Compact zoom lens

BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to compact zoom lenses, and more particularly to compact zoom lenses of large zoom ratio with a reduced weight of the entire lens system suited to still cameras and video cameras.
2. Description of the Related Art
An example of the conventional comparatively high range zoom lens adapted to be used in a photographic camera or video camera is shown in FIG. 1, and comprises a first unit 11 of positive refractive power for focusing, a second unit 12 of negative refractive power movable for zooming in a mono-direction throughout, a third unit 13 of negative refractive power movable for zooming in a forward-and-rearward direction to compensate for image shift, a fourth unit 14 of positive refractive power which is not always necessary but is stationary during zooming so that the emerging rays are almost afocal, and a fixed fifth unit 15 of positive refractive power. A diaphragm 16, in most cases, is arranged in between the third and fourth, or fourth and fifth units. This type of zoom lens has an advantage that the physical length of the entire system can be minimized because the spaces in which the second and third units move for zooming respectively can be partly overlapped. To achieve a further minimization of the physical length, the refractive power of the second unit 12 must be strengthened as much as possible so that the total zooming movement of the second unit 12 is much reduced. The increase in the power of the second unit 12, however, gives rise to problems that fluctuation of aberrations with zooming is increased, and that the manufacturing accuracy is required to be set at a higher level. Besides these, the long-time investigation and experience of the inventor has proven that when the power of the second unit is too strong, the lens thickness must be increased in view of the minimum acceptable edge thickness of the lens, and, in some cases, therefore, the physical length of the entire system is, on the contrary, increased. Hence, the refractive power of the second unit cannot be greatly strengthened.
As for an increase of the angular field by shortening the minimum focal length, because the oblique pencil comes in on determination of the diameter of the first unit, the wider the angle of field, the larger the diameter of the first unit becomes. Thus, the entire system is increased in the lateral direction. On the other hand, when the focal length for the wide angle end is shifted to longer ones, whichever, the oblique light bundle near or at the wide angle end, or the axial maximum light bundle at the telephoto end, has a larger diameter and determines the diameter of the first unit. With the prescribed zoom ratio when preserved, the focal length for the telephoto end becomes too long. This leads to an increase in the diameter of the first unit.
Another disadvantage of the type of zoom lens shown in FIG. 1 is that because the second and third units both are negative in refractive power, the axial rays emerging from the zoom section diverge so that the diameter of the aperture of the diaphragm that follows it tends to increase. In general, it is in the nature of zoom lenses that as the focal length increases, the diameter of the aperture of the diaphragm increases to maintain the constant speed of the entire system. Also, the required diameter of the casing for the diaphragm is equal to about 2 times the maximum value of the aperture diameter. When in designing a compact lens, it is, therefore, not preferable to choose such a type that the longest focal length of the entire system should be shifted toward longer ones.
Meanwhile, Japanese Patent Publication No. SHO 51-12424 has proposed another type of 5-unit zoom lens in which as shown in FIG. 2, the sign of refractive power of the third unit 23 is changed to positive, and the direction of its movement is made monotonous and opposite to that of movement of the negative second unit 22 in order to achieve an increase in the zoom ratio. In FIG. 2, 21 is the first unit for focusing; 24 is the fourth unit for making almost afocal the rays of light passed through the first to third units; 25 is the fifth unit having the image forming function; 27 is an optical member for splitting off part the light to a finder; 26 is the diaphragm. In the zoom lens of FIG. 2, the rays of light emerging from the third unit become somewhat convergent, thereby giving an advantage that the diaphragm is sufficient with a comparatively small maximum diameter of aperture. However, in order to reduce the diameter of the first unit, the separation between the second and third units must be somewhat increased. As a result, the physical length of the entire system becomes longer. Also, the diameter of the third unit is caused to increase. In order to reduce the physical length of the entire system, the refractive powers of the second and third units may be strengthened to decrease the total zooming movements of both of them. But, the increase in the power leads to increase the fluctuation of the aberration with zooming. On this account, the power cannot be too much strengthened.
SUMMARY OF THE INVENTION
An object of the invention is to facilitate a much-desired shortening of the total length of the zoom lens.
Another object is to achieve a shortening of the diameter of the first lens unit with a decrease of the weight thereof.
Still another object is to provide a zoom lens whose bulk and size is greatly reduced, while nevertheless permitting good correction of various aberrations to be achieved.

BRIEF DESCRIPTION OF THE DRAWINGS
FIGS. 1 and 2 are schematic sectional views of two conventional examples of zoom lens.
FIG. 3 is a schematic sectional view of the predesign of a zoom lens according to the present invention.
FIGS. 4 to 9 are block diagrams of six specific examples 1-6 of zoom lenses of the invention respectively.
FIGS. 10(A), 10(B), 10(C) to 15(A), 15(B), 15(C) are graphic representations of the various aberrations of the zoom lenses of FIGS. 4 to 9 respectively.
FIGS. 16(A) and 16(B) are schematic diagrams of the power arrangement of another zoom lens of the invention.
FIGS. 17 to 21 are block diagrams of five specific examples 7-11 of zoom lenses of the invention respectively.
FIGS. 22(A), 22(B) to 26(A), 26(B) are graphic representations of the various aberrations of the zoom lenses of FIGS. 17 to 21 respectively.
FIGS. 27 to 32 are block diagrams of six examples 12-17 of zoom lenses of the present invention respectively.
FIGS. 33(A), 33(B), 33(C) to 38(A), 38(B), 38(C) are graphic representations of the various aberrations of the zoom lenses of FIGS. 27 to 32 respectively.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
In all the examples shown in FIG. 3 and those that follow, the zoom lens of the invention comprises, from front to rear, a first unit of positive refractive power for focusing, a second unit of negative refractive power which, when zooming, axially moves in a mono-direction throughout, a third unit of positive refractive power which, when zooming, axially moves in the opposite mono-direction to that of movement of the second unit, and a fourth unit of positive refractive power having an image forming function which is held stationary during zooming. One of the features of the invention is that a diaphragm for determining the F-number of the entire system is fixedly positioned between the second and third units at such a location as to satisfy the following condition:
0.4<ls/lw<0.75 (1)
where ls is the axial separation between the second unit and the diaphragm in the wide angle end, and lw is the axial separation between the second and third units in the wide angle end.
Further, another following condition is satisfied:
1<.vertline.f.sub.3 /f.sub.2 .vertline.<2 (2)
where f.sub.2 and f.sub.3 are the focal lengths of the second and third units respectively.
Also, the fourth unit is constructed with two sub-units, or a 4-1st sub-unit of negative refractive power and a 4-2nd sub-unit of positive refractive power.
In application of the invention to a zoom lens in which the zoom section is followed by a fixed section having an image forming function, their arrangement being such that, during zooming, the rays incident on the image forming section are maintained convergent, additional features of the invention are that the aforesaid image forming section comprises, from front to rear, a 4-st lens unit of negative refractive power and a 4-2nd lens unit of positive refractive power, the 4-1st lens unit including at least one negative lens whose front surface is concave toward the front, and the 4-2nd lens unit including at least one negative lens L.sub.2N whose rear surface is concave toward the rear, and at least two positive lenses, whereby the following conditions are satisfied:
1.74<.vertline.R.sub.1H /f.sub.W .vertline.<2.82, R.sub.1N <0 (a)
1.28<R.sub.2N /f.sub.W <2.2 (b)
1.69<R.sub.2P /f.sub.W <2.6 (c)
1.65<d/f.sub.W <1.42 (d)
where R.sub.1N is the radius of curvature of the one of the forwardly concave surfaces in the 4-1st lens unit whose curvature is strongest; R.sub.2N is the radius of curvature of the one of the rearwardly concave surfaces in the 4-2nd lens unit whose curvature is strongest; R.sub.2P is the radius of curvature of the one of the forwardly convex surfaces of the positive lenses on the image side of the negative lens L.sub.2N whose curvature is strongest; d is the air separation between the 4-1st and 4-2nd lens units; and f.sub.W is the shortest focal length of the entire system.
The embodiments of the invention are described in detail by reference to the drawings. FIG. 3 shows one of the embodiments of the invention in which each lens unit is depicted as one lens. In the same figure, 31 is a first unit of positive refractive power for focusing; 32 is a second unit of negative refractive power arranged upon zooming from the wide angle to the telephoto end to move monotonously rearwardly; 33 is a third unit of positive refractive power arranged to move monotonously in the opposite or forward direction to that of movement of the second unit; 34 is a fourth unit of positive refractive power having the image forming function which remains stationary during zooming; 35 is a fixed diaphragm whose aperture opening varies in size to change the F-number arranged between the second and third units.
Referring also to FIGS. 16(A) and 16(B), the fourth unit 35 is divided into two parts or a front sub-unit 34.sub.1 of negative refractive power and a rear sub-unit 34.sub.2 of positive refractive power spaced apart by a longest distance in the fourth unit.
