JPH0990227A - Variable power optical system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To shorten the overall length of the system at its telephoto end and reduce the size by moving a 1st and a 5th lens group toward a body so that the air intervals between 1st and 2nd groups, and 3rd and 4th lens groups increase and the air intervals between the 2nd and 3rd lens groups, and 4th and 5th lens groups decrease, and specifying the on-axis air interval and focal length. SOLUTION: When the power is varied, the 1st and 5th lens groups G1 and G5 move toward the body so that the air intervals between the 1st and 2nd lens groups G1 and G2, and 3rd and 4th lens groups G3 and G4 increase and the air intervals between the 2nd and 3rd lens groups G2 and G3, and 4th and 5th lens groups G4 and G5 decrease. Then the conditions shown by the formulae are met, where D1W and D1T are the on-axis air intervals between the 1st and 2nd lens groups G1 and G2 at the wide-angle end and telephoto end, f1-f3 are the focal lengths of the 1st-3rd lens groups G1-G3, and ft and fw are the focal lengths of the whole system at the telephoto end and wide-angle end.

Description

Detailed Description of the Invention

[0001]

The present invention relates to a variable power optical system,
In particular, it relates to a compact variable power optical system having a short overall lens length at the telephoto end.

[0002]

2. Description of the Related Art In recent years, in lens shutter type cameras,
Cameras equipped with zoom lenses are becoming mainstream. In particular, a camera provided with a so-called high-zoom zoom lens having a zoom ratio of more than 3 is becoming popular. In the case of a lens shutter type camera, the camera is required to be small and lightweight even if the zoom ratio of the taking lens is high.
Therefore, it is important to develop a lens system suitable for downsizing the lens system and shortening the total lens length.

A zoom lens having a zoom ratio of about 2 is composed of a positive lens group and a negative lens group in order from the object side, and the distance between the positive lens group and the negative lens group is changed during zooming. The positive and negative two-group type in which each lens group is moved was the mainstream. In the case of this type of zoom lens, only the second lens group was responsible for zooming. Therefore, if it is attempted to realize a zoom ratio exceeding 2 times,
The use magnification of the lens group is positively increased, and performance deterioration during manufacturing tends to be large. Further, the total lens length changes greatly due to zooming, and it is difficult to shorten the total lens length at the telephoto end.

In order to realize a compact high-magnification zoom lens, the positive lens group of the positive / negative two-group zoom lens is divided into a plurality of lens groups, etc., to increase the number of movable lens groups constituting the zoom lens. Various proposals for zoom lenses have been made. These proposals are disclosed in, for example, Japanese Patent Laid-Open No.
No. 265788 and Japanese Patent Application Laid-Open No. 7-27979 filed by the present applicant.

The zoom lens disclosed in Japanese Unexamined Patent Publication No. 6-265788 has a first lens group having a positive refractive power, a second lens group having a negative refractive power, a third lens group having a positive refractive power, and It is composed of a fourth lens unit having a negative refractive power. The zoom lens disclosed in Japanese Patent Laid-Open No. 7-27979 discloses a first lens group having a positive refractive power in order from the object side.
The second lens unit has a negative refractive power, the third lens unit has a positive refractive power, the fourth lens unit has a positive refractive power, and the fifth lens unit has a negative refractive power. Both lens systems have in common that a negative lens group is arranged closest to the image side and that all lens groups move to the object side during zooming from the wide-angle end to the telephoto end.

This is the most image in a lens system, such as a lens shutter type camera, in which back focus is not restricted and the lens diameter of the lens group constituting the lens system is required to be small and the total lens length is required to be shortened. This is because it is effective to dispose the negative lens group on the side. Also, at the wide-angle end, the back focus is shortened so that the off-axis light flux that passes through the negative lens group moves away from the optical axis due to the change in the angle of view, thereby correcting the on-axis aberration and the off-axis aberration independently. ing.

Further, by increasing the back focus at the time of zooming from the wide-angle end to the telephoto end, the height of the off-axis light flux passing through the negative lens group is changed by zooming, and the fluctuation of off-axis aberrations due to zooming is changed. Is suppressed so that good imaging performance can be obtained. Further, by shortening the total lens length at the wide-angle end, the off-axis light flux passing through the first lens group is brought closer to the optical axis, and the lens diameter of the first lens group is reduced.

[0008]

However, in the zoom lens disclosed in Japanese Patent Laid-Open No. 6-265788, the proportion of the fourth lens group that is responsible for zooming is small, but the proportion of the second lens group that is responsible for zooming is small. large. As a result, when changing the magnification,
Since the height of the off-axis light beam that passes through the second lens group changes largely, but the height hardly changes, it is difficult to suppress the fluctuation of the off-axis aberration that occurs during zooming.

Certainly, by using many aspherical surfaces, it is possible to correct aberrations in a limited focal length range such as the wide-angle end, the intermediate focal length state, and the telephoto end, but from the wide-angle end to the telephoto end. It is difficult to suppress the fluctuation of the off-axis aberration over the entire focal length range to the edge. Further, although the manufacturing technique of the aspherical lens is improved, a high spatial frequency component of an image is lost due to an error in surface accuracy that occurs during manufacturing. Therefore, especially in an optical system that uses many aspherical surfaces,
It was easy to obtain image quality with low contrast. Further, in the aspherical lens, the performance is easily deteriorated even with a small amount of eccentricity, and it is difficult to manufacture.

Also in the zoom lens disclosed in Japanese Patent Laid-Open No. 7-27979, since the focal length of the second lens group is negatively small with respect to the focal length of the entire system at the telephoto end, the diverging action is strong, and therefore the lens at the telephoto end is strong. It was not very suitable for shortening the total length.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a compact variable power optical system having a short total lens length at the telephoto end.

[0012]

In order to solve the above problems, in the present invention, a first lens group G1 having a positive refractive power and a second lens group having a negative refractive power are arranged in order from the object side. G2 and the third lens group G3 having a positive refractive power
And a fourth lens group G4 having a positive refracting power and a fifth lens group G5 having a negative refracting power, in the variable power optical system, when changing the magnification from the wide-angle end to the telephoto end, The air gap between the lens group G1 and the second lens group G2 increases, the air gap between the second lens group G2 and the third lens group G3 decreases, and the third lens group G3 and the fourth lens The air distance from the group G4 increases, and the fourth lens group G
At least the fifth lens group G1 and the fifth lens group G5 move to the object side so that the air gap between the fourth lens group G5 and the fifth lens group G5 decreases, and the first lens group G1 and the first lens group G1 at the wide-angle end. The axial air distance between the second lens group G2 and the second lens group G2 is D1W, the axial air distance between the first lens group G1 and the second lens group G2 at the telephoto end is D1T, and the fourth lens group G4 at the wide-angle end is The fifth lens group G5
D4W is the axial air space between the
The axial air distance between the lens group G4 and the fifth lens group G5 is D4T, the focal length of the first lens group G1 is f1, the focal length of the second lens group G2 is f2, and the third lens is When the focal length of the group G3 is f3, the focal length of the entire system at the telephoto end is ft, and the focal length of the entire system at the wide-angle end is fw, 1.5 <(D1T-D1W) / (D4W-D4T) Provided is a variable power optical system which satisfies the condition of <2.1 0.39 <f3 / f1 <0.55 0.25 <f2 / (fw · ft) ^1/2 <0.32. .

According to a preferred aspect of the present invention, the use magnification of the second lens group G2 at the telephoto end is β2t, the use magnification of the second lens group G2 at the wide-angle end is β2w, and the fifth magnification at the telephoto end. The use magnification of the lens group G5 is β5t, the use magnification of the fifth lens group G5 at the wide-angle end is β5w, and the focal length of the entire system at the telephoto end is ft.
When the focal length of the entire system at the wide-angle end is fw, 0.32 <(β2t / β2w) / (ft / fw) <0.45 0.5 <(β5t / β5w) / (ft / fw) The condition <0.7 is satisfied.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION First, the function of each lens group constituting the variable power optical system according to the present invention will be described. In the present invention, the fifth lens group G5 disposed closest to the image side also has a negative refractive power, as in the multi-group zoom lens according to the related art. Then, by shortening the back focus at the wide-angle end, the height of the off-axis light flux passing through the fifth lens group G5 is changed according to the angle of view, so that the on-axis aberration and the off-axis aberration are independently corrected. I have to.

However, if the back focus is made too short, the off-axis light flux passing through the fifth lens group G5 is too far away from the optical axis, so that the lens diameter cannot be reduced. Further, dust is likely to be attached to the lens surface closest to the image side, but if the back focus becomes too short, the dust attached to the lens surface will be reflected in the photograph. Therefore, it is important to set an appropriate back focus at the wide-angle end.

At the wide-angle end, the first lens group G1 having a positive refractive power and the second lens group G2 having a negative refractive power are brought close to each other to make the combined refractive power a strong negative refractive power so that a sufficient back focus can be obtained. I have to. In addition, the first lens group G1
The off-axis light flux passing through the lens is made as close to the optical axis as possible to reduce the lens diameter. At the telephoto end, by widening the distance between the first lens group G1 and the second lens group G2, the converging action of the first lens group G1 is strengthened and the overall lens length is shortened.

In the present invention, the second lens group G
By increasing the ratio responsible for the scaling of 2 to a certain degree,
High zoom ratio is realized. In addition, the second lens group G2,
By constructing a biconcave lens having a strong negative refractive power, a biconvex lens, and a negative lens having a concave surface facing the object side in order from the object side, fluctuations of off-axis aberrations occurring in the second lens group G2 during zooming. Can be satisfactorily corrected.

Among the lenses constituting the second lens group G2, the biconcave lens arranged on the object side is provided with sufficient back focus while suppressing the off-axis aberration generated when the off-axis light flux passes at the wide-angle end. As can be obtained, it is desirable to use high refractive index glass. Then, by making the curvature of the image-side lens surface stronger than the curvature of the object-side lens surface, it is possible to favorably correct the axial aberration by the air gap formed between the biconcave lens and the negative lens. .

The third lens group G3 and the fourth lens group G4 are both lens groups having a positive refracting power, but at the wide-angle end, the third lens group G3 and the fourth lens group G4 are brought close to each other to combine them. The refractive power is a strong positive refractive power. Then, at the telephoto end, the third lens group G3 and the fourth lens group G4
Not only is the combined refracting power weakened by widening the distance between the second lens group G2 and the third lens group G3, but the converging action is strengthened by shortening the distance between the second lens group G2 and the third lens group G3, thereby shortening the overall lens length.

