Zoom lens device

RELATED APPLICATION

[0001] This application is based on application No. 2003-93528 filed in Japan, the content of which is hereby incorporated by reference.

[0002] 2. Field of the Invention

[0003] The present invention relates to a zoom lens device having an image sensor that converts, into electric signals, optical images formed on the light receiving surface of a charge coupled device (CCD), a complementary metal-oxide semiconductor (CMOS) sensor or the like, and more particularly, to a compact zoom lens device having a zoom lens system.

[0004] 2. Description of the Prior Art

[0005] In recent years, digital cameras have become prevalent that convert optical images into electronic signals by using an image sensor such as a CCD or a CMOS sensor instead of silver halide film, convert the data to digital form, and record or transfer the digitized data. In such digital cameras, since CCDs and CMOS sensors having high pixels such as two million pixels and three million pixels are comparatively inexpensively provided recently, high-performance zoom lens devices mounted with a high-pixel image sensor are in greatly increasing demand. Of these zoom lens devices, compact zoom lens devices are particularly desired that are provided with a zoom lens system capable of performing zooming without any image quality degradation.

[0006] Further, in recent years, zoom lens devices have been becoming incorporated in or externally attached to personal computers, mobile computers, mobile telephones, personal digital assistances (PDAs) and the like because of improvements in the image processing capability of semiconductor elements and the like, which spurs the demand for high-performance zoom lens devices.

[0007] As zoom lens systems used for such zoom lens devices, so-called minus lead zoom lens systems in which the lens unit disposed on the most object side has a negative optical power are proposed in large numbers. Minus lead zoom lens systems have features such that they are easily made wide-angle and that the lens back focal length necessary for inserting an optical low-pass filter is easily secured.

[0008] Conventional examples of minus lead zoom lens systems include zoom lens systems proposed as taking lens systems for film-based cameras. However, in these zoom lens systems, since the exit pupil of the lens system is situated comparatively near the image plane in the shortest focal length condition, it does not match with the pupil of the microlens provided so as to correspond to each pixel of the image sensor having high pixels, so that a sufficient quantity of peripheral light cannot be secured. In addition, since the position of the exit pupil largely varies during zooming, the setting of the pupil of the microlens is difficult. Further, since required optical performance such as spatial frequency characteristics is completely different between silver halide film and image sensors, optical performance required of image sensors cannot be sufficiently secured. For these reasons, there has emerged a need for the development of a dedicated zoom lens system optimized for zoom lens devices having an image sensor.

[0009] As a minus lead zoom lens system for zoom lens devices having an image sensor, for example, U.S. Pat. No. 5,745,301 discloses a two-unit zoom lens system comprising a first lens unit having a negative optical power and a second lens unit having a positive optical power.

[0010] Moreover, U.S. Pat. No. 4,999,007 discloses a three-unit zoom lens system for video cameras comprising a first lens unit having a negative optical power, a second lens unit having a positive optical power and a third lens unit having a positive optical power.

[0011] The above-mentioned U.S. Pat. No. 4,999,007 also discloses a four-unit zoom lens system for video cameras comprising a first lens unit having a negative optical power, a second lens unit having a positive optical power, a third lens unit having a negative optical power and a fourth lens unit having a positive optical power.

[0012] Further, U.S. Pat. No. 5,999,329 discloses a four-unit zoom lens system for electronic still cameras comprising a first lens unit having a negative optical power, a second lens unit having a positive optical power, a third lens unit having a negative optical power and a fourth lens unit having a positive optical power.

[0013] However, the zoom lens systems disclosed in U.S. Pat. No. 5,745,301 and U.S. Pat. No. 4,999,007 where the zoom ratio is approximately 2× are low in zoom ratio.

[0014] Moreover, in the zoom lens system disclosed in U.S. Pat. No. 5,999,329, although the zoom ratio is approximately 3×, the f-number in the longest focal length condition is as high as 7. Thus, this is not a bright zoom lens system.

[0015] Further, these zoom lens systems all require a great number of lens elements, and therefore lack in compactness, particularly compactness in the direction of the optical system when housed (collapsed).

SUMMARY OF THE INVENTION

[0016] An object of the present invention is to provide a zoom lens device having a zoom lens system whose length in the direction of the optical axis when the lens system is housed is sufficiently short although the zoom ratio is high.

[0017] Another object of the present invention is to provide a zoom lens device having a zoom lens system that is bright even in the longest focal length condition and whose length in the direction of the optical axis when the lens system is housed is sufficiently short.

[0018] To attain the above-mentioned objects, a first zoom lens device of the present invention comprises from the object side: a zoom lens system; and an image sensor converting an optical image formed by the zoom lens system, into electric image data. The zoom lens system comprises a plurality of lens units including a first lens unit disposed on the most object side and including only one negative lens element and a second lens unit being overall positive and including a positive lens element and a negative lens element that are independent of each other. The lens surfaces constituting the zoom lens system are all refracting surfaces. Zooming is performed by varying the distances between the lens units. The following conditions are satisfied:

Fnt≦6.0

2.3≦fw/ft≦5.5

0.1<T23w/fw<1.5

[0019] where Fnt is the minimum f-number of the zoom lens system in the longest focal length condition, fw is the focal length of the zoom lens system in the shortest focal length condition, ft is the focal length of the zoom lens system in the longest focal length condition, and T23w is the axial distance between the second lens unit and the adjoining lens unit on the image side in the shortest focal length condition.

[0020] To attain the above-mentioned objects, a second zoom lens device of the present invention comprises from the object side: a zoom lens system; and an image sensor converting an optical image formed by the zoom lens system, into electric image data. The zoom lens system comprises a plurality of lens units including a first lens unit disposed on the most object side and including only one negative lens element and a second lens unit being overall positive and including a positive lens element and a negative lens element that are independent of each other. The lens surfaces constituting the zoom lens system are all refracting surfaces. Zooming is performed by varying the distances between the lens units. The following conditions are satisfied:

Fnt≦6.0

2.3≦fw/ft≦5.5

0.6<Tsum/fw<2.6

[0021] where Fnt is the minimum f-number of the zoom lens system in the longest focal length condition, fw is the focal length of the zoom lens system in the shortest focal length condition, ft is the focal length of the zoom lens system in the longest focal length condition, and Tsum is the sum of the axial thicknesses of all the lens elements included in the zoom lens system.

[0022] Another aspect of the present invention is a digital camera including the above-described zoom lens device. While the term digital camera conventionally denotes cameras that record only optical still images, cameras that can handle moving images as well and home digital video cameras have also been proposed and at present, there is no distinction between cameras that record only still images and cameras that can handle moving images as well. Therefore, the term digital camera used in this specification includes all of the cameras such as digital still cameras, digital movie cameras and web cameras (cameras connected to apparatuses enabling image transmission and reception by being connected to a network irrespective of whether it is an open type or a private one; including both of cameras directly connected to the network and cameras connected through an apparatus having an information processing function such as a personal computer) where an image forming device having an image sensor that converts optical images formed on the light receiving surface into electric signals is a principal element.

