JPH0996762A - Image shiftable variable power optical system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a miniaturized and image shiftable variable power optical system constituting of shifting images by moving at least one lens component in a direction almost vertical to an optical axis as a shift lens group and by satisfying specified conditions. SOLUTION: A first lens group G1 and a fifth lens group G5 are moved to an object side, one lens component among the lens components for constituting a forth lens group G4 is moved in the direction almost vertical to the optical axis as the shift lens group and thus, the image is shifted. Then, when a using magnification at the telescopic end of the shift lens group is defined as βat , the using magnification at the telescopic end of a lens group arranged more on an image side than the shift lens group is defined as βbt , the focal distance of the entire lens system at the telescopic end is defined as ft and a synthetic focus distance at the telescopic end of the lens group arranged more on the object side than the shift lens group is defined as fct, the conditions of 2.5<(1-βat ).βbt <5 and -0.1<ft/fct<-0.005 are satisfied.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a variable-magnification optical system capable of image shifting, and more specifically, it shifts an image by moving a shift lens group in a direction substantially perpendicular to an optical axis to prevent image stabilization. The present invention relates to a variable power optical system that can function as an optical system.

[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, the number of cameras equipped with so-called high-magnification zoom lenses whose zoom ratio exceeds 3 times is increasing, and the focal length at the telephoto end is becoming longer and longer. In such a high zoom ratio zoom lens, as the zoom ratio increases, the aperture ratio changes greatly between the wide-angle end and the telephoto end, and the aperture ratio tends to increase at the telephoto end.

As described above, in the high zoom lens, since the aperture ratio is large at the telephoto end, the exposure time is long and the focal length is long. For this reason, at the telephoto end, a change in the image position (image blur) occurs due to camera shake or the like, and it is easy for shooting failure to occur. By the way, conventionally, there has been known a technique of shifting an image by decentering a part of lens groups constituting a lens system. For example, Japanese Patent Publication Sho 41-8
Japanese Patent No. 558 discloses an image shiftable optical system configured to obtain good image forming performance even when an image is shifted by decentering some lens groups.

In order to solve the problem of shooting failure due to the above-mentioned camera shake and the like, a combination of a detection system for detecting camera shake and a drive system for decentering some lens groups is combined with an image shiftable optical system. In addition, various proposals have been made regarding so-called anti-vibration optical systems. In the anti-vibration optical system, the detection system detects camera shake, and the drive system decenters the lens group to perform image shift so as to cancel the fluctuation of the image position caused by the detected camera shake. In this way, in the image stabilization optical system, it is possible to correct the image position variation due to camera shake or the like due to the image shift.

In Japanese Laid-Open Patent Publication No. 1-116619, the first lens unit having negative refracting power and the second lens unit having positive refracting power are arranged in order from the object side.
A zoom lens including a lens group and a third lens group having a negative refractive power is disclosed. Then, in this zoom lens, a technique has been proposed in which the second lens group is driven in a direction perpendicular to the optical axis to shift the image and correct the fluctuation in the image position due to camera shake.

Further, in Japanese Patent Laid-Open No. 6-95039,
A zoom lens including a first lens group having a positive refractive power, a second lens group having a positive refractive power, and a third lens group having a negative refractive power is disclosed in order from the object side. Then, in this zoom lens, a technique has been proposed in which a part of the second lens group that constitutes the second lens group is driven in a direction perpendicular to the optical axis to shift the image and correct the image blur caused by camera shake. ing.

When a part of the lens group constituting the lens system, that is, the shift lens group is moved in the direction substantially perpendicular to the optical axis to shift the image, the image shift amount Δ with respect to the shift amount δ of the shift lens group is as follows. It is represented by formula (a). Δ = δ × (1−βa) βb (a) Here, βa: Use magnification of the shift lens group βb: Use magnification of the lens group arranged on the image side of the shift lens group

[0008]

However, in the zoom lens disclosed in Japanese Unexamined Patent Publication No. 1-116619, the lens group arranged on the object side of the shift lens group has a negative refractive power. Therefore, it is difficult to reduce the total lens length at the telephoto end.

In the above equation (a), | (1-β
a) When βb | becomes large, the image is largely shifted even if the shift lens group moves slightly, so that control becomes difficult. Conversely, if | (1-βa) βb | becomes smaller,
The amount of movement of the shift lens group necessary to shift the image by a predetermined amount becomes too large, and the configuration of the drive system becomes complicated and large. Therefore, it is necessary to set (1-βa) βb to an appropriate value.

By the way, in the zoom lens disclosed in Japanese Patent Laid-Open No. 6-95039, the second lens group is composed of a second lens group having a negative refractive power and a second lens group having a positive refractive power, and a second lens group is formed. The lens subgroup is a shift lens group. Therefore, the use magnification βa of the 2b-th lens subgroup that is the shift lens group is always 0 <βa <1 during zooming,
The value of (1-βa) βb is small. as a result,
Especially at the telephoto end where the image position fluctuates greatly with respect to a small camera shake, there is a disadvantage that the required movement amount of the shift lens group becomes large.

The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to provide a variable-magnification optical system that is compact and capable of image shifting.