In the embodiment of the invention, by making one-directionally monotonous the zooming movements of the second and third units on either side of the diaphragm from one end of the entire range to the other, a shortening of the front members of the first unit is achieved, and at the same time a shortening of the total length of the entire system is achieved.
In the popular type of zoom lens, suppose the diaphragm is displaced to between the second and third units. As the third unit takes reciprocating movement convex toward the front when zooming from one end of the entire range to the other, because there is no advantage that the second and third units have a common space, the total length of the entire system is increased. In other words, because, in the type having the reciprocating third unit, the second and third units come nearest to each other at the intermediate zooming position, and because they are prevented from mechanical interference with each other, a surplus space must be created therebetween. By this factor, the total length of the entire system is increased.
In the invention, on the other hand, the feature that the diaphragm is positioned between the second and third units is combined with the feature that the second and third units move in opposite direction from each other from one end of the entire range to the other. Thus, the necessity of the surplus space is obviated. And, not only the second unit has the image magnification varying effect, but also the third unit, too, is allowed to get an image magnification varying effect, thereby giving another advantage that the prescribed zoom ratio can be obtained efficiently, as will be seen from the numerical embodiments to be described later where a great increase of the zoom ratio to as high as about 6 is achieved. Also, the feature that a reduced space is enough of the zooming of the second and third units is combined with a feature that the total zooming movement of the second and third units is lessened, whereby a further shortening of the total length of the entire system is achieved.
Another disadvantage of the conventional zoom lenses is that in most cases the first unit accounts for 50 to 80% of the weight of the entire system. The effective method for reducing the weight of the zoom lens is, therefore, to choose glass of lower specific gravity for employment in the first unit, or to reduce the volume of the first unit by decreasing its diameter. Of these, the former leads to a lesser degree of freedom of the optical design. To achieve reduction of the weight of the zoom lens while preserving high grade of imagery, therefore, it is advantageous to rely on the latter. On assumption that the thickness of the lens varies in proportion to its diameter, then, as the volume of the lens is proportional to the cube of its diameter, if the diameter can be reduced, for example, 10%, it becomes possible to reduce the weight by as much as 27% for the volume decreases to (0.9).sup.3. For this reason, in the invention, particularly the first unit is given priority of shortening the diameter, when attempt to reduce the weight of the entire system is made. For this purpose, whilst in the prior art shown in FIG. 1 or 2, the diaphragm lies behind the fourth unit, in the invention the diaphragm is brought to as near a position to the first unit as possible, taking its place between the second and third units at almost the center of the longitudinal length of the entire system. Another feature is that the diaphragm and the lens units are so arranged that the diameter of the first unit which is determined by the oblique pencil in the wide angle end and that diameter of the first unit which is determined by the axial pencil in the telephoto end both contribute to a minimum of the effective diameter.
To achieve an increase in the angular field in such a manner that the longitudinal and lateral lengths of the entire lens system fall in a good balance, for the flexibility of design of the effective diameter of the first unit is increased, the effective diameter of the first unit is prevented from increasing with increase in the angle of oblique pencil in the wide angle end, and is made partly determined by the diameter of the axial light bundle in the telephoto end at the regulated value of F-number for the telephone end.
The requirements of achieving a great increase of the zoom ratio and of facilitating a shortening of the entire system in the longitudinal and lateral directions are fulfilled without having the second and third lens units to mechanically interfere with the diaphragm, when the inequalities of condition (1) are satisfied.
Though, as has been described above, the positioning of the diaphragm nearer the first unit than before is advantageous to shorten the diameter of the first unit, the diameter of those behind the diaphragm, for example, the fourth unit, is caused to increase. The inequalities of condition (1) represent achievement of the reduction of the size of the entire system while preserving good balance between the effective diameters of the first lens and those that follow. When the lower limit of the inequalities of condition (1) is exceeded, the diameter of the second to fourth lens units is caused to increase, although the diameter of the first unit decreases. Moreover, particularly the problem that, as the third unit moves relative to the diaphragm, the height of incidence of the oblique pencil on the fourth unit varies to a large extent with an increase in the fluctuation of aberrations becomes very serious, because the difficulty of correcting such aberrations increases. When the distance from the diaphragm to the first unit increases beyond the upper limit, the diameter of the first unit increases. With this, when to achieve an increase of the angular field, the rate of growth of that diameter is increased objectionably.
The compact zoom lens of the invention can be realized by setting forth the foregoing features. Yet, in order to maintain the aberrations stable throughout the entire zooming range with the limitation of the bulk and size of the entire system to the minimum, it is preferred to further satisfy the following condition:
0.5<.vertline.E/X.vertline.<1.3 (3)
where X and E are respectively the total zooming movements of the second and third units. When the total zooming movement of the third unit is decreased beyond the lower limit of the inequalities of condition (3), the refractive power of the second unit for the prescribed zoom ratio can be weakened with advantages on the manufacture and the aberration correction, but the movement of the second unit is increased. Therefore, even if the diaphragm is positioned as near the second unit as possible, the resultant increase in the distance between the first unit and the diaphragm calls for an objectionably large increase in the diameter of the first unit. Conversely when the movement of the third unit is increased beyond the upper limit of the inequalities of condition (3), the movement of the second unit can be relatively reduced with decrease of the diameter of the first unit, but, because the image magnification varying effect of the second unit is lowered with increase in the difficulty of obtaining the prescribed zoom ratio.
In the case of the type of zoom lens used in the invention, because the rays travelling from the second to the third unit are diverging, the height of incidence of the axial rays on the third unit is higher than that of incidence of the second unit. If the difference between these heights of incidence is large, good stability of aberrations, particularly spherical aberration, becomes difficult to maintain. On this account, in the invention, the refractive powers of the second and third units are related to each other by the inequalities of condition (2). When this condition is satisfied, the aberrations are maintained stable throughout the extended zooming range. In more detail, with the use of the type in which the second and third units move in opposite direction to each other throughout the zooming range, when to achieve the great increase in the zoom ratio, it is recommended as proposed in, for example, Japanese Patent Publication No. SHO 51-12424, that the image magnifications of the second and third unit change across a point of -1 times simultaneously during zooming. From the interval, e, between the principal planes of the second and third units at this point, one has
af.sub.3 =-2f.sub.2 +e
The principal planes of the second and third units take their places usually within their own units. According to the prior art of Japanese Patent Publication No. SHO 51-12424, the ratio of the movement of the second unit from the wide angle end to a position at which unity of image magnification occurs to the total zooming movement thereof, that is, the relative distance of the switching point, .alpha., measured from the wide angle end, lies
0.5<.alpha.<0.95
To meet this condition, it is preferable to set forth at least e>0, and, from the point of view of avoiding the mechanical interference between the second and third units, the principal plane interval, e, takes as large a value as possible. Because the increase in the principal plane interval, e, calls for an increase in the total length of the entire system, it cannot, however, be too much greatly enlarged.
Also, in application of the zoom lens to some fields of photography, it is not always necessary that the range of switching points .alpha. is as such. For example, taking a low-magnification zoom lens, the limits for the switching point .alpha. may be increased up to 0.95<.alpha.<1.2. Nevertheless, the prescribed zoom ratio can be obtained, and, moreover, the shortening of the total length of the zoom lens can be attained.
According to the invention, therefore, on assumption that 0.5<.alpha.<1.2, and that the interval between the principal planes of the second and third units is so chosen as to avoid mechanical interference therebetween, the ratio of the powers of the second and third units is found to lie in the following range:
0.95<.vertline.f.sub.3 /f.sub.2 .vertline.<2
When this condition is, however, violated, since, as .vertline.f.sub.3 /f.sub.2 .vertline.<1, the third unit gets too strong a power, because the height at which the diverging rays from the second unit are incident on the third unit is much increased, the range of variation with zooming of the aberrations is increased objectionably.
Conversely when .vertline.f.sub.3 /f.sub.2 .vertline.>2, the refractive power of the third unit becomes so weak that the total zooming movement is increased to obtain the prescribed zoom ratio. As a result, the difference between the heights of incidence of the axial pencil on the third unit in the wide angle and telephoto ends becomes too large. Therefore, the resultant aberrations are difficult to correct well. Hence, it is preferred to set forth the inequalities of condition (2) for the second and third units in order to achieve a great increase in the range while still permitting good stability of aberration correction throughout the extended range.
The present invention has an additional feature that the fourth unit having the image forming function stationary during zooming is so formed with positive overall power that the limits for the zooming range are properly adjusted, whereby the fourth unit is divided into a front or 4-1st sub-unit of negative power and a rear or 4-2nd sub-unit of positive power to facilitate assurance of the prescribed back-focal distance and good correction of the image aberrations over the entire area of the picture format, when the relative aperture is increased to as high as 1.2 in F-number.