[0023] Moreover, another aspect of the present invention is a portable information apparatus including the above-described zoom lens device. Here, the portable information apparatus means a compact portable information apparatus terminal for private use such as a mobile telephone terminal and a PDA (personal digital assistant).

BRIEF DESCRIPTION OF THE DRAWINGS

[0024] This and other objects and features of this invention will become clear from the following description, taken in conjunction with the preferred embodiments with reference to the accompanied drawings in which:

[0025]
FIG. 1 is a lens construction view of a first embodiment (first example);

[0026]
FIG. 2 is a lens construction view of a second embodiment (second example);

[0027]
FIG. 3 is a lens construction view of a third embodiment (third example);

[0028]
FIG. 4 is a lens construction view of a fourth embodiment (fourth example);

[0029]
FIG. 5 is a lens construction view of a fifth embodiment (fifth example);

[0030]
FIG. 6 is a lens construction view of a sixth embodiment (sixth example);

[0031]
FIG. 7 is a lens construction view of a seventh embodiment (seventh example);

[0032]
FIG. 8 is a lens construction view of an eighth embodiment (eighth example);

[0033]
FIG. 9 is a lens construction view of a ninth embodiment (ninth example);

[0034]
FIG. 10 graphic representations of aberrations of the first embodiment in in-focus state at infinity;

[0035]
FIG. 11 is graphic representations of aberrations of the second embodiment in in-focus state at infinity;

[0036]
FIG. 12 is graphic representations of aberrations of the third embodiment in in-focus state at infinity;

[0037]
FIG. 13 is graphic representations of aberrations of the fourth embodiment in in-focus state at infinity;

[0038]
FIG. 14 is graphic representations of aberrations of the fifth embodiment in in-focus state at infinity;

[0039]
FIG. 15 is graphic representations of aberrations of the sixth embodiment in in-focus state at infinity;

[0040]
FIG. 16 is graphic representations of aberrations of the seventh embodiment in in-focus state at infinity;

[0041]
FIG. 17 is graphic representations of aberrations of the eighth embodiment in in-focus state at infinity;

[0042]
FIG. 18 is graphic representations of aberrations of the ninth embodiment in in-focus state at infinity;

[0043]
FIG. 19 graphic representations of aberrations of the first embodiment in in-focus state at finite distance;

[0044]
FIG. 20 is graphic representations of aberrations of the second embodiment in in-focus state at finite distance;

[0045]
FIG. 21 is graphic representations of aberrations of the third embodiment in in-focus state at finite distance;

[0046]
FIG. 22 is graphic representations of aberrations of the fourth embodiment in in-focus state at finite distance;

[0047]
FIG. 23 is graphic representations of aberrations of the fifth embodiment in in-focus state at finite distance;

[0048]
FIG. 24 is graphic representations of aberrations of the sixth embodiment in in-focus state at finite distance;

[0049]
FIG. 25 is graphic representations of aberrations of the seventh embodiment in in-focus state at finite distance;

[0050]
FIG. 26 is graphic representations of aberrations of the eighth embodiment in in-focus state at finite distance;

[0051]
FIG. 27 is graphic representations of aberrations of the ninth embodiment in in-focus state at finite distance; and

[0052]
FIG. 28 is a construction view showing the present invention in outline.

DESCRIPTION OF THE PREFERRED EMBODIMENT

[0053] Referring to the drawings, an embodiment of the present invention will be described.

[0054] An image forming device according to the embodiment of the present invention comprises, for example as shown in FIG. 28, from the object side (subject side): a zoom lens system TL forming an optical image of an object so as to be zoomable; an optical low-pass filter LPF; and an image sensor SR converting the optical image formed by the zoom lens system TL into electric signals. The image forming device is a principal element of cameras incorporated in or externally attached to digital cameras, video cameras, personal computers, mobile computers, mobile telephones, PDAs and the like.

[0055] The optical low-pass filter LPF has a specific cutoff frequency for adjusting the spatial frequency characteristics of the taking lens system to thereby eliminate the color moire generated in the image sensor. The optical low-pass filter of the embodiment is a birefringent low-pass filter formed by laminating a birefringent material such as crystal having its crystallographic axis adjusted in a predetermined direction, wave plates changing the plane of polarization, or the like. As the optical low-pass filter, a phase low-pass filter or the like may be adopted that attains necessary optical cutoff frequency characteristics by a diffraction effect.

[0056] The image sensor SR comprises a CCD having a plurality of pixels, and converts the optical image formed by the zoom lens system into electric signals by the CCD. The signals generated by the image sensor SR undergo predetermined digital image processing or image compression processing as required, and are recorded into a memory (a semiconductor memory, an optical disk, etc.) as digital video signals or in some cases, transferred to another apparatus through a cable or by being converted into infrared signals. A CMOS sensor may be used instead of a CCD.

[0057]
FIG. 1 shows the lens arrangement of a zoom lens system of a first embodiment. This zoom lens system is a four-unit zoom lens system of negative, positive, positive, positive configuration comprising from the object side: a first lens unit Gr1 including only a first lens element L1 of a bi-concave configuration; a second lens unit Gr2 including a diaphragm ST, a second lens element L2 of a bi-convex configuration and a third lens element L3 of a bi-concave configuration; a third lens unit Gr3 including only a fourth lens element L4 of a bi-convex configuration; and a fourth lens unit Gr4 including a fifth lens element L5 of a negative meniscus configuration convex to the object side and a sixth lens element L6 of a bi-convex configuration. In zooming from the shortest focal length condition to the longest focal length condition, the first lens unit Gr1 moves so as to draw a locus of a U-turn convex to the image side, and the second lens unit Gr2 and the third lens unit Gr3 monotonously move toward the object side while increasing the distance therebetween. In focusing from the infinity in-focus state to the finite object in-focus state, the third lens element L3 alone is moved toward the object side.

[0058]
FIG. 2 shows the lens arrangement of a zoom lens system of a second embodiment. This zoom lens system is a four-unit zoom lens system of negative, positive, positive, positive configuration comprising from the object side: a first lens unit Gr1 including only a first lens element L1 of a bi-concave configuration; a second lens unit Gr2 including a second lens element L2 of a bi-convex configuration, a diaphragm ST and a third lens element L3 of a bi-concave configuration; a third lens unit Gr3 including only a fourth lens element L4 of a bi-convex configuration; and a fourth lens unit Gr4 including a fifth lens element L5 of a negative meniscus configuration convex to the object side and a sixth lens element L6 of a positive meniscus configuration convex to the object side. In zooming from the shortest focal length condition to the longest focal length condition, the first lens unit Gr1 moves so as to draw a locus of a U-turn convex to the image side, the second lens unit Gr2 and the third lens unit Gr3 monotonously move toward the object side while slightly increasing the distance therebetween, and the fourth lens unit Gr4 is stationary with respect to the image surface. In focusing from the infinity in-focus state to the finite object in-focus state, the fourth lens element L4 alone is moved toward the object side.

