at the time of the infinite object point focusing of the zoom lens according to the twenty ninth embodiment, where, FIG. 58A shows the state at the wide angle end, FIG. 58B shows the intermediate state, and FIG. 58C shows the state at the telephoto end.

The zoom lens of the twenty ninth embodiment, as shown in FIG. 57, has a first lens group G1, a second lens group G2, an aperture stop S, a third lens group G3, a fourth lens group G4, in this order from an object side. In the diagram, LPF is a low-pass filter, CG is a cover glass, and I is an image pickup surface of an electronic image pickup element.

The first lens group G1 includes a negative meniscus lens L211 having a convex surface directed toward the object side, a prism L212, and a cemented lens which formed by a biconvex lens L213 and a biconcave lens L214, and has a negative refracting power as a whole.

The second lens group G2 includes a cemented lens which is formed by a biconvex lens L221 and a negative meniscus lens L222 having a convex surface directed toward an image side, and has a positive refracting power as a whole.

The third lens group G3 includes a cemented lens which is formed by a biconvex lens L231 and a positive meniscus lens L232 having a convex surface directed toward the object side, and has a negative refracting power as a whole.

The fourth lens group G4 includes a cemented lens which is formed by a biconvex lens L241 and a negative meniscus lens L242 having a concave surface directed toward the object, and has a positive refracting power as a whole.

At the time of zooming from the wide angle end to the telephoto end, the first lens group G1 is fixed, the second lens group G2 moves toward the object side, the aperture stop S is fixed, the third lens group moves toward the image side, and the fourth lens group G4 moves toward the image side.

An aspheric surface is provided on a surface of the object side of the biconvex lens L213 in the first lens group G1, a surface on the object side of the biconvex lens L212 and a surface on the image side of the negative meniscus lens L222 having the convex surface directed toward the image side in the second lens group G2, and a surface on the object side of the biconvex lens in the fourth lens group G4.

Next, numerical data of the twenty ninth embodiment will be enumerated.

Numerical data 29
r1 = 35.88	d1 = 1.1	Nd1 = 1.7432	νd1 = 49.34
r2 = 10.46	d2 = 3
r3 = ∞	d3 = 12.5	Nd3 = 1.801	νd3 = 34.97
r4 = ∞	d4 = 0.4
r5 = 41.274	d5 = 2.2	Nd5 = 1.8061	νd5 = 40.92
(Aspheric surface)
r6 = −18.146	d6 = 0.7	Nd6 = 1.51823	νd6 = 58.9
r7 = 13.541	d7 = D7
r8 = 10.842	d8 = 4	Nd8 = 1.497	νd8 = 81.54
(Aspheric surface)
r9 = −12	d9 = 0.35	Nd9 = 1.60687	νd9 = 27.03
r10 = −22.804	d10 = D10
(Aspheric surface)
r11 = Aperture stop	d11 = D11
r12 = −11.383	d12 = 0.7	Nd12 = 1.48749	νd12 = 70.23
r13 = 9.58	d13 = 1.6	Nd13 = 1.83481	νd13 = 42.71
r14 = 25.054	d14 = D14
r15 = 13.793	d15 = 3.5	Nd15 = 1.7432	νd15 = 49.34
(Aspheric surface)
r16 = −6	d16 = 0.7	Nd16 = 1.84666	νd16 = 23.78
r17 = −14.524	d17 = D17
r18 = ∞	d18 = 1.44	Nd18 = 1.54771	νd18 = 62.84
r19 = ∞	d19 = 0.8
r20 = ∞	d20 = 0.6	Nd20 = 1.51633	νd20 = 64.14
r21 = ∞	d21 = D21
Aspherical coefficients
	5th surface
	k = 0
	A4 = 2.93525E−05
	A6 = 4.07936E−07
	A8 = 0.00000E+00
	8th surface
	k = 0
	A4 = −6.76006E−05
	A6 = −2.34849E−07
	A8 = −4.21441E−07
	10th surface
	k = 0
	A4 = 2.25820E−05
	A6 = 5.99132E−07
	A8 = −1.28129E−06
	15th surface
	k = 0
	A4 = −1.63254E−04
	A6 = −9.51105E−07
	A8 = 5.27383E−08
Zoom data
When D0 (distance from object up to 1st surface) is ∞
	wide-angle end	intermediate	telephoto end
Focal length	6.011	13.702	17.986
FNO.	2.85	3.41	3.73
D7	13.83	4.09	0.8
D10	1.6	11.34	14.64
D11	1.4	5.76	8.78
D14	6.21	4.99	3
D17	5.32	2.18	1.15
D21	1.36	1.36	1.36

Thirtieth Embodiment

FIG. 59 is a cross-sectional view along the optical axis showing an optical arrangement at the time of the infinite object point focusing at the wide angle end of a zoom lens according to a thirtieth embodiment of the present invention.

FIG. 60A, FIG. 60B, and FIG. 60C are diagrams showing the spherical aberration, the astigmatism, the distortion, and the chromatic aberration of magnification at the time of the infinite object point focusing of the zoom lens according to the thirtieth embodiment, where, FIG. 60A shows the state at the wide angle end, FIG. 60B shows the intermediate state, and FIG. 60C shows the state at the telephoto end.

The zoom lens of the thirtieth embodiment, as shown in FIG. 59, has a first lens group G1, a second lens group G2, an aperture stop S, a third lens group G3, and a fourth lens group G4, in this order from an object side. In the diagram, LPF is a low-pass filter, CG is a cover glass, and I is an image pickup surface of an electronic image pickup element.

The first lens group G1 includes a negative meniscus lens L211 having a convex surface directed toward the object side, a prism L212, and a cemented lens which is formed by a biconvex lens L213 and a biconcave lens L214, and has a negative refracting power as a whole.

The second lens group G2 includes a cemented lens which is formed by a biconvex lens L221 and a negative meniscus lens L222 having a convex surface directed toward an image side, and has a positive refracting power as a whole.

The third lens group G3 includes a cemented lens which is formed by a biconvex lens L231 and a positive meniscus lens L232 having a convex surface directed toward the object side, and has a negative refracting power as a whole.

The fourth lens group G4 includes a cemented lens which is formed by a biconvex lens L241 and a negative meniscus lens L242 having a concave surface directed toward the object side, and has a positive refracting power as a whole.

At the time of zooming from the wide angle end to the telephoto end, the first lens group G1 is fixed, the second lens group G2 moves toward the object side, the aperture stop S is fixed, the third lens group moves toward the image side, and the fourth lens group moves toward the image side.

An aspheric surface is provided on a surface of the object side of the biconvex lens L213 in the first lens group G1, a surface on the object side of the biconvex lens L221 and a surface on the image side of the negative meniscus lens L222 having the convex surface directed toward the image side in the second lens group G2, and a surface on the object side of the biconvex lens L241 in the fourth lens group G4.

Next, numerical data of the thirtieth embodiment will be enumerated.