[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 toward the object side so that the air gap between the fourth lens group G5 and the fourth lens group G5 decreases, and The image is shifted by moving at least one of the lens components as a shift lens group in a direction substantially perpendicular to the optical axis, and the use magnification at the telephoto end of the shift lens group is set to βat, and the image side is closer to the shift lens group than the shift lens group. Let βbt be the use magnification at the telephoto end of the lens group arranged at, and ft be the focal length of the entire lens system at the telephoto end, and the combined focal length at the telephoto end of the lens group arranged on the object side of the shift lens group. Where fct is an image shiftable variable characterized by satisfying the condition of 2.5 <(1-βat) · βbt <5-0.1 <ft / fct <-0.005. To provide an optical system.

According to a preferred aspect of the present invention, the focal length of the entire lens system at the wide-angle end is fw, and the combined focal length of the lens units arranged on the object side of the shift lens unit at the wide-angle end is fcw. At this time, the condition of -0.3 <fw / fcw <-0.02 is satisfied.

According to another aspect of the present invention, in the variable power optical system capable of shifting an image by moving the shift lens group in a direction substantially perpendicular to the optical axis, the shift lens A lens group GA including a group, and a lens group GB that is disposed on the image side of the lens group GA and includes at least one lens group, and changes the air gap between the lens group GA and the lens group GB. Thereby, at least one of zooming from the wide-angle end to the telephoto end and focusing on a short-distance object is performed, and the use magnification at the telephoto end of the shift lens group is set to βat,
A lens group G arranged on the image side of the shift lens group
Provided is a variable-magnification optical system capable of image shifting, which satisfies the condition of 2.5 <(1-βat) · βbt <5, where βbt is the use magnification at the telephoto end of B.

In this case, according to a preferred embodiment, a lens group GC including at least one lens group is arranged on the object side of the lens group GA, and the use magnification at the telephoto end of the shift lens group is βat, The use magnification at the telephoto end of the lens group GB arranged on the image side of the shift lens group is βbt, the use magnification at the wide-angle end of the shift lens group is βaw, and the use magnification is set to the image side of the shift lens group. When the use magnification at the wide-angle end of the lens group GB is βbw, the focal length of the entire lens system at the telephoto end is ft, and the focal length of the entire lens system at the wide-angle end is fw, 0.3 <{[(1-βat ) Βbt] / [(1-βaw) βbw]} / (ft
/ fw) <0.75 is satisfied.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION In the present invention, the lens system is downsized and the shift lens group is controlled relatively easily by considering the following conditions and conditions. The use magnification βa of the shift lens group at the telephoto end and the use magnification βb of the lens group arranged on the image side of the shift lens group are set to appropriate values. Set the combined focal length of the lens groups that are located closer to the object side than the shift lens group to an appropriate value.

Assuming that the lens system rotates about the principal point position of the lens system, the image blur amount Δ'with respect to the blur angle ε of the lens system is expressed by the following equation (b). Δ ′ = f · tan ε (b) where, f: focal length of the entire lens system

When the blur angle ε is relatively small, it can be approximated to tan ε≈ε, so the image blur amount Δ'is expressed by the following equation (c). Δ′≈f · ε (c) When the image blur amount Δ ′ is relatively small, it cannot be identified on the photograph as the image blur. However, when the blur amount Δ'becomes large to some extent, it can be discriminated from the blur of the image, and a blurred photograph can be obtained.

At the telephoto end, since the focal length f of the entire lens system becomes large, it is easy to obtain a blurred photograph even at a small blur angle. Therefore, assuming that the blur angle ε of the lens system generated by camera shake or the like is constant, the blur amount of the image generated at the telephoto end is larger than the blur amount of the image generated at the wide angle end.
In other words, it is important to configure so that the amount of image blur at the telephoto end can be corrected more than at the wide-angle end.

As described above, the image shift amount Δ with respect to the movement amount δ in the direction orthogonal to the optical axis of a part of the lens groups constituting the lens system, that is, the shift lens group is expressed by the following equation (a). Δ = δ × (1−βa) βb (a) To offset the image blur amount Δ ′ due to camera shake or the like by the image shift amount Δ due to movement of the shift lens group, and to correct the fluctuation of the image position due to camera shake or the like. , The relationship shown in the following equation (d) must be established. Δ + Δ '= 0 (d)

By substituting the expressions (a) and (c) into the expression (d), the relationship shown in the following expression (e) is obtained. δ = − {f / (1-βa) βb} ε (e) By the way, when the movement amount of the shift lens group increases, the work amount for driving the shift lens group also increases.
This leads to an increase in size and complexity of the drive mechanism.

Therefore, it is important to reduce the amount of movement of the shift lens group, and the size and simplification of the drive mechanism cannot be achieved unless (1-βa) βb is large to some extent at the telephoto end. On the contrary, if (1-βa) βb becomes too large, the image blurring due to the control error of the shift lens group becomes large. Therefore, in the present invention, as shown in the above, (1-
It is desirable to set βa and βb to appropriate values.

On the contrary, conditions for setting the (1-βa) βb to an appropriate value and reducing the size of the lens system will be described. FIG. 38 shows the use magnification β of the shift lens group.
The relationship between a and the use magnification βb of the lens unit arranged on the image side of the shift lens unit is shown. In FIG. 38, (A) shows a case of -1 <1 / βa <1 and -1 <βb <1, and (B) shows a case of -1 <βa <1 and -1 <1 / βb <1. (C) shows the case where -1 <βa <1 and -1 <βb <1.