[0059]
FIG. 3 shows the lens arrangement of a zoom lens system of a third embodiment. This zoom lens system is a four-unit zoom lens system of negative, positive, positive, positive configuration comprising from the object side: a first lens unit Gr1 including only a first lens element L1 of a bi-concave configuration; a second lens unit Gr2 including a second lens element L2 of a substantially plano-convex configuration convex to the object side, a diaphragm ST and a third lens element L3 of a bi-concave configuration; a third lens unit Gr3 including only a fourth lens element L4 of a bi-convex configuration; and a fourth lens unit Gr4 including only a fifth lens element L5 of a positive meniscus configuration convex to the object side. In zooming from the shortest focal length condition to the longest focal length condition, the first lens unit Gr1 moves so as to draw a locus of a U-turn convex to the image side, the second lens unit Gr2 and the third lens unit Gr3 monotonously move toward the object side while slightly varying the distance therebetween, and the fourth lens unit Gr4 moves so as to draw a locus of a U-turn convex to the object side. In focusing from the infinity in-focus state to the finite object in-focus state, the fourth lens element L4 alone is moved toward the object side.

[0060]
FIG. 4 shows the lens arrangement of a zoom lens system of a fourth embodiment. This zoom lens system is a four-unit zoom lens system of negative, positive, positive, positive configuration comprising from the object side: a first lens unit Gr1 including only a first lens element L1 of a bi-concave configuration; a second lens unit Gr2 including a diaphragm ST, a second lens element L2 of a bi-convex configuration and a third lens element L3 of a bi-concave configuration; a third lens unit Gr3 including only a fourth lens element L4 of a bi-convex configuration; and a fourth lens unit Gr4 including a fifth lens element L5 of a bi-convex configuration and a sixth lens element L6 of a bi-concave configuration. In zooming from the shortest focal length condition to the longest focal length condition, the first lens unit Gr1 moves so as to draw a locus of a U-turn convex to the image side, the second lens unit Gr2 and the third lens unit Gr3 monotonously move toward the object side while slightly increasing the distance therebetween, and the fourth lens unit Gr4 moves so as to draw a locus convex to the object side. In focusing from the infinity in-focus state to the finite object in-focus state, the fourth lens element L4 alone is moved toward the object side.

[0061]
FIG. 5 shows the lens arrangement of a zoom lens system of a fifth embodiment. This zoom lens system is a four-unit zoom lens system of negative, positive, positive, positive configuration comprising from the object side: a first lens unit Gr1 including only a first lens element L1 of a bi-concave configuration; a second lens unit Gr2 including a second lens element L2 of a bi-convex configuration, a diaphragm ST and a third lens element L3 of a bi-concave configuration; a third lens unit Gr3 including only a fourth lens element L4 of a bi-convex configuration; and a fourth lens unit Gr4 including a fifth lens element L5 of a negative meniscus configuration convex to the object side and a sixth lens element L6 of a positive meniscus configuration convex to the object side. In zooming from the shortest focal length condition to the longest focal length condition, the first lens unit Gr1 moves so as to draw a locus of a U-turn convex to the image side, the second lens unit Gr2 and the third lens unit Gr3 monotonously move toward the object side while varying the distance therebetween, and the fourth lens unit Gr4 moves toward the image side. In focusing from the infinity in-focus state to the finite object in-focus state, the fourth lens element L4 alone is moved toward the object side.

[0062]
FIG. 6 shows the lens arrangement of a zoom lens system of a sixth embodiment. This zoom lens system is a four-unit zoom lens system of negative, positive, positive, positive configuration comprising from the object side: a first lens unit Gr1 including only a first lens element L1 of a bi-concave configuration; a second lens unit Gr2 including a second lens element L2 of a bi-convex configuration, a third lens element L3 of a bi-concave configuration, a diaphragm ST and a fourth lens element L4 of a bi-convex configuration; and a third lens unit Gr3 including a fifth lens element L5 of a negative meniscus configuration convex to the object side and a sixth lens element L6 of a positive meniscus configuration convex to the object side. In zooming from the shortest focal length condition to the longest focal length condition, the first lens unit Gr1 moves so as to draw a locus of a U-turn convex to the image side, the second lens unit Gr2 monotonously moves toward the object side, and the third lens unit Gr3 is stationary with respect to the image surface. In focusing from the infinity in-focus state to the finite object in-focus state, the fourth lens element L4 alone is moved toward the object side.

[0063]
FIG. 7 shows the lens arrangement of a zoom lens system of a seventh embodiment. This zoom lens system is a four-unit zoom lens system of negative, positive, positive, positive configuration comprising from the object side: a first lens unit Gr1 including only a first lens element L1 of a bi-concave configuration; a second lens unit Gr2 including a second lens element L2 of a bi-convex configuration, a diaphragm ST, a third lens element L3 of a bi-concave configuration and a fourth lens element L4 of a bi-convex configuration; and a third lens unit Gr3 including a fifth lens element L5 of a negative meniscus configuration convex to the object side and a sixth lens element L6 of a positive meniscus configuration convex to the object side. In zooming from the shortest focal length condition to the longest focal length condition, the first lens unit Gr1 moves so as to draw a locus of a U-turn convex to the image side, the second lens unit Gr2 monotonously moves toward the object side, and the third lens unit Gr3 is stationary with respect to the image surface. In focusing from the infinity in-focus state to the finite object in-focus state, the fourth lens element L4 alone is moved toward the object side.

[0064]
FIG. 8 shows the lens arrangement of a zoom lens system of an eighth embodiment. This zoom lens system is a four-unit zoom lens system of negative, positive, positive, positive configuration comprising from the object side: a first lens unit Gr1 including only a first lens element L1 of a bi-concave configuration; a second lens unit Gr2 including only a second lens element L2 of a bi-convex configuration; a third lens unit Gr3 including a third lens element L3 of a bi-concave configuration, a diaphragm ST and a fourth lens element L4 of a bi-convex configuration; and a fourth lens unit Gr4 including a fifth lens element L5 of a negative meniscus configuration convex to the object side and a sixth lens element L6 of a positive meniscus configuration convex to the object side. In zooming from the shortest focal length condition to the longest focal length condition, the first lens unit Gr1 moves so as to draw a locus of a U-turn convex to the image side, the second lens unit Gr2 and the third lens unit Gr3 monotonously move toward the object side, and the fourth lens unit Gr4 is stationary with respect to the image surface. In focusing from the infinity in-focus state to the finite object in-focus state, the fourth lens element L4 alone is moved toward the object side.