Numerical data 30
r1 = 27.959	d1 = 1.1	Nd1 = 1.8061	νd1 = 40.92
r2 = 10.419	d2 = 3
r3 = ∞	d3 = 12.5	Nd3 = 1.801	νd3 = 34.97
r4 = ∞	d4 = 0.4
r5 = 2302.245	d5 = 2.2	Nd5 = 1.8061	νd5 = 40.92
(Aspheric surface)
r6 = −13.25	d6 = 0.7	Nd6 = 1.51823	νd6 = 58.9
r7 = 19.658	d7 = D7
r8 = 13.858	d8 = 4	Nd8 = 1.51633	νd8 = 64.14
(Aspheric surface)
r9 = −12	d9 = 0.35	Nd9 = 1.60689	νd9 = 18.58
r10 = −18.551	d10 = D10
(Aspheric surface)
r11 = Aperture stop	d11 = D11
r12 = −12.567	d12 = 0.7	Nd12 = 1.48749	νd12 = 70.23
r13 = 10.171	d13 = 1.6	Nd13 = 1.834	νd13 = 37.16
r14 = 23.736	d14 = D14
r15 = 13.541	d15 = 3.5	Nd15 = 1.7432	νd15 = 49.34
(Aspheric surface)
r16 = −6	d16 = 0.7	Nd16 = 1.84666	νd16 = 23.78
r17 = −15.389	d17 = D17
r18 = ∞	d18 = 1.44	Nd18 = 1.54771	νd18 = 62.84
r19 = ∞	d19 = 0.8
r20 = ∞	d20 = 0.6	Nd20 = 1.51633	νd20 = 64.14
r21 = ∞	d21 = D21
Aspherical coefficients
	5th surface
	k = 0
	A4 = 1.94948E−05
	A6 = 1.62504E−07
	A8 = 0
	8th surface
	k = 0
	A4 = 2.80468E−04
	A6 = −7.76543E−06
	A8 = 0.00000E+00
	10th surface
	k = 0
	A4 = −6.44783E−06
	A6 = −3.55641E−06
	A8 = 0.00000E+00
	15th surface
	k = 0
	A4 = −1.50887E−04
	A6 = 5.00830E−07
	A8 = 0.00000E+00
Zoom data
When D0 (distance from object up to 1st surface) is ∞
	wide-angle end	intermediate	telephoto end
Focal length	6.062	10.406	17.989
FNO.	2.85	3.29	3.9
D7	13.35	7.2	0.8
D10	1.58	7.74	14.14
D11	1.39	5.06	10.1
D14	7.11	5.69	2.99
D17	5.77	3.52	1.19
D21	1.36	1.36	1.36

Thirty First Embodiment

FIG. 61 is a cross-sectional view along the optical axis showing an optical arrangement at the time of the infinite object point focusing at the wide angle end of a zoom lens according to a thirty first embodiment of the present invention.

FIG. 62A, FIG. 62B, and FIG. 62C are diagrams showing the spherical aberration, the astigmatism, the distortion, and the chromatic aberration of magnification at the time of the infinite object point focusing of the zoom lens according to the thirty first embodiment, where, FIG. 62A shows the state at the wide angle end, FIG. 62B shows the intermediate state, and FIG. 62C shows the state at the telephoto end.

The zoom lens of the thirty first embodiment, as shown in FIG. 61, has a first lens group G1, a second lens group G2, an aperture stop S, a third lens group G3, and a fourth lens group G4, in this order from an object side. In the diagram LPF is a low-pass filter, CG is a cover glass, and I is an image pickup surface of an electronic image pickup element.

The first lens group G1 includes a negative meniscus lens L211 having a convex surface directed toward the object side, a prism L212, and a cemented lens which is formed by a biconvex lens L213 and a biconcave lens L214, and has a negative refracting power as a whole.

The second lens group G2 includes a cemented lens which is formed by a biconvex lens L221 and a negative meniscus lens L222 having a convex surface directed toward an image side, and has a positive refracting power as a whole.

The third lens group G3 includes a cemented lens which is formed by a biconcave lens L231 and a positive meniscus lens L232 having a convex surface directed toward the object side, and has a positive refracting power as a whole.

The fourth lens group G4 includes a cemented lens which is formed by a biconvex lens L241 and a negative meniscus lens L242 having a concave surface directed toward the object side, and has a positive refracting power as a whole.

At the time of zooming from the wide angle end to the telephoto end, the first lens group G1 is fixed, the second lens group G2 moves toward the object side, the aperture stop S is fixed, the third lens group G3 moves toward the image side, and the fourth lens group G4 moves toward the image side.

An aspheric surface is provided on a surface of the object side of the biconvex lens L213 in the first lens group G1, a surface on the object side, of the biconvex lens L221 and a surface on the image side, of the negative meniscus lens L222 having the convex surface directed toward the image side in the second lens group G2, and a surface on the object side, of the biconvex lens L241 in the fourth lens group G4.

Next, numerical data of the thirty first embodiment will be enumerated.

Numerical data 31
r1 = 34.959	d1 = 1.1	Nd1 = 1.7432	νd1 = 49.34
r2 = 10.58	d2 = 3
r3 = ∞	d3 = 12.5	Nd3 = 1.801	νd3 = 34.97
r4 = ∞	d4 = 0.4
r5 = 40.088	d5 = 2.2	Nd5 = 1.8061	νd5 = 40.92
(Aspheric surface)
r6 = −17.816	d6 = 0.7	Nd6 = 1.51823	νd6 = 58.9
r7 = 13.677	d7 = D7
r8 = 10.733	d8 = 4	Nd8 = 1.497	νd8 = 81.54
(Aspheric surface)
r9 = −12	d9 = 0.35	Nd9 = 1.69556	νd9 = 25.02
r10 = −22.311	d10 = D10
(Aspheric surface)
r11 = Aperture stop	d11 = D11
r12 = −11.366	d12 = 0.7	Nd12 = 1.48749	νd12 = 70.23
r13 = 9.599	d13 = 1.6	Nd13 = 1.83481	νd13 = 42.71
r14 = 24.942	d14 = D14
r15 = 13.911	d15 = 3.5	Nd15 = 1.7432	νd15 = 49.34
(Aspheric surface)
r16 = −6	d16 = 0.7	Nd16 = 1.84666	νd16 = 23.78
r17 = −14.707	d17 = D17
r18 = ∞	d18 = 1.44	Nd18 = 1.54771	νd18 = 62.84
r19 = ∞	d19 = 0.8
r20 = ∞	d20 = 0.6	Nd20 = 1.51633	νd20 = 64.14
r21 = ∞	d21 = D21
Aspherical coefficients
	5th surface
	k = 0
	A4 = 3.14995E−05
	A6 = 2.53620E−07
	A8 = 0
	8th surface
	k = 0
	A4 = −6.23568E−05
	A6 = −2.89371E−07
	A8 = 0.00000E+00
	10th surface
	k = 0
	A4 = 1.93955E−05
	A6 = 2.23840E−07
	A8 = 0.00000E+00
	15th surface
	k = 0
	A4 = −1.66755E−04
	A6 = 4.47680E−07
	A8 = 0.00000E+00
Zoom data
When D0 (distance from object up to 1st surface) is ∞
	wide-angle end	intermediate	telephoto end
Focal length	6.274	13.898	18.212
FNO.	2.89	3.44	3.75
D7	13.83	4.09	0.8
D10	1.6	11.34	14.64
D11	1.4	5.76	8.78
D14	6.21	4.99	3
D17	5.32	2.18	1.15
D21	1.73	1.86	1.77

Thirty Second Embodiment

FIG. 63 is a cross-sectional view along the optical axis showing an optical arrangement at the time of the infinite object point focusing at the wide angle end of a zoom lens according to a thirty second embodiment of the present invention.

FIG. 64A, FIG. 64B, and FIG. 64C are diagram showing the spherical aberration, the astigmatism, the distortion, and the chromatic aberration of magnification at the time of the infinite object point focusing of the zoom lens according to the thirty second embodiment, where, FIG. 64A shows the state at the wide angle end, FIG. 64B shows the intermediate state, and FIG. 64C shows the state at the telephoto end.

The zoom lens of the thirty second embodiment, as shown in FIG. 63, has a first lens group G1, a second lens group G2, an aperture stop S, a third lens group G3, and a fourth lens group G4, in this order from an object side. In this diagram, LPF is a low-pass filter, CG is a cover glass, and I is an image pickup surface of an electronic image pickup element.

The first lens group G1 includes a negative meniscus lens L211 having a convex surface directed toward the object side, a prism L212, and a cemented lens which is formed by a positive meniscus lens L213 having a convex surface directed toward an image side and a biconcave lens L214, and has a negative refracting power as a whole.

The second lens group G2 includes a cemented lens which is formed by a biconvex lens L221 and a negative meniscus lens L222 having a convex surface directed toward the image side, and has a positive refracting power as a whole.

The third lens group G3 includes a cemented lens which is formed by a biconcave lens L231 and a positive meniscus lens L232 having a convex surface directed toward the object side, and has a negative refracting power as a whole.