From the above, in the variable power optical system according to the present invention, the first lens group G1 having a positive refractive power is arranged in order from the object side.
A second lens group G2 having negative refracting power, a third lens group G3 having positive refracting power, a fourth lens group G4 having positive refracting power, and a fifth lens group G5 having negative refracting power. At the time of zooming from the telephoto end to the telephoto end, the distance between the first lens group G1 and the second lens group G2 increases, and the second lens group G2 and the third lens group G3.
The distance between the third lens group G3 and the fourth lens group G3 decreases.
At least the fifth lens group G1 and the fifth lens group G5 move toward the object side such that the distance between the fourth lens group G4 and the fourth lens group G4 increases and the distance between the fourth lens group G4 and the fifth lens group G5 decreases. By satisfying predetermined conditional expressions (1) to (3) described later, a variable power optical system having a short overall lens length at the telephoto end and a high zoom ratio is achieved.

Hereinafter, each conditional expression of the present invention will be described. In the present invention, the following conditional expressions (1) to (3)
To be satisfied. 1.5 <(D1T-D1W) / (D4W-D4T) <2.1 (1) 0.39 <f3 / f1 <0.55 (2) 0.25 <f2 / (fw · ft) ^1/2 <0.32 (3)

Here, D1W: axial air distance between the first lens group G1 and the second lens group G2 at the wide-angle end D1T: axial air distance between the first lens group G1 and the second lens group G2 at the telephoto end D4W: axial air distance between the fourth lens group G4 and the fifth lens group G5 at the wide-angle end D4T: axial air distance between the fourth lens group G4 and the fifth lens group G5 at the telephoto end

F1: focal length of first lens group G1 f2: focal length of second lens group G2 f3: focal length of third lens group G3 ft: focal length of entire system at telephoto end fw: entire system at wide angle end Focal length

Conditional expression (1) is defined by the first lens group G1 and the second lens group G1.
The amount of change ΔD1 (D1W-D1T) in changing the first variable interval formed by the lens group G2 and the fourth lens group G
The ratio of the fourth variable interval formed by the fourth and fifth lens groups G5 to the change amount ΔD4 (D4W-D4T) at the time of zooming is defined, and the total lens length at the telephoto end is shortened and This is a conditional expression for achieving a balance with scaling.

If the upper limit of conditional expression (1) is exceeded, the amount of change ΔD1 of the first variable interval becomes large, so the converging action of the first lens group G1 at the telephoto end becomes stronger, and the total lens length can be shortened. Becomes However, the change in the use magnification of the second lens group G2 during zooming becomes large,
The variation of off-axis aberration that occurs in the second lens group G2 during zooming cannot be suppressed well, and high zooming cannot be achieved.

On the other hand, when the value goes below the lower limit of the conditional expression (1), the change amount ΔD4 of the fourth variable interval becomes large, and the ratio of the fifth lens group G5 responsible for zooming becomes extremely large. As a result, it is not possible to equalize the proportion of each lens group responsible for zooming, and it becomes impossible to achieve both high zooming and high performance at the same time.

Conditional expression (2) defines an appropriate range of the ratio between the focal length of the third lens group G3 and the focal length of the first lens group G1. If the upper limit of conditional expression (2) is exceeded, the focal length of the first lens group G1 becomes positively small, and the off-axis light flux passing through the first lens group G1 is too far away from the optical axis especially at the telephoto end. . As a result, when trying to secure a predetermined amount of peripheral light, the lens diameter of the first lens group G1 becomes large, and it becomes impossible to achieve miniaturization. Further, when the focal length of the third lens group G3 is positively increased, the third lens group G3 and the fourth lens group G4 cannot be positively contributed to zooming. As a result, it is not possible to achieve equalization of the proportion of each lens group responsible for zooming, and it becomes impossible to achieve high zooming.

On the other hand, when the value goes below the lower limit of conditional expression (2), the focal length of the third lens group G3 becomes positively small, and the off-axis light flux passing through the third lens group G3 is separated from the optical axis. . As a result, unless the diameter of the third lens group G3 is increased, the off-axis aberration generated in the third lens group 3 cannot be sufficiently corrected, and as a result, the entire lens system becomes large. Further, when the focal length of the first lens group G1 is positively increased, it becomes impossible to reduce the total lens length at the telephoto end.

Conditional expression (3) defines the refractive power of the second lens group G2, and is a conditional expression for achieving a balance between miniaturization and high performance of the lens system. If the upper limit of conditional expression (3) is exceeded, the diverging action of the second lens group G2 becomes weak, and it becomes impossible to obtain sufficient back focus at the wide-angle end.

Further, in a lens system including a wide angle range, it is essential to correct off-axis aberrations satisfactorily, and Petzval sum is a standard for correcting the field curvature. When the upper limit of conditional expression (3) is exceeded, the Petzval sum becomes extremely positive and it becomes impossible to correct negative field curvature, or the refractive power of the fifth lens group G5 becomes negatively large. Therefore, it becomes impossible to suppress the fluctuation of the off-axis aberration that occurs in the fifth lens group G5 during zooming. On the other hand, if the lower limit value of conditional expression (3) is not reached, it becomes impossible to suppress the fluctuation of the off-axis aberration that occurs in the second lens group G2 during zooming.

In the present invention, in order to equalize the proportion of each lens unit responsible for zooming, obtain higher optical performance, and achieve high zooming and simplification at the same time, the following conditional expression (4) ) And (5) are desirable. 0.32 <(β2t / β2w) / (ft / fw) <0.45 (4) 0.5 <(β5t / β5w) / (ft / fw) <0.7 (5)

Here, β2t: Use magnification of the second lens group G2 at the telephoto end β2w: Use magnification of the second lens group G2 at the wide angle end β5t: Use magnification of the fifth lens group G5 at the telephoto end β5w: At the wide angle end Use magnification of the fifth lens group G5

Conditional expression (4) defines the ratio of the use magnification of the second lens group G2 at the wide-angle end to the use magnification of the second lens group G2 at the telephoto end, and changes the magnification of the entire lens system. This is a conditional expression that defines the ratio of the second lens group G2 that accounts for the zooming in the action. If the upper limit of conditional expression (4) is exceeded, the second
The proportion of the lens group G2 that bears the zooming action increases, and it becomes difficult to favorably suppress the fluctuation of the off-axis aberration that occurs in the second lens group G2 during zooming.

On the other hand, when the value goes below the lower limit of conditional expression (4), the proportion of the second lens group G2 responsible for the zooming action decreases. As a result, when an attempt is made to obtain a predetermined zoom ratio, the combined focal length of the third lens group G3 and the fourth lens group G4 is greatly changed by zooming, and the third lens group G3 and the fourth lens group G4
Unless the aberrations generated by the lens group G4 are properly corrected independently, it is impossible to suppress variations in various aberrations that occur during zooming, and as a result it becomes difficult to make the lens system compact and simple. I will end up.

Conditional expression (5) defines the ratio of the use magnification of the fifth lens group G5 at the wide-angle end to the use magnification of the fifth lens group G5 at the telephoto end, and varies the magnification of the entire lens system. This is a conditional expression that defines the proportion of the fifth lens group G5 that accounts for zooming in the action. If the upper limit of conditional expression (5) is exceeded, the fifth
The proportion of the lens group G5 that bears the zooming action increases, and it becomes difficult to favorably suppress the fluctuation of the off-axis aberration that occurs in the fifth lens group G5 during zooming.

On the other hand, when the value goes below the lower limit of conditional expression (5), the ratio of the fifth lens group G5 responsible for the zooming action decreases,
As a result, it is not possible to satisfactorily correct the fluctuation of the off-axis aberration that occurs at the time of zooming in each lens group of the second lens group G2 to the fourth lens group G4, and it becomes impossible to achieve high performance. .

In the variable power optical system according to the present invention, the second lens group G2 and the fifth lens group G5 are responsible for a large proportion of the variable power operation in order to downsize and simplify the lens system. Is suitable. Therefore, in order to achieve higher performance, it is desirable that conditional expressions (4) and (5) are satisfied at the same time. That is, it is preferable to satisfy the following conditional expression (8). 0.4 <(β2t / β2w) / (β5t / β5w) <0.8 (8)

Conditional expression (8) is defined by the second lens group G2 and the fifth lens group G2.
This is a conditional expression for balancing the ratio responsible for zooming with the lens group G5. If the upper limit of conditional expression (8) is exceeded, the proportion of the second lens group G2 responsible for zooming increases, and it is not possible to favorably correct fluctuations in off-axis aberration that occur during zooming. On the other hand, if the lower limit of conditional expression (8) is exceeded,
The proportion of the fifth lens group G5 responsible for zooming increases, and it is not possible to satisfactorily correct fluctuations in off-axis aberration that occur during zooming.

Further, in the present invention, it is desirable that the following conditional expression (6) is satisfied in order to suppress the occurrence of camera shake and the like while achieving high zoom ratio. 0.35 <(Bft-Bfw) / (ft-fw) <0.5 (6) Here, Bft: Back focus at the telephoto end Bfw: Back focus at the wide angle end

Conditional expression (6) is a conditional expression which defines the rate of change in back focus with respect to change in focal length. Generally, in a zoom lens with a high zoom ratio, the total lens length tends to increase as the focal length at the telephoto end increases.

As described above, in the case of a lens shutter type camera, the body of the camera is becoming smaller and lighter. Therefore, if the total length of the lens at the telephoto end becomes long, the zooming when the camera is placed in the normal position is increased. The movement of the center of gravity due to the movement becomes large, which is likely to cause camera shake. In particular, in the present invention, by shortening the back focus at the telephoto end, the amount of movement of the second lens group G2 to the fifth lens group G5 toward the object side due to zooming is reduced, and movement of the center of gravity is suppressed. It suppresses the occurrence of blurring.

Therefore, if the upper limit of conditional expression (6) is exceeded, camera shake is likely to occur at the telephoto end. Conversely, if the lower limit of conditional expression (6) is exceeded,
The ratio of the fifth lens group G5 responsible for the zooming action decreases,
The use magnification of the lens group G2 will change significantly during zooming. As a result, it is not possible to satisfactorily correct the fluctuation of the off-axis aberration that occurs during zooming, and it becomes difficult to obtain a predetermined zoom ratio.

