JPH10142506A - Variable magnification optical system capable of image shift - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a high performance and a high variable magnification ratio by providing plural partial lens groups to the positive lens group having a both side lens group and letting focal distances to satisfy a specific condition. SOLUTION: The system is provided with a lens group G4 having a positive refractive power, lens groups G1 to G3 arranged adjacent to the body side of the group G4 having a negative refractive power and a lens group G5 arranged adjacent to the image side of the group G4. In order to change from a wide angle end condition to a telephoto end condition by varying the position conditions, the air interval between the groups G4 and G5 is reduced and the air interval between the group G4 and the groups G1 to G3 is varied. The group G4 has at least two partial lens groups L41 and L42. By moving one group L42 along the direction approximately perpendicular to an optical axis, the image is shifted in the approximately perpendicular direction to the optical axis. Let the focal distance of the group G4 be fs, the focal distance of the group L42 be fh and then, the condition given by an equation 0.3<fs<fh<0.6 is 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 particularly to a variable-magnification optical system capable of shifting an image by moving some lens groups in a direction substantially perpendicular to the optical axis. It relates to a magnification optical system.

[0002]

2. Description of the Related Art In recent years, a zoom lens is generally used in a photographing optical system used for a still camera, a video camera, and the like. In particular, cameras equipped with a so-called high zoom ratio zoom lens having a zoom ratio exceeding 3 times are becoming mainstream.
In this type of camera, a standard zoom lens (a zoom lens having a focal length range including an angle of view with a focal length of about 50 mm in a 35 mm format) is generally used. Note that a so-called multi-unit zoom lens, which is configured so that three or more lens units move at the time of zooming, is mainly used as the high-magnification zoom lens. In addition, in an integrated camera in which a photographing optical system and a camera body are integrally formed, portability is regarded as important, so that a reduction in size and weight is required. Therefore, various proposals regarding zoom lenses suitable for miniaturization and weight reduction have been made. In these zoom lenses, the focal length has been increased with an increase in the zoom ratio.

By the way, conventionally, when the shutter speed is low, there is a case where an image is blurred during exposure due to camera shake due to hand shake or the like, and photographing fails.
In general, when a part of lens groups (hereinafter, referred to as a “shift lens group”) of a lens group constituting a lens system is moved in a direction perpendicular to the optical axis, an image is shifted in a direction perpendicular to the optical axis. It is known. In this case, an optical system capable of obtaining good imaging performance even when the shift lens group is moved in a direction perpendicular to the optical axis is called an image shiftable optical system.

[0004] In order to solve the above-mentioned problem of photographing failure due to camera shake or the like, an optical system capable of image shift, a shake detection system for detecting shake of the optical system and outputting shake information, and a shift lens group A so-called anti-vibration optical system is known, which is combined with a drive system for moving the optical system. In the anti-vibration optical system, the shake detection system detects the shake of the optical system due to hand shake, etc., and shifts the drive system so as to cancel the fluctuation of the image position caused by the detected shake of the optical system. The image shift is performed by moving the lens group. Thus, in the image stabilizing optical system, the fluctuation of the image position, that is, the image blur caused by the blur of the optical system can be corrected by the image shift intentionally generated.

[0005]

However, with a small and lightweight camera, it is difficult to hold the camera without blurring. For this reason, when the release button is pressed, camera shake is likely to occur, and as a result, image blur is often recorded. In particular, in a photographing lens with a long focal length in order to increase the zoom ratio, remarkable image blur easily occurs even with a minute amount of blur of the lens system, and photographing is likely to fail. In this case, by incorporating an anti-vibration optical system in the camera, it is possible to correct a change in the image position due to camera shake due to camera shake or the like. However, in the image stabilizing optical system, since the aberration correction is excessively restricted, the entire lens system becomes large due to an increase in the overall length of the lens and the diameter of the aperture, and as a result, the portability of the camera body is easily deteriorated. .

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and has as its object to provide a variable-magnification optical system which is compact and capable of image shifting suitable for high magnification.

[0007]

According to the present invention, there is provided a lens group G having a positive refractive power.
s, a lens group Gn having a negative refractive power disposed adjacent to the object side of the lens group Gs, and a lens group Ga disposed adjacent to the image side of the lens group Gs, and has a wide angle. When the lens position state changes from the end state to the telephoto end state, the air gap between the lens group Gn and the lens group Gs decreases, and the air gap between the lens group Gs and the lens group Ga changes. The lens group Gs has at least two partial lens groups, and by moving one of the at least two partial lens groups Gh in a direction substantially perpendicular to the optical axis, the lens group Gs is substantially perpendicular to the optical axis. When the image is shifted along the direction and the focal length of the lens group Gs is fs and the focal length of the partial lens group Gh is fh, the following condition is satisfied: 0.3 <fs / fh <0.6 Characterized by To provide an image shiftable variable magnification optical system.