In (C), -1 <βa <1 and -1 <βb <1
In the case of, the size of (1-βa) βb cannot be increased so much. In (A), -1 <1 / βa <1, and -1 <
In the case of βb <1, if the refractive power of the lens group on the image side of the shift lens group becomes a negative refractive power, the image by the shift lens group is reduced, so that the lens system cannot be downsized. Even if the refractive power of the lens unit on the image side of the shift lens unit is a positive refractive power, it is difficult to reduce the total lens length at the telephoto end.

By the way, as a method of shortening the total lens length, a negative lens group is arranged closest to the image plane of the lens system, and the refractive power of the lens group arranged on the object side of the negative lens group is changed to the positive refractive power. The telephoto type is known. Also in the present invention, disposing the negative lens group closest to the image side is effective for shortening the total lens length.

Therefore, the negative lens group is arranged on the image side of the shift lens group, the refractive power of the shift lens group is made positive, and the refractive power of the lens group on the image side of the shift lens group is made negative. And In this way, by enlarging the image by the shift lens group, it is possible to reduce the total lens length. In this case, the relationship between the use magnification βa of the shift lens group and the use magnification βb of the lens group arranged on the image side of the shift lens group corresponds to the case of (B) described above, and is particularly 0.
<1 / βb <1.

In the present invention, the shift lens group has a positive refracting power, and its use magnification βa is -1 <1 / βa <1.
The refractive powers of the lens groups arranged on the object side of the shift lens group are set so that Furthermore, the focal length of the lens group arranged on the image side of the shift lens group is negative (negative refractive power), and the use magnification βb is 0 <1 / βb <
It is set to 1. By setting in this way, the shift lens group can be efficiently controlled. In particular, in the present invention, by making the refractive power of the lens group arranged on the object side of the shift lens group to be a weak negative refractive power, that is, by making the use magnification of the shift lens group negative, The values of βa and βb are increased, and the amount of movement of the shift lens group necessary to shift the image by a predetermined amount is decreased.

At this time, if the refracting power of the lens group disposed closer to the object side than the shift lens group is made negative, (1-
Since the values of βa and βb become large, it is possible to further reduce the amount of movement of the shift lens group necessary to shift the image by a predetermined amount. However, since the total length of the lens becomes large, it is desirable to set the refracting power of the lens group arranged on the object side of the shift lens group to an appropriate value, as described above.

Each conditional expression of the present invention will be described below. In the present invention, the following conditional expressions (1) and (2)
To be satisfied. 2.5 <(1-βat) · βbt <5 (1) -0.1 <ft /fct<-0.005 (2)

Here, βat: Use magnification at the telephoto end of the shift lens group βbt: Use magnification at the telephoto end of the lens group arranged on the image side of the shift lens group ft: Focal length fct of the entire lens system at the telephoto end : Synthetic focal length at the telephoto end of the lens group arranged closer to the object than the shift lens group

The conditional expressions (1) and (2) are conditional expressions in which the above-mentioned conditions and an appropriate range are provided. If the upper limit of conditional expression (1) is exceeded, the position of the shift lens group becomes difficult to control because the image shifts greatly even if the shift lens group moves by a minute amount.
On the contrary, if the lower limit of conditional expression (1) is not reached, the amount of movement of the shift lens group necessary to shift the image by a predetermined amount becomes extremely large. As a result, the drive mechanism for moving the shift lens group becomes large in size, and it becomes impossible to downsize the lens system.

If the upper limit of conditional expression (2) is exceeded, the refracting power of the lens unit arranged on the object side of the shift lens unit becomes positive, and the above-mentioned coefficient (1-βa) β
The value of b becomes small. As a result, the amount of movement of the shift lens group required to shift the image by a predetermined amount increases, which is not preferable. On the other hand, if the lower limit of conditional expression (2) is not reached, the refractive power of the lens group disposed closer to the object side than the shift lens group becomes negatively large, making it difficult to shorten the total lens length. .

As described above, shortening the total lens length at the telephoto end is a necessary condition for downsizing the lens system. However, at the wide-angle end, if the back focus becomes too short, the off-axis light flux that passes through the negative lens group disposed closest to the image plane separates from the optical axis, and the lens diameter becomes too large. Therefore, it is desirable to make the refracting power of the lens unit arranged on the object side of the shift lens unit negative at the wide-angle end more negative than at the telephoto end.

Therefore, in the present invention, it is desirable to satisfy the following conditional expression (3). −0.3 <fw / fcw <−0.02 (3) where, fw: focal length of the entire lens system at the wide-angle end fcw: composition at the wide-angle end of the lens group arranged on the object side of the shift lens group Focal length

Conditional expression (3) is a conditional expression which defines the focal length at the wide-angle end of the lens unit arranged on the object side of the shift lens unit. If the upper limit of conditional expression (3) is exceeded, the back focus at the wide-angle end becomes too short, and the lens diameter becomes large. On the contrary, if the lower limit value of the conditional expression (3) is not reached, the back focus at the telephoto end becomes large and the total lens length becomes large, which is not preferable.

In the present invention, the fourth lens group G
It is preferable that 4 has a lens unit fixed to the optical axis on the image side of the shift lens unit during image shifting, and satisfies the following conditional expression (4). 0.38 <fa / (fw * ft) ^1/2 <0.7 (4) where fa: focal length of shift lens group

Conditional expression (4) is a conditional expression which defines the focal length of the shift lens group. If the upper limit of conditional expression (4) is exceeded, the use magnification of the shift lens group and the use magnification of the lens group disposed on the image side of the shift lens group are set to values suitable for image shift, and at the same time. It becomes difficult to achieve a high zoom ratio.