In more detail, the first to third units constitute a partial system of positive refractive power. Since this partial system is small-sized in the lateral direction, because the emerging rays from the partial system are convergent, it is necessary that the arriving rays at the fourth unit are made once nearly or exactly afocal by the diverging function of the 4-1st sub-unit of negative refractive power, before they are focused to an image at the prescribed back-focal distance by the 4-2nd sub-unit of positive refractive power.
The 4-1st sub-unit is also used for correcting the residual under-corrected spherical aberration of the partial system, and the 4-2nd sub-unit is also used for correcting the coma and sagittal halo over the entire area of the picture format. Further, the negative curvature of field ascribable to the positive refractive powers of the third unit and the 4-2nd sub-unit is compensated for the 4-1st sub-unit of negative refractive power.
When the above-stated features or conditions are satisfied, improved results for the compact zoom lens of the invention can be attained. Yet, it is preferred to further set forth a range for the focal lengths f.sub.4-1 and f.sub.4-2 of the 4-1st and 4-2nd sub-units as follows:
1.3<.vertline.f.sub.4-1 /f.sub.4-2 .vertline.<8.0 (4)
The inequalities of condition (4) enable the various aberrations over the entire area of the picture format to be corrected in good balance, while preserving the prescribed back focal distance. When the power of the 4-1st sub-unit is stronger than the lower limit of the inequalities of condition (4), though the back focal distance becomes sufficiently long, over-correction of spherical aberration results, and the curvature of field is increased to the positive direction. Furthermore, the effective diameter of the 4-2nd sub-unit must be increased with increase of the size of the lens system. Conversely when the power of the 4-1st sub-unit is weaker than the upper limit, the back focal distance becomes too short. Also, under-correction of spherical aberration results and the curvature of field is increased in negative sense when in the wide angle positions.
To achieve a further improvements of the aberration, the 4-1st sub-unit is made include at least a negative lens whose front surface is concave toward the front, whereby the spherical aberration produced from the zoom section can be well corrected over the entire range of visible wavelengths. The 4-2nd sub-unit also is made include at least one negative lens L.sub.2N whose rear surface is of strong concave curvature toward the rear, whereby the coma produced from the zoom section and the 4-1st sub-unit can be well corrected. Further concerning the 4-2nd sub-unit, in order that, while the amount of aberrations it produces being minimized, its refractive power is made positive as a whole, if the number of positive lenses in it is only one, the duty of each lens surface for bearing the power becomes too heavy. So, the 4-2nd sub-unit is made include at least two positive lenses. After all, despite the relative aperture being greatly increased, it is possible to well correct the various aberrations over the entire area of the picture format.
The specific zoom lenses of FIGS. 27 to 32 each comprise, from front to rear, a first lens unit I for focusing which is held stationary during zooming, a second lens unit II for zooming which moves rearward as zooming from the wide angle to the telephoto end, a third lens unit III which moves to compensate for the image shift resulting from the variation of the image magnification, and an image forming section IV which constitutes part of the features of the invention, being held stationary during zooming. The image forming section IV comprises, front to rear, a 4-1st sub-unit IV-1 of negative refractive power and a 4-2nd sub-unit IV-2 of positive refractive power spaced apart from each other by the longest distance in the image forming section.
In this embodiment, the lens units I, II and III are so constructed and arranged that the rays emerging from the zoom section of the second and third lens units II and III are always convergent to the image forming section throughout the entire zooming range.
And, in this embodiment, the image forming section IV is constructed with the 4-1st sub-unit of negative refractive power and the 4-2nd sub-unit of positive refractive power, so that the convergent rays from the zoom section are first made almost afocal by the 4-1st sub-unit and then focused to an image on a photosensitive surface while maintaining the prescribed back focal distance. Thereby, in the case of the video cameras, the low pass filter, infrared cut filter, and other necessarry optical members can occupy the space between the rear vertex of the zoom lens and the image pickup device. In the case of the photographic cameras, the quick return mirror box can be positioned in that space.
And, further, by the 4-1st sub-unit of negative refractive power, the on-axis aberrations mainly produced from the zoom section are corrected. By the 4-2nd sub-unit of positive refractive power the off-axis aberrations such as coma and sagittal halo are mainly corrected. With this, a great increase of the relative aperture to 1.25 in F-number is achieved. That is, in this embodiment, the 4-1st sub-unit is made to include at least a negative lens facing the concave surface toward the front. By this negative lens, the spherical aberration produced from the zoom section is corrected over the entire wavelength region. Also the 4-2nd sub-unit is made to include at least one negative lens L.sub.2N facing the strong concave surface toward the rear, thereby the coma produced from the negative lens of the 4-1st sub-unit and the zoom section is corrected.
Further, the 4-2nd lens sub-unit is made to include at least two positive lenses. Otherwise, because there is only one positive lens, the duty of each surface for refractive power would be very heavy in order that the amount of various aberrations produced is lessened, and the overall refractive power is made positive. Thus, a zoom lens of reduced total length and increased relative aperture with the various aberrations well corrected over the entire area of the picture format is achieved with as few a total number of lens elements as possible.
And, further, each lens is constructed so as to satisfy the conditions (a) to (d), whereby the various aberrations produced from the zoom section are well corrected for high optical performance.
The inequalities of condition (a) enable the back focal distance to be maintained at the prescribed value and the spherical aberration produced from the zoom section to be properly corrected while preserving the negative refractive power of the 4-1st sub-unit. When the upper limit is exceeded, under-correction of spherical aberration results. When the lower limit is exceeded, over-correction results.
The inequalities of condition (b) enable the total length of the lens to be shortened while minimizing the amounts of field curvature and coma, particularly outward coma. When the upper limit is exceeded, under-correction of curvature of field results, and the total length of the lens is increased. Conversely when the lower limit is exceeded, the amount of outward coma produced is increased, which is difficult to correct well.
The inequalities of condition (c) enable the outward coma and halo aberration of the sagittal light beam produced from the negative lens L.sub.2N of the 4-2nd sub-unit to be corrected well. When the upper limit is exceeded, the outward coma and sagittal halo produced from the negative lens L.sub.2N become difficult to correct well. When the lower limit is exceeded, the amount of inward coma produced is increased.
The inequalities of condition (d) enable the separation between the 4-1st sub-unit and 4-2nd sub-unit to be properly maintained, and the aberrations, mainly the off-axis aberrations to be corrected in good balance over the entire area of the picture frame while achieving the shortening of the entire system. When the upper limit is exceeded, the total length of the lens becomes too long, and the diameter of the 4-2nd lens unit also increases, being an obstacle for small-sizing the entire lens system. Also, when the lower limit is exceeded, astigmatism, coma and other off-axis aberrations become difficult to correct.
The zoom lenses shown in FIGS. 27 to 30 have the diaphragm between the second lens unit II and the third lens unit III. The zoom lenses shown in FIGS. 31 and 32 have the diaphragm between the third lens unit III and the fourth lens unit IV. And, when zooming, while the second lens unit II and the third lens unit III do not interfere with each other, and, particularly when the diaphragm is arranged between the second lens unit II and third lens unit III, also with the diaphragm, the second lens unit II moves rearward, and the third lens unit III moves either monotonously forward, or reciprocably. In this embodiment, the zoom section of such zoom type is combined with the above-described image forming section when, while the prescribed zoom ratio is efficiently obtained, the diameter of the lens unit I is shortened, and the total length of the lens is shortened.
The zoom type in which the two lens units on either side of the diaphragm unit are moved to effect zooming as in the embodiment of the invention, if the operating mechanism is constructed by using the conventional cylinder cam, the diameter of the outer barrel of the lens mounting is increased. For this reason, in this embodiment, it is preferred that the operating mechanism is constructed in such a manner that the cam sleeve is arranged either ahead or behind the diaphragm unit, or that the plate cam is arranged on one side of the diaphragm unit. Also, in the bar type in which the movable lens is guided for linear movement by a bar, it is a disadvantage that this bar is merely positioned outside the diaphragm unit from the standpoint of the increase of the diameter of the outer barrel. To avoid this, instead of the round iris diaphragm, a slide type of diaphragm unit in which, for example, two blades are slidingly moved to the left or right, may be used so that spaces above and below the diaphragm unit are formed to pass the respective bars therethrough, with an advantage that the structure of the operating mechanism is simplified and the diameter of the outer barrel of the lens mounting is shortened.
Examples of specific zoom lenses of the invention can be constructed in accordance with the numerical data given in the following tables for the radii of curfature, R, the axial thicknesses or air separations, D, and the refractive indices, N, and Abbe numbers, .nu., of the glasses of the lens elements with the subscripts numbered consecutively from front to rear. I, II, III, IV denote respectively the first, the second, the third and the fourth units, f.sub.1, f.sub.2, f.sub.3 and f.sub.4 are the focal lengths of the first, second, third and fourth lens units respectively.