[0065]
FIG. 9 shows the lens arrangement of a zoom lens system of a ninth embodiment. This zoom lens system comprises from the object side: a first lens unit Gr1 including only a first lens element L1 of a bi-concave configuration; a second lens unit Gr2 including a second lens element L2 of a bi-convex configuration, a diaphragm ST and a third lens element L3 of a bi-concave configuration; a third lens unit Gr3 including a fifth lens element L5 of a bi-convex configuration; a third lens unit Gr3 including a fifth lens element L5 of a bi-convex configuration; and a fourth lens element Gr4 including a sixth lens element L6 of a negative meniscus configuration convex to the object side and a seventh lens element L7 of a positive meniscus configuration convex to the object side. In zooming from the shortest focal length condition to the longest focal length condition, the first lens unit Gr1 moves so as to draw a locus of a U-turn convex to the image side, the second lens unit Gr2 and the third lens unit Gr3 monotonously move toward the object side, and the fourth lens unit Gr4 moves toward the image side. In focusing from the infinity in-focus state to the finite object in-focus state, the fourth lens element L4 is moved toward the object side.

[0066] The zoom lens systems of these embodiments have the first lens unit disposed on the most object side and including only one negative lens element. In zoom lens systems in which the first lens unit has a negative optical power, normally, the lens diameter of the first lens unit in the direction vertical to the optical axis is the largest to secure the f-number. When the first lens unit includes a plurality of lens elements, the effective diameter of the first lens element necessarily increases to secure the light ray incident on the zoom lens system. Therefore, to reduce the outside diameter, it is desirable that the first lens unit include one, which is the minimum number, lens element. Moreover, when a lens element having a large diameter has a curvature, the axial air distance between the lens elements increases accordingly. That is, the number of lens elements of the first lens unit is an important element that increases the overall length of the zoom lens system. In the zoom lens systems of the embodiments, since the negative lens unit includes one, which is the minimum number, lens element, the overall length of the zoom lens system can be shortened and the thickness in a condition where the zoom lens system is housed (hereinafter, referred to as collapsed condition) can be reduced.

[0067] It is desirable that in zooming, the first lens unit move so as to draw a locus convex to the image side like in the zoom lens systems of the embodiments. By the first lens unit moving in this manner, the curvature of field in the middle focal length condition can be excellently corrected.

[0068] The zoom lens systems of the embodiments include the second lens unit being overall positive and including a positive lens element and a negative lens element that are independent of each other. In minus lead zoom lens systems, the negative optical power of the second lens unit most contributes to zooming. Therefore, variation in aberrations, particularly axial chromatic aberration, caused in the second lens unit due to zooming is large. To correct this, unless the second lens unit at least includes a positive lens element and a negative lens element that are independent of each other, it is impossible to balance the axial chromatic aberration in the entire zoom range.

[0069] Moreover, the zoom lens systems satisfy the following conditions:

Fnt≦6.0 (1)

2.3≦fw/ft≦5.5 (2)

[0070] where Fnt is the minimum f-number of the zoom lens system in the longest focal length condition, fw is the focal length of the zoom lens system in the shortest focal length condition, and ft is the focal length of the zoom lens system in the longest focal length condition.

[0071] The condition (1) defines the minimum f-number of the zoom lens system in the longest focal length condition. When the minimum f-number exceeds 6.0, it is impossible to maintain image quality equivalent to that of film-based cameras. In particular, when the f-number exceeds 6.0, it is difficult to obtain moving images.

[0072] The condition (2) defines the zoom ratio of the zoom lens system. This condition (2) is defined because the zoom lens system intended by the present invention is a compact zoom lens system whose main target magnification is 3× to 4×. When the zoom ratio is lower than the lower limit of the condition (2), the significance of optical zooming is low, so that user benefit cannot be attained. When the zoom ratio is higher than the upper limit of the condition (2), the overall length is too large particularly in the longest focal length condition, so that it is difficult to attain size reduction as a zoom lens device. It is more desirable that the zoom lens systems have a zoom ratio satisfying the following range:

3.1≦fw/ft (2)′

[0073] Moreover, the zoom lens systems of the embodiments satisfy the following condition (3):

0.1<T23w/fw<1.5 (3)

[0074] where T23w is the axial distance between the second lens unit (most image side) and the adjoining lens unit on the image side (most object side) in the shortest focal length condition, and fw is the focal length of the zoom lens system in the shortest focal length condition.

[0075] The condition (3) defines the axial distance between the second lens unit and the adjoining lens unit on the image side in the zoom lens system. When the lower limit of the condition (3) is exceeded, the possibility is high that interference such that the lens elements of the second and the third lens units come into contact with each other occurs in the shortest focal length condition, so that it is difficult to structure the lens barrel. When the upper limit of the condition (3) is exceeded, the overall length in the direction of the optical axis is large in the shortest focal length condition, so that it is impossible to attain a compact zoom lens system. Moreover, when the upper limit is exceeded, because of the power arrangement, the distance between the first lens unit and the image surface is large and the overall length in the direction of the optical axis is large accordingly, and to secure illuminance on the image surface, the diameter of the lens element constituting the first lens unit is large, so that it is impossible to attain a compact zoom lens system.

[0076] The zoom lens systems of the embodiments satisfy the following condition (4):

0.6<Tsum/fw<2.6 (4)

[0077] where Tsum is the sum of the axial thicknesses of all the lens elements included in the zoom lens system; and fw is the foal length of the zoom lens system in the shortest focal length condition.

[0078] The condition (4) defines the sum of the axial thicknesses of all the lens elements included in the zoom lens system. The size of the zoom lens system in the direction of the optical axis in the collapsed condition is the greatest factor that substantially decides the size of the digital camera and the portable information apparatus in the direction of the thickness. The size in the direction of the optical axis in the collapsed condition cannot be physically smaller than the sum of the axial thicknesses of the lens elements. Therefore, unless Tsum can be reduced, a zoom lens system that is compact in the collapsed condition cannot be attained. The condition (4) is just a condition that defines the thickness in the collapsed condition. When the lower limit of the condition (4) is exceeded, it is physically difficult to structure the optical system. When the upper limit thereof is exceeded, the lens thickness is too large and exceeds the limit permitted in digital cameras and portable information apparatuses. It is more effective that the range of the condition (4) is as follows:

Tsum/fw
<2.2 (4)′

Tsum/fw
<2.0 (4)″

[0079] It is desirable to satisfy the conditions (3) and (4) at the same time because by doing so, the zoom lens system can be more effectively structured while the effects of the conditions are produced.

[0080] The zoom lens systems of the embodiments satisfy the following condition (5):

ν1>45 (5)

[0081] where ν1 is the Abbe number of the single negative lens element constituting the first lens unit.