On the contrary, if the lower limit value of the conditional expression (4) is not reached, the shift lens group must be of a lens structure suitable for a larger aperture and capable of suppressing the fluctuation of the off-axis aberration that occurs during image shift. , Spherical aberration that occurs independently cannot be suppressed well. Further, good image forming performance cannot be obtained at the time of image shift, resulting in an increase in the number of lens components.

When the shift lens group is arranged closest to the object side, the use magnification βa of the shift lens group becomes zero. Therefore, the coefficient portion (1-βa) βb on the right side of the expression (a) becomes βb, and the ratio of the coefficient at the wide-angle end to the coefficient at the telephoto end matches the zoom ratio. For this reason, when trying to achieve a high zoom ratio, the amount of movement of the shift lens group necessary to shift the image by a predetermined amount becomes extremely smaller at the telephoto end than at the wide-angle end. Then, the positional accuracy of the shift lens group along the direction perpendicular to the optical axis largely changes due to zooming,
It becomes difficult to control the position of the shift lens group.

Therefore, in the present invention, at least one lens group is arranged on the object side of the shift lens group, and the coefficient portion (1-β at the right side of the equation (a) at the wide-angle end and the telephoto end is used.
a) The change in the value of βb is reduced to suppress the change in the moving amount of the shift lens group necessary for shifting the image by a predetermined amount due to the magnification change. In particular, if the following conditional expression (5) is satisfied, image shift can be performed with a small movement amount of the shift lens group, and position control of the shift lens group can be easily performed. 0.3 <{[(1-βat) βbt] / [(1-βaw) βbw]} / (ft / fw) <0.75 (5)

If the upper limit of conditional expression (5) is exceeded, as described above, it becomes difficult to control the position of the shift lens group. On the contrary, when the lower limit value of the conditional expression (5) is exceeded, the zooming effect of the lens unit arranged on the object side of the shift lens unit becomes extremely large. As a result, it is not possible to equalize the proportions of the lens units constituting the variable power optical system that are responsible for the variable power, and it becomes impossible to achieve high performance with a small number of constituent lenses.

In the present invention, the lens group including the shift lens group is composed of a plurality of lens subgroups in order to increase the image shift amount and achieve high zoom performance while simultaneously achieving high performance. It is desirable to shift the image by moving the lens portion group arranged closer to the object than the lens portion group arranged on the image side in a direction substantially perpendicular to the optical axis.

The shift lens group is usually required to have an aberration correction state so that a good image forming performance can be obtained even when the image is shifted. Specifically, it is required 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 image is shifted by moving the shift lens group. The appropriate Petzval sum is a condition for suppressing the curvature of field that occurs at the periphery of the screen when the image is shifted by moving the shift lens group.

When the entire 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. In the present invention, one lens group is composed of a plurality of lens sub-groups, and a part of the lens sub-groups is a shift lens group, so that it is possible to correct a larger blur while maintaining high optical performance. I am trying.

In particular, by using a lens portion group arranged closer to the object than the lens portion group arranged closest to the image side as a shift lens group, the use magnification of the shift lens group and the image side of the shift lens group are closer to each other. It is possible to set the use magnification of the arranged lens group to an appropriate value.

In particular, in the present invention, by satisfying the following conditional expression (6), good image forming performance can be obtained even during image shifting. Db / fw <0.2 (6) where, Db: distance along the optical axis between the aperture stop and the surface of the shift lens group closest to the aperture stop.

If the upper limit of conditional expression (6) 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 that 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. It is also possible to solve the above-mentioned problems by configuring the shift lens group with a larger number of lenses. However,
Not only is the lens system increased in size, but the drive mechanism for driving the shift lens group is also complicated, which is not preferable.

According to another aspect, in the present invention, a blur detection system for detecting a blur of an optical system and a driving means are provided in order to prevent a photographing failure due to an image blur caused by a camera shake or the like. It can be combined with a variable power optical system capable of image shift by. Then, by decentering all or part of one lens group among the lens groups forming the optical system as a decentering lens group, the image is shifted,
By correcting the image blur (image position fluctuation) caused by the blur of the optical system detected by the blur detection system, the variable power optical system of the present invention can be used as a so-called anti-vibration optical system.

Further, according to the present invention, it is possible to perform focusing by moving a part of the lens group constituting the lens system along the optical axis. In particular, the first lens group G is arranged closer to the object side than the shift lens group and is
It is preferable to perform focusing by moving the lens unit arranged on the image side of the lens unit 1 along the optical axis. Hereinafter, the reason will be described. Since the first lens group G1 is disposed on the most object side of the lens system, the lens diameter tends to be large, and the driving mechanism driven during focusing becomes complicated. Further, when focusing is performed by the lens group disposed on the image side of the shift lens group, the use magnification βa of the shift lens group changes depending on the subject position, which makes control difficult.

[0050]

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 embodiment, 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 (f).

[Equation 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 + ··· (f) in each example, the aspherical surface is provided with mark * 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 consisting of 1, a biconcave lens L21, a biconvex lens L22, a second lens group G2 consisting of a negative meniscus lens L23 having a concave surface facing the object side, and a biconvex lens L
A third lens group G3 composed of three, a negative meniscus lens L41 having a concave surface facing the object side, a positive lens L42 cemented with a biconvex lens and a negative meniscus lens having a concave surface facing the object side, and a concave surface facing the object side. From a fourth lens group G4 including a positive meniscus lens L43, 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. And the fifth lens group G5.