In the present invention, as described above, the fifth lens group G5 has a large ratio of zooming. Therefore, in order to improve the performance, it is necessary to reduce the amount of aberration generated in the fifth lens group G5, and in order to suppress the occurrence of spherical aberration, the fifth lens group G5 includes at least one positive lens. It is desirable to be composed of one negative lens. Further, in order to reduce the diameter of the lens closest to the image side, it is desirable to dispose a positive lens closest to the object side and a negative lens closest to the image side of the fifth lens group G5.

Further, in the present invention, as described above, a large proportion is responsible for the zooming of the second lens group G2, but it occurs in the second lens group G2 while making the second lens group G2 with the smallest possible number of lenses. In order to suppress the aberration, the second lens group G2 is composed of three lenses, in order from the object side, a biconcave lens, a biconvex lens, and a negative lens having a concave surface facing the object side, and the following conditional expression (7) It is desirable to satisfy.

2 <r21 / Da <3.5 (7) where, r21: radius of curvature of the lens surface of the second lens group G2 closest to the object side Da: an aperture stop arranged in the variable power optical system and Distance along the optical axis between the lens surface of the second lens group G2 closest to the object side

The role of each lens constituting the second lens group G2 in correcting the aberration is as described above, but in order to satisfactorily correct the positive distortion aberration generated at the wide-angle end, the viewpoint of the arrangement of the refracting power. Therefore, it is desirable that the principal point position of the second lens group G2 be as close to the object as possible.
Is preferably a negative and positive structure.

In particular, as shown in conditional expression (7), it is desirable to set the value of the radius of curvature of the lens surface of the second lens group G2 closest to the object side in an appropriate range. If the upper limit of conditional expression (7) is exceeded, it will be difficult to obtain sufficient back focus at the wide-angle end. On the other hand, when the value goes below the lower limit of conditional expression (7), it becomes impossible to suppress the variation of coma aberration due to the angle of view at the wide-angle end.

According to another aspect, in the present invention, in order to prevent a photographing failure due to an image blur caused by a camera shake that is likely to occur in a high zoom lens, a blur detection for detecting a blur of an optical system. The system and the driving means can be combined in a lens system. An image caused by the blur of the optical system detected by the blur detection system is shifted by decentering one or all of the lens groups constituting the optical system as an eccentric lens group. By correcting the blur (change in image position), the variable power optical system of the present invention can be used as a so-called anti-vibration optical system.

Particularly, in the present invention, the fourth lens group G
4 is composed of three partial lens groups, the image can be shifted by moving the central partial lens group in a direction substantially perpendicular to the optical axis, and various aberrations that occur when the image is shifted. It is possible to satisfactorily correct the fluctuation. Normally, the shift lens group (the lens group that moves in a direction substantially perpendicular to the optical axis) is required to have an aberration correction state that allows good image formation even during image shifting. Specifically, it is required for the shift lens group that the spherical aberration and the sine condition are corrected and that the Petzval sum is appropriate.

The correction of the spherical aberration and the sine condition is a condition for suppressing the decentering coma aberration generated at the center of the screen when the shift lens group is moved to shift the image. Further, the appropriate Petzval sum is a condition for suppressing the curvature of field that occurs in the peripheral portion of the screen when the image is shifted by moving the shift lens group.

When the entire one lens group constituting the zoom lens is a shift lens group, the aberration correction state required at the time of zooming and the aberration correction state required to suppress the performance deterioration at the time of image shift match. Not necessarily. Especially,
It is difficult to correct larger blurs while maintaining high optical performance. Therefore, in the present invention, one lens group is made up of three partial lens groups, and the central partial lens group is used as a shift lens group to correct larger blurring while maintaining high optical performance. Is possible.

In particular, in the present invention, by satisfying the following conditional expression (9), good image forming performance can be obtained even during image shifting. 0.04 <Db / fw <0.2 (9) where: Db: along the optical axis between the aperture stop arranged in the variable power optical system and the surface of the shift lens group closest to the aperture stop. distance

If the upper limit of conditional expression (9) is exceeded, the difference in height between the on-axis light beam and the off-axis light beam passing through the shift lens group becomes large, so the shift lens group must be made large in diameter. It becomes impossible to suppress variations in various aberrations that occur when the shift lens group is moved. Although it is possible to solve the above-mentioned point by configuring the shift lens group with a larger number of lenses, not only the lens system becomes large, but also the driving mechanism for driving the shift lens group becomes complicated. It is not preferable because it will occur.

Further, according to the present invention, it is possible to perform focusing by moving a part of the lens units constituting the lens system along the optical axis.
In particular, it is arranged closer to the object side than the shift lens group and
Focusing is preferably performed by moving the lens group disposed on the image side of the lens group G1.

[0055]

Embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 1 is a diagram showing the distribution of refractive power of a variable power optical system according to each example of the present invention, and the movement of each lens group during zooming from the wide-angle end (W) to the telephoto end (T). . As shown in FIG. 1, the variable power optical system according to each example of the present invention has, in order from the object side, a first lens group G1 having a positive refractive power and a second lens group G2 having a negative refractive power. A third lens group G3 having a positive refractive power, a fourth lens group G4 having a positive refractive power, and a fifth lens group G5 having a negative refractive power. When zooming from the wide-angle end to the telephoto end, the first lens group G1 and the second lens unit
The air gap with the lens group G2 increases, and the second lens group G2
The air gap between the third lens group G3 and the fourth lens group G4 increases, and the air gap between the third lens group G3 and the fourth lens group G4 increases.
Each lens group moves toward the object side so that the air gap between the lens group G4 and the fifth lens group G5 decreases. In addition,
During zooming, the second lens group G2 and the fourth lens group G4 move integrally.

In each of the embodiments, the aspherical surface has a height y in the direction perpendicular to the optical axis, a displacement amount S (y) in the optical axis direction at the height y, a reference radius of curvature R, and a conic coefficient. When κ and the aspherical coefficient of order n are Cn, they are expressed by the following mathematical expression (a).

[Number 1] ^{S (y) = (y 2} / R) / ^{[1+ (1-κ · y 2} / R 2) 1/2 ] ^{_{+ C 4 · y 4 + C}} 6 · y 6 + C 8 · y 8 + C 10 · Y ¹⁰ + ... (a) In each embodiment, an aspherical surface is marked with an asterisk on the right side of the surface number.

[Embodiment 1] FIG. 2 is a view showing the lens arrangement of a variable power optical system according to the first embodiment of the present invention. FIG.
Is a cemented positive lens L in which, in order from the object side, a biconvex lens and a negative meniscus lens having a concave surface facing the object side are cemented in order.
1st lens group G1 which consists of 1 and 2nd lens group G2 which consists of biconcave lens L21, biconvex lens L22 and biconcave lens L23, and 3rd lens group G3 which consists of biconvex lens L3
And a negative meniscus lens L41 having a concave surface facing the object side, a cemented positive lens L42 having a biconvex lens and a negative meniscus lens having a concave surface facing the object side, and a positive meniscus lens L43 having a concave surface facing the object side. From the lens group G4, a positive meniscus lens L51 having a concave surface facing the object side, a negative meniscus lens L52 having a concave surface facing the object side, and a fifth lens group G5 including a negative meniscus lens L53 having a concave surface facing the object side. It is configured.

The aperture stop S is arranged between the third lens group G3 and the fourth lens group G4, and moves integrally with the fourth lens group G4 during zooming from the wide-angle end to the telephoto end. FIG. 2 shows the positional relationship between the lens groups at the wide-angle end, and when the magnification is changed to the telephoto end, the lens units move on the optical axis along the zoom orbit shown by the arrow in FIG. Further, focusing is performed by moving the third lens group G3 along the optical axis. Further, the fourth lens group G4
The cemented positive lens L42 therein is moved in a direction substantially orthogonal to the optical axis to shift the image, and the fluctuation of the image position due to camera shake or the like is corrected.

The following table (1) shows the values of specifications of the first embodiment of the present invention. In Table (1), f is the focal length, F
NO is the F number, ω is the half angle of view, Bf is the back focus, and D0 is the distance between the object and the surface closest to the object along the optical axis. Further, the surface number indicates the order of the lens surface from the object side along the traveling direction of the light ray, and the refractive index and Abbe number indicate the d-line (λ = 587.6n).
m).

[0060]

[Table 1] f = 39.02 to 75.70 to 184.29 FNO = 4.05 to 6.38 to 11.00 ω = 29.43 to 15.43 to 6.54 ° Surface number Curvature radius Surface spacing Refractive index Abbe number 1 62.14311 4.039 1.48749 70.45 2 -43.66775 1.388 1.84666 23.83 3 -70. (D3 = variable) 4 -39.39279 1.010 1.83500 42.97 5 21.45187 0.884 6 18.37810 2.902 1.80518 25.46 7 -65.20540 0.757 8 -21.95246 1.010 1.83500 43.97 9 906.50213 (D9 = variable) 10 604.15858 2.272 1.48749 70.45 1111-19.10775 (D19 = variable) ∞ 2.272 (aperture stop S) 13 * -40.83436 1.262 1.58518 30.24 14 -63.10680 0.884 15 28.11534 3.155 1.48749 70.45 16 -15.30773 1.010 1.84666 23.83 17 -25.88995 1.767 18 -34.72285 1.641 1.49108 57.57 19 -26.11828 (D19 = variable) 21-22. 0.126 22 -49.52550 1.262 1.80420 46.51 23 -476.62746 4.922 24 -15.11835 1.515 1.80420 46.51 25 -152.99121 (Bf) (aspherical data) (13 faces) R = -40.83436 κ = 0.9156 C ₄ = -2.05320 × 10 ^-5 C ₆ = -1.69360 × 10 ^-8 C ₈ = -3.12880 × 10 ^-9 C ₁₀ = 3.09490 × 10 ^-11 F 39.0158 75.6995 184.2870 D3 2.1456 13.0157 29.6288 D9 5.0581 3.0306 1.8932 D11 2.5147 4.5423 5.6796 D19 18.5191 11.0107 1.8932 Bf 7.9275 27.9672 75.7687 (focusing amount of the third lens group G3 at 1/30 magnification) Focal length f 39.0158 75.6995 184.2870 D0 1122.5175 2191.3814 5338.9142 Movement amount 1.0514 0.8192 0.8389 However, the sign of the movement amount is the movement from the object side to the image side is positive (the movement amount of the cemented positive lens L42 when the image is shifted by 0.01 [rad]) Focal length f 39.0158 75.6995 184.2870 Lens movement amount 0.3155 0.3891 0.5523 Image shift amount 0.3901 0.7570 1.8430 (Condition corresponding value) f1 = 87.061 f2 = −23.320 f3 = 38.040 β2t = −0.7583 β2w = − 0.4004 β5t = +3.8706 β5w = +1.3093 (1) (D1T-D1W) / (D4W-D4T) = 1.653 (2) f3 / f1 0.437 (3) f2 / (fw · ft) 1/2 = 0.275 (4) (β2t / β2w) / (ft / fw) = 0.401 (5) (β5t / β5w) / (ft / fw) = 0.626 (6) (Bft-Bfw) / (ft-fw) = 0.467 (7) r21 / Da = 2.401 (8) (β2t / β2w) / (β5t / β5w) = 0 .641 (9) Db / fw = 0.113