[0082] The condition (5) defines the Abbe number of the negative lens element constituting the first lens unit. In zoom lens systems, normally, a certain extent of aberration correction is performed in each lens unit to minimize variation in aberrations caused during zooming. However, since the first lens unit is constituted by one negative lens element, correction of aberrations, particularly axial chromatic aberration, in lens units is extremely difficult. Therefore, in the zoom lens systems of the embodiments, it is necessary to balance the aberrations by canceling the axial chromatic aberration generated in the first lens unit by another lens unit. However, it is undesirable to form the negative lens element of the first lens unit of a material having an Abbe number exceeding the upper limit of the condition (5) because when this is done, variation in axial chromatic aberration exceeds the permissible range that can be corrected by another lens unit.

[0083] It is more desirable that the condition (5)′, further the condition (5)″ be satisfied:

ν1>60 (5)′

ν1>80 (5)″

[0084] Moreover, it is desirable to use a material having anomalous dispersibility for the negative lens element constituting the first lens unit because by doing so, further chromatic aberration correction can be attained. Moreover, since it is desirable that the negative lens element constituting the first lens unit have an aspherical configuration for the purpose of distortion correction and the like, the negative lens element may be a resin lens element, satisfying the condition (5), where it is easy to form an aspherical surface.

[0085] Moreover, in the zoom lens systems of the embodiments, the diaphragm is disposed on the object or the image side of the second lens unit, or in the second lens unit. When the diaphragm is disposed on the image side of these positions, the outside diameter of the first lens unit are too large, so that a compact zoom lens system cannot be attained.

[0086] Moreover, in the zoom lens systems of the embodiments, focusing is performed by moving along the optical axis a positive lens unit or a single lens element disposed in a position on the image side of the diaphragm and not included in the most image side lens unit. By the focusing lens unit being the positive lens unit or the single lens element disposed in the position on the image side of the diaphragm and not included in the most image side lens unit, a lens unit or a single lens element being light in weight and whose movement amount during focusing is small is moved for focusing, so that effects are produced on the lens barrel structure and reduction in the load on the driving motor.

[0087] Moreover, in the zoom lens systems of the embodiments, the most image side lens unit is overall positive and includes a positive lens element and a negative lens element. With this structure, variation in axial chromatic aberration caused due to zooming, particularly, in the single negative lens element of the first lens unit can be excellently corrected. In addition, this structure is also effective in correcting off-axial coma aberration, particularly, in the shortest focal length condition. Further, by the most image side lens unit being stationary with respect to the image surface, variation in axial chromatic aberration due to zooming can be more excellently corrected, and the lens barrel structure can be simplified.

[0088] Moreover, a reflecting member may be added that bends the optical axis of the incident ray by appropriately adjusting the air distances existing in the lens units and between the lens units. It is desirable to bend the optical axis of the incident ray because by doing this, the degree of freedom of the arrangement of the optical system improves and the thickness of the optical device in the direction of the optical axis of the incident ray can be reduced.

[0089] The construction of zoom lens systems embodying the present invention will be more concretely described with reference to construction data, graphic representations of aberrations and the like. A first to ninth example shown below corresponds to the above-described first to ninth embodiments, respectively. FIGS. 1 to 9 showing the lens arrangements of the first to the ninth embodiments show the lens arrangements of the corresponding first to ninth examples.

[0090] In the construction data of the examples, ri (i=1, 2, 3, . . . ) is the radius of curvature of the i-th surface counted from the object side, di (i=1, 2, 3, . . . ) is the i-th axial distance counted from the object side, and Ni (i=1, 2, 3, . . . ) and νi (i=1, 2, 3, . . . ) are the refractive index (Nd) and the Abbe number (νd), to the d-line, of the i-th optical element counted from the object side. In the construction data, the axial distances that vary during zooming (variable distances) are axial air distances between the lens units in the shortest focal length condition (short focal length side end) [W], in the middle (middle focal length condition) [M] and in the longest focal length condition (long focal length side end) [T]. The overall focal lengths f and the f-numbers FNO in the focal length conditions [W], [M] and [T] are shown together with other data.

[0091] When the symbol * is added to ri which is the symbol for the radius of curvature, this surface is an aspheric surface whose shape is defined by the following formula (AS). Aspheric surface data according to the respective examples are shown together with other data.

\begin{matrix} x = \frac{C_{0} y^{2}}{1 + \sqrt{1 - ε C_{0}^{2} y^{2}}} + \sum {Aiy}^{'} & (AS) \end{matrix}

[0092] where,

[0093] x represents the shape (mm) of the aspherical surface (i.e., the displacement along the optical axis at the height y in a direction perpendicular to the optical axis of the aspherical surface),

[0094] Co represents the curvature (mm−1) of the reference aspherical surface of the aspherical surface,

[0095] y represents the height in a direction perpendicular to the optical axis,

[0096] ε represents the quadric surface parameter, and

[0097] Ai represents the aspherical coefficient of order i.

EXAMPLE 1

[0098]

1

f = 6.0-12.0-17.3 mm FNo. =2.95-3.56-3.85

[Radius of
[Axial
[Refractive
[Abbe

Curvature]
Distance]
Index(nd)]
Number (νd)]

r1* = −60.355
d1 = 1.200
N1 = 1.52510
ν1 = 56.38

r2* = 9.499
d2 = 24.034-8.365-2.022

r3 = ∞
d3 = 1.000

r4 = 7.102
d4 = 2.620
N2 = 1.73713
ν2 = 52.17

r5 = −15.425
d5 = 0.650

r6 = 10.502
d6 = 0.800
N3 = 1.58340
ν3 = 30.23

r7* = 8.528
d7 = 2.226-6.979-7.757

r8 = 19.538
d8 = 2.405
N4 = 1.82498
ν4 = 42.31

r9 = −25.473
d9 = 3.541-6.756-10.687

r10 = −91.207
d10 = 0.800
N5 = 1.84666
ν5 = 23.82

r11 = 5.726
d11 = 0.100

r12* = 5.594
d12 = 3.625
N6 = 1.52510
ν6 = 56.38

r13* = −10.505
d13 = 1.000

r14 = ∞
d14 = 2.000
N7 = 1.51680
ν7 = 64.20

r15 = ∞

[Aspherical Coefficient]

r1

ε = 0.1000E+01

A4 = −0.74580E−03

A6 = 0.34138E−04

A8 = −0.50023E−06

A10 = 0.2808E−08

r2

ε = 0.1000E+01

A4 = −0.97039E−03

A6 = 0.28781E−04

A8 = 0.43747E−06

A10 = −0.14397E−07

r7

ε = 0.1000E+01

A4 = 0.85555E−03

A6 = 0.35264E−04

A8 = −0.24596E−05

A10 = 0.15775E−06

r12

ε = 0.10000E+01

A4 = 0.32648E−04

A6 = −0.95567E−04

A8 = 0.35230E−05

A10 = −0.25253E−06

r13

ε = 0.10000E+01

A4 = 0.21988E−02

A6 = −0.22925E−03

A8 = 0.11804E−04

A10 = −0.48219E−06

EXAMPLE 2

[0099]