__________________________________________________________________________Numerical Example 1__________________________________________________________________________F = 1.00-5.52 FNO = 1:1.25-1.75 2.omega. = 57.0.degree.-11.0.degree.__________________________________________________________________________ R1 = 16.3271 D1 = 0.2153 N1 = 1.80518 .nu.1 = 25.4 R2 = 4.1903 D2 = 0.8419 N2 = 1.60311 .nu.2 = 60.7I R3 = -8.2045 D3 = 0.0144 R4 = 2.9687 D4 = 0.3636 N3 = 1.62299 .nu.3 = 58.2 R5 = 6.3151 D5 = Variable R6 = 19.4638 D6 = 0.1052 N4 = 1.6968 .nu.4 = 55.5 R7 = 1.749 D7 = 0.4114II R8 = -2.1231 D8 = 0.0957 N5 = 1.6968 .nu.5 = 55.5 R9 = 2.1236 D9 = 0.3061 N6 = 1.84666 .nu.6 = 23.9 R10 = 17.1111 D10 = Variable R11 = Stop D11 = Variable R12 = 111.1357 D12 = 0.3157 N7 = 1.7495 .nu.7 = 35.3 R13 = -3.3613 D13 = 0.0144III R14 = 3.6305 D14 = 0.5932 N8 = 1.62299 .nu.8 = 58.2 R15 = -2.3417 D15 = 0.1129 N9 = 1.84666 .nu.9 = 23.9 R16 = -5.7841 D16 = Variable R17 = -2.0491 D17 = 0.1148 N10 = 1.5927 .nu.10 = 35.3 R18 = -24.8116 D18 = 0.7845 R19 = -56.2850 D19 = 0.4401 N11 = 1.72 .nu.11 = 50.2 R20 = -2.6179 D20 = 0.0144 R21 = 5.644 D21 = 0.1244 N12 = 1.84666 .nu.12 = 23.9IV R22 = 1.9298 D22 = 0.2822 R23 = 7.6877 D23 = 0.3683 N13 = 1.64 .nu.13 = 60.1 R24 = -3.9225 D24 = 0.0144 R25 = 2.3208 D25 = 0.3779 N14 = 1.60311 .nu.14 = 60.7 R26 = 19.0217 D26 = 0.4784 R27 = .infin. D27 = 0.4724 N15 = 1.51633 .nu.15 = 64.1 R28 = .infin.__________________________________________________________________________F 1. 3.1 5.52__________________________________________________________________________D5 0.1530 1.588 2.040D10 2.1992 0.7642 0.3126D11 1.6231 0.8344 0.2552D16 0.4302 1.2189 1.7981__________________________________________________________________________f1 = 5.236f2 = -1.392f3 = 2.27f4 = 2.665__________________________________________________________________________
__________________________________________________________________________Numerical Example 2__________________________________________________________________________F = 1.00-5.52 FNO = 1:1.40-2.00 2.omega. = 51.6.degree.-10.0.degree.__________________________________________________________________________ R1 = 12.1932 D1 = 0.2173 N1 = 1.80518 .nu.1 = 25.4 R2 = 5.4181 D2 = 0.6941 N2 = 1.60311 .nu.2 = 60.7I R3 = -11.5323 D3 = 0.0181 R4 = 3.2998 D4 = 0.3561 N3 = 1.62299 .nu.3 = 58.2 R5 = 6.3479 D5 = Variable R6 = -36.2586 D6 = 0.3803 N4 = 1.84666 .nu.4 = 23.9 R7 = -2.5477 D7 = 0.1086 N5 = 1.69680 .nu.5 = 55.5II R8 = 1.9960 D8 = 0.4241 R9 = -2.0773 D9 = 0.1207 N6 = 1.77256 .nu.6 = 49.6 R10 = -19.7915 D10 = Variable R11 = Stop D11 = Variable R12 = 208.1219 D12 = 0.1207 N7 = 1.84666 .nu.7 = 23.9 R13 = 2.5604 D13 = 0.4225 N8 = 1.69680 .nu.8 = 55.5III R14 = -3.4792 D14 = 0.0181 R15 = 4.0314 D15 = 0.4467 N9 = 1.77250 .nu.9 = 49.6 R16 = -7.6102 D16 = Variable R17 = -2.0944 D17 = 0.1207 N10 = 1.51633 .nu.10 = 64.1 R18 = 12.3126 D18 = 0.9457 R19 = 6.6933 D19 = 0.4225 N11 = 1.65844 .nu.11 = 50.9 R20 = -3.1399 D20 = 0.0181IV R21 = 2.1461 D21 = 0.1207 N12 = 1.84666 .nu.12 = 23.9 R22 = 1.4045 D22 = 0.2258 R23 = 2.4569 D23 = 0.4587 N13 = 1.69680 .nu.13 = 55.5 R24 = -7.9511 D24 = 0.2414 R25 = .infin. D25 = 0.6640 N14 = 1.51633 .nu.14 = 64.1 R26 = .infin.__________________________________________________________________________F 1. 3.11 5.52__________________________________________________________________________D5 0.1127 1.6217 2.092D10 2.2738 0.7648 0.2945D11 1.6135 0.8188 0.2411D16 0.4587 1.2534 1.8311__________________________________________________________________________f1 = 5.726f2 = -1.449f3 = 2.294f4 = 2.856__________________________________________________________________________
__________________________________________________________________________Numerical Example 3__________________________________________________________________________F = 1.00-5.52 FNO = 1:1.40-1.75 2.omega. = 51.5.degree.-10.0.degree.__________________________________________________________________________ R1 = 15.1717 D1 = 0.1928 N1 = 1.80518 .nu.1 = 25.4 R2 = 5.0971 D2 = 0.6506 N2 = 1.60311 .nu.2 = 60.7I R3 = -10.0692 D3 = 0.0181 R4 = 3.2671 D4 = 0.3614 N3 = 1.62299 .nu.3 = 58.2 R5 = 6.3240 D5 = Variable R6 = -14.6297 D6 = 0.1205 N4 = 1.7725 .nu.4 = 49.6 R7 = 1.9562 D7 = 0.3460II R8 = -3.0111 D8 = 0.1205 N5 = 1.69680 .nu.5 = 55.5 R9 = 2.0179 D9 = 0.4217 N6 = 1.84666 .nu.6 = 23.9 R10 = 104.2199 D10 = Variable R11 = Stop D11 = Variable R12 = 11.7622 D12 = 0.3855 N7 = 1.71300 .nu.7 = 53.8 R13 = -3.9049 D13 = 0.0181III R14 = 3.8392 D14 = 0.5542 N8 = 1.69680 .nu.8 = 55.5 R15 = -2.9425 D15 = 0.1205 N9 = 1.84666 .nu.9 = 23.9 R16 = -47.3102 D16 = Variable R17 = -2.2482 D17 = 0.1205 N10 = 1.60311 .nu.10 = 60.7 R18 = 36.2018 D18 = 0.8447 R19 = 6.7139 D19 = 0.5181 N11 = 1.69680 .nu.11 = 55.5 R20 = -3.3161 D20 = 0.0181IV R21 = 2.5036 D21 = 0.1205 N12 = 1.84666 .nu.12 = 23.9 R22 = 1.4558 D22 = 0.1743 R23 = 2.3658 D23 = 0.5181 N13 = 1.77250 .nu.13 = 49.6 R24 = -11.5514 D24 = 0.6024 R25 = .infin. D25 = 0.6627 N14 = 1.51633 .nu.14 = 64.1 R26 = .infin.__________________________________________________________________________F 1. 2.59 5.52__________________________________________________________________________D5 0.2560 1.7018 2.4156D10 2.7509 1.3051 0.5914D11 1.6594 0.9502 0.1374D16 0.4578 1.1671 1.9798__________________________________________________________________________f1 = 5.895f2 = -1.566f3 = 2.560f4 = 3.025__________________________________________________________________________
__________________________________________________________________________Numerical Example 4__________________________________________________________________________F = 1.00-5.52 FNO = 1:1.25-1.75 2.omega. = 51.6.degree.-10.0.degree.