The fourth lens group G4 includes a cemented lens which is formed by a biconvex lens L241 and a negative meniscus lens L242 having a concave surface directed toward the object side, and has a positive refracting power as a whole.

At the time of zooming from the wide angle end to the telephoto end, the first lens group G1 is fixed, the second lens group G2 moves toward the object side, the aperture stop S is fixed, the third lens group G3 moves toward the image side, and the fourth lens group G4 moves toward the image side.

An aspheric surface is provided on a surface on the object side of the positive meniscus lens L213 having the convex surface directed toward the image side in the first lens group G1, a surface on the object side of the biconvex lens L221 and a surface on the image side of the negative meniscus lens L222 having a convex surface directed toward the image side in the second lens group G2, and a surface on the object side of the biconvex lens L241 in the fourth lens group G4.

Next, numerical data of the thirty second embodiment will be enumerated.

Numerical data 32
r1 = 25.752	d1 = 1.1	Nd1 = 1.804	νd1 = 46.57
r2 = 11.454	d2 = 3
r3 = ∞	d3 = 12.5	Nd3 = 1.801	νd3 = 34.97
r4 = ∞	d4 = 0.4
r5 = −50.569	d5 = 2.2	Nd5 = 1.8061	νd5 = 40.92
(Aspheric surface)
r6 = −44.029	d6 = 0.7	Nd6 = 1.51823	νd6 = 58.9
r7 = 22.199	d7 = D7
r8 = 10.827	d8 = 4	Nd8 = 1.51633	νd8 = 64.14
(Aspheric surface)
r9 = −12	d9 = 0.35	Nd9 = 1.72568	νd9 = 18.68
r10 = −13.508	d10 = D10
(Aspheric surface)
r11 = Aperture stop	d11 = D11
r12 = −34.096	d12 = 0.7	Nd12 = 1.51823	νd12 = 58.9
r13 = 9.63	d13 = 1.6	Nd13 = 1.816	νd13 = 46.62
r14 = 14.496	d14 = D14
r15 = 14.344	d15 = 3.5	Nd15 = 1.7432	νd15 = 49.34
(Aspheric surface)
r16 = −6	d16 = 0.7	Nd16 = 1.84666	νd16 = 23.78
r17 = −17.129	d17 = D17
r18 = ∞	d18 = 1.44	Nd18 = 1.54771	νd18 = 62.84
r19 = ∞	d19 = 0.8
r20 = ∞	d20 = 0.6	Nd20 = 1.51633	νd20 = 64.14
r21 = ∞	d21 = D21
Aspherical coefficients
	5th surface
	k = 0
	A4 = 5.21908E−05
	A6 = −4.28063E−08
	A8 = 0
	8th surface
	k = 0
	A4 = 1.63431E−04
	A6 = −1.97723E−06
	A8 = 0.00000E+00
	10th surface
	k = 0
	A4 = 1.01894E−04
	A6 = −8.53272E−07
	A8 = 0.00000E+00
	15th surface
	k = 0
	A4 = −1.18081E−04
	A6 = 9.84689E−07
	A8 = 0.00000E+00
Zoom data
When D0 (distance from object up to 1st surface) is ∞
	wide-angle end	intermediate	telephoto end
Focal length	6.276	10.303	17.983
FNO.	2.85	2.9	3.56
D7	12.32	6.49	0.8
D10	1.63	7.34	13.14
D11	1.43	1.02	9.61
D14	8.72	10.15	2.97
D17	3.72	2.7	1.28
D21	1.36	1.36	1.36

Thirty Third Embodiment

FIG. 65 is a cross-sectional view along the optical axis showing an optical arrangement at the time of the infinite object point focusing at the wide angle end of a zoom lens according to a thirty third embodiment of the present invention.

FIG. 66A, FIG. 66B, and FIG. 66C are diagrams showing the spherical aberration, the astigmatism, the distortion, and the chromatic aberration of magnification at the time of the infinite object point focusing of the zoom lens according to the thirty third embodiment, where, FIG. 66A shows the state at the wide angle end, FIG. 66B shows the intermediate state, and FIG. 66C shows the state at the telephoto end.

The zoom lens of the thirty third embodiment, as shown in FIG. 65, has a first lens group G1, a second lens group G2, an aperture stop S, a third lens group G3, and a fourth lens group G4, in this order from an object side. In this diagram, LPF is a low-pass filter, CG is a cover glass, and I is an image pickup surface of an electronic image pickup element.

The first lens group G1 includes a negative meniscus lens L211 having a convex surface directed toward the object side, a prism L212, and a cemented lens which is formed by a positive meniscus lens L213 having a convex surface directed toward an image side and a biconcave lens L214, and has a negative refracting power as a whole.

The second lens group G2 includes a cemented lens which is formed by a biconvex lens L221 and a negative meniscus lens L222 having a convex surface directed toward the image side, and has positive refracting power as a whole.

The third lens group G3 includes a cemented lens which is formed by a biconcave lens L231 and a positive meniscus lens L232 having a convex surface directed toward the object side, and has a negative refracting power as a whole.

The fourth lens group G4 includes a cemented lens which is formed by a biconvex lens L241 and a negative meniscus lens L242 having a concave surface directed toward the object side, and has a positive refracting power as a whole.

At the time of zooming from the wide angle end to the telephoto end, the first lens group G1 is fixed, the second lens group G2 moves toward the object side, the aperture stop S is fixed, the third lens group G3 moves toward the image side, and the fourth lens group G4 moves toward the image side.

An aspheric surface is provided on a surface on the object side of the positive meniscus lens L213 having the convex surface directed toward the image side in the first lens group G1, a surface on the object side of the biconvex lens L221 and a surface on the image side of the negative meniscus lens L222 having the convex surface directed toward the image side in the second lens group G2, and a surface on the object side of the biconvex lens L241 in the fourth lens group G4.

Next, numerical data of the thirty third embodiment will be enumerated.

Numerical data 33
r1 = 25.752	d1 = 1.1	Nd1 = 1.804	νd1 = 46.57
r2 = 11.454	d2 = 3
r3 = ∞	d3 = 12.5	Nd3 = 1.801	νd3 = 34.97
r4 = ∞	d4 = 0.4
r5 = −50.569	d5 = 2.2	Nd5 = 1.8061	νd5 = 40.92
(Aspheric surface)
r6 = −44.029	d6 = 0.7	Nd6 = 1.51823	νd6 = 58.9
r7 = 22.199	d7 = D7
r8 = 10.827	d8 = 4	Nd8 = 1.51633	νd8 = 64.14
(Aspheric surface)
r9 = −12	d9 = 0.35	Nd9 = 1.72568	νd9 = 18.68
r10 = −13.508	d10 = D10
(Aspheric surface)
r11 = Aperture stop	d11 = D11
r12 = −34.096	d12 = 0.7	Nd12 = 1.51823	νd12 = 58.9
r13 = 9.63	d13 = 1.6	Nd13 = 1.816	νd13 = 46.62
r14 = 14.496	d14 = D14
r15 = 14.344	d15 = 3.5	Nd15 = 1.7432	νd15 = 49.34
(Aspheric surface)
r16 = −6	d16 = 0.7	Nd16 = 1.84666	νd16 = 23.78
r17 = −17.129	d17 = D17
r18 = ∞	d18 = 1.44	Nd18 = 1.54771	νd18 = 62.84
r19 = ∞	d19 = 0.8
r20 = ∞	d20 = 0.6	Nd20 = 1.51633	νd20 = 64.14
r21 = ∞	d21 = D21
Aspherical coefficients
	5th surface
	k = 0
	A4 = 5.21908E−05
	A6 = −4.28063E−08
	A8 = 0
	8th surface
	k = 0
	A4 = 1.63431E−04
	A6 = −1.97723E−06
	A8 = 0.00000E+00
	10th surface
	k = 0
	A4 = 1.01894E−04
	A6 = −8.53272E−07
	A8 = 0.00000E+00
	15th surface
	k = 0
	A4 = −1.18081E−04
	A6 = 9.84689E−07
	A8 = 0.00000E+00
Zoom data
When D0 (distance from object up to 1st surface) is ∞
	wide-angle end	intermediate	telephoto end
Focal length	6.276	10.303	17.983
FNO.	2.85	2.9	3.56
D7	12.32	6.49	0.8
D10	1.63	7.34	13.14
D11	1.43	1.02	9.61
D14	8.72	10.15	2.97
D17	3.72	2.7	1.28
D21	1.36	1.36	1.36

Thirty Fourth Embodiment

FIG. 67 is a cross-sectional view along the optical axis showing an optical arrangement at the time of the infinite object point focusing at the wide angle end of a zoom lens according to a thirty fourth embodiment of the present invention.