3 to 8 show d line (λ = 587.6n).
FIG. 9 is a diagram of various types of aberration of Example 1 for m). FIG. 3 is a diagram of various aberrations at the wide-angle end (shortest focal length state) in the infinity focused state, FIG. 4 is a diagram of various aberrations at the intermediate focal length state in the infinity focused state, and FIG. 5 is a telephoto state. FIG. 9 is a diagram of various types of aberration at the end (the longest focal length state) in the in-focus state at infinity.
6 is a diagram of various aberrations at a wide-angle end at a photographing magnification of −1/30, FIG. 7 is a diagram of various aberrations at a wide-angle end at a photographing magnification of −1/30, and FIG. 8 is a graph at the telephoto end. FIG. 9 is a diagram of various aberrations at a photographing magnification of −1/30.

9 to 11 are coma aberration diagrams when the image is shifted by 0.01 rad (radian) with respect to the optical axis in the first embodiment. 9 is a coma aberration diagram at the wide-angle end in the infinity focused state, FIG. 10 is a coma aberration diagram at the infinity focused state in the intermediate focal length state, and FIG. 11 is an infinity focusing state at the telephoto end. It is a coma aberration figure in a focus state. The aberration diagrams of FIGS. 9 to 11 show the image height Y
Y when moving the cemented positive lens L42 in the positive direction of
The coma aberrations at 5.0, 0 and -15.0 are shown.

In each aberration diagram, FNO represents an F number,
NA indicates the numerical aperture, Y indicates the image height, A indicates the half angle of view for each image height, and H indicates the object height for each image height. In the aberration diagram showing astigmatism, a solid line indicates a sagittal image plane, and a broken line indicates a meridional image plane. Further, in the aberration diagram showing the spherical aberration, a broken line indicates a sine condition (sine condition). As is clear from the aberration diagrams, in this embodiment, various aberrations are favorably corrected even at the time of image shift in each shooting distance state and each focal length state.

[Embodiment 2] FIG. 12 is a view showing the lens arrangement of a variable power optical system according to the second embodiment of the present invention. The variable power optical system of FIG. 12 includes, in order from the object side, a first lens group G1 including a biconvex lens and a positive lens L1 cemented with a negative meniscus lens having a concave surface facing the object side, a biconcave lens L21,
A second lens group G2 including a biconvex lens L22 and a biconcave lens L23, and a third lens group G including a biconvex lens L3.
3 and a negative meniscus lens L41 having a concave surface facing the object side,
A fourth lens group G4 including a cemented positive lens L42 including a biconvex lens and a negative meniscus lens having a concave surface facing the object side, and a positive meniscus lens L43 having a concave surface facing the object side, and a positive meniscus having a concave surface facing the object side. It includes a lens L51, a negative meniscus lens L52 having a concave surface facing the object side, and a fifth lens group G5 including a negative meniscus lens L53 having a concave surface facing the object side.

The aperture stop S is arranged between the third lens group G3 and the fourth lens group G4, and moves integrally with the fourth lens group G4 during zooming from the wide-angle end to the telephoto end. FIG. 12 shows the positional relationship between the lens groups at the wide-angle end, which moves on the optical axis along the zoom orbit shown by the arrow in FIG. 1 during zooming to the telephoto end. Further, focusing is performed by moving the third lens group G3 along the optical axis. Furthermore, the fourth lens group G
The cemented positive lens L42 in 4 is moved in the direction substantially orthogonal to the optical axis to shift the image, and the fluctuation of the image position due to the camera shake or the like is corrected.

The following table (2) lists the values of specifications of the second embodiment of the present invention. In Table (2), f is the focal length, F
NO is the F number, ω is the half angle of view, Bf is the back focus, and D0 is the distance between the object and the surface closest to the object along the optical axis. Further, the surface number indicates the order of the lens surface from the object side along the traveling direction of the light ray, and the refractive index and Abbe number indicate the d-line (λ = 587.6n).
m).

[0067]

[Table 2] f = 39.01 ~ 75.66 ~ 184.27 FNO = 3.99 ~ 6.30 ~ 11.00 ω = 29.41 ~ 15.43 ~ 6.54 ° Surface number Curvature radius Surface spacing Refractive index Abbe number 1 62.31549 4.039 1.48749 70.45 2 -43.65634 1.388 1.84666 23.83 3 -70. (D3 = variable) 4 -39.91555 1.010 1.83500 42.97 5 21.49049 0.884 6 18.37810 2.903 1.80518 25.46 7 -64.20963 0.757 8 -21.85140 1.010 1.83500 42.97 9 654.53592 (D9 = variable) 10 800.51790 2.272 1.48749 70.45 11 -18.96622 (D11 = variable) ∞ 2.272 (Aperture stop S) 13 * -40.83436 1.262 1.58518 30.24 14 -63.10680 0.884 15 28.17317 3.155 1.48749 70.45 16 -15.14766 1.010 1.84666 23.83 17 -25.65505 1.767 18 -34.72285 1.641 1.49108 57.57 19 -26.11828 (D19 = variable) 20 -59. 3.218 1.84666 23.83 21 -22.86360 0.126 22 -49.70550 1.262 1.80420 46.51 23 -487.70330 4.922 24 -15.07171 1.515 1.80420 46.51 25 -152.99119 (Bf) (aspheric surface data) (13 faces) R = -40.83436 κ = 0.9156 C ₄ = -1.98700 × 10 ^-5 C ₆ = -5.60 230 × 10 ^-8 C ₈ = -1.71840 × 10 ^-9 C ₁₀ = 1.6 0910 × 10 ^-11 (Variable spacing during zooming) f 39.0126 75.6632 184.2741 D3 2.1456 13.0157 29.6288 D9 5.0581 3.0306 1.8932 D11 2.5147 4.5423 5.6796 D19 18.5191 11.0107 1.8932 Bf 7.9293 27.9573 75.8402 (3rd lens group G3 at 1:30) Focusing movement amount) Focal length f 39.0126 75.6632 184.2741 D0 1122.4348 2190.3944 5339.4056 Movement amount 1.0503 0.8177 0.8332 However, the sign of the movement amount is positive when moving from the object side to the image side (0.01 [rad] when the image is shifted) Moving amount of cemented positive lens L42) Focal length f 39.0126 75.6632 184.2741 Lens moving amount 0.3156 0.3887 0.5513 Image shift amount 0.3903 0.7565 1.8427 (condition corresponding value) f1 = 87.238 f2 = −23.320 f3 = 38.040 β2t = -0.7548 β2w = -0.3995 β5t = +3.8702 β5w = + 1.3082 (1) (D1T-D1W) / (D4W-D4T) = 1.6 3 (2) f3 / f1 = 0.436 (3) f2 / (fw · ft) 1/2 = 0.275 (4) (β2t / β2w) / (ft / fw) = 0.400 (5) ( β5t / β5w) / (ft / fw) = 0.626 (6) (Bft-Bfw) / (ft-fw) = 0.468 (7) r21 / Da = 2.433 (8) (β2t / β2w) / (Β5t / β5w) = 0.639 (9) Db / fw = 0.113

13 to 18 show the d line (λ = 587.
FIG. 6 is a diagram of various types of aberration of Example 2 for 6 nm). FIG. 13 is a diagram of various aberrations at the wide-angle end in the infinity focused state, FIG. 14 is a diagram of various aberrations at the infinity focused state at the intermediate focal length state, and FIG. 15 is a diagram of the infinity focused state at the telephoto end. FIG. 9 is a diagram of various aberrations in a state. 16 is a diagram of various aberrations at a wide-angle end at a photographing magnification of −1/30, FIG. 17 is a diagram of various aberrations at a wide-angle end at a photographing magnification of −1/30, and FIG. 18 is a graph at the telephoto end. FIG. 9 is a diagram of various aberrations at a photographing magnification of −1/30.

19 to 21 are coma aberration diagrams when the image is shifted by 0.01 rad (radian) with respect to the optical axis in the second embodiment. FIG. 19 is a coma aberration diagram at the wide-angle end in the in-focus state at infinity.
FIG. 21 is a coma aberration diagram in the infinity in-focus state in the intermediate focal length state, and FIG. 21 is a coma aberration diagram in the infinity-in-focus state in the telephoto end. The aberration diagrams of FIGS. 19 to 21 are
The coma aberration at Y = 15.0, 0, -15.0 when the cemented positive lens L42 is moved in the positive direction of the image height Y is shown.

In each aberration diagram, FNO is the F number,
NA indicates the numerical aperture, Y indicates the image height, A indicates the half angle of view for each image height, and H indicates the object height for each image height. In the aberration diagram showing astigmatism, a solid line indicates a sagittal image plane, and a broken line indicates a meridional image plane. Further, in the aberration diagram showing the spherical aberration, a broken line indicates a sine condition (sine condition). As is clear from the aberration diagrams, in this embodiment, various aberrations are favorably corrected even at the time of image shift in each shooting distance state and each focal length state.