__________________________________________________________________________ R1 = 15.2954 D1 = 0.2173 N1 = 1.80518 .nu.1 = 25.4 R2 = 5.0694 D2 = 0.6941 N2 = 1.51633 .nu.2 = 64.1I R3 = -9.9980 D3 = 0.0181 R4 = 3.1081 D4 = 0.3561 N3 = 1.63854 .nu.3 = 55.4 R5 = 7.8559 D5 = Variable R6 = -11.2545 D6 = 0.1207 N4 = 1.78590 .nu.4 = 44.2 R7 = 1.8052 D7 = 0.3458II R8 = -3.2227 D8 = 0.1086 N5 = 1.60311 .nu.5 = 60.7 R9 = 1.9118 D9 = 0.3803 N6 = 1.84666 .nu.6 = 23.9 R10 = 9.5983 D10 = Variable R11 = Stop D11 = Variable R12 = 8.0065 D12 = 0.4467 N7 = 1.65844 .nu.7 = 50.9 R13 = -3.2508 D13 = 0.0181III R14 = 3.3195 D14 = 0.6157 N8 = 1.65844 .nu.8 = 50.9 R15 = -2.6560 D15 = 0.1207 N9 = 1.84666 .nu.9 = 23.9 R16 = -81.1255 D16 = Variable R17 = -1.9997 D17 = 0.1207 N10 = 1.51633 .nu.10 = 64.1 R18 = 11.5917 D18 = 0.9102 R19 = 8.9981 D19 = 0.4225 N11 = 1.65844 .nu.11 = 50.9 R20 = -2.6952 D20 = 0.0181IV R21 = 2.5713 D21 = 0.1207 N12 = 1.84666 .nu.12 = 23.9 R22 = 1.3604 D22 = 0.1418 R23 = 2.2585 D23 = 0.4587 N13 = 1.69680 .nu.13 = 55.5 R24 = -7.1526 D24 = 0.2414 R25 = .infin. D25 = 0.6640 N14 = 1.51633 .nu.14 = 64.1 R26 = .infin.__________________________________________________________________________F 1. 2.73 5.52__________________________________________________________________________D5 0.1609 1.6699 2.3304D10 3.0545 1.5455 0.8850D11 1.4262 0.7754 0.1155D16 0.4587 1.1096 1.7695__________________________________________________________________________f1 = 5.702f2 = -1.449f3 = 2.354f4 = 3.433__________________________________________________________________________
__________________________________________________________________________Numerical Example 5__________________________________________________________________________F = 1.00-5.52 FNO = 1:1.25-1.75 2.omega. = 51.6.degree.-10.0.degree.__________________________________________________________________________ R1 = 9.4632 D1 = 0.2173 N1 = 1.80518 .nu.1 = 25.4 R2 = 3.9788 D2 = 0.6941 N2 = 1.60311 .nu.2 = 60.7I R3 = -11.0830 D3 = 0.0181 R4 = 3.0476 D4 = 0.3863 N3 = 1.69680 .nu.3 = 55.5 R5 = 4.4949 D5 = Variable R6 = -101.0634 D6 = 0.1207 N4 = 1.77250 .nu.4 = 49.6 R7 = 1.9551 D7 = 0.3564II R8 = -2.8723 D8 = 0.1207 N5 = 1.69700 .nu.5 = 48.5 R9 = 2.1208 D9 = 0.3803 N6 = 1.84666 .nu.6 = 23.9 R10 = -25.1832 D10 = Variable R11 = Stop D11 = Variable R12 = 23.1783 D12 = 0.4467 N7 = 1.7725 .nu.7 = 49.6 R13 = -4.0743 D13 = 0.0181III R14 = 3.6035 D14 = 0.6157 N8 = 1.69700 .nu.8 = 48.5 R15 = -3.6749 D15 = 0.1207 N9 = 1.84666 .nu.9 = 23.9C R16 = 9.6393 D16 = Variable R17 = -2.0868 D17 = 0.1207 N10 = 1.69680 .nu.10 = 55.5 R18 = -7.0810 D18 = 0.6045 R19 = 3.6021 D19 = 0.6036 N11 = 1.80610 .nu.11 = 40.9 R20 = -8.6183 D20 = 0.0181 R21 = 3.6281 D21 = 0.1207 N12 = 1.84666 .nu.12 = 23.9IV R22 = 1.7616 D22 = 0.3234 R23 = 6.6746 D23 = 0.3863 N13 = 1.56384 .nu.13 = 60.7 R24 = -3.7392 D24 = 0.0181 R25 = 2.4395 D25 = 0.4225 N14 = 1.60311 .nu.14 = 60.7 R26 = -132.8169 D26 = 0.3622 R27 = .infin. D27 = 0.6640 N15 = 1.51633 .nu.15 = 64.1 R28 = .infin.__________________________________________________________________________F 1. 2.28 5.52__________________________________________________________________________D5 0.1332 1.3404 2.1372D10 2.2157 1.0085 0.2117D11 2.6044 1.7049 0.3175D16 0.4587 1.3582 2.7457__________________________________________________________________________f1 = 5.867f2 = -1.811f3 = 3.259f4 = 2.293__________________________________________________________________________
__________________________________________________________________________Numerical Example 6__________________________________________________________________________F = 1.00-5.52 FNO = 1:1.40-2.00 2.omega. = 45.6.degree.-8.8.degree.__________________________________________________________________________ R1 = 5.4504 D1 = 0.2895 N1 = 1.77250 .nu.1 = 49.6 R2 = 10.8059 D2 = 0.0158I R3 = 4.8950 D3 = 0.1895 N2 = 1.80518 .nu.2 = 25.4 R4 = 2.2143 D4 = 0.5263 N3 = 1.77250 .nu.3 = 49.6 R5 = 26.9677 D5 = Variable R6 = -7.8906 D6 = 0.1053 N4 = 1.78590 .nu.4 = 44.2 R7 = 1.6429 D7 = 0.2794II R8 = -2.8976 D8 = 0.0947 N5 = 1.60311 .nu.5 = 60.7 R9 = 1.6441 D9 = 0.3316 N6 = 1.84666 .nu.6 = 23.9 R10 = 7.6211 D10 = Variable R11 = Stop D11 = Variable R12 = 8.4797 D12 = 0.3895 N7 = 1.65844 .nu.7 = 50.9 R13 = -2.8606 D13 = 0.0158III R14 = 2.6423 D14 = 0.5368 N8 = 1.65844 .nu.8 = 50.9 R15 = -2.5323 D15 = 0.1053 N9 = 1.84666 .nu.9 = 23.9 R16 = 1449.2905 D16 = Variable R17 = -1.9317 D17 = 0.1053 N10 = 1.51633 .nu.10 = 64.1 R18 = 9.4622 D18 = 0.7647 R19 = 63.0253 D19 = 0.3684 N11 = 1.65844 .nu.11 = 50.9 R20 = -2.2605 D20 = 0.0158IV R21 = 2.3409 D21 = 0.1053 N12 = 1.84666 .nu.12 = 23.9 R22 = 1.2711 D22 = 0.1499 R23 = 2.4216 D23 = 0.4000 N13 = 1.69680 .nu.13 = 55.5 R24 = -5.2788 D24 = 0.2105 R25 = .infin. D25 = 0.5789 N14 = 1.51633 .nu.14 = 64.1 R26 = .infin.__________________________________________________________________________F 1. 2.73 5.52__________________________________________________________________________D5 0.1181 1.4339 2.010D10 2.6191 1.3033 0.7273D11 1.2408 0.6733 0.0979D16 0.40 0.9675 1.5429__________________________________________________________________________fl = 5.182f2 = -1.263f3 = 2.053f4 = 3.886__________________________________________________________________________
__________________________________________________________________________Numerical Example 7__________________________________________________________________________F = 8.30-45.84 FNO = 1:1.2-1.7 2.omega. = 51.5.degree.-10.0.degree.__________________________________________________________________________ R1 = 126.02 D1 = 1.6 N1 = 1.80518 .nu.1 = 25.4 R2 = 41.71 D2 = 5.5 N2 = 1.60311 .nu.2 = 60.7I R3 = -82.70 D3 = 0.15 R4 = 26.94 D4 = 2.8 N3 = 1.62299 .nu.3 = 58.2 R5 = 52.37 D5 = Variable R6 = -126.00 D6 = 1.00 N4 = 1.77250 .nu.4 = 49.6 R7 = 16.21 D7 = 2.88II R8 = -24.86 D8 = 1.0 N5 = 1.6968 .nu.5 = 55.5 R9 = 16.83 D9 = 3.5 N6 = 1.84666 .nu.6 = 23.9 R10 = 886.33 D10 = Variable R11 = Stop D11 = Variable R12 = 101.08 D12 = 3.2 N7 = 1.71300 .nu.7 = 53.8 R13 = -32.81 D13 = 0.15III R14 = 32.19 D14 = 4.6 N8 = 1.69680 .nu.8 = 55.5 R15 = -24.48 D15 = 1.0 N9 = 1.84666 .nu.9 = 23.9 R16 = -280.56 D16 = Variable R17 = -18.73 D17 = 1.0 N10 = 1.60311 .nu.10 = 60.7IV-1 R18 = 339.07 D18 = 7.01 R19 = 62.92 D19 = 4.3 N11 = 1.69680 .nu.11 = 55.5 R20 = -26.84 D20 = 0.15 R21 = 19.50 D21 = 1.0 N12 = 1.84666 .nu.12 = 23.9IV-2 R22 = 11.89 D22 = 1.41 R23 = 18.74 D23 = 4.3 N13 = 1.71300 .nu.13 = 53.8 R24 = -91.08 D24 = 5.0 R25 = .infin. D25 = 5.5 N14 = 1.51633 .nu.14 = 64.1 R26 = .infin.