FIG. 68A, FIG. 68B, and FIG. 68C are diagrams showing the spherical aberration, the astigmatism, the distortion, and the chromatic aberration of magnification at the time of the infinite object point focusing of the zoom lens according to the thirty fourth embodiment, where, FIG. 68A shows the state at the wide angle end, FIG. 68B shows the intermediate state, and FIG. 68C shows the state at the telephoto end.

The zoom lens of the thirty fourth embodiment, as shown in FIG. 67, has a first lens group G1, a second lens group G2, an aperture stop S, a third lens group G3, and a fourth lens group G4, in this order from an object side. In this diagram, LPF is a low-pass filter, CG is a cover glass, and I is an image pickup surface of an electronic image pickup element.

The first lens group G1 includes a negative meniscus lens L211 having a convex surface directed toward the object side, a prism L212, and a cemented lens which is formed by a positive meniscus lens L213 having a convex surface directed toward an image side and a biconcave lens L214, and has a negative refracting power as a whole.

The second lens group G2 includes a cemented lens which is formed by a biconvex lens L221 and a negative meniscus lens L222 having a convex surface directed toward the image side, and has a positive refracting power as a whole.

The third lens group G3 includes a cemented lens which is formed by a biconcave lens L231 and a positive meniscus lens L232 having a convex surface directed toward the object side, and has a negative refracting power as a whole.

The fourth lens group G4 includes a cemented lens which is formed by a biconvex lens L241 and a negative meniscus lens L242 having a concave surface directed toward the object side, and has a positive refracting power as a whole.

At the time of zooming from the wide angle end to the telephoto end, the first lens group G1 is fixed, the second lens group G2 moves toward the object side, the aperture stop S is fixed, the third lens group G3 moves toward the image side, and the fourth lens group G4 moves toward the image side.

An aspheric surface is provided on a surface on the object side of the positive meniscus lens L213 having the convex surface directed toward the image side in the first lens group G1, a surface on the object side of the biconvex lens L221 and a surface on the image side of the negative meniscus lens L222 having the convex surface directed toward the image side in the second lens group G2, and a surface on the object side of the biconvex lens L241 in the fourth lens group G4.

Next, numerical data of the thirty fourth embodiment will be enumerated.

Numerical data 34
r1 = 21.697	d1 = 1.1	Nd1 = 1.7432	vd1 = 49.34
r2 = 8.621	d2 = 3
r3 = ∞	d3 = 12.5	Nd3 = 1.94891	vd3 = 23.05
r4 = ∞	d4 = 0.4
r5 = −61.481	d5 = 2.2	Nd5 = 1.82367	vd5 = 32.14
(Aspheric surface)
r6 = 12.879	d6 = 0.7	Nd6 = 1.55419	vd6 = 58.44
r7 = 30.673	d17 = D7
r8 = 15.245	d8 = 4	Nd8 = 1.50278	vd8 = 78.82
(Aspheric surface)
r9 = −12	d9 = 0.35	Nd9 = 1.65228	vd9 = 12.75
r10 = 14.968	d10 = D10
(Aspheric surface)
r11 = Aperture stop	d11 = D11
r12 = −19.694	d12 = 0.7	Nd12 = 1.55228	vd12 = 49.08
r13 = 7.159	d13 = 1.6	Nd13 = 1.85942	vd13 = 42.23
r14 = 24.86	d14 = D14
r15 = 15.192	d15 = 3.5	Nd15 = 1.7501	vd15 = 51.93
(Aspheric surface)
r16 = −6	d16 = 0.7	Nd16 = 1.80849	vd16 = 35.3
r17 = −39.907	d17 = D17
r18 = ∞	d18 = 1.44	Nd18 = 1.54771	vd18 = 62.84
r19 = ∞	d19 = 0.8
r20 = ∞	d20 = 0.6	Nd20 = 1.51633	vd20 = 64.14
r21 = ∞	d21 = D21
Aspherical coefficients
	5th surface
	k = 0
	A4 = 4.46958E-05
	A6 = 4.51820E-07
	A8 = 0
	8th surface
	k = 0
	A4 = −1.07884E−04
	A6 = −2.45135E−06
	A8 = 0.00000E+00
	10th surface
	k = 0
	A4 = 2.92065E−06
	AG = 1.30323E−06
	A8 = 0.00000E+00
	15th surface
	k = 0
	A4 = −1.69708E−04
	AG = 4.01584E−07
	A8 = 0.00000E+00
Zoom data
When D0 (distance from object up to 1st surface) is ∞
	wide-angle end	intermediate	telephoto end
Focal length	6.1	13.42	17.995
FNO.	3.45	3.91	4.55
D7	18.29	3.07	0.58
D10	2.88	11.62	14.96
D11	0.85	5.17	12
D14	7.15	5.14	2.53
D17	4.47	4.43	2.92
D21	1.36	1.36	1.36

Thirty Fifth Embodiment

FIG. 69 is a cross-sectional view along the optical axis showing an optical arrangement at the time of the infinite object point focusing at the wide angle end of a zoom lens according to a thirty fifth embodiment of the present invention.

FIG. 70A, FIG. 70B, and FIG. 70C are diagrams showing the spherical aberration, the astigmatism, the distortion, and the chromatic aberration of magnification at the time of the infinite object point focusing of the zoom lens according to the thirty fifth embodiment, where, FIG. 70A shows the state at the wide angle end, FIG. 70B shows the intermediate state, and FIG. 70C shows the state at the telephoto end.

The zoom lens of the thirty fifth embodiment, as shown in FIG. 69, has a first lens group G1, a second lens group G2, an aperture stop S, a third lens group G3, and a fourth lens group G4, in this order from an object side. In this diagram, LPF is a low-pass filter, CG is a cover glass, and I is an image pickup surface of an electronic image pickup element.

The first lens group G1 includes a negative meniscus lens L211 having a convex surface directed toward the object side, a prism L212, and a cemented lens which is formed by a biconvex lens L213 and a biconcave lens L214, and has a negative refracting power as a whole.

The second lens group G2 includes a cemented lens which is formed by a biconvex lens L221 and a negative meniscus lens L222 having a convex surface directed toward an image side, and has a positive refracting power as a whole.

The third lens group G3 includes a cemented lens which is formed by a biconcave lens L231 and a positive meniscus lens L232 having a convex surface directed toward the object side, and has a negative refracting power as a whole.

The fourth lens group G4 includes a cemented lens which is formed by a biconvex lens L241 and a negative meniscus lens L242 having a concave surface directed toward the object side, and has a positive refracting power as a whole.

At the time of zooming from the wide angle end to the telephoto end, the first lens group G1 is fixed, the second lens group G2 moves toward the object side, the aperture stop S is fixed, the third lens group G3 moves toward the image side, and the fourth lens group G4 moves toward the image side.

An aspheric surface is provided on a surface on the object side of the biconvex lens L213 in the first lens group G1, a surface on the object side of the biconvex lens L221 and a surface on the image side of the negative meniscus lens L222 having the convex surface directed toward the image side in the second lens group G2, and a surface on the object side of the biconvex lens in the fourth lens group G4.

Next, numerical data of the thirty fifth embodiment will be enumerated.