[Third Embodiment] FIG. 22 is a diagram showing a lens structure of a variable power optical system according to the third embodiment of the present invention. The variable power optical system of FIG. 22 includes, in order from the object side, a first lens group G1 made up of a cemented positive lens L1 composed of a biconvex lens and a negative meniscus lens having a concave surface facing the object side, a biconcave lens L21,
A second lens group G2 including a biconvex lens L22 and a negative meniscus lens L23 having a concave surface facing the object side, a third lens group G3 including a positive meniscus lens L3 having a concave surface facing the object side, and a concave surface facing the object side. The fourth lens unit G4 including a negative meniscus lens L41 directed toward the object side, a positive lens L42 cemented with a biconvex lens and a negative meniscus lens having a concave surface directed toward the object side, and a positive meniscus lens L43 having a concave surface directed toward the object side.
And a fifth lens group G5 including a positive meniscus lens L51 having a concave surface facing the object side, a negative meniscus lens L52 having a concave surface facing the object side, and a negative meniscus lens L53 having a concave surface facing the object side. There is.

The aperture stop S is arranged between the third lens group G3 and the fourth lens group G4, and moves integrally with the fourth lens group G4 during zooming from the wide-angle end to the telephoto end. FIG. 22 shows the positional relationship between the lens groups at the wide-angle end, and when the zoom lens moves to the telephoto end, it moves along the optical axis along the zoom orbit shown by the arrow in FIG. Further, focusing is performed by moving the third lens group G3 along the optical axis. Furthermore, the fourth lens group G
The cemented positive lens L42 in 4 is moved in the direction substantially orthogonal to the optical axis to shift the image, and the fluctuation of the image position due to the camera shake or the like is corrected.

Table (3) below lists values of specifications of the third embodiment of the present invention. In Table (3), f is the focal length, F
NO is the F number, ω is the half angle of view, Bf is the back focus, and D0 is the distance between the object and the surface closest to the object along the optical axis. Further, the surface number indicates the order of the lens surface from the object side along the traveling direction of the light ray, and the refractive index and Abbe number indicate the d-line (λ = 587.6n).
m).

[0074]

[Table 3] f = 38.99 ~ 75.40 ~ 184.27 FNO = 4.05 ~ 6.41 ~ 11.01 ω = 29.56 ~ 15.54 ~ 6.55 ° Surface number Curvature radius Surface spacing Refractive index Abbe number 1 60.01206 4.039 1.48749 70.41 2 -52.29252 1.389 1.86074 23.01 3 -86.55 (D3 = variable) 4 -44.58813 1.010 1.84042 43.35 5 21.23473 0.884 6 18.10575 2.903 1.76182 26.55 7 -58.17945 0.757 8 -20.44479 1.010 1.84042 43.35 9 -497.50686 (D9 = variable) 10 -578.28121 2.272 1.51680 64.20 11 11-19.02114 (D3 = variable) ) 12 ∞ 2.272 (Aperture stop S) 13 * -42.07360 1.262 1.58518 30.24 14 -63.10680 0.379 15 27.57729 3.660 1.48749 70.41 16 -15.48975 1.010 1.86074 23.01 17 -26.09981 1.767 18 -37.31372 1.641 1.49108 57.57 19 -27.41089 (D19 = variable) 20 -93.48459 3.282 1.80458 25.50 21 -20.84985 2.272 22 -17.45299 1.262 1.83500 42.97 23 -142.31147 2.903 24 -22.20848 1.515 1.78800 47.50 25 -133.79268 (Bf) (aspherical data) (13 faces) R = -42.07360 κ = 0.3313 C ₄ = -1.88420 × 10 ^-5 C ₆ = -9.34560 × 10 ^-8 C ₈ = -3.73950 × 10 ^-10 C ₁₀ =- 1.02900 × 10 ^-11 (Variable spacing during zooming) f 38.9900 75.4021 184.2660 D3 2.1569 13.4164 31.3238 D9 5.0452 3.0718 1.5181 D11 2.4697 4.4431 5.9968 D19 17.6099 10.3507 1.8987 Bf 7.9510 28.0463 74.1264 (3rd lens group G3 at 1/30 hour) Focusing amount f) Focal length f 38.9900 75.4021 184.2660 D0 1122.5739 2184.1911 5344.5913 Moving amount 1.0182 0.7805 0.7748 However, the sign of the moving amount is positive when moving from the object side to the image side (0.01 [rad] when the image is shifted) Moving amount of cemented positive lens L42) Focal length f 38.9900 75.4021 184.2660 Lens moving amount 0.3158 0.3869 0.5542 Image shift amount 0.3899 0.7541 1.8427 (Condition corresponding value) f1 = 92.134 f2 = −23.425 f3 = 37.864 β2t = -0.6949 β2w = -0.3725 β5t = +3.8312 β5w = +1.3214 (1) (D1T-D1W) / (D4W-D4T) = 1. 56 (2) f3 / f1 = 0.411 (3) f2 / (fw · ft) 1/2 = 0.276 (4) (β2t / β2w) / (ft / fw) = 0.395 (5) ( β5t / β5w) / (ft / fw) = 0.614 (6) (Bft-Bfw) / (ft-fw) = 0.456 (7) r21 / Da = 2.727 (8) (β2t / β2w) / (Β5t / β5w) = 0.643 (9) Db / fw = 0.100

23 to 28 show d line (λ = 587.
FIG. 6 is a diagram of various types of aberration of Example 3 for 6 nm). FIG. 23 is a diagram of various aberrations at the wide-angle end in the infinity focused state, FIG. 24 is a diagram of various aberrations at the infinity focused state at the intermediate focal length state, and FIG. 25 is a diagram of the infinity focused state at the telephoto end. FIG. 9 is a diagram of various aberrations in a state. FIG. 26 is a diagram of various aberrations at a wide-angle end at a shooting magnification of −1/30, FIG. 27 is a diagram of various aberrations at a shooting magnification of −1/30 in an intermediate focal length state, and FIG. 28 is at a telephoto end. FIG. 9 is a diagram of various aberrations at a photographing magnification of −1/30.

29 to 31 are coma aberration diagrams when the image is shifted by 0.01 rad (radian) with respect to the optical axis in the third embodiment. FIG. 29 is a coma aberration diagram at the wide-angle end in the infinity in-focus state.
[Fig. 31] is a coma aberration diagram in the infinity in-focus state in the intermediate focal length state, and Fig. 31 is a coma aberration diagram in the infinity in-focus state in the telephoto end. The aberration diagrams of FIGS. 29 to 31 are
The coma aberration at Y = 15.0, 0, -15.0 when the cemented positive lens L42 is moved in the positive direction of the image height Y is shown.

In each aberration diagram, FNO represents an F number,
NA indicates the numerical aperture, Y indicates the image height, A indicates the half angle of view for each image height, and H indicates the object height for each image height. In the aberration diagram showing astigmatism, a solid line indicates a sagittal image plane, and a broken line indicates a meridional image plane. Further, in the aberration diagram showing the spherical aberration, a broken line indicates a sine condition (sine condition). As is clear from the aberration diagrams, in this embodiment, various aberrations are favorably corrected even at the time of image shift in each shooting distance state and each focal length state.

[Fourth Embodiment] FIG. 32 is a diagram showing a lens structure of a variable power optical system according to the fourth embodiment of the present invention. The variable power optical system of FIG. 32 has, in order from the object side, a first lens group G1 including a cemented positive lens L1 including a biconvex lens and a negative meniscus lens having a concave surface facing the object side, a biconcave lens L21,
A second lens group G2 including a biconvex lens L22 and a biconcave lens L23, and a third lens group G including a biconvex lens L3.
3 and a negative meniscus lens L41 having a concave surface facing the object side,
A fourth lens group G4 including a cemented positive lens L42 including a biconvex lens and a negative meniscus lens having a concave surface facing the object side, and a positive meniscus lens L43 having a concave surface facing the object side, and a positive meniscus having a concave surface facing the object side. It includes a lens L51, a negative meniscus lens L52 having a concave surface facing the object side, and a fifth lens group G5 including a negative meniscus lens L53 having a concave surface facing the object side.

The aperture stop S is arranged between the third lens group G3 and the fourth lens group G4, and moves integrally with the fourth lens group G4 during zooming from the wide-angle end to the telephoto end. FIG. 32 shows the positional relationship of each lens group at the wide-angle end, and when the magnification is changed to the telephoto end, it moves along the optical axis along the zoom orbit shown by the arrow in FIG. Further, focusing is performed by moving the third lens group G3 along the optical axis. Furthermore, the fourth lens group G
The cemented positive lens L42 in 4 is moved in the direction substantially orthogonal to the optical axis to shift the image, and the fluctuation of the image position due to the camera shake or the like is corrected.

The following table (4) lists the values of specifications of the fourth embodiment of the present invention. In Table (4), f is the focal length, F
NO is the F number, ω is the half angle of view, Bf is the back focus, and D0 is the distance between the object and the surface closest to the object along the optical axis. Further, the surface number indicates the order of the lens surface from the object side along the traveling direction of the light ray, and the refractive index and Abbe number indicate the d-line (λ = 587.6n).
m).

[0081]