2

f = 5.6-12.9-16.1 mm FNo. = 2.95-4.01-4.45

[Radius of
[Axial
[Refractive
[Abbe

Curvature]
Distance]
Index(nd)]
Number (νd)]

r1* = −24.000
d1 = 1.200
N1 = 1.49310
ν1 = 83.58

r2* = 8.123
d2 = 20.351-5.732-3.353

r3 = 6.991
d3 = 2.638
N2 = 1.72375
ν2 = 52.66

r4 = −34.740
d4 = 0.900

r5 = ∞
d5 = 1.000

r6* = −9.988
d6 = 0.800
N3 = 1.84666
ν3 = 23.82

r7* = 247.216
d7 = 6.049-6.611-6.879

r8 = 16.911
d8 = 1.806
N4 = 1.77436
ν4 = 48.39

r9 = −46.007
d9 = 0.800-9.345-13.337

r10 = 9.008
d10 = 0.800
N5 = 1.84666
ν5 = 23.82

r11 = 4.749
d11 = 0.301

r12* = 5.048
d12 = 3.555
N6 = 1.52510
ν6 = 56.38

r13* = 21.908
d13 = 0.800

r14 = ∞
d14 = 2.000
N7 = 1.51680
ν7 = 64.20

r15 = ∞

[Aspherical Coefficient]

r1

ε = 0.10000E+01

A4 = −0.63439E−04

A6 = 0.68501E−05

A8 = −0.66696E−07

A10 = −0.17038E−09

r2

ε = 0.10000E+01

A4 = −0.47028E−03

A6 = 0.69477E−06

A8 = 0.66535E−06

A10 = −0.15800E−07

r6

ε = 0.10000E+01

A4= 0.59417E−03

A6 = 0.46685E−04

A8 = −0.77214E−05

A10 = 0.39203E−06

r7

ε = 0.10000E+01

A4 = 0.12314E−02

A6 = 0.80651E−04

A8 = −0.10222E−04

A10 = 0.55470E−06

r12

ε = 0.10000E+01

A4 = −0.59528E−03

A6 = −0.10325E−04

A8 = −0.14170E−06

A10 = −0.31345E−06

r13

ε = 0.10000E+01

A4 = −0.55636E−03

A6 = 0.13842E−03

A8 = −0.20578E−04

A10 = 0.36116E−06

EXAMPLE 3

[0100]

3

f = 6.0-12.0-17.3 mm FNo. = 2.95-3.60-3.84

[Radius of
[Axial
[Refractive
[Abbe

Curvature]
Distance]
Index(nd)]
Number (νd)]

r1* = 72.689
d1 = 1.200
N1 = 1.49310
ν1 = 83.58

r2* = 8.018
d2 = 28.005-8.738-1.125

r3 = 5.404
d3 = 2.577
N2 = 1.70206
ν2 = 53.53

r4 = −4231.909
d4 = 0.900

r5 = ∞
d5 = 1.271

r6* = −10.108
d6 = 0.800
N3 = 1.84666
ν3 = 23.82

r7* = 19.972
d7 = 4.900-5.414-4.248

r8 = 12.483
d8 = 2.589
N4 = 1.69005
ν4 = 54.04

r9 = −18.055
d9 = 0.800-2.578-8.087

r10* = 7.794
d10 = 1.157
N5 = 1.80518
ν5 = 25.43

r11* = 5.486
d11 = 0.800-2.807-1.046

r12 = ∞
d12 = 2.000
N6 = 1.51680
ν6 = 64.20

r13 = ∞

[Aspherical Coefficient]

r1

ε = 0.10000E+01

A4 = −0.15783E−03

A6 = 0.29784E−05

A8 = −0.83049E−07

A10 = 0.69898E−09

r2

ε = 0.10000E+01

A4 = −0.37748E−03

A6 = 0.46708E−05

A8 = −0.33213E−06

A10 = 0.30433E−08

r6

ε = 0.10000E+01

A4 = −0.36757E−02

A6 = 0.36847E−03

A8 = −0.10565E−04

A10 = −0.20504E−05

r7

ε = 0.10000E+01

A4 = −0.21103E−02

A6 = 0.46641E−03

A8 = −0.26240E−04

r10

ε= 0.10000E+01

A4 = −0.57224E−02

A6 = −0.62282E−05

A8 = 0.46111E−05

A10 = −0.39249E−06

r11

ε = 0.10000E+01

A4 = −0.81522E−02

A6 = 0.16684E−03

A8 = −0.53316E−05

EXAMPLE 4

[0101]

4

f = 6.0-10.8-17.3mm FNo. = 2.95-3.46-4.24

[Radius of
[Axial
[Refractive
[Abbe

Curvature]
Distance]
Index(nd)]
Number (νd)]

r1* = −180.565
d1 = 1.000
N1 = 1.49310
ν1 = 83.58

r2* = 8.101
d2 = 22.102-8.977-3.301

r3 = ∞
d3 = 0.600

r4 = 6.286
d4 = 2.725
N2 = 1.74159
ν2 = 43.17

r5 = −29.861
d5 = 1.300

r6* = −11.145
d6 = 1.000
N3 = 1.84666
ν3 = 23.82

r7* = 10.004
d7 = 3.742-4.916-4.596

r8 = 21.104
d8 = 2.414
N4 = 1.80513
ν4 = 44.41

r9 = −20.523
d9 = 1.000-6.985-16.317

r10 = 10.089
d10 = 3.566
N5 = 1.48749
ν5 = 70.44

r11 = −8.086
d11 = 0.100

r12 = −7.873
d12 = 0.800
N6 = 1.58340
ν6 = 30.23

r13* = 25.439
d13 = 2.550-2.460-1.116

r14 = ∞
d14 = 2.000
N7 = 1.51633
ν7 = 64.14

r15 = ∞

[Aspherical Coefficient]

r1

ε = 0.10000E+01

A4 = −0.75826E−03

A6 = 0.34105E−04

A8 = −0.50991E−06

A10 = 0.25871E−08

r2

ε = 0.10000E+01

A4 = −0.10941E−02

A6 = 0.2633 8E−04

A8 = 0.51284E−06

A10 = −0.16952E−07

r6

ε = 0.10000E+01

A4 = −0.31416E−03

A6 = 0.93704E−05

A8 = 0.43331E−05

A10 = −0.34297E−06

r7

ε = 0.10000E+01

A4 = 0.55006E−03

A6 = 0.43702E−04

A8 = 0.29782E−05

A10 = −0.26895E−06

r13

ε = 0.10000E+01

A4 = 0.55321E−03

A6 = −0.23535E−04

A8 = 0.11220E−05

A10 = −0.93429E−08

EXAMPLE 5

[0102]