Numerical data 35
r1 = 39.511	d1 = 1.1	Nd1 = 1.7432	νd1 = 49.34
r2 = 9.954	d2 = 3
r3 = ∞	d3 = 12.5	Nd3 = 1.801	νd3 = 34.97
r4 = ∞	d4 = 0.4
r5 = 50.212	d5 = 2.14	Nd5 = 1.8061	νd5 = 40.92
(Aspheric surface)
r6 = −12.508	d6 = 0.7	Nd6 = 1.52	νd6 = 57
r7 = 15.872	d7 = D7
r8 = 11.955	d8 = 4.86	Nd8 = 1.497	νd8 = 81.54
(Aspheric surface)
r9 = −29.183	d9 = 0.35	Nd9 = 1.59885	νd9 = 6.52
r10 = −36.717	d10 = D10
(Aspheric surface)
r11 = Aperture stop	d11 = D11
r12 = −13.687	d12 = 0.7	Nd12 = 1.48749	νd12 = 70.23
r13 = 8.399	d13 = 1.6	Nd13 = 1.83481	νd13 = 40.7
r14 = 18.182	d14 = D14
r15 = 12.005	d15 = 3.5	Nd15 = 1.7432	νd15 = 49.34
(Aspheric surface)
r16 = −6	d16 = 0.7	Nd16 = 1.84666	νd16 = 23.78
r17 = −16.33	d17 = D17
r18 = ∞	d18 = 1.44	Nd18 = 1.54771	νd18 = 62.84
r19 = ∞	d19 = 0.8
r20 = ∞	d20 = 0.6	Nd20 = 1.51633	νd20 = 64.14
r21 = ∞	d21 = D21
Aspherical coefficients
	5th surface
	k = 0
	A4 = 1.86622E−05
	A6 = −1.24351E−08
	A8 = 0
	8th surface
	k = 0
	A4 = −5.16885E−05
	A6 = 3.34589E−07
	A8 = 0.00000E+00
	10th surface
	k = 0
	A4 = 2.45844E−05
	A6 = 6.28246E−07
	A8 = 0.00000E+00
	15th surface
	k = 0
	A4 = −1.76798E−04
	A6 = 4.99749E−07
	A8 = 0.00000E+00
Zoom data
When D0 (distance from object up to 1st surface) is ∞
	wide-angle end	intermediate	telephoto end
Focal length	6	13.7	17.999
FNO.	2.85	3.49	3.73
D7	15.39	4.68	0.8
D10	1.6	12.31	16.2
D11	1.4	7.01	9.12
D14	6.3	4.1	3
D17	5.63	2.21	1.21
D21	1.36	1.36	1.36

Thirty Sixth Embodiment

FIG. 71 is a cross-sectional view along the optical axis showing an optical arrangement at the time of the infinite object point focusing at the wide angle end of a zoom lens according to a thirty sixth embodiment of the present invention.

FIG. 72A, FIG. 72B, and FIG. 72C are diagrams showing the spherical aberration, the astigmatism, the distortion, and the chromatic aberration of magnification at the time of the infinite object point focusing of the zoom lens according to the thirty sixth embodiment, where, FIG. 72A shows the state at the wide angle end, FIG. 72B shows the intermediate state, and FIG. 72C shows the state at the telephoto end.

The zoom lens of the thirty sixth embodiment, as shown in FIG. 71, has a first lens group G1, a second lens group G2, an aperture stop S, a third lens group G3, and a fourth lens group G4, in this order from an object side. In this diagram, LPF is a low-pass filter, CG is a cover glass, and I is an image pickup surface of an electronic image pickup element.

The first lens group G1 includes a negative meniscus lens L211 having a convex surface directed toward the object side, a prism L212, and a cemented lens which is formed by a biconvex lens L213 and a biconcave lens L214, and has a negative refracting power as a whole.

The second lens group G2 includes a cemented lens which is formed by a biconvex lens L221 and a negative meniscus lens L222 having a convex surface directed toward an image side, and has a positive refracting power as a whole.

The third lens group G3 includes a cemented lens which is formed by a biconcave lens L231 and a positive meniscus lens L232 having a convex surface directed toward the object side, and has a negative refracting power as a whole.

The fourth lens group G4 includes a cemented lens which is formed by a biconvex lens L241 and a negative meniscus lens L242 having a concave surface directed toward the object side, and has a positive refracting power as a whole.

At the time of zooming from the wide angle end to the telephoto end, the first lens group G1 is fixed, the second lens group G2 moves toward the object side, the aperture stop S is fixed, the third lens group G3 moves toward the image side, and the fourth lens group G4 moves toward the image side.

An aspheric surface is provided on a surface on the object side of the biconvex lens L213 in the first lens group G1, a surface on the object side of the biconvex lens L221 and a surface on the image side of the negative meniscus lens L222 having the convex surface directed toward the image side in the second lens group G2, and a surface on the object side of the biconvex lens in the fourth lens group G4.

Next, numerical data of the thirty sixth embodiment will be enumerated.

Numerical data 36
r1 = 38.962	d1 = 1.1	Nd1 = 1.7432	νd1 = 49.34
r2 = 9.911	d2 = 3
r3 = ∞	d3 = 12.5	Nd3 = 1.801	νd3 = 34.97
r4 = ∞	d4 = 0.4
r5 = 47.772	d5 = 2.11	Nd5 = 1.8061	νd5 = 40.92
(Aspheric surface)
r6 = −12.757	d6 = 0.7	Nd6 = 1.52	νd6 = 57
r7 = 15.478	d7 = D7
r8 = 11.780	d8 = 5.1	Nd8 = 1.497	νd8 = 81.54
(Aspheric surface)
r9 = −23.99	d9 = 0.35	Nd9 = 1.79525	νd9 = 9.95
r10 = −31.574	d10 = D10
(Aspheric surface)
r11 = Aperture stop	d11 = D11
r12 = −13.748	d12 = 0.7	Nd12 = 1.48749	νd12 = 70.23
r13 = 8.46	d13 = 1.6	Nd13 = 1.83481	νd13 = 40.7
r14 = 18.241	d14 = D14
r15 = 12.049	d15 = 3.5	Nd15 = 1.7432	νd15 = 49.34
(Aspheric surface)
r16 = −6	d16 = 0.7	Nd16 = 1.84666	νd16 = 23.78
r17 = −16.277	d17 = D17
r18 = ∞	d18 = 1.44	Nd18 = 1.54771	νd18 = 62.84
r19 = ∞	d19 = 0.8
r20 = ∞	d20 = 0.6	Nd20 = 1.51633	νd20 = 64.14
r21 = ∞	d21 = D21
Aspherical coefficients
	5th surface
	k = 0
	A4 = 2.09655E−05
	A6 = 1.33197E−08
	A8 = 0
	8th surface
	k = 0
	A4 = −5.05955E−05
	A6 = 3.02697E−07
	A8 = 0.00000E+00
	10th surface
	k = 0
	A4 = 2.20076E−05
	A6 = 4.81649E−07
	A8 = 0.00000E+00
	15th surface
	k = 0
	A4 = −1.74494E−04
	A6 = 4.58302E−07
	A8 = 0.00000E+00
Zoom data
When D0 (distance from object up to 1st surface) is ∞
	wide-angle end	intermediate	telephoto end
Focal length	5.999	10.399	17.999
FNO.	2.85	3.32	3.72
D7	15.36	8.57	0.8
D10	1.6	8.39	16.16
D11	1.4	5.88	9.07
D14	6.29	4.21	3
D17	5.58	3.18	1.21
D21	1.36	1.36	1.36

Thirty Seventh Embodiment

FIG. 73 is a cross-sectional view along the optical axis showing an optical arrangement at the wide angle end of a zoom lens according to a thirty seventh embodiment of the present invention.

FIG. 74A, FIG. 74B, and FIG. 74C are diagrams showing the spherical aberration, the astigmatism, the distortion, and the chromatic aberration of magnification at the time of the infinite object point focusing of the zoom lens according to the thirty seventh, where, FIG. 74A shows the state at the wide angle end, FIG. 74B shows the intermediate state, and FIG. 74C shows the state at the telephoto end.