[Table 4] f = 38.99 ~ 75.40 ~ 126.15 ~ 184.27 FNO = 4.03 ~ 6.31 ~ 8.60 ~ 10.95 ω = 29.43 ~ 15.53 ~ 9.44 ~ 6.54 ° Surface number Curvature radius Surface spacing Refractive index Abbe number 1 62.3666 4.039 1.48749 70.41 2 -44.0029 1.389 1.84666 23.83 3 -71.5087 (D3 = variable) 4 -37.3341 1.010 1.83500 42.97 5 22.4608 0.884 6 18.7866 2.966 1.80518 25.46 7 -59.7420 0.694 8 -22.4443 1.010 1.83500 42.97 9 301.9140 (D9 = variable) 10 484.6795 2.146 1.48749 70.45 11 (D11 = variable) 12 ∞ 2.272 (aperture stop S) 13 * -40.8344 1.262 1.58518 30.24 14 -63.1068 0.884 15 27.9496 3.155 1.48749 70.41 16 -15.3979 1.010 1.84666 23.83 17 -26.1317 1.767 18 -35.2952 1.641 1.49108 57.57 19 -26.4292 (D19) = Variable) 20 -68.6289 3.282 1.84666 23.83 21 -23.4090 0.189 22 -47.9518 1.262 1.83500 42.97 23 -443.8415 4.922 24 -15.1363 1.515 1.80420 46.51 25 -155.1574 (Bf) (aspherical data) (13 faces) R = -40.8344 κ = 0.3035 C ₄ = -2.11448 × 10 ^-5 C ₆ = -2.10943 × 10 ^-8 C ₈ = -3.40864 × 10 ^-9 C ₁₀ = + 4.21 496 × 10 ^-11 (Variable spacing during zooming) f 39.0148 75.6936 126.1536 184.2538 D3 2.1456 13.1337 23.1364 29.8573 D9 5.0951 3.0629 1.9452 1.8932 D11 2.4777 4.5099 5.6277 5.6796 D19 18.6071 11.0764 5.9943 1.8932 Bf 7.9276 27.9017 50.1922 75.5530 (shooting) Focusing movement amount of the third lens group G3) Focal length f 39.0148 75.6936 126.1536 184.2538 D0 1123.4126 2192.4691 3657.7655 5342.4822 Movement amount 1.0194 0.7935 0.7694 0.8023 However, the sign of the movement amount is positive from the object side to the image side (0.01 Movement amount of cemented positive lens L42 when shifting image by [rad]) Focal length f 39.0148 75.6936 126.1536 184.2538 Lens movement amount 0.3152 0.3890 0.4775 0.5523 Image shift amount 0.3900 0.7569 1.2617 1.8428 (condition corresponding value) f1 = 87.584 f2 = −23.128 f3 = 37.864 β2t = −0.7404 β2w = −0.3923 β5t = + 3.8356 β5w = + 1.32020 (1) (D1T-D1W) / (D4W-D4T) = 1.658 (2) f3 / f1 = 0.432 (3) f2 / (fw · ft) ^1/2 = 0.273 (4) (β2t / β2w) / (ft / fw) = 0.400 (5) (β5t / β5w) / (ft / fw) = 0.624 (6) (Bft-Bfw) / (ft-fw) = 0.466 (7) r21 / Da = 2.293 (8) (β2t / β2w) / (β5t / β5w) = 0.641 (9) Db / fw = 0.113

33 to 40, the d line (λ = 587.
FIG. 6 is a diagram of various types of aberration of Example 4 for 6 nm). FIG. 33 is a diagram of various aberrations at the wide-angle end in the infinity focused state, FIG. 34 is a diagram of various aberrations at the infinity focused state in the first intermediate focal length state, and FIG. 35 is a second intermediate focal length. FIG. 36 is a diagram of various aberrations in the in-focus state at infinity, and FIG. 36 is a diagram of various aberrations in the in-focus state at the telephoto end. Also,
FIG. 37 is a diagram of various aberrations at a wide-angle end at a shooting magnification of −1/30, FIG. 38 is a diagram of various aberrations at a shooting magnification of −1/30 at a first intermediate focal length state, and FIG. 39 is a second intermediate view. FIG. 40 is a diagram of various aberrations at a photographing magnification of −1/30 in a focal length state, and FIG. 40 is a diagram of various aberrations at a photographing magnification of −1/30 at the telephoto end.

41 to 44 are coma aberration diagrams when the image is shifted by 0.01 rad (radian) with respect to the optical axis in the fourth embodiment. FIG. 41 is a coma aberration diagram at the wide-angle end in the infinity in-focus state.
FIG. 43 is a coma aberration diagram in the infinity in-focus state in the first intermediate focal length state, FIG. 43 is a coma aberration diagram in the infinity in-focus state in the second intermediate focal length state, and FIG. 44 is in the telephoto end. It is a coma aberration figure in the infinite point focusing state. FIG.
The aberration diagrams of FIGS. 1 to 44 are Y = 15.0, 0, −1 when the cemented positive lens L42 is moved in the positive direction of the image height Y.
The figure shows the coma aberration at 5.0.

In each aberration diagram, FNO is the F number,
NA indicates the numerical aperture, Y indicates the image height, A indicates the half angle of view for each image height, and H indicates the object height for each image height. In the aberration diagram showing astigmatism, a solid line indicates a sagittal image plane, and a broken line indicates a meridional image plane. Further, in the aberration diagram showing the spherical aberration, a broken line indicates a sine condition (sine condition). As is clear from the aberration diagrams, in this embodiment, various aberrations are favorably corrected even at the time of image shift in each shooting distance state and each focal length state.

[Embodiment 5] FIG. 45 is a diagram showing a lens configuration of a variable power optical system according to the fifth embodiment of the present invention. The variable power optical system of FIG. 45 includes, in order from the object side, a first lens group G1 including a positive lens L1 cemented with a biconvex lens and a negative meniscus lens having a concave surface facing the object side, a biconcave lens L21,
A second lens group G2 including a biconvex lens L22 and a biconcave lens L23, and a third lens group G including a biconvex lens L3.
3 and a negative meniscus lens L41 having a concave surface facing the object side,
A fourth lens group G4 including a cemented positive lens L42 including a biconvex lens and a negative meniscus lens having a concave surface facing the object side, and a positive meniscus lens L43 having a concave surface facing the object side, and a positive meniscus having a concave surface facing the object side. It includes a lens L51, a biconcave lens L52, and a fifth lens group G5 including a negative meniscus lens L53 having a concave surface facing the object side.

Further, the aperture stop S is arranged between the third lens group G3 and the fourth lens group G4, and moves integrally with the fourth lens group G4 upon zooming from the wide-angle end to the telephoto end. FIG. 45 shows the positional relationship of each lens group at the wide-angle end, and when the magnification is changed to the telephoto end, the lens units move on the optical axis along the zoom orbit shown by the arrow in FIG. Further, focusing is performed by moving the third lens group G3 along the optical axis. Furthermore, the fourth lens group G
The cemented positive lens L42 in 4 is moved in the direction substantially orthogonal to the optical axis to shift the image, and the fluctuation of the image position due to the camera shake or the like is corrected.

Table (5) below shows the values of specifications of the fifth embodiment of the present invention. In Table (5), f is the focal length, F
NO is the F number, ω is the half angle of view, Bf is the back focus, and D0 is the distance between the object and the surface closest to the object along the optical axis. Further, the surface number indicates the order of the lens surface from the object side along the traveling direction of the light ray, and the refractive index and Abbe number indicate the d-line (λ = 587.6n).
m).

[0088]

[Table 5] f = 38.99 ~ 71.33 ~ 121.51 ~ 184.27 FNO = 3.96 ~ 5.95 ~ 8.34 ~ 11.00 ω = 29.26 ~ 16.27 ~ 9.78 ~ 6.54 ° Surface number Curvature radius Surface spacing Refractive index Abbe number 1 64.8786 4.039 1.48749 70.41 2 -44.0268 1.389 1.84666 23.83 3 -71.2983 (D3 = variable) 4 -47.9671 1.010 1.83500 42.97 5 23.3210 1.010 6 18.5288 2.903 1.80518 25.46 7 -82.6139 0.694 8 -22.7213 1.010 1.83500 42.97 9 134.9364 (D9 = variable) 10 1262.1360 2.146 1.51680 64.20 11 (D11 = variable) 12 ∞ 2.272 (aperture stop S) 13 * -40.8344 1.262 1.58518 30.24 14 -63.1068 0.884 15 29.3204 3.155 1.48749 70.41 16 -14.5314 1.010 1.84666 23.83 17 -23.7048 1.767 18 -34.8120 1.641 1.49108 57.57 19 -26.1669 (D19) = Variable) 20 -92.0506 3.282 1.84666 23.83 21 -24.0797 0.126 22 -51.8483 1.262 1.83500 42.97 23 527.5741 5.049 24 -14.9064 1.515 1.83500 42.97 25 -125.8215 (Bf) (aspherical data) (13 faces) R = -40.8344 κ = 0.3072 C ₄ = -2.19013 × 10 ^-5 C ₆ = -9.86635 × 10 ^-9 C ₈ = -2.20304 × 10 ^-9 C ₁₀ = + 2.30 576 × 10 ^-11 (Variable spacing during zooming) f 38.9916 71.3347 121.5085 184.2739 D3 2.1456 13.1825 23.1413 29.6264 D9 5.0942 3.4256 2.2828 1.8932 D11 2.4786 4.1472 5.2900 5.6796 D19 17.6699 10.7902 5.7074 1.8932 Bf 8.2242 25.6272 48.2883 75.6604 (shooting magnification-1 / 30) Focusing movement amount of the third lens group G3) Focal length f 38.9916 71.3347 121.5085 184.2739 D0 1122.7788 2062.0027 3521.1028 5353.6429 Movement amount 1.0190 0.8343 0.7750 0.7459 However, the sign of the movement amount is positive when moving from the object side to the image side (0.01 (Amount of movement of cemented positive lens L42 when shifting image by [rad]) Focal length f 38.9916 71.3347 121.5085 184.2739 Lens movement amount 0.3049 0.3718 0.4535 0.5227 Image shift amount 0.3899 0.7134 1.2151 1.8428 (condition corresponding value) f1 = 89.612 f2 = −23.224 f3 = 38.274 β2t = −0.7041 β2w = −0.3841 β5t = + 3.9235 β5w = + 1.3176 (1) (D1T-D1W) / (D4W-D4T) = 1.742 (2) f3 / f1 = 0.427 (3) f2 / (fw.ft) ^1/2 = 0.274 (4) (β2t / β2w) / (ft / fw) = 0.388 (5) (β5t / β5w) / (ft / fw) = 0.631 (6) (Bft-Bfw) / (ft-fw) = 0.464 (7) r21 / Da = 2.935 (8) (β2t / β2w) / (β5t / β5w) = 0.615 (9) Db / fw = 0.113

46 to 53 show the d line (λ = 587.
FIG. 6 is a diagram of various types of aberration of Example 5 for 6 nm). FIG. 46 is a diagram of various aberrations at the wide-angle end in the infinity focused state, FIG. 47 is a diagram of various aberrations at the infinity focused state in the first intermediate focal length state, and FIG. 48 is a second intermediate focal length. FIG. 50 is a diagram of various aberrations in a state of focusing at infinity, and FIG. 49 is a diagram of various aberrations in a state of focusing at infinity at the telephoto end. Also,
50 is a diagram of various aberrations at a photographing magnification of −1/30 at the wide-angle end, FIG. 51 is a diagram of various aberrations at a photographing magnification of −1/30 in a first intermediate focal length state, and FIG. 52 is a second intermediate diagram. FIG. 53 is a diagram of various aberrations at a shooting magnification of −1/30 in a focal length state, and FIG. 53 is a diagram of various aberrations at a shooting magnification of −1/30 at the telephoto end.