__________________________________________________________________________F 8.3 45.84__________________________________________________________________________D5 2.1140 20.039D10 22.838 4.914D11 13.701 1.068D16 3.800 16.433__________________________________________________________________________f4-1 = -29.41f4-2 = 18.83__________________________________________________________________________
__________________________________________________________________________Numerical Example 8__________________________________________________________________________F = 10.4-57.6 FNO = 1:1.20-1.70 2.omega. = 56.4.degree.-11.1.degree.__________________________________________________________________________ R1 = 172.71 D1 = 2.25 N1 = 1.80518 .nu.1 = 25.4 R2 = 43.6 D2 = 8.8 N2 = 1.60311 .nu.2 = 60.7I R3 = -85.13 D3 = 0.15 R4 = 30.91 D4 = 3.8 N3 = 1.62299 .nu.3 = 58.2 R5 = 65.49 D5 = Variable R6 = 203.42 D6 = 1.2 N4 = 1.69680 .nu.4 = 55.5 R7 = 18.28 D7 = 4.3II R8 = -22.25 D8 = 1.05 N5 = 1.69680 .nu.5 = 55.5 R9 = 22.26 D9 = 3.2 N6 = 1.84666 .nu.6 = 23.9 R10 = 175.74 D10 = Variable R11 = Stop D11 = Variable R12 = 4913.99 D12 = 3.3 N7 = 1.74950 .nu.7 = 35.3 R13 = -34.63 D13 = 0.15III R14 = 37.25 D14 = 6.2 N8 = 1.62299 .nu.8 = 58.2 R15 = -24.96 D15 = 1.18 N9 = 1.84666 .nu.9 = 23.9 R16 = -61.95 D16 = Variable R17 = -21.24 D17 = 1.2 N10 = 1.59270 .nu.10 = 35.3IV-1 R18 = -480.10 D18 = 8.2 R19 = -449.16 D19 = 4.55 N11 = 1.7130C .nu.11 = 53.8 R20 = -26.86 D20 = 0.15 R21 = 47.81 D21 = 1.3 N12 = 1.84666 .nu.12 = 23.9 R22 = 19.77 D22 = 2.9IV-2 R23 = 68.25 D23 = 4.2 N13 = 1.60311 .nu.13 = 60.7 R24 = -42.60 D24 = 0.15 R25 = 22.85 D25 = 4.2 N14 = 1.51633 .nu.14 = 64.1 R26 = 360.36 D26 = 5.0 R27 = .infin. D27 = 5.0 N15 = 1.51633 .nu.15 = 64.1 R28 = .infin.__________________________________________________________________________F 10.44 57.57__________________________________________________________________________D5 1.550 21.270D10 22.841 3.121D11 17.102 2.844D16 4.485 18.743__________________________________________________________________________f4-1 = -37.55f4-2 = 23.19__________________________________________________________________________
__________________________________________________________________________Numerical Example 9__________________________________________________________________________F = 10.5-57.9 FNO = 1:1.20-1.7 2.omega. = 56.3.degree.-11.0.degree.__________________________________________________________________________ R1 = 176.89 D1 = 2.3 N1 = 1.80518 .nu.1 = 25.4 R2 = 48.64 D2 = 8.2 N2 = 1.51633 .nu.2 = 64.1I R3 = -85.44 D3 = 0.15 R4 = 32.26 D4 = 4.1 N3 = 1.63854 .nu.3 = 55.4 R5 = 97.78 D5 = Variable R6 = -118.54 D6 = 1.2 N4 = 1.78590 .nu.4 = 44.2 R7 = 17.62 D7 = 3.8II R8 = -25.15 D8 = 1.1 N5 = 1.60311 .nu.5 = 60.7 R9 = 20.77 D9 = 3.6 N6 = 1.84666 .nu.6 = 23.9 R10 = 334.24 D10 = Variable R11 = Stop D11 = Variable R12 = 146.27 D12 = 4.1 N7 = 1.65844 .nu.7 = 50.9 R13 = -29.62 D13 = 0.15III R14 = 35.85 D14 = 6.0 N8 = 1.65844 .nu.8 = 50.9 R15 = -25.88 D15 = 1.3 N9 = 1.84666 .nu.9 = 23.9 R16 = -173.81 D16 = Variable R17 = -19.86 D17 = 1.2 N10 = 1.51633 .nu.10 = 64.1IV-1 R18 = 117.72 D18 = 7.6 R19 = 102.99 D19 = 4.6 N11 = 1.65844 .nu.11 = 50.9 R20 = -27.17 D20 = 3.08 R21 = 110.25 D21 = 1.2 N12 = 1.84666 .nu.12 = 23.9 R22 = 19.40 D22 = 3.4IV-2 R23 = 1604.82 D23 = 3.4 N13 = 1.62299 .nu.13 = 58.2 R24 = -29.39 D24 = 0.15 R25 = 20.64 D25 = 5.4 N14 = 1.62299 .nu.14 = 58.2 R26 = -425.86 D26 = 2.0 R27 = .infin. D27 = 5.5 N15 = 1.51633 .nu.15 = 64.1 R28 = .infin.__________________________________________________________________________F 10.46 57.92__________________________________________________________________________D5 2.1860 22.771D10 22.888 2.932D11 16.349 2.493D16 4.025 18.081__________________________________________________________________________f4-1 = -32.82f4-2 = 22.42__________________________________________________________________________
__________________________________________________________________________Numerical Example 10__________________________________________________________________________F = 10.8-81.8 FNO = 1:1.60-1.80 2.omega. = 54.8.degree.-7.8.degree.__________________________________________________________________________ R1 = 159.99 D1 = 2.2 N1 = 1.80518 .nu.1 = 25.4 R2 = 48.72 D2 = 8.0 N2 = 1.60311 .nu.2 = 60.7I R3 = -106.25 D3 = 0.15 R4 = 31.35 D4 = 4.3 N3 = 1.62299 .nu.3 = 58.2 R5 = 63.09 D5 = Variable R6 = -100.99 D6 = 1.1 N4 = 1.77250 .nu.4 = 49.6 R7 = 19.74 D7 = 4.26II R8 = -31.02 D8 = 1.0 N5 = 1.69680 .nu.5 = 55.5 R9 = 19.71 D9 = 4.0 N6 = 1.84666 .nu.6 = 23.9 R10 = 170.54 D10 = Variable R11 = Stop D11 = Variable R12 = 160.59 D12 = 1.2 N7 = 1.84666 .nu.7 = 23.9 R13 = 29.84 D13 = 6.0 N8 = 1.69350 .nu.8 = 53.2III R14 = -35.49 D14 = 0.15 R15 = 43.14 D15 = 4.0 N9 = 1.77250 .nu.9 = 49.6 R16 = -115.44 D16 = Variable R17 = -27.55 D17 = 1.2 N10 = 1.77250 .nu.10 = 49.6 R18 = 99.14 D18 = 8.15IV-1 R19 = 664.99 D19 = 4.6 N11 = 1.63636 .nu.11 = 35.4 R20 = -28.70 D20 = 10.93 R21 = -487.44 D21 = 1.2 N12 = 1.84666 .nu.12 = 23.9 R22 = 24.54 D22 = 0.48 R23 = 30.12 D23 = 6.0 N13 = 1.48749 .nu.13 = 70.2IV-2 R24 = -26.61 D24 = 0.15 R25 = 21.22 D25 = 4.3 N14 = 1.48749 .nu.14 = 70.2 R26 = -981.01 D26 = 5.0 R27 = .infin. D27 = 5.0 N15 = 1.51633 .nu.15 = 64.1 R28 = .infin.__________________________________________________________________________F 10.80 81.82__________________________________________________________________________D5 1.997 26.338D10 25.223 0.882D11 16.787 1.036D16 5.000 20.751__________________________________________________________________________f4-1 = -288.78f4-2 = 38.37__________________________________________________________________________
__________________________________________________________________________Numerical Example 11__________________________________________________________________________F = 10.3-57.0 FNO = 1:1.20-1.70 2.omega. = 57.0.degree.-11.2.degree.