The zoom lens of the thirty seventh embodiment, as shown in FIG. 73, has a first lens group G1, a second lens group G2, an aperture stop S, a third lens group G3, and the fourth lens group G4, in this order from an object side. In this diagram, LPF is a low-pass filter, CG is a cover glass, and I is an image pickup surface of an electronic image pickup element.

The first lens group G1 includes a negative meniscus lens L211 having a convex surface directed toward the object side, a prism L212, and a cemented lens which is formed by a biconvex lens L213 and a biconcave lens L214, and has a negative refracting power as a whole.

The second lens group G2 includes a cemented lens which is formed by a biconvex lens L221 and a negative meniscus lens L222 having a convex surface directed toward an image side, and has positive refracting power as a whole.

The third lens group G3 includes a cemented lens which is formed by a biconcave lens L231 and a positive meniscus lens L232 having a convex surface directed toward the object side, and has a negative refracting power as a whole.

The fourth lens group G4 includes a cemented lens which is formed by a biconvex lens L241 and a negative meniscus lens L242 having a concave surface directed toward the object side, and has a positive refracting power as a whole.

At the time of zooming from the wide angle end to the telephoto end, the first lens group G1 is fixed, the second lens group G2 moves toward the object side, the aperture stop S is fixed, the third lens group G3 moves toward the image side, and the fourth lens group G4 moves toward the image side.

An aspheric surface is provided on a surface on the object side of the biconvex lens L213 in the first lens group G1, a surface on the object side of the biconvex lens L221 and a surface on the image side of the negative meniscus lens L222 having the convex surface directed toward the image side in the second lens group G2, and a surface on the object side of the biconvex lens L241 in the fourth lens group G4.

Next, numerical data of the thirty seventh embodiment will be enumerated.

Numerical data 37
r1 = 39.372	d1 = 1.1	Nd1 = 1.7432	νd1 = 49.34
r2 = 9.927	d2 = 3
r3 = ∞	d3 = 12.5	Nd3 = 1.801	νd3 = 34.97
r4 = ∞	d4 = 0.4
r5 = 45.949	d5 = 2.12	Nd5 = 1.8061	νd5 = 40.92
(Aspheric surface)
r6 = −12.875	d6 = 0.7	Nd6 = 1.52	νd6 = 57
r7 = 15.221	d7 = D7
r8 = 11.744	d8 = 5.22	Nd8 = 1.497	νd8 = 81.54
(Aspheric surface)
r9 = −20.824	d9 = 0.35	Nd9 = 1.9712	νd9 = 12.88
r10 = −27.330	d10 = D10
(Aspheric surface)
r11 = Aperture stop	d11 = D11
r12 = −13.73	d12 = 0.7	Nd12 = 1.48749	νd12 = 70.23
r13 = 8.492	d13 = 1.6	Nd13 = 1.83481	νd13 = 40.7
r14 = 18.325	d14 = D14
r15 = 12.076	d15 = 3.5	Nd15 = 1.7432	νd15 = 49.34
(Aspheric surface)
r16 = −6	d16 = 0.7	Nd16 = 1.84666	νd16 = 23.78
r17 = −16.273	d17 = D17
r18 = ∞	d18 = 1.44	Nd18 = 1.54771	νd18 = 62.84
r19 = ∞	d19 = 0.8
r20 = ∞	d20 = 0.6	Nd20 = 1.51633	νd20 = 64.14
r21 = ∞	d21 = D21
Aspherical coefficients
	5th surface
	k = 0
	A4 = 2.17207E−05
	A6 = 1.35440E−08
	A8 = 0
	8th surface
	k = 0
	A4 = −5.21380E−05
	A6 = 2.41157E−07
	A8 = 0.00000E+00
	10th surface
	k = 0
	A4 = 1.71590E−05
	A6 = 3.51620E−07
	A8 = 0.00000E+00
	15th surface
	k = 0
	A4 = −1.73599E−04
	A6 = 4.60077E−07
	A8 = 0.00000E+00
Zoom data
When D0 (distance from object up to 1st surface) is ∞
	wide-angle end	intermediate	telephoto end
Focal length	5.999	10.399	17.999
FNO.	2.85	3.32	3.73
D7	15.34	8.57	0.8
D10	1.6	8.37	16.14
D11	1.4	5.88	9.07
D14	6.29	4.22	3
D17	5.58	3.17	1.21
D21	1.36	1.36	1.36

Thirty Eighth Embodiment

FIG. 75 is a cross-sectional view along the optical axis showing an optical arrangement at the time of the infinite object point focusing at the wide angle end of a zoom lens according to a thirty eighth embodiment of the present invention.

FIG. 76A, FIG. 76B, and FIG. 76C are diagrams showing the spherical aberration, the astigmatism, the distortion, and the chromatic aberration of magnification at the time of the infinite object point focusing of the zoom lens according to the thirty eighth embodiment, where, FIG. 76A shows the state at the wide angle end, FIG. 76B shows the intermediate state, and FIG. 76C shows the state at the telephoto end.

The zoom lens of the thirty eighth embodiment, as shown in FIG. 75, has a first lens group G1, a second lens group G2, an aperture stop S, a third lens group G3, and a fourth lens group G4, in this order from an object side. In this diagram, LPF is a low-pass filter, CG is a cover glass, and I is an image pickup surface of an electronic image pickup element.

The first lens group includes a negative meniscus lens L211 having a convex surface directed toward the object side, a prism L212, and a cemented lens which is formed by a biconvex lens L213 and a biconcave lens L214, and has a negative refracting power as a whole.

The second lens group G2 includes a cemented lens which is formed by a biconvex lens L221 and a negative meniscus lens L222 having a convex surface directed toward an image side, and has a positive refracting power as a whole.

The third lens group G3 includes a cemented lens which is formed by a biconcave lens L231 and a positive meniscus lens L232 having a convex surface directed toward the object side, and has a positive refracting power as a whole.

The fourth lens group G4 includes a cemented lens which formed by a biconvex lens L241 and a negative meniscus lens L242 having a concave surface directed toward the object side, and has a positive refracting power as a whole.

At the time of zooming from the wide angle end to the telephoto end, the first lens group G1 is fixed, the second lens group G2 moves toward the object side, the aperture S is fixed, the third lens group G3 moves toward the image side, and the fourth lens group G4 moves toward the image side.

An aspheric surface is provided on a surface on the object side of the biconvex lens L213 in the first lens group G1, a surface on the object side of the biconvex lens L221 in the second lens group G2 and a surface on the image side of the negative meniscus lens L222 having the convex surface directed toward the image side in the second lens group, and a surface on the object side of the biconvex lens L241 in the fourth lens group G4.

Next, numerical data of the thirty eighth embodiment will be enumerated.

Numerical data 38
r1 = 39.906	d1 = 1.1	Nd1 = 1.7432	νd1 = 49.34
r2 = 9.964	d2 = 3
r3 = ∞	d3 = 12.5	Nd3 = 1.801	νd3 = 34.97
r4 = ∞	d4 = 0.4
r5 = 44.825	d5 = 2.13	Nd5 = 1.8061	νd5 = 40.92
(Aspheric surface)
r6 = −12.948	d6 = 0.7	Nd6 = 1.52	νd6 = 57
r7 = 15.168	d7 = D7
r8 = 11.641	d8 = 5.09	Nd8 = 1.497	νd8 = 81.54
(Aspheric surface)
r9 = −29.171	d9 = 0.35	Nd9 = 2.05122	νd9 = 6.28
r10 = −33.680	d10 = D10
(Aspheric surface)
r11 = Aperture stop	d11 = D11
r12 = −13.644	d12 = 0.7	Nd12 = 1.48749	νd12 = 70.23
r13 = 8.503	d13 = 1.6	Nd13 = 1.83481	νd13 = 40.7
r14 = 18.44	d14 = D14
r15 = 12.109	d15 = 3.5	Nd15 = 1.7432	νd15 = 49.34
(Aspheric surface)
r16 = −6	d16 = 0.7	Nd16 = 1.84666	νd16 = 23.78
r17 = −16.133	d17 = D17
r18 = ∞	d18 = 1.44	Nd18 = 1.54771	νd18 = 62.84
r19 = ∞	d19 = 0.8
r20 = ∞	d20 = 0.6	Nd20 = 1.51633	νd20 = 64.14
r21 = ∞	d21 = D21
Aspherical coefficients
	5th surface
	k = 0
	A4 = 2.13457E−05
	A6 = 1.64989E−08
	A8 = 0
	8th surface
	k = 0
	A4 = −4.96465E−05
	A6 = 3.28544E−07
	A8 = 0.00000E+00
	10th surface
	k = 0
	A4 = 1.83684E−05
	A6 = 4.02729E−07
	A8 = 0.00000E+00
	15th surface
	k = 0
	A4 = −1.75253E−04
	A6 = 4.15528E−07
	A8 = 0.00000E+00
Zoom data
When D0 (distance from object up to 1st surface) is ∞
	wide-angle end	intermediate	telephoto end
Focal length	6	10.399	17.999
FNO.	2.84	3.31	3.72
D7	15.34	8.56	0.8
D10	1.6	8.37	16.14
D11	1.4	5.89	9.04
D14	6.27	4.18	3
D17	5.57	3.17	1.21
D21	1.36	1.36	1.36