54 to 57 are coma aberration diagrams when the image is shifted by 0.01 rad (radian) with respect to the optical axis in the fifth embodiment. 54 is a coma aberration diagram at the wide-angle end in the infinity in-focus state, and FIG.
Is a coma aberration diagram in the infinity in-focus state in the first intermediate focal length state, FIG. 56 is a coma aberration diagram in the infinity in-focus state in the second intermediate focal length state, and FIG. 57 is in the telephoto end. It is a coma aberration figure in the infinite point focusing state. FIG.
The aberration diagrams of FIGS. 4 to 57 are Y = 15.0, 0, −1 when the cemented positive lens L42 is moved in the positive direction of the image height Y.
The figure shows the coma aberration at 5.0.

In each aberration diagram, FNO is the F number,
NA indicates the numerical aperture, Y indicates the image height, A indicates the half angle of view for each image height, and H indicates the object height for each image height. In the aberration diagram showing astigmatism, a solid line indicates a sagittal image plane, and a broken line indicates a meridional image plane. Further, in the aberration diagram showing the spherical aberration, a broken line indicates a sine condition (sine condition). As is clear from the aberration diagrams, in this embodiment, various aberrations are favorably corrected even at the time of image shift in each shooting distance state and each focal length state.

[Sixth Embodiment] FIG. 58 is a view showing the lens arrangement of a variable power optical system according to the sixth embodiment of the present invention. The variable power optical system of FIG. 58 includes, in order from the object side, a first lens group G1 including a cemented positive lens L1 including a biconvex lens and a negative meniscus lens having a concave surface facing the object side, a biconcave lens L21,
A second lens group G2 including a biconvex lens L22 and a biconcave lens L23, and a third lens group G including a biconvex lens L3.
3 and a negative meniscus lens L41 having a concave surface facing the object side,
A fourth lens group G4 including a positive lens L42, which is a cemented biconvex lens and a negative meniscus lens having a concave surface facing the object side, and a positive meniscus lens L43 having a concave surface facing the object side, and a positive meniscus having a concave surface facing the object side. It includes a lens L51, a negative meniscus lens L52 having a concave surface facing the object side, and a fifth lens group G5 including a negative meniscus lens L53 having a concave surface facing the object side.

The aperture stop S is arranged between the third lens group G3 and the fourth lens group G4, and moves integrally with the fourth lens group G4 during zooming from the wide-angle end to the telephoto end. FIG. 58 shows the positional relationship of each lens group at the wide-angle end, and when the magnification is changed to the telephoto end, the lens units move on the optical axis along the zoom orbit shown by the arrow in FIG. Further, focusing is performed by moving the third lens group G3 along the optical axis. Furthermore, the fourth lens group G
The cemented positive lens L42 in 4 is moved in the direction substantially orthogonal to the optical axis to shift the image, and the fluctuation of the image position due to the camera shake or the like is corrected.

The following table (6) lists the values of specifications of the sixth embodiment of the present invention. In Table (6), f is the focal length, F
NO is the F number, ω is the half angle of view, Bf is the back focus, and D0 is the distance between the object and the surface closest to the object along the optical axis. Further, the surface number indicates the order of the lens surface from the object side along the traveling direction of the light ray, and the refractive index and Abbe number indicate the d-line (λ = 587.6n).
m).

[0095]

[Table 6] f = 38.99 ~ 71.33 ~ 121.51 ~ 184.27 FNO = 3.96 ~ 5.95 ~ 8.34 ~ 11.00 ω = 29.26 ~ 16.27 ~ 9.78 ~ 6.54 ° Surface number Curvature radius Surface spacing Refractive index Abbe number 1 70.9089 4.039 1.48749 70.41 2 -43.6667 1.389 1.84666 23.83 3 -70.7874 (D3 = variable) 4 -46.3038 1.010 1.83500 42.97 5 24.5894 1.010 6 19.4033 2.903 1.80518 25.46 7 -67.5285 0.757 8 -22.5641 1.010 1.83500 42.97 9 128.7035 (D9 = variable) 10 416.6934 2.146 1.51680 64.20 11 (D11 = variable) 12 ∞ 2.272 (aperture stop S) 13 * -40.8347 1.262 1.58518 30.24 14 -63.1068 0.884 15 30.1461 3.155 1.48749 70.41 16 -14.2517 1.010 1.84666 23.83 17 -23.8071 1.767 18 -32.0616 1.641 1.49108 57.57 19 -24.6369 (D19) = Variable) 20 -85.5884 3.282 1.84666 23.83 21 -23.4859 0.618 22 -40.4859 1.262 1.83500 42.97 23 -992.8714 4.903 24 -14.8901 1.515 1.83500 42.97 25 -97.4552 (Bf) (aspherical data) (13 faces) R = -40.8344 κ = 0.3072 C ₄ = -2.19013 × 10 ^-5 C ₆ = -9.86635 × 10 ^-9 C ₈ = -2.20304 × 10 ^-9 C ₁₀ = + 2.305 76 × 10 ^-11 (Variable spacing during zooming) f 38.9855 72.8565 122.8549 184.2862 D3 2.1456 13.7953 23.3414 30.4992 D9 5.0821 3.4037 1.9255 1.8932 D11 2.4907 4.1692 5.6474 5.6797 D19 17.6700 10.4440 5.9656 1.8932 Bf 7.9517 26.4274 48.6728 / 76.3285 (shooting) Focusing movement amount of the third lens group G3) Focal length f 38.9855 72.8565 122.8549 184.2862 D0 1121.3881 2105.6730 3565.1357 5357.2181 Movement amount 1.0190 0.8343 0.7750 0.7459 However, the sign of the movement amount is positive from the object side to the image side (0.01 (Amount of movement of cemented positive lens L42 when shifting image by [rad]) Focal length f 38.9855 72.8565 122.8549 184.2862 Lens movement amount 0.3187 0.3882 0.4678 0.5360 Image shift amount 0.3899 0.7285 1.2285 1.8427 (condition corresponding value) f1 = 94.7776 f2 = −23.714 f3 = 37.100 β2t = −0.6435 β2w = −0.3637 β5t = + 3.9100 5w = +1.3030 (1) (D1T -D1W) / (D4W-D4T) = 1.797 (2) f3 / f1 = 0.391 (3) f2 / (fw · ft) 1/2 = 0.280 (4) (β2t / β2w) / (ft / fw) = 0.374 (5) (β5t / β5w) / (ft / fw) = 0.635 (6) (Bft-Bfw) / (ft-fw) = 0.471 (7) r21 / Da = 3.109 (8) (β2t / β2w) / (β5t / β5w) = 0.589 (9) Db / fw = 0.113

59 to 66 show the d line (λ = 587.
FIG. 6 is a diagram of various types of aberration of Example 6 for 6 nm). 59 is a diagram of various aberrations at the wide-angle end in the infinity focused state, FIG. 60 is a diagram of various aberrations at the first intermediate focal length state in the infinity focused state, and FIG. 61 is a second intermediate focal length. FIG. 63 is a diagram of various aberrations in the in-focus state at infinity, and FIG. 62 is a diagram of various aberrations in the in-focus state at the telephoto end. Also,
FIG. 63 is a diagram of various aberrations at a wide-angle end at a shooting magnification of −1/30, FIG. 64 is a diagram of various aberrations at a shooting magnification of −1/30 at a first intermediate focal length state, and FIG. 65 is a second intermediate view. FIG. 66 is a diagram of various aberrations at a photographing magnification of −1/30 in a focal length state, and FIG. 66 is a diagram of various aberrations at a photographing magnification of −1/30 at the telephoto end.

67 to 70 are coma aberration diagrams when the image is shifted by 0.01 rad (radian) with respect to the optical axis in the sixth embodiment. FIG. 67 is a coma aberration diagram at the wide-angle end in the in-focus state at infinity.
69 is a coma aberration diagram in the first intermediate focal length state in the infinity in-focus state, FIG. 69 is a coma aberration diagram in the second intermediate focal length state in the infinity in-focus state, and FIG. 70 in the telephoto end. It is a coma aberration figure in the infinite point focusing state. Figure 6
Each of the aberration diagrams in FIGS. 7 to 70 shows Y = 15.0, 0, −1 when the cemented positive lens L42 is moved in the positive direction of the image height Y.
The figure shows the coma aberration at 5.0.

In each aberration diagram, FNO is the F number,
NA indicates the numerical aperture, Y indicates the image height, A indicates the half angle of view for each image height, and H indicates the object height for each image height. In the aberration diagram showing astigmatism, a solid line indicates a sagittal image plane, and a broken line indicates a meridional image plane. Further, in the aberration diagram showing the spherical aberration, a broken line indicates a sine condition (sine condition). As is clear from the aberration diagrams, in this embodiment, various aberrations are favorably corrected even at the time of image shift in each shooting distance state and each focal length state.

[0099]

As described above, according to the present invention, it is possible to realize a compact variable power optical system having a short overall lens length at the telephoto end.

[Brief description of drawings]

FIG. 1 is a diagram showing the distribution of refractive power of a variable power optical system according to each example of the present invention, and how each lens unit moves during zooming from a wide-angle end (W) to a telephoto end (T). .

FIG. 2 is a diagram showing a lens configuration of a variable power optical system according to a first example of the present invention.

FIG. 3 is a diagram of various types of aberration in Example 1 at the wide-angle end and at infinity.

FIG. 4 is a diagram of various types of aberration in Example 1 at the intermediate focal length state and in the in-focus state at infinity.

FIG. 5 is a diagram of various types of aberration in Example 1 at the telephoto end in the in-focus state at infinity.

FIG. 6 is a photographing magnification −1/30 at the wide-angle end in Embodiment 1.
FIG. 7 is a diagram of various types of aberrations at.

FIG. 7 is a diagram of various types of aberration at an imaging magnification of −1/30 in the intermediate focal length state of Example 1.

FIG. 8: Magnification at the telephoto end of Example 1 -1/30
FIG. 7 is a diagram of various types of aberrations at.

FIG. 9 is a coma aberration diagram at the time of image shift in the in-focus state at infinity at the wide-angle end according to the first exemplary embodiment.

FIG. 10 is a coma aberration diagram at the time of image shift in an in-focus state at infinity in the intermediate focal length state of Example 1.

FIG. 11 is a coma aberration diagram at the time of image shift in the in-focus state at infinity at the telephoto end according to the first exemplary embodiment.