__________________________________________________________________________ R1 = 152.46 D1 = 2.25 N1 = 1.80518 .nu.1 = 25.4 R2 = 41.36 D2 = 8.8 N2 = 1.60311 .nu.2 = 60.7I R3 = -85.05 D3 = 0.15 R4 = 30.41 D4 = 3.8 N3 = 1.62299 .nu.3 = 58.2 R5 = 60.91 D5 = Variable R6 = 203.44 D6 = 1.1 N4 = 1.69680 .nu.4 = 55.5 R7 = 18.43 D7 = 4.3II R8 = -21.78 D8 = 1.0 N5 = 1.69680 .nu.5 = 55.5 R9 = 21.78 D9 = 3.2 N6 = 1.84666 .nu.6 = 23.9 R10 = 184.02 D10 = Variable R11 = Stop D11 = Variable R12 = -474.39 D12 = 3.3 N7 = 1.74950 .nu.7 = 35.3 R13 = -33.26 D13 = 0.15III R14 = 39.4 D14 = 6.2 N8 = 1.62299 .nu.8 = 58.2 R15 = -23.23 D15 = 1.18 N9 = 1.84666 .nu.9 = 23.9 R16 = -52.34 D16 = Variable R17 = -24.76 D17 = 1.2 N10 = 1.59270 .nu.10 = 35.3 R18 = 308.42 D18 = 0.24IV-1 R19 = 275.06 D19 = 3.4 N11 = 1.74400 .nu.11 = 44.7 R20 = -181.12 D20 = 10.0 R21 = -149.24 D21 = 4.6 N12 = 1.72000 .nu.12 = 50.2 R22 = -28.86 D22 = 0.15 R23 = 73.25 D23 = 1.3 N13 = 1.84666 .nu.13 = 23.9 R24 = 19.7 D24 = 2.95IV-2 R25 = 65.08 D25 = 3.85 N14 = 1.64000 .nu.14 = 60.1 R26 = -40.45 D26 = 0.15 R27 = 19.32 D27 = 3.95 N15 = 1.60311 .nu.15 = 60.7 R28 = 218.42 D28 = 5.0 R29 = .infin. D29 = 5.5 N16 = 1.51633 .nu.16 = 64.1 R30 = .infin.__________________________________________________________________________F 10.32 57.00__________________________________________________________________________D5 1.365 21.085D10 23.000 3.280D11 16.688 2.390D16 4.497 18.795__________________________________________________________________________f4-1 = -53.39f4-2 = 22.20__________________________________________________________________________
______________________________________Numerical Example 12______________________________________F = 1-5.52 FNO = 1:1.425-1.75 2.omega. = 51.4.degree.-10.0.degree.______________________________________R1 = 15.1717 D1 = 0.1928 N1 = 1.80518 .nu.1 = 25.4R2 = 5.0971 D2 = 0.6506 N2 = 1.60311 .nu.2 = 60.7R3 = -10.0692 D3 = 0.0181R4 = 3.2671 D4 = 0.3614 N3 = 1.62299 .nu.3 = 58.2R5 = 6.3240 D5 = VariableR6 = -14.6297 D6 = 0.1205 N4 = 1.77250 .nu.4 = 49.6R7 = 1.9562 D7 = 0.3460R8 = -3.0111 D8 = 0.1205 N5 = 1.69680 .nu.5 = 55.5R9 = 2.0179 D9 = 0.4217 N6 = 1.84666 .nu.6 = 23.9R10 = 104.2199 D10 = VariableR11 = Stop D11 = VariableR12 = 11.7622 D12 = 0.3855 N7 = 1.71300 .nu.7 = 53.8R13 = - 3.9049 D13 = 0.0181R14 = 3.8392 D14 = 0.5542 N8 = 1.69680 .nu.8 = 55.5R15 = -2.9425 D15 = 0.1205 N9 = 1.84666 .nu.9 = 23.9R16 = -47.3102 D16 = VariableR17 = -2.2482 D17 = 0.1205 N10 = 1.60311 .nu.10 = 60.7R18 = 36.2018 D18 = 0.8447R19 = 6.7139 D19 = 0.5181 N11 = 1.69680 .nu.11 = 55.5R20 = -3.3161 D20 = 0.0181R21 = 2.5036 D21 = 0.1205 N12 = 1.84666 .nu.12 = 23.9R22 = 1.4558 D22 = 0.1743R23 = 2.3658 D23 = 0.5181 N13 = 1.77250 .nu.13 = 49.6R24 = -11.5514 D24 = 0.6024R25 = .infin. D25 = 0.6627 N14 = 1.51633 .nu.14 = 64.1R26 = .infin.______________________________________F 1 2.59 5.52______________________________________D5 0.2560 1.7018 2.4156D10 2.7509 1.3051 0.5914D11 1.6594 0.9502 0.1374D16 0.4578 1.1671 1.9798______________________________________f4-1 = -3.5056f4-2 = 2.2467______________________________________
______________________________________Numerical Example 13______________________________________F = 1-5.52 FNO = 1:1.25-1.77 2.omega. = 51.6.degree.-10.degree.______________________________________R1 = 16.1923 D1 = 0.2171 N1 = 1.80518 .nu.1 = 25.4R2 = 5.1674 D2 = 0.6936 N2 = 1.51633 .nu.2 = 64.1R3 = -8.8452 D3 = 0.0181R4 = 3.2259 D4 = 0.3559 N3 = 1.63854 .nu.3 = 55.4R5 = 7.8033 D5 = VariableR6 = -10.8380 D6 = 0.1206 N4 = 1.78590 .nu.4 = 44.2R7 = 1.8100 D7 = 0.3607R8 = -3.2322 D8 = 0.1086 N5 = 1.60311 .nu.5 = 60.7R9 = 1.9383 D9 = 0.3800 N6 = 1.84666 .nu.6 = 23.9R10 = 18.3253 D10 = VariableR11 = Stop D11 = VariableR12 = 8.0362 D12 = 0.4463 N7 = 1.65844 .nu.7 = 50.9R13 = - 3.3229 D13 = 0.0181R14 = 3.3031 D14 = 0.6152 N8 = 1.65844 .nu.8 = 50.9R15 = -2.6940 D15 = 0.1206 N9 = 1.84666 .nu.9 = 23.9R16 = 32.6153 D16 = VariableR17 = -1.9274 D17 = 0.1206 N10 = 1.51633 .nu.10 = 64.1R18 = 12.2160 D18 = 0.8974R19 = 8.6309 D19 = 0.4222 N11 = 1.65844 .nu.11 = 50.9R20 = -2.7877 D20 = 0.0181R21 = 2.4131 D21 = 0.1206 N12 = 1.84666 .nu.12 = 23.9R22 = 1.4212 D22 = 0.1435R23 = 2.2034 D23 = 0.4584 N13 = 1.69680 .nu.13 = 55.5R24 = -6.8488 D24 = 0.2413R25 = .infin. D25 = 0.6634 N14 = 1.51633 .nu.14 = 64.1R26 = .infin.______________________________________F 1 2.74 5.52______________________________________D5 0.2589 1.7667 2.4152D10 2.7421 1.2343 0.5858D11 1.6550 0.8987 0.1426D16 0.4584 1.2146 1.9708______________________________________f4-1 = -3.2149f4-2 = -2.1368______________________________________
______________________________________Numerical Example 14______________________________________F = 1-5.52 FNO = 1:1.25-1.75 2.omega. = 56.4.degree.-11.0.degree.______________________________________R1 = 16.3271 D1 = 0.2153 N1 = 1.80518 .nu.1 = 25.4R2 = 4.1903 D2 = 0.8419 N2 = 1.60311 .nu.2 = 60.7R3 = -8.2045 D3 = 0.0144R4 = 2.9687 D4 = 0.3636 N3 = 1.62299 .nu.3 = 58.2R5 = 6.3151 D5 = VariableR6 = 19.4638 D6 = 0.1052 N4 = 1.69680 .nu.4 = 55.5R7 = 1.7490 D7 = 0.4114R8 = -2.1231 D8 = 0.0957 N5 = 1.69680 .nu.5 = 55.5R9 = 2.1236 D9 = 0.3061 N6 = 1.84666 .nu.6 = 23.9R10 = 17.1111 D10 = VariableR11 = Stop D11 = VariableR12 = 111.1357 D12 = 0.3157 N7 = 1.74950 .nu.7 = 35.3R13 = -3.3613 D13 = 0.0144R14 = 3.6305 D14 = 0.5932 N8 = 1.62299 .nu.8 = 58.2R15 = -2.3417 D15 = 0.1129 N9 = 1.84666 .nu.9 = 23.9R16 = -5.7841 D16 = VariableR17 = -2.0491 D17 = 0.1148 N10 = 1.59270 .nu.10 = 35.3R18 = 24.8116 D18 = 0.7845R19 = -56.2850 D19 = 0.4401 N11 = 1.72000 .nu.11 = 50.2R20 = -2.6179 D20 = 0.0144R21 = 5.6440 D21 = 0.1244 N12 = 1.84666 .nu.12 = 23.9R22 = 1.9298 D22 = 0.2822R23 = 7.6877 D23 = 0.3683 N13 = 1.64000 .nu.13 = 60.1R24 = -3.9225 D24 = 0.0144R25 = 2.3208 D25 = 0.3779 N14 = 1.60311 .nu.14 = 60.7R26 = 19.0217 D26 = 0.4784R27 = .infin. D27 = 0.4784 N15 = 1.51633 .nu.15 = 64.1R28 = .infin.______________________________________F 1.00 3.10 5.52______________________________________D5 0.1530 1.5880 2.0396D10 2.1992 0.7642 0.3126D11 1.6231 0.8344 0.2552D16 0.4302 1.2189 1.7981______________________________________f4-1 = -3.7756f4-2 = 2.2396______________________________________
______________________________________Numerical Example 15______________________________________F = 1-5.52 FNO = 1:1.25-1.78 2.omega. = 56.4.degree.