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) lists 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).

[0055]

[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 73.7417 4.039 1.48749 70.45 2 -41.5811 1.388 1.86074 23.01 3 -63.8257 (D3 = variable) 4 -41.0313 1.136 1.79968 45.37 5 21.9975 0.884 6 18.8960 3.155 1.78472 25.80 7 -125.8654 1.010 8 -21.0597 1.136 1.79668 45.37 9 -222.7733 (D9 = variable) 10 440.0524 2.146 1.51680 64.10 11 -20.2051 (D11 = variable) 12 ∞ 2.272 (Aperture stop S) 13 * -44.7010 1.262 1.58518 30.24 14 -65.6383 0.379 15 27.9565 3.408 1.48749 70.45 16 -15.0304 1.262 1.86074 23.01 17 -24.8801 2.019 18 -26.1571 1.641 1.49108 57.57 19 -21.9891 (D19 = variable) 20- 63.2306 3.155 1.80458 25.50 21 -22.5326 0.252 22 -53.6801 1.262 1.79668 45.37 23 -215.3584 4.291 24 -15.1445 1.515 1.77279 49.45 25 -832.1512 (Bf) (aspherical data) (13 faces) R = -44.7010 κ = 1.0000 C ₄ =- _{^{2.11756 × 10 -5 C 6 = -5.38090}} × 10 -8 C 8 = -1.35276 × 10 -9 C 10 = 9.45620 × 10 -12 ( strange F 38.9904 75.3947 154.0058 D3 2.1456 12.6142 25.1214 D9 4.4282 2.4447 1.2621 D11 3.1446 5.1281 6.3107 D19 16.8858 8.9850 1.8869 Bf 9.1062 30.8789 70.4949 (focusing movement amount of the third lens group G3 at a photographing magnification of 1/30 times) focal length f 38.9904 75.3947 154.0058 D0 1121.5052 2184.8579 4481.6968 Moving amount 1.0470 0.7862 0.6890 However, the sign of the moving amount is positive when moving from the object side to the image side (the moving amount of the cemented positive lens L42 when the image is shifted by 0.01 [rad]) ) Focal length f 38.9904 75.3947 154.0058 Lens movement amount 0.3135 0.3806 0.4861 Image shift amount 0.3899 0.7539 1.5401 (Conformance value) βat = -0.0103 βbt = + 3.1354 fct = -4755.573 fcw = -5266.648 fa = 37.092 βaw = −0.0633 βbw = + 1.1699 (1) (1-βat) · βbt = 3.168 (2) ft / fct = −0 0.0324 (3) fw / fcw = -0.0740 (4) fa / (fw * ft) ^1/2 = 0.479 (5) {[(1- [beta] at) [beta] bt] / [(1- [beta] aw) [beta] bw ]} / (Ft / fw) = 0.645 (6) Db / fw = 0.100

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.
Further, FIG. 6 is a diagram showing various aberrations at a wide-angle end at a photographing magnification of −1/30, FIG. 7 is a diagram of various aberrations at a medium magnification of −1/30, and FIG. FIG. 7 is a diagram of various types of aberration at a photographing magnification of −1/30 at the edge.

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 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 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 biconcave lens L52, 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 No. 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 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).

[0062]

[Table 2] f = 39.00 〜 75.72 〜 126.21 〜 184.70 FNO ＝ 4.00 〜 6.30 〜 8.71 〜 11.00 ω ＝ 29.37 〜 15.42 〜 9.45 〜 6.53 ° Surface number Curvature radius Surface spacing Refractive index Abbe number 1 65.2395 4.039 1.48749 70.41 2 -43.6661 1.389 1.84666 23.83 3 -71.1881 (D3 = variable) 4 -39.3377 1.010 1.83500 42.97 5 21.9280 0.884 6 18.9681 3.029 1.78472 25.70 7 -59.8735 0.757 8 -21.9898 1.010 1.83500 42.97 9 2328.2941 (D9 = variable) 10 351.9850 2.146 1.51680 641. (D11 = variable) 12 ∞ 2.272 (aperture stop S) 13 * -40.8344 1.262 1.58518 30.24 14 -63.1068 0.884 15 29.7540 3.155 1.48749 70.41 16 -15.2696 1.010 1.84666 23.83 17 -25.6097 1.767 18 -34.1715 1.641 1.49108 57.57 19 -25.8162 (D19 = Variable) 20 -91.9033 3.282 1.84666 23.83 21 -25.0732 0.757 22 -47.1652 1.262 1.83500 42.97 23 1154.6027 4.922 24 -15.2572 1.515 1.83500 42.97 25 -104.7092 (Bf) (aspherical data) (13 faces) R = -40.8344 κ = 0.0032 C ₄ = -2.09374 × 10 ^-5 C ₆ = -5.62266 × 10 ^-8 C ₈ = -3.18563 × 10 ^-10 C ₁₀ = -7 .24641 × 10 ^-12 (Variable spacing during zooming) f 38.9990 57.2487 126.2058 184.7072 D3 2.1456 13.9265 23.6373 30.4002 D9 5.1283 3.3381 2.4329 1.8932 D11 2.4445 4.2347 5.1399 5.6796 D19 18.2183 10.5213 5.4203 1.8932 Bf 7.9381 27.8415 50.9-1 74.9010 Focusing movement amount of the third lens group G3 at the time of magnification) Focal length f 38.9990 57.2487 126.2058 184.7072 D0 1123.3552 2192.0352 3660.9259 5363.3944 Movement amount 0.9881 0.7777 0.7279 0.7349 However, the sign of the movement amount is positive from the object side to the image side. (Moving amount of cemented positive lens L42 when the image is shifted by 0.01 [rad]) Focal length f 38.9990 57.2487 126.2058 184.7072 Lens moving amount 0.3203 0.3958 0.4781 0.5555 Image shift amount 0.3900 0.7572 1.2620 1.8470 (Condition corresponding value) βat =- 0.0055 βbt = + 3.3063 fct = −102222.42 fcw = −337.221 fa = 38.903 βaw = −0.1 050 βbw = + 1.1018 (1) (1-βat) · βbt = 3.324 (2) ft / fct = −0.0181 (3) fw / fcw = −0.1156 (4) fa / (fw · ft) ^1/2 = 0.458 (5) {[(1-βat) βbt] / [(1-βaw) βbw]} / (ft / fw) = 0.557 (6) Db / fw = 0. 113