5

f = 5.8-16.7-22.1 mm FNo. = 2.95-4.29-4.87

[Radius of
[Axial
[Refractive
[Abbe

Curvature]
Distance]
Index(nd)]
Number (νd)]

r1* = −22.547
d1 = 1.200
N1 = 1.49310
ν1 = 83.58

r2* = 9.725
d2 = 23.490-3.594-0.800

r3 = 9.159
d3 = 2.432
N2 = 1.76665
ν2 = 49.56

r4 = −30.086
d4 = 1.000

r5 = ∞
d5 = 1.000

r6* = −24.422
d6 = 0.800
N3 = 1.84666
ν3 = 23.82

r7* = 18.027
d7 = 7.205-6.196-6.784

r8 = 25.785
d8 = 2.331
N4 = 1.75834
ν4 = 50.91

r9 = −22.433
d9 = 1.000-15.349-22.085

r10 = 11.255
d10 = 0.800
N5 = 1.75834
ν5 = 24.23

r11 = 5.259
d11 = 0.307

r12 = 5.644
d12 = 3.649
N6 = 1.52510
ν6 = 56.38

r13* = 64.108
d13 = 2.286-1.182-1.122

r14 = ∞
d14 = 2.000
N7 = 1.51680
ν5 = 64.20

r15 = ∞

[Aspherical Coefficient]

r1

ε = 0.10000E+01

A4 = −0.33304E−03

A6 = 0.15726E−04

A8 = −0.21793E−06

A10 = 0.10196E−08

r2

ε = 0.10000E+01

A4 = −0.60051E−03

A6 = 0.10239E−04

A8 = 0.23630E−06

A10 = −0.63119E−08

r6

ε = 0.10000E+01

A4 = −0.90055E−03

A6 = 0.77029E−04

A8 = −0.64898E−05

A10 = 0.29702E−06

r7

ε = 0.10000E+01

A4 = −0.49704E−03

A6 = 0.10218E−03

A8 = −0.89580E−05

A10 = 0.30820E−06

r13

ε = 0.10000E+01

A4 = 0.40975E−03

A6 = 0.15831E−04

A8 = −0.17176E−05

A10 = 0.58797E−07

EXAMPLE 6

[0103]

6

f = 5.6-16.1-21.2 mm FNo. = 2.95-4.51-5.27

[Radius of
[Axial
[Refractive
[Abbe

Curvature]
Distance]
Index(nd)]
Number (νd)]

r1* = −39.852
d1 = 1.200
N1 = 1.49310
ν1 = 83.58

r2* = 7.943
d2 = 27.324-5.086-2.210

r3 = 9.089
d3 = 2.617
N2 = 1.75450
ν2 = 51.57

r4 = −26.827
d4 = 1.220

r5* = −45.076
d5 = 0.800
N3 = 1.84666
ν3 = 23.82

r6* = 18.718
d6 = 1.188

r7 = ∞
d7 = 8.466

r8 = 19.274
d8 = 1.710
N4 = 1.76213
ν4 = 50.28

r9 = −79.564
d9 = 1.000-13.487-19.631

r10 = 19.602
d10 = 0.800
N5 = 1.79850
ν5 = 22.60

r11 = 6.499
d11 = 0.100

r12* = 5.624
d12 = 3.076
N6 = 1.52510
ν6 = 56.38

r13* = 67.250
d13 = 1.000

r14 = ∞
d14 = 2.000
N7 = 1.51680
ν7 = 64.20

r15 = ∞

[Aspherical Coefficient]

r1

ε = 0.10000E+01

A4 = −0.64385E−03

A6 = 0.20445E−04

A8 = −0.22702E−06

A10 = 0.79381E−09

r2

ε = 0.10000E+01

A4 = −0.10137E−02

A6 = 0.90231E−05

A8 = 0.49260E−06

A10 = −0.10596E−07

r5

ε = 0.10000E+01

A4 = −0.61443E−03

A6 = 0.40451E−04

A8 = −0.38476E−05

A10 = 0.18991E−06

r6

ε = 0.10000E+01

A4 = −0.28745E−03

A6 = 0.58066E−04

A8 = −0.54298E−05

A10 = 0.27306E−06

r12

ε = 0.10000E+01

A4 = 0.65072E−03

A6 = −0.30424E−03

A8 = 0.28044E−04

A10 = −0.12221E−05

r13

ε = 0.10000E+01

A4 = 0.27656E−02

A6 = −0.45141E−03

A8 = 0.33907E−04

A10 = −0.12549E−05

EXAMPLE 7

[0104]

7

f = 5.6-16.1-21.3 mm FNo. = 2.95-4.07-4.61

[Radius of
[Axial
[Refractive
[Abbe

Curvature]
Distance]
Index(nd)]
Number (νd)]

r1* = −35.240
d1 = 1.200
N1 = 1.49310
ν1 = 83.58

r2* = 8.469
d2 = 27.719-4.808-1.846

r3 = 8.794
d3 = 2.582
N2 = 1.74754
ν2 = 51.81

r4 = −25.730
d4 = 0.600

r5 = ∞
d5 = 0.600
N3 = 1.84666
ν3 = 23.82

r6* = −42.662
d6 = 0.800

r7* = 17.339
d7 = 8.811

r8 = 18.677
d8 = 2.126
N4 = 1.78578
ν4 = 46.80

r9 = −72.376
d9 = 1.000-12.250-17.785

r10 = 21.040
d10 = 0.800
N5 = 1.79850
ν5 = 22.60

r11 = 6.402
d11 = 0.115

r12* = 5.787
d12 = 3.146
N6 = 1.52510
ν6 = 56.38

r13* = 69.497
d13 = 1.000

r14 = ∞
d14 = 2.000
N7 = 1.51680
ν7 = 64.20

r15 = ∞

[Aspherical Coefficient]

r1

ε = 0.10000E+01

A4 = −0.62293E−03

A6 = 0.22312E−04

A8 = −0.26635E−06

A10 = 0.96658E−09

r2

ε = 0.10000E+01

A4 = −0.92271E−03

A6 = 0.10117E−04

A8 = 0.59055E−06

A10 = −0.13036E−07

r6

ε = 0.10000E+01

A4 = −0.68242E−03

A6 = 0.42598E−04

A8 = −0.36680E−05

A10 = 0.18704E−06

r7

ε = 0.10000E+01

A4 = −0.32785E−03

A6 = 0.63607E−04

A8 = −0.55179E−05

A10 = 0.28183E−06

r12

ε = 0.10000E+01

A4 = 0.57448E−03

A6 = −0.28415E−03

A8 = 0.26250E−04

A10 = −0.11729E−05

r13

ε = 0.10000E+01

A4 = 0.26346E−02

A6 = −0.43696E−03

A8 = 0.33701E−04

A10 = −0.12629E−05

EXAMPLE 8

[0105]