-11.0.degree.______________________________________R1 = 16.5397 D1 = 0.2201 N1 = 1.80518 .nu.1 = 25.4R2 = 4.6294 D2 = 0.7847 N2 = 1.51633 .nu.2 = 64.1R3 = -8.3162 D3 = 0.0144R4 = 3.1504 D4 = 0.3923 N3 = 1.63854 .nu.3 = 55.4R5 = 10.0607 D5 = VariableR6 = -12.4582 D6 = 0.1148 N4 = 1.78590 .nu.4 = 44.2R7 = 1.6793 D7 = 0.3636R8 = -2.3591 D8 = 0.1053 N5 = 1.60311 .nu.5 = 60.7R9 = 1.9954 D9 = 0.3445 N6 = 1.84666 .nu.6 = 23.9R10 = 33.9903 D10 = VariableR11 = Stop D11 = VariableR12 = 13.9294 D12 = 0.3923 N7 = 1.65844 .nu.7 = 50.9R13 = - 2.8614 D13 = 0.0144R14 = 3.4504 D14 = 0.5742 N8 = 1.65844 .nu.8 = 50.9R15 = -2.4751 D15 = 0.1244 N9 = 1.84666 .nu.9 = 23.9R16 = -15.4552 D16 = VariableR17 = -1.9267 D17 = 0.1148 N10 = 1.51633 .nu.10 = 64.1R18 = 17.7685 D18 = 0.7273R19 = 10.5337 D19 = 0.4402 N11 = 1.65844 .nu.11 = 50.9R20 = -2.6152 D20 = 0.2947R21 = 8.5295 D21 = 0.1148 N12 = 1.84666 .nu.12 = 23.9R22 = 1.7630 D22 = 0.3254R23 = 26.8853 D23 = 0.3254 N13 = 1.62299 .nu.13 = 58.2R24 = -2.9308 D24 = 0.0144R25 = 1.9921 D25 = 0.5167 N14 = 1.62299 .nu.14 = 58.2R26 = -338.6609 D26 = 0.4785R27 = .infin. D27 = 0.5263 N15 = 1.51633 .nu.15 = 64.1R28 = .infin.______________________________________F 1.00 2.76 5.52______________________________________D5 0.2701 1.6098 2.1797D10 2.0893 0.7496 0.1797D11 1.6853 1.0109 0.3438D16 0.3828 1.0572 1.7242______________________________________f4-1 = -3.3599f4-2 = -2.1681______________________________________
______________________________________Numerical Example 16______________________________________F = 1-7.6 FNO = 1:1.45-1.97 2.omega. = 53.4.degree.-7.6.degree.______________________________________R1 = 9.0182 D1 = 0.2155 N1 = 1.80518 .nu.1 = 25.4R2 = 3.6301 D2 = 0.7182 N2 = 1.60311 .nu.2 = 60.7R3 = -466.7563 D3 = 0.0135R4 = 4.0205 D4 = 0.5746 N3 = 1.69680 .nu.3 = 55.5R5 = 32.3816 D5 = VariableR6 = .infin. D6 = 0.0988 N4 = 1.77250 .nu.4 = 49.6R7 = 1.6411 D7 = 0.4182R8 = -2.2175 D8 = 0.0898 N5 = 1.77250 .nu.5 = 49.6R9 = 1.8445 D9 = 0.4040 N6 = 1.84666 .nu.6 = 23.9R10 = -39.4252 D10 = VariableR11 = 29.6558 D11 = 0.1257 N7 = 1.84666 .nu.7 = 23.9R12 = 2.4178 D12 = 0.8080 N8 = 1.69350 .nu.8 = 53.2R13 = -3.4184 D13 = 0.0135R14 = 3.7126 D14 = 0.4489 N9 = 1.77250 .nu.9 = 49.6R15 = -172.6061 D15 = VariableR16 = Stop D16 = 0.3477R17 = -2.5609 D17 = 0.1077 N10 = 1.69680 .nu.10 = 55.5R18 = -20.1238 D18 = 0.8890R19 = -12.0853 D19 = 0.4040 N11 = 1.64769 .nu.11 = 33.8R20 = -2.4900 D20 = 0.6550R21 = -15.7120 D21 = 0.0898 N12 = 1.84666 .nu.12 = 23.9R22 = 1.8773 D22 = 0.1622R23 = 5.8664 D23 = 0.3591 N13 = 1.48749 .nu.13 = 70.2R24 = -2.0975 D24 = 0.0135R25 = 1.8748 D25 = 0.4040 N14 = 1.48749 .nu.14 = 70.2R26 = -9.4738 D26 = 0.4489R27 = .infin. D27 = 0.5387 N15 = 1.51633 .nu.15 = 64.1R28 = .infin.______________________________________F 1.00 2.48 7.60______________________________________D5 0.169 1.516 2.454D10 4.734 2.812 0.803D15 0.467 1.042 2.114______________________________________f4-1 = -4.2217f4-2 = 2.8228______________________________________
______________________________________Numerical Example 17______________________________________F = 1-7.61 FNO = 1:1.45-1.97 2.omega. = 51.4.degree.-7.2.degree.______________________________________R1 = 8.4913 D1 = 0.2063 N1 = 1.80518 .nu.1 = 25.4R2 = 3.5392 D2 = 0.6876 N2 = 1.60311 .nu.2 = 60.7R3 = -347.8193 D3 = 0.0129R4 = 3.9690 D4 = 0.5501 N3 = 1.69680 .nu.3 = 55.5R5 = 35.4997 D5 = VariableR6 = 24.8261 D6 = 0.0945 N4 = 1.77250 .nu.4 = 49.6R7 = 1.7915 D7 = 0.4003R8 = -2.4276 D8 = 0.0859 N5 = 1.77250 .nu.5 = 49.6R9 = 1.6691 D9 = 0.3868 N6 = 1.84666 .nu.6 = 23.9R10 = 8.8759 D10 = VariableR11 = 29.2530 D11 = 0.1203 N7 = 1.84666 .nu.7 = 23.9R12 = 3.2585 D12 = 0.7735 N8 = 1.69350 .nu.8 = 53.2R13 = -3.2590 D13 = 0.0129R14 = 3.4123 D14 = 0.4297 N9 = 1.77250 .nu.9 = 49.6R15 = 142.4386 D15 = VariableR16 = Stop D16 = 0.3400R17 = -2.2712 D17 = 0.1031 N10 = 1.69680 .nu.10 = 55.5R18 = 117.6700 D18 = 0.4788R19 = -5.0501 D19 = 0.3868 N11 = 1.68893 .nu.11 = 31.1R20 = -2.1241 D20 = 1.2921R21 = -12.0468 D21 = 0.0859 N12 = 1.84666 .nu.12 = 23.9R22 = 2.0094 D22 = 0.0452R23 = 3.4921 D23 = 0.3438 N13 = 1.48749 .nu.13 = 70.2R24 = -1.8264 D24 = 0.0129R25 = 1.8865 D25 = 0.3868 N14 = 1.48749 .nu.14 = 70.2R26 = -17.7691 D26 = 0.4297R27 = .infin. D27 = 0.5157 N15 = 1.51633 .nu.15 = 64.1R28 = .infin.______________________________________F 1.00 2.48 7.61______________________________________D5 0.1087 1.3979 2.2957D10 4.6037 2.7635 0.8401D15 0.4469 0.9980 2.0235______________________________________f4-1 = -17.1895f4-2 = 3.8417______________________________________
According to the invention, a high range compact zoom lens which enables a shortening of the total length and a shortening of the diameter of the first unit to be achieved with achievement of a reduction of the weight of the entire system.
Also, in the invention, even if the angular field is widened, the height of incidence of the oblique pencil on the first unit in the wide angle end can be relatively low, whereby the diameter of the first unit is prevented from increasing. Further, since the effective diameters of the third and fourth units behind the diaphragm are not so much increased, a wide angle compact zoom lens which enables the entire lens system to be reduced can be easily realized.
Also, because the position responsivity of each lens unit becomes small, the assembly can be made easy. Further, as the telephoto setting of narrow angular field is often used in outdoor photography, if the F-number in the telephoto end is regulated so as not to be an obstacle in actual practice, the diameter of the first unit can be controlled. Thus, a compact zoom lens can be easily achieved.

Number	Date	Country
60-139382	Jun 1985	JPX
60-139383	Jun 1985	JPX
60-139384	Jun 1985	JPX
60-139385	Jun 1985	JPX
60-139386	Jun 1985	JPX

Number	Name	Date	Kind
4256381	Kreitzer	Mar 1981
4439017	Yamaguchi	Mar 1984

Compact zoom lens

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