13 to 20 show 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 in the first intermediate focal length state, and FIG. 15 is a second intermediate focal length. FIG. 16 is a diagram of various types of aberration in the in-focus state at infinity, and FIG. 16 is a diagram of various types of aberration in the in-focus state at the telephoto end. Also,
FIG. 17 is a diagram of various aberrations at the wide-angle end at a shooting magnification of −1/30, FIG. 18 is a diagram of various aberrations at the shooting magnification of −1/30 at the first intermediate focal length state, and FIG. Two
FIG. 20 is a diagram of various aberrations at a photographing magnification of −1/30 in the intermediate focal length state, and FIG.
It is a various-aberration figure at 30 times.

21 to 24 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. 21 is a coma aberration diagram at the wide angle end in the infinity in-focus state.
FIG. 23 is a coma aberration diagram in the first intermediate focal length state in the infinity in-focus state, FIG. 23 is a coma aberration diagram in the second intermediate focal length state in the infinity in-focus state, and FIG. It is a coma aberration figure in the infinite point focusing state. FIG.
The aberration diagrams of FIGS. 1 to 24 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.

[Third Embodiment] FIG. 25 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. 25 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 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. 25 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 No. 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 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).

[0069]

[Table 3] f = 39.00 〜 75.72 〜 126.21 〜 184.70 FNO ＝ 3.99 〜 6.29 〜 8.76 〜 11.00 ω ＝ 29.42 〜 15.43 〜 9.45 〜 6.55 ° Surface number Curvature radius Surface spacing Refractive index Abbe number 1 65.7370 4.039 1.48749 70.41 2 -42.8784 1.389 1.84666 23.83 3 -70.2484 (D3 = variable) 4 -41.5732 1.010 1.83500 42.97 5 21.6117 0.884 6 18.8002 3.029 1.78472 25.70 7 -59.6951 0.757 8 -21.9524 1.010 1.83500 42.97 9 706.2746 (D9 = variable) 10 362.5145 2.146 1.5-1680 64.20 11 (D11 = variable) 12 ∞ 2.272 (aperture stop S) 13 * -38.2648 1.262 1.69666 35.07 14 -63.1068 0.884 15 30.7040 3.155 1.48749 70.41 16 -15.4556 1.010 1.84666 23.83 17 -26.2986 1.767 18 -35.6782 1.641 1.50960 68.00 19 -23.4281 (D19 = Variable) 20 -134.0509 3.282 1.84666 23.83 21 -27.2217 1.080 22 -49.4004 1.262 1.83500 42.97 23 240.5891 4.951 24 -15.5276 1.515 1.83500 42.97 25 -105.0734 (Bf) (aspherical data) (13 faces) R = -38.2648 κ = 0.2132 C ₄ = -2.12247 × 10 ^-5 C ₆ = -1.34104 × 10 ^-7 C ₈ = + 1.82166 × 10 ^-9 C ₁₀ = -2.8 7798 × 10 ^-11 (Variable spacing during zooming) f 38.9990 57.7249 126.2058 184.2574 D3 2.1456 13.9070 22.9667 30.2305 D9 5.1188 3.4217 2.2193 1.8932 D11 2.4540 4.1512 5.3535 5.7696 D19 17.9511 10.2425 5.6195 1.8932 Bf 7.9381 27.8415 50.9669 74.9010 (shooting magnification-1 / 10) Focusing movement amount of the third lens group G3 at the time) Focal length f 38.9990 57.7249 126.2058 184.2574 D0 1122.5995 2190.9721 3664.0949 5349.6204 Movement amount 0.9965 0.7828 0.7054 0.7324 However, the movement amount sign is positive when moving from the object side to the image side ( The amount of movement of the cemented positive lens L42 when the image is shifted by 0.01 [rad]) Focal length f 38.9990 57.7249 126.2058 184.2574 The amount of lens movement 0.3338 0.4114 0.4937 0.5758 The amount of image shift 0.3900 0.7573 1.2620 1.8426 (Conditional value) βat = −0 0.0081 βbt = + 2.9609 fct = −771.956 fcw = −201.971 fa = 40.574 βaw = −0.19 0 βbw = + 0.9752 (1) (1-βat) · βbt = 2.985 (2) ft / fct = −0.239 (3) fw / fcw = −0.153 (4) fa / (fw · ft) ^1/2 = 0.538 (5) {[(1-βat) βbt] / [(1-βaw) βbw]} / (ft / fw) = 0.428 (6) Db / fw = 0. 113