Thirty Ninth Embodiment

Thus, it is possible to use such image forming optical system of the present invention in a photographic apparatus in which an image of an object is photographed by an electronic image pickup element such as a CCD and a CMOS, particularly a digital camera and a video camera, a personal computer, a telephone, and a portable terminal which are examples of an information processing unit, particularly a portable telephone which is easy to carry. Embodiments thereof will be exemplified below.

In FIG. 77 to FIG. 79 show conceptual diagrams of structures in which the image forming optical system according to the present invention is incorporated in a photographic optical system 41 of a digital camera. FIG. 77 is a frontward perspective view showing an appearance of a digital camera 40, FIG. 78 is a rearward perspective view of the same, and FIG. 79 is a cross-sectional view showing an optical arrangement of the digital camera 40.

The digital camera 40, in a case of this example, includes the photographic optical system 41 (an objective optical system for photography 48) having an optical path for photography 42, a finder optical system 43 having an optical path for finder 44, a shutter 45, a flash 46, and a liquid-crystal display monitor 47. Moreover, when the shutter 45 disposed at an upper portion of the camera 40 is pressed, in conjugation with this, a photograph is taken through the photographic optical system 41 (objective optical system for photography 48) such as the zoom lens in the first embodiment.

An object image formed by the photographic optical system 41 (photographic objective optical system 48) is formed on an image pickup surface 50 of a CCD 49. The object image photoreceived at the CCD 49 is displayed on the liquid-crystal display monitor 47 which is provided on a camera rear surface as an electronic image, via an image processing means 51. Moreover, a memory etc. is disposed in the image processing means 51, and it is possible to record the electronic image photographed. This memory may be provided separately from the image processing means 51, or may be formed by carrying out by writing by recording (recorded writing) electronically by a floppy (registered trademark) disc, memory card, or an MO etc.

Furthermore, an objective optical system for finder 53 is disposed in the optical path for finder 44. This objective optical system for finder 53 includes a cover lens 54, a first prism 10, an aperture stop 2, a second prism 20, and a lens for focusing 66. An object image is formed on an image forming surface 67 by this objective optical system for finder 53. This object image is formed in a field frame of a Porro prism which is an image erecting member equipped with a first reflecting surface 56 and a second reflecting surface 58. On a rear side of this Porro prism, an eyepiece optical system 59 which guides an image formed as an erected normal image is disposed.

By the digital camera 40 structured in such manner, it is possible to realize an optical image pickup apparatus having a zoom lens with a reduced size and thickness, in which the number of structural components is reduced.

Next, a personal computer which is an example of an information processing apparatus with a built-in image forming system as an objective optical system is shown in FIG. 80 to FIG. 82. FIG. 80 is a frontward perspective view of a personal computer 300 with its cover opened, FIG. 81 is a cross-sectional view of a photographic optical system 303 of the personal computer 300, and FIG. 82 is a side view of FIG. 80. As it is shown in FIG. 80 to FIG. 82, the personal computer 300 has a keyboard 301, an information processing means and a recording means, a monitor 302, and a photographic optical system 303.

Here, the keyboard 301 is for an operator to input information from an outside. The information processing means and the recording means are omitted in the diagram. The monitor 302 is for displaying the information to the operator. The photographic optical system 303 is for photographing an image of the operator or a surrounding. The monitor 302 may be a display such as a liquid-crystal display or a CRT display. As the liquid-crystal display, a transmission liquid-crystal display device which illuminates from a rear surface by a backlight not shown in the diagram, and a reflection liquid-crystal display device which displays by reflecting light from a front surface are available. Moreover, in the diagram, the photographic optical system 303 is built-in at a right side of the monitor 302, but without restricting to this location, the photographic optical system 303 may be anywhere around the monitor 302 and the keyboard 301.

This photographic optical system 303 has an objective optical system 100 which includes the zoom lens in the first embodiment for example, and an electronic image pickup element chip 162 which receives an image. These are built into the personal computer 300.

At a front end of a mirror frame, a cover glass 102 for protecting the objective optical system 100 is disposed.

An object image received at the electronic image pickup element chip 162 is input to a processing means of the personal computer 300 via a terminal 166. Further, the object image is displayed as an electronic image on the monitor 302. In FIG. 40, an image 305 photographed by the user is displayed as an example of the electronic image. Moreover, it is also possible to display the image 305 on a personal computer of a communication counterpart from a remote location via a processing means. For transmitting the image to the remote location, the Internet and telephone are used.

Next, a telephone which is an example of an information processing apparatus in which the image forming optical system of the present invention is built-in as a photographic optical system, particularly a portable telephone which is easy to carry is shown in FIG. 83A, FIG. 83B, and FIG. 83C. FIG. 83A is a front view of a portable telephone 400, FIG. 83B is a side view of the portable telephone 400, and FIG. 83C is a cross-sectional view of a photographic optical system 405. As shown in FIG. 3A to FIG. 83C, the portable telephone 400 includes a microphone section 401, a speaker section 402, an input dial 403, a monitor 404, the photographic optical system 405, an antenna 406, and a processing means.

Here, the microphone section 401 is for inputting a voice of the operator as information. The speaker section 402 is for outputting a voice of the communication counterpart. The input dial 403 is for the operator to input information. The monitor 404 is for displaying a photographic image of the operator himself and the communication counterpart, and information such as a telephone number. The antenna 406 is for carrying out a transmission and a reception of communication electric waves. The processing means (not shown in the diagram) is for carrying out processing of image information, communication information, and input signal etc.

Here, the monitor 404 is a liquid-crystal display device. Moreover, in the diagram, a position of disposing each structural element is not restricted in particular to a position in the diagram. This photographic optical system 405 has an objective optical system 100 which is disposed in a photographic optical path 407 and an image pickup element chip 162 which receives an object image. As the objective optical system 100, the zoom lens in the first embodiment for example, is used. These are built into the portable telephone 400.

At a front end of a mirror frame, a cover glass 102 for protecting the objective optical system 100 is disposed.

An object image received at the electronic image pickup element chip 162 is input to an image processing means which is not shown in the diagram, via a terminal 166. Further, the object image finally displayed as an electronic image on the monitor 404 or a monitor of the communication counterpart, or both. Moreover, a signal processing function is included in the processing means. In a case of transmitting an image to the communication counterpart, according to this function, information of the object image received at the electronic image pickup element chip 162 is converted to a signal which can be transmitted.

As it has been described above, the image forming optical system of the present invention, and the electronic image pickup apparatus in which the image forming optical system used have the following characteristics.