8

f= 5.4-10.8-20.6 mm FNo. = 2.95-3.77-5.17

[Radius of
[Axial
[Refractive
[Abbe

Curvature]
Distance]
Index(nd)]
Number (νd)]

r1* = −33.963
d1 = 1.200
N1 = 1.49310
ν1 = 83.58

r2* = 7.832
d2 = 27.659-10.472-2.342

r3 = 8.778
d3 = 2.602
N2 = 1.75450
ν2 = 51.57

r4 = −28.962
d4 = 1.203-1.124-1.059

r5* = −57.008
d5 = 0.800
N3 = 1.84666
ν3 = 23.82

r6* = 17.293
d6 = 0.959

r7 = ∞
d7 = 8.277

r8 = 18.935
d8 = 1.734
N4 = 1.75450
ν4 = 51.57

r9 = −62.011
d9 = 1.000-7.377-18.676

r10 = 311.066
d10 = 0.800
N5 = 1.79850
ν5 = 22.60

r11 = 9.528
d11 = 0.285

r12* = 6.284
d12 = 2.980
N6 = 1.52510
ν6 = 56.38

r13* = −722.778
d13 = 1.000

r14 = ∞
d14 = 2.000
N7 = 1.51680
ν7 = 64.20

r15 = ∞

[Aspherical Coefficient]

r1

ε = 0.10000E+01

A4 = −0.59643E−03

A6 = 0.20229E−04

A8 = −0.23184E−06

A10 = 0.84402E−09

r2

ε = 0.10000E+01

A4 = −0.10131E−02

A6 = 0.96708E−05

A8 = 0.51386E−06

A10 = −0.11445E−07

r5

ε = 0.10000E+01

A4 = −0.62295E−03

A6 = 0.42687E−04

A8 = −0.37154E−05

A10 = 0.18640E−06

r6

ε = 0.10000E+01

A4 = −0.255 88E−03

A6 = 0.59760E−04

A8 = −0.52924E−05

A10 = 0.27944E−06

r12

ε = 0.10000E+01

A4= 0.70969E−03

A6 = −0.26918E−03

A8 = 0.25775E−04

A10 = −0.10884E−05

r13

ε = 0.10000E+01

A4 = 0.31398E−02

A6 = −0.41392E−03

A8 = 0.33785E−04

A10 = −0.13132E−05

EXAMPLE 9

[0106]

9

f = 5.8-17.4-27.3 mm FNo. = 2.80-4.34-4.40

[Radius of
[Axial
[Refractive
[Abbe

Curvature]
Distance]
Index(nd)]
Number (νd)]

r1* = −22.070
d1 = 1.200
N1 = 1.49310
ν1 = 83.58

r2* = 9.494
d2 = 24.369-4.409-0.800

r3 = 8.798
d3 = 2.582
N2 = 1.76650
ν2 = 49.58

r4 = −31.132
d4 = 1.000

r5 = ∞
d5 = 1.000

r6* = −21.422
d6 = 0.800
N3 = 1.84666
ν3 = 23.82

r7* = 17.214
d7 = 7.695-5.806-6.183

r8 = 25.220
d8 = 2.306
N4 = 1.78148
ν4 = 45.82

r9 = −26.647
d9 = 1.022-17.033-29.983

r10 = 11.922
d10 = 0.800
N5 = 1.77945
ν5 = 23.20

r11 = 5.629
d11 = 0.436

r12 = 5.762
d12 = 3.569
N6 = 1.52510
ν6 = 56.38

r13* = 148.618
d13

r14 = ∞
d14 = 2.000
N7 = 1.51680
ν7 = 64.20

r15 = ∞

[Aspherical Coefficient]

r1

ε = 0.10000E+01

A4 = 0.33078E−03

A6 = 0.16001E−04

A8 = −0.21531E−06

A10 = 0.99631E−09

r2

ε = 0.10000E+01

A4 = −0.60713E−03

A6 = 0.98174E−05

A8 = 0.25688E−06

A10 = −0.59297E−08

r6

ε = 0.10000E+01

A4 = −0.91072E−03

A6 = 0.77957E−04

A8 = −0.65057E−05

A10 = 0.29025E−06

r7

ε = 0.10000E+01

A4 = −0.48772E−03

A6 = 0.10174E−03

A8 = −0.88218E−05

A10 = 0.38477E−06

r13

ε = 0.10000E+01

A4 = 0.39623E−03

A6 = 0.34623E−04

A8 = −0.29175E−05

A10 = 0.11686E−06

[0107]
FIGS. 10 through 18 are aberration diagrams of the first through the ninth examples, each showing aberrations when the zoom lens system according to each example is an infinite focus state. Shown in FIGS. 10 through 18 are aberrations in the shortest focal length state, the intermediate focal length state, the longest focal length state from the top.

[0108]
FIGS. 19 through 27 are aberration diagrams of the first through the ninth examples, each showing aberrations when the zoom lens system according to each example is an finite focus state (object distance=0.4 m). Shown in FIGS. 19 through 27 are aberrations in the shortest focal length state, the longest focal length state from the top.

[0109] In FIGS. 10 through 27, shown from the left hand side are spherical aberrations or the like, astigmatisms and distortion aberrations, and Y′ (mm) denotes a maximum image height (which corresponds to a distance from the optical axis) on the imaging sensor.

[0110] In the spherical aberration diagrams, the solid line (d) represents spherical aberrations to the d-line, the dashed line (g) represents spherical aberrations to the g-line, and the broken line (SC) represents the level of dissatisfaction of the sine condition. In the astigmatism diagrams, the broken line (DM) represents astigmatisms at a meriodional surface and the solid line (DS) represents astigmatisms at a sagital surface. In the distortion aberration diagrams, the solid line represents a distortion % to the d-line.

[0111] As described above, according to the zoom lens device of the present invention, a zoom lens device can be provided that is provided with a zoom lens system whose length in the direction of the optical axis in the collapsed condition is sufficiently short although the zoom ratio is high.

[0112] Moreover, according to the zoom lens device of the present invention, a zoom lens device can be provided that is provided with a zoom lens system that is bright even in the longest focal length condition and whose length in the direction of the optical axis in the collapsed condition is sufficiently short.

[0113] Although the present invention has been fully described by way of example with reference to the accompanying drawings, it is to be understood that various changes and modifications will be apparent to those skilled in the art. Therefore, unless otherwise such changes and modification depart from the scope of the present invention, they should be construed as being included therein.

Zoom lens device

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