26 to 33 show d line (λ = 587.
FIG. 6 is a diagram of various types of aberration of Example 3 for 6 nm). FIG. 26 is a diagram of various aberrations at the wide-angle end in the infinity focused state, FIG. 27 is a diagram of various aberrations at the infinity focused state in the first intermediate focal length state, and FIG. 28 is a second intermediate focal length. FIG. 29 is a diagram of various aberrations in the in-focus state at infinity, and FIG. 29 is a diagram of various aberrations in the in-focus state at the telephoto end. Also,
FIG. 30 is a diagram of various aberrations at a photographing magnification of −1/30 times at the wide-angle end, FIG. 31 is a diagram of various aberrations at a photographing magnification of −1/30 times in the first intermediate focal length state, and FIG. Two
FIG. 33 is a diagram of various aberrations at a shooting magnification of −1/30 in the intermediate focal length state, and FIG. 33 shows a shooting magnification at the telephoto end −1 //
It is a various-aberration figure at 30 times.

34 to 37 are coma aberration diagrams when the image is shifted by 0.01 rad (radian) with respect to the optical axis in the third embodiment. 34 is a coma aberration diagram at the wide-angle end in the infinity in-focus state, and FIG.
FIG. 36 is a coma aberration diagram in the first intermediate focal length state in the infinity in-focus state, FIG. 36 is a coma aberration diagram in the second intermediate focal length state in the infinity in-focus state, and FIG. 37 in the telephoto end. It is a coma aberration figure in the infinite point focusing state. FIG.
The aberration diagrams of FIGS. 4 to 37 show 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 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.

[0073]

As described above, according to the present invention, it is possible to realize a compact variable-magnification optical system capable of achieving high variable power and efficiently performing image shift.

[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 aberrations at a magnification of 2 ×

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 aberrations at a magnification of 2 ×

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 in the first intermediate focal length state of Example 2 when focused on an object at infinity;

FIG. 15 is a diagram of various types of aberration in a second intermediate focal length state of Example 2 at an infinity in-focus state.

FIG. 16 is a diagram of various types of aberration at the telephoto end of Example 2 in the in-focus state at infinity.

FIG. 17 is a photographing magnification at the wide-angle end of Embodiment 2-1 / 3.
FIG. 7 is a diagram illustrating various aberrations at a magnification of 0.

FIG. 18 is a diagram of various types of aberration at a photographing magnification of −1/30 in the first intermediate focal length state of Example 2.

FIG. 18 is a diagram of various types of aberration at a shooting magnification of −1/30 in the second intermediate focal length state of Example 2.

FIG. 20 is a photographing magnification at the telephoto end of Embodiment 2-1 / 3.
FIG. 7 is a diagram illustrating various aberrations at a magnification of 0.

21 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 2. FIG.

FIG. 22 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 2.

FIG. 23 is a coma aberration diagram at the time of image shifting in the in-focus state at infinity in the second intermediate focal length state of Example 2.

24 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.

FIG. 25 is a diagram showing a lens configuration of a variable power optical system according to the third example of the present invention.

FIG. 26 is a diagram of various types of aberration of Example 3 at the wide-angle end when focused on infinity.

FIG. 27 is a diagram of various types of aberration in the first intermediate focal length state of Example 3 in the infinity in-focus state.

FIG. 28 is a diagram of various types of aberration in the second intermediate focal length state of Example 3 in the infinity in-focus state.

FIG. 29 is a diagram of various types of aberration of Example 3 at the telephoto end in the in-focus state at infinity.

FIG. 30 is a photographing magnification at the wide-angle end of Example 3-1 / 3.
FIG. 7 is a diagram illustrating various aberrations at a magnification of 0.

FIG. 31 is a diagram of various types of aberration at a shooting magnification of −1/30 in the first intermediate focal length state of Example 3.

FIG. 32 is a diagram of various types of aberration at a shooting magnification of −1/30 in the second intermediate focal length state of Example 3;

FIG. 33 is a photographing magnification −1/3 at the telephoto end in Embodiment 3;
FIG. 7 is a diagram illustrating various aberrations at a magnification of 0.

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

FIG. 35 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 3.

FIG. 36 is a coma aberration diagram at the time of image shifting in the in-focus state at infinity in the second intermediate focal length state of Example 3.

FIG. 37 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. 38 is a diagram showing the relationship between the use magnification βa of the shift lens group and the use magnification βb of the lens group arranged on the image side of the shift lens group.

[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

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[Procedure amendment]

[Submission date] January 12, 1996

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] Brief description of drawings

[Correction method] Change

[Correction contents]

[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 aberrations at a magnification of 2 ×

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 aberrations at a magnification of 2 ×

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 in the first intermediate focal length state of Example 2 when focused on an object at infinity;

FIG. 15 is a diagram of various types of aberration in a second intermediate focal length state of Example 2 at an infinity in-focus state.

FIG. 16 is a diagram of various types of aberration at the telephoto end of Example 2 in the in-focus state at infinity.

FIG. 17 is a photographing magnification at the wide-angle end of Embodiment 2-1 / 3.
FIG. 7 is a diagram illustrating various aberrations at a magnification of 0.