• (1) It is characterized in that, instead of condition (1a), the following conditional expression is satisfied.1.48<β<2.04Here, Nd denotes a refractive index of a glass used in a cemented lens, νd denotes the Abbe's number for the glass used in the cemented lens, and a relation Nd=α×νd+β is satisfied.
• (2) It is characterized in that, instead of condition (1a), the following conditional expression is satisfied.1.50<β<2.00Here, Nd denotes a refractive index of the glass used in the cemented lens, νd denotes the Abbe's number for the glass used in the cemented lens, and the relation Nd=α×νd+β is satisfied.
• (3) It is characterized in that, instead of condition (2a), the following conditional expression is satisfied.1.58<Nd<2.10Here, Nd denotes the refractive index of the glass used in the cemented lens.
• (4) It is characterized in that, instead of condition (2a), the following conditional expression is satisfied.1.63<Nd<1.95Here, Nd denotes the refractive index of the glass used in the cemented lens.
• (5) It is characterized in that, instead of condition (3a), the following conditional expression is satisfied.5<νd<10Here, νd denotes the Abbe's number for the glass used in the cemented lens.
• (6) It is characterized in that, instead of condition (3a), the following conditional expression is satisfied.6<νd<9Here, νd denotes the Abbe's number for the glass used in the cemented lens.
• (7) It is characterized in that, instead of condition (1b), the following conditional expression is satisfied.1.48<β<2.04Here, Nd denotes the refractive index of the glass used in the cemented lens, νd denotes the Abbe's number for the glass used in the cemented lens, and the relation Nd=α×νd+β is satisfied.
• (8) It is characterized in that, instead of condition (1b), the following conditional expression is satisfied.1.50<β<2.00Here, Nd denotes the refractive index of the glass used in the cemented lens, νd denotes the Abbe's number for the glass used in the cemented lens, and the relation Nd=α×νd+β is satisfied.
• (9) It is characterized in that, instead of condition (2b), the following conditional expression is satisfied.1.60<Nd<2.10Here, Nd denotes the refractive index of the glass used in the cemented lens.
• (10) It is characterized in that, instead of condition (2b), the following conditional expression is satisfied.1.63<Nd<1.95Here, Nd denotes the refractive index of the glass used in the cemented lens.
• (11) It is characterized in that, instead of condition (3b), the following conditional expression is satisfied.5<νd<30Here, νd denotes the Abbe's number for the glass used in the cemented lens.
• (12) It is characterized in that, instead of condition (3b), the following conditional expression is satisfied.6<νd<25Here, νd denotes the Abbe's number for the glass used in the cemented lens.
• (13) It is characterized in that, instead of condition (7), the following conditional expression is satisfied at the time of almost infinite object point focusing.0.75<y₀₇/(fw·tan ω_07w)<0.94

where, y₀₇ is indicated as y₀₇=0.7y₁₀ when, in an effective image pickup surface (surface in which, image pickup is possible), a distance from a center up to a farthest point (maximum image height) is let to be y₁₀. Moreover, ω_07w is an angle with respect to an optical axis in a direction of an object point corresponding to an image point connecting from a center on the image pickup surface in a wide angle end up to a position of y₀₇.

• (14) It is characterized in that, instead of condition (7), the following conditional expression is satisfied at the time of almost infinite object point focusing.0.80<y₀₇/(fw·tan ω_07w)<0.92

where, y₀₇ is indicated by y₀₇=0.7y₁₀ when, in an effective image pickup surface (surface in which, image pickup is possible), a distance from a center up to a farthest point (maximum image height) is let to be y₁₀. Moreover, ω_07w is an angle with respect to an optical axis in a direction of an object point corresponding to an image point connecting from a center on the image pickup surface in a wide angle end up to a position of y₀₇.

INDUSTRIAL APPLICABILITY

An image forming optical system according to the present invention is useful in an optical system with a reduced size and thickness (made thin), and furthermore, an electronic image pickup apparatus of the present invention is useful in an apparatus in which both a favorable correction and a widening of an angle have been realized.

Claims

1. An image forming optical system comprising: a positive lens group;a negative lens group; andan aperture stop, whereinthe positive lens group is disposed at an object side of the aperture stop, andthe positive lens group includes a cemented lens which is formed by cementing a plurality of lenses, andin a rectangular coordinate system in which, a horizontal axis is let to be Nd and a vertical axis is let to be νd, when a straight line indicated by Nd =α×νd +β is set, where α=−0.017 and β is a predetermined constant,Nd and νd of at least one lens forming the cemented lens are included in both of areas namely, an area which is determined by a line when a lower limit value is in a range of a following conditional expression (1a), and a line when an upper limit value is in a range of the following conditional expression (1a), and an area determined by following conditional expressions (2a′″) and (3a) 1.45<β<2.15  (1a)1.59885≦Nd <2.20  (2a′″)3<νd <12  (3a)where, Nd denotes a refractive index, and νd denotes an Abbe's number.

2. The image forming optical system according to claim 1, wherein when the one lens of which Nd and vd are included in both the areas is let to be a predetermined lens, a center thickness of the predetermined lens along an optical axis of the predetermined lens is less than a center thickness of the other lens of the cemented lens along an optical axis of the other lens.

3. The image forming optical system according to claim 2, wherein the image forming optical system satisfies a following conditional expression 0.22<t1<2.0where, t1 is the center thickness of the predetermined lens along an optical axis of the predetermined lens.

4. The image forming optical system according to claim 1, wherein the cemented lens is a compound lens which is formed by closely adhering and hardening a resin on a lens surface of the one lens which forms the cemented lens.

5. The image forming optical system according to claim 1, wherein the cemented lens is a compound lens which is formed by closely adhering and hardening a glass on a lens surface of the one lens which forms the cemented lens.

6. The image forming optical system according to claim 1, wherein the image forming optical system is a zoom lens of which a closest side toward an object is a positive group.

7. The image forming optical system according to claim 1, wherein the image forming optical system is a zoom lens of which a closest side toward an object is a negative group.

8. The image forming optical system according to claim 1, further comprising: a prism for folding.

9. The image forming optical system according to claim 8, wherein the prism is in a lens group on a closest side toward an object.

10. An electronic image pickup apparatus comprising: an image forming optical system according to claim 1;an electronic image pickup element; andan image processing means which processes image data obtained by image pickup by the electronic image pickup element an image which is formed through the image forming optical system, and outputs as image data in which a shape is changed upon processing, whereinthe image forming optical system is a zoom lens, and the zoom lens satisfies a following conditional expression at a time of infinite object point focusing

11. An image forming optical system comprising: a positive lens group;a negative lens group; andan aperture stop, whereinthe positive lens group is disposed at an object side of the aperture stop, andthe positive lens group has a cemented lens in which a plurality of lenses are cemented, andin a rectangular coordinate system in which, a horizontal axis is let to be Nd and a vertical axis is let to be νd, when a straight line indicated by Nd =α×νd+β is set, where α=−0.017 and βis a predetermined constant,Nd and νd of at least one lens forming the cemented lens are included in both of areas namely, an area which is determined by a line when a lower limit value is in a range of a following conditional expression (1b′″), and a line when an upper limit value is in a range of the following conditional expression (1b′″), and an area determined by following conditional expressions (2b) and (3b) 1.86903≦β<2.15  (1b′″)1.58<Nd <2.20  (2b)3νd <40  (3b)where, Nd denotes a refractive index, and νd denotes an Abbe's number,wherein the image forming optical system is a zoom lens of which a closest side toward an object is a negative group.

12. An electronic image pickup apparatus comprising: an image forming optical system which includes: a positive lens group; a negative lens group; and an aperture stop, wherein the positive lens group is disposed at an object side of the aperture stop, and the positive lens group has a cemented lens in which a plurality of lenses are cemented, and in a rectangular coordinate system in which, a horizontal axis is let to be Nd and a vertical axis is let to be νd, when a straight line indicated by Nd =α×νd+β is set, where α=−0.017 and β is a predetermined constant, Nd and νd of at least one lens forming the cemented lens are included in both of areas namely, an area which is determined by a line when a lower limit value is in a range of a following conditional expression (1b′″), and a line when an upper limit value is in a range of the following conditional expression (1b′″), and an area determined by following conditional expressions (2b) and (3b) 1.86903≦β<2.15  (1b′″)1.58<Nd <2.20  (2b)3<νd <40  (3b)