FIG. 12 is a diagram showing a lens configuration of a variable power optical system according to a second example of the present invention.

FIG. 13 is a diagram of various types of aberration at the wide-angle end according to Example 2 in the in-focus state at infinity.

FIG. 14 is a diagram of various types of aberration of Example 2 in an in-focus state at an intermediate focal length.

FIG. 15 is a diagram of various types of aberration at the telephoto end of Example 2 in the in-focus state at infinity.

16 is a photographing magnification at the wide-angle end of Embodiment 2-1 / 3. FIG.
It is a various-aberration figure at 0.

FIG. 17 is a diagram of various types of aberration at an imaging magnification of −1/30 in the intermediate focal length state of Example 2.

FIG. 18 is a photographing magnification at the telephoto end of Embodiment 2-1 / 3.
It is a various-aberration figure at 0.

FIG. 19 is a coma aberration diagram at the time of image shift in the in-focus state at infinity at the wide-angle end in Example 2;

20 is a coma aberration diagram at the time of image shifting in the in-focus state at infinity in the intermediate focal length state of Example 2. FIG.

FIG. 21 is a coma aberration diagram at the time of image shift in the infinity in-focus state at the telephoto end according to Example 2;

FIG. 22 is a diagram showing a lens configuration of a variable power optical system according to the third example of the present invention.

FIG. 23 is a diagram of various types of aberration of Example 3 at the wide-angle end in the in-focus state at infinity.

FIG. 24 is a diagram of various types of aberration in Example 3 at the intermediate focal length state and in the in-focus state at infinity.

FIG. 25 is a diagram of various types of aberration in Example 3 at the telephoto end in the in-focus state at infinity.

FIG. 26 is a photographing magnification at the wide-angle end of Embodiment 3-1 / 3.
It is a various-aberration figure at 0.

FIG. 27 is a diagram of various types of aberration at an imaging magnification of −1/30 in the intermediate focal length state of Example 3.

FIG. 28 is a photographing magnification at the telephoto end of Example 3-1 / 3.
It is a various-aberration figure at 0.

FIG. 29 is a coma aberration diagram at the time of image shift in the in-focus state at infinity at the wide angle end in Example 3;

FIG. 30 is a coma aberration diagram at the time of image shift in the in-focus state at infinity in the intermediate focal length state of Example 3;

FIG. 31 is a coma aberration diagram at the time of image shift in the infinity in-focus state at the telephoto end according to Example 3;

FIG. 32 is a diagram showing a lens configuration of a variable power optical system according to the fourth example of the present invention.

FIG. 33 is a diagram of various types of aberration of Example 4 at the wide-angle end when focused on infinity.

FIG. 34 is a diagram of various types of aberration in the fourth intermediate focal length state of Example 4 in the infinite focusing state.

FIG. 35 is a diagram of various types of aberration in a second intermediate focal length state of Example 4 in an in-focus state at infinity;

FIG. 36 is a diagram of various types of aberration at the telephoto end of Example 4 when focused on an object at infinity;

FIG. 37 is a photographing magnification at the wide-angle end of Example 4-1 / 3.
It is a various-aberration figure at 0.

38 is a diagram of various types of aberration at a shooting magnification of −1/30 in the first intermediate focal length state of Example 4. FIG.

FIG. 39 is a diagram of various types of aberration at a shooting magnification of −1/30 in the second intermediate focal length state of Example 4.

FIG. 40 is a photographing magnification at the telephoto end of Example 4-1 / 3.
It is a various-aberration figure at 0.

41 is a coma aberration diagram at the time of image shift in the in-focus state at infinity at the wide-angle end according to Example 4. FIG.

FIG. 42 is a coma aberration diagram at the time of image shift in the in-focus state at infinity in the first intermediate focal length state of Example 4.

FIG. 43 is a coma aberration diagram at the time of image shift in the in-focus state at infinity in the second intermediate focal length state of Example 4.

FIG. 44 is a coma aberration diagram at the time of image shift in the infinity in-focus state at the telephoto end according to Example 4;

FIG. 45 is a diagram showing a lens configuration of a variable power optical system according to the fifth example of the present invention.

FIG. 46 is a diagram of various types of aberration in Example 5 at the wide-angle end in the in-focus state at infinity.

FIG. 47 is a diagram of various types of aberration in a fifth intermediate focal length state of Example 5 when focused on an object at infinity;

FIG. 48 is a diagram of various types of aberration in a second intermediate focal length state of Example 5 in the in-focus state at infinity.

FIG. 49 is a diagram of various types of aberration in Example 5 at the telephoto end in the in-focus state at infinity.

50 is a photographing magnification at the wide-angle end of Embodiment 5-1 / 3.
It is a various-aberration figure at 0.

FIG. 51 is a diagram of various types of aberration at a shooting magnification of −1/30 in the first intermediate focal length state of Example 5.

52 is an aberration diagram of Example 5 at a shooting magnification of −1/30 in a second intermediate focal length state. FIG.

53 is a photographing magnification at the telephoto end of Embodiment 5-1 / 3.
It is a various-aberration figure at 0.

FIG. 54 is a coma aberration diagram at the time of image shift in the in-focus state at infinity at the wide-angle end in Example 5;

FIG. 55 is a coma aberration diagram at the time of image shifting in the infinity in-focus state in the first intermediate focal length state of Example 5.

FIG. 56 is a coma aberration diagram at the time of image shifting in the infinity in-focus state in the second intermediate focal length state of Example 5.

57 is a coma aberration diagram at the time of image shift in the infinity in-focus state at the telephoto end according to Example 5; FIG.

FIG. 58 is a diagram showing a lens configuration of a variable power optical system according to the sixth example of the present invention.

FIG. 59 is a diagram of various types of aberration at the wide-angle end and at infinity in Example 6;

FIG. 60 is a diagram of various types of aberration in a sixth intermediate focal length state of Example 6 in the infinity in-focus state.

FIG. 61 is a diagram of various types of aberration in a second intermediate focal length state of Example 6 at an infinity in-focus state.

FIG. 62 is a diagram of various types of aberration at the telephoto end of Example 6 in the in-focus state at infinity;

FIG. 63 is a photographing magnification at the wide-angle end of Example 6-1 / 3.
It is a various-aberration figure at 0.

FIG. 64 is a diagram of various types of aberration at a shooting magnification of −1/30 in the first intermediate focal length state of Example 6.

FIG. 65 is a diagram of various types of aberration at a shooting magnification of −1/30 in the second intermediate focal length state of Example 6.

FIG. 66 is a photographing magnification at the telephoto end of Embodiment 6-1 / 3.
It is a various-aberration figure at 0.

67 is a coma aberration diagram at the time of image shifting in the in-focus state at infinity at the wide-angle end according to Example 6; FIG.

68 is a coma aberration diagram at the time of image shift in the infinity in-focus state in the first intermediate focal length state of Example 6. FIG.

FIG. 69 is a coma aberration diagram at the time of image shift in the in-focus state at the second intermediate focal length state in Example 6;

70 is a coma aberration diagram at the time of image shift in the infinity in-focus state at the telephoto end according to Example 6; FIG.

[Explanation of symbols]

 G1 first lens group G2 second lens group G3 third lens group G4 fourth lens group G5 fifth lens group Li each lens component S aperture stop

Claims (5)

[Claims] 1. A first lens group G1 having a positive refractive power and a second lens group G having a negative refractive power in order from the object side.
2, a third lens group G3 having a positive refractive power, a fourth lens group G4 having a positive refractive power, and a fifth lens group G5 having a negative refractive power, Upon zooming from the wide-angle end to the telephoto end, the air gap between the first lens group G1 and the second lens group G2 increases, and the air gap between the second lens group G2 and the third lens group G3 becomes The air gap between the third lens group G3 and the fourth lens group G4 increases, and the air gap between the fourth lens group G4 and the fifth lens group G5 decreases, so that at least The lens group G1 and the fifth lens group G
5 moves to the object side, and an axial air gap between the first lens group G1 and the second lens group G2 at the wide-angle end is D1W, and the first lens group G1 and the second lens group G2 at the telephoto end. D1T is the axial air distance from the fourth lens group G at the wide-angle end.
4 and the fifth lens group G5 have an axial air distance of D4W, and the fourth lens group G4 and the fifth lens group G5 have an axial air distance of D4T at the telephoto end, and the first lens group G1. F1 as the focal length of the second lens group G2
Is f2, the focal length of the third lens group G3 is f3, the focal length of the entire system at the telephoto end is ft, and the focal length of the entire system at the wide-angle end is fw, 1.5 < Satisfies the condition of (D1T-D1W) / (D4W-D4T) <2.1 0.39 <f3 / f1 <0.55 0.25 <f2 / (fw · ft) ^1/2 <0.32 A variable power optical system characterized by. 2. The use magnification of the second lens group G2 at the telephoto end is β2t, the use magnification of the second lens group G2 at the wide-angle end is β2w, and the use magnification of the fifth lens group G5 at the telephoto end is When β5t, the use magnification of the fifth lens group G5 at the wide-angle end is β5w, the focal length of the entire system at the telephoto end is ft, and the focal length of the entire system at the wide-angle end is fw, 0.32 <( 2. The variation according to claim 1, wherein the condition of β2t / β2w) / (ft / fw) <0.45 0.5 <(β5t / β5w) / (ft / fw) <0.7 is satisfied. Double optics. 3. The variable power optical system according to claim 1, wherein the fifth lens group G5 has a positive lens closest to the object side and a negative lens closest to the image side. 4. The back focus at the telephoto end is set to Bf.
When t is the back focus at the wide-angle end, Bfw is the focal length of the entire system at the telephoto end, and ft is the focal length of the entire system at the wide-angle end, then 0.35 <(Bft-Bfw) / (ft -Fw) <0.
The variable power optical system according to any one of claims 1 to 3, wherein the condition 5 is satisfied. 5. The second lens group G2 includes, in order from the object side, a biconcave lens, a biconvex lens, and a negative lens having a concave surface facing the object side, and the second lens group G2 is closest to the object side. The radius of curvature of the lens surface is r21, and the distance along the optical axis between the aperture stop arranged in the variable power optical system and the lens surface of the second lens group G2 closest to the object side is Da. At this time, the variable power optical system according to any one of claims 1 to 4, wherein the condition of 2 <r21 / Da <3.5 is satisfied.