FIG. 18 is a diagram of various types of aberration at a photographing magnification of −1/30 in the first intermediate focal length state of Example 2.

FIG. 19 is a diagram of various types of aberration at a shooting magnification of −1/30 in the second intermediate focal length state of Example 2.

FIG. 20 is a photographing magnification at the telephoto end of Embodiment 2-1 / 3.
FIG. 7 is a diagram illustrating various aberrations at a magnification of 0.

21 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 2. FIG.

FIG. 22 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 2.

FIG. 23 is a coma aberration diagram at the time of image shifting in the in-focus state at infinity in the second intermediate focal length state of Example 2.

24 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.

FIG. 25 is a diagram showing a lens configuration of a variable power optical system according to the third example of the present invention.

FIG. 26 is a diagram of various types of aberration of Example 3 at the wide-angle end when focused on infinity.

FIG. 27 is a diagram of various types of aberration in the first intermediate focal length state of Example 3 in the infinity in-focus state.

FIG. 28 is a diagram of various types of aberration in the second intermediate focal length state of Example 3 in the infinity in-focus state.

FIG. 29 is a diagram of various types of aberration of Example 3 at the telephoto end in the in-focus state at infinity.

FIG. 30 is a photographing magnification at the wide-angle end of Example 3-1 / 3.
FIG. 7 is a diagram illustrating various aberrations at a magnification of 0.

FIG. 31 is a diagram of various types of aberration at a shooting magnification of −1/30 in the first intermediate focal length state of Example 3.

FIG. 32 is a diagram of various types of aberration at a shooting magnification of −1/30 in the second intermediate focal length state of Example 3;

FIG. 33 is a photographing magnification −1/3 at the telephoto end in Embodiment 3;
FIG. 7 is a diagram illustrating various aberrations at a magnification of 0.

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

FIG. 35 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 3.

FIG. 36 is a coma aberration diagram at the time of image shifting in the in-focus state at infinity in the second intermediate focal length state of Example 3.

FIG. 37 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. 38 is a diagram showing the relationship between the use magnification βa of the shift lens group and the use magnification βb of the lens group arranged on the image side of the shift lens group.

[Description of Reference Signs] 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 (7)

[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, shifts the image by moving at least one lens component of the lens components constituting the fourth lens group G4 as a shift lens group in a direction substantially perpendicular to the optical axis, The use magnification at the telephoto end of the lens group is βat, the use magnification at the telephoto end of the lens group arranged on the image side of the shift lens group is βbt, and the focal length of the entire lens system at the telephoto end is ft. Assuming that the combined focal length at the telephoto end of the lens unit arranged on the object side of the shift lens unit is fct, then 2.5 <(1-βat) · βbt <5-0.1 <ft / fct <-0 A variable-magnification optical system capable of image shifting, which satisfies the condition of 0.005. 2. When the focal length of the entire lens system at the wide-angle end is fw, and the combined focal length at the wide-angle end of the lens unit arranged on the object side of the shift lens unit is fcw, -0.3 < The variable-magnification optical system according to claim 1, wherein the condition fw / fcw <-0.02 is satisfied. 3. The fourth lens group G4 has a lens group fixed with respect to the optical axis at the image side of the shift lens group at the time of image shifting, and the focal length of the shift lens group is fa and the telephoto end Suppose that the focal length of the entire lens system at is ft and the focal length of the entire lens system at the wide-angle end is fw, the condition of 0.38 <fa / (fw.ft) ^1/2 <0.7 must be satisfied. An image-shiftable variable power optical system according to claim 1 or 2. 4. A variable power optical system capable of shifting an image by moving a shift lens group in a direction substantially perpendicular to an optical axis, a lens group GA including the shift lens group, and the lens. A lens group GB, which is arranged on the image side of the group GA and includes at least one lens group, is provided. By changing the air gap between the lens group GA and the lens group GB, the distance from the wide-angle end to the telephoto end is changed. At least one of zooming and focusing on a short-distance object is performed, and the use magnification at the telephoto end of the shift lens group is βat, and use at the telephoto end of the lens group GB arranged on the image side of the shift lens group. A variable-magnification optical system capable of image shift, which satisfies the condition of 2.5 <(1-βat) · βbt <5 when the magnification is βbt. 5. A lens group GC including at least one lens group is disposed on the object side of the lens group GA, and a use magnification at a telephoto end of the shift lens group is βat, and an image is formed more than the shift lens group. The use magnification at the telephoto end of the lens group GB arranged on the side is βbt, the use magnification at the wide-angle end of the shift lens group is βaw, and the wide-angle end of the lens group GB arranged closer to the image side than the shift lens group is Let β bw be the use magnification at the telephoto end, ft be the focal length of the entire lens system at the telephoto end, and fw be the focal length of the entire lens system at the wide-angle end. 0.3 <{[(1-βat) βbt] / [(1 −βaw) βbw]} / (ft
The image-shiftable variable power optical system according to claim 4, wherein the condition of /fw)<0.75 is satisfied. 6. The lens group GA has a plurality of lens part groups, and the lens part group disposed closest to the image side among the plurality of lens part groups is fixed with respect to the optical axis during image shifting. The variable-magnification optical system capable of image shifting according to claim 4 or 5. 7. An image shiftable variable magnification according to claim 4, wherein an aperture stop is provided adjacent to the object side or the image side of the lens group GA. Optical system.