According to a preferred aspect of the present invention, an aperture stop S is provided in the lens group Gs or adjacent to the lens group Gs. Further, the lens group Ga has a negative refractive power, and when the lens position state changes from the wide-angle end state to the telephoto end state, the lens group Ga moves toward the object side, and the lens group Ga in the wide-angle end state. The lateral magnification of the lens group Ga in the telephoto end state is β5t, the focal length of the entire optical system in the wide-angle end state is fw, and the focal length of the entire optical system in the telephoto end state is ft. At this time, the condition of 0.4 <(β5t / β5w) / (ft / fw) <0.7 is satisfied.

According to another aspect of the present invention, a first lens group G1 having a positive refractive power and a second lens group G2 having a positive refractive power or a negative refractive power are arranged in order from the object side.
A third lens group G3 having a negative refractive power, a fourth lens group G4 having a positive refractive power, and a fifth lens group G5 having a negative refractive power. When the lens position changes to the first lens group G,
1 and the second lens group G2, the air gap between the second lens group G2 and the third lens group G3 increases, and the third lens group G3 and the fourth lens group G increase.
4 and the air gap between the fourth lens group G4 and the fifth lens group G5 is reduced so that at least the first lens group G1 and the fifth lens group G
5 moves to the object side, and moves a part of the fourth lens group G4 in a direction substantially perpendicular to the optical axis, thereby shifting the image along a direction substantially perpendicular to the optical axis, and wide-angle The lateral magnification of the fifth lens group G5 in the end state is β5w
When the lateral magnification of the fifth lens group G5 in the telephoto end state is β5t, the focal length of the entire optical system in the wide-angle end state is fw, and the focal length of the entire optical system in the telephoto end state is ft, 0 0.4 <(β5t / β5w) / (ft / fw) <0.7 Provided is an image-shifting zoom optical system characterized by satisfying the following condition.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS First, a description will be given of an image shift amount generated when a shift lens group including a part of lens groups in an optical system is moved in a direction perpendicular to an optical axis. Assuming that the lateral magnification of the shift lens group is βa and the lateral magnification of the entire lens group arranged on the image side of the shift lens group is βb, the image shift amount δ with respect to the shift amount Δ of the shift lens group is represented by the following equation ( a). δ = (1−βa) βb · Δ = k · Δ (a) where, k: blurring coefficient (k = (1−βa) βb)

If the blur coefficient k is small, the amount of movement of the shift lens group required to shift the image by a predetermined amount becomes large, and the driving mechanism of the shift lens group becomes complicated. Conversely, when the blur coefficient k is large, if the movement amount of the shift lens group slightly fluctuates due to a control error, the image shift amount largely fluctuates, and contrast for a high spatial frequency is lacking. Therefore, it is desirable to set the blur coefficient k to an appropriate value.

Next, the function of correcting aberration required for the shift lens group will be described. Normally, the shift lens group is required to be in an aberration correction state such that good imaging performance can be obtained even during image shifting. Specifically, it is required that the spherical aberration and the sine condition (sine condition) are properly corrected and that an appropriate Petzval sum is used. That the spherical aberration and the sine condition are corrected well is a condition for suppressing the eccentric coma generated at the center of the screen when the shift lens group is moved to shift the image. 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 one of the plurality of lens units constituting the zoom lens is a shift lens unit, the aberration correction state and the image shift required when the lens position state changes (ie, during zooming). The aberration correction state required to suppress the performance degradation at the time does not always match. Therefore, it is difficult to achieve both high zoom ratio and correction of larger blur of the optical system. In the present invention, one lens group is constituted by a plurality of partial lens groups, and one of the plurality of partial lens groups is a shift lens group, so that a high zoom ratio and a larger optical system can be achieved. This makes it possible to compensate for blurring.

When the shift lens group is arranged away from the aperture stop, an off-axis light beam passing through the shift lens group is separated from the optical axis. As a result, when the image is shifted, decentered coma is likely to occur in the peripheral portion of the screen. In particular, when the off-axis light beam entering the shift lens group forms a large angle with respect to the optical axis, eccentric coma aberration is likely to occur in the peripheral portion of the screen. Therefore, it is desirable to appropriately set the positional relationship between the shift lens group and the aperture stop.

As described above, the variable power optical system of the present invention is configured to satisfy the following three conditions to suppress the performance deterioration due to the image shift while maintaining the predetermined variable power ratio. I have. The refractive power of the lens group including the shift lens group is defined as positive refractive power, and the negative lens group is arranged adjacent to the object side. An aperture stop is arranged between the shift lens group and the negative lens group. The amount of change in the blur coefficient k when the lens position state changes from the wide-angle end state to the telephoto end state is set to an appropriate value.

As described above, in order to correct the decentering coma generated at the periphery of the screen due to the image shift, the angle between the off-axis light beam incident on the shift lens group and the optical axis is set to an appropriate value. Is desirable. In the present invention, a negative lens group having a strong refractive power is arranged adjacent to the object side of the lens group including the shift lens group to strongly diverge a light beam emitted from the negative lens group, and the image side of the negative lens group. The aperture stop is arranged at the center. With this configuration, the angle formed between the off-axis light beam incident on the shift lens group and the optical axis is not increased, thereby realizing high performance.

In particular, in order to suppress the performance degradation at the time of image shift, it is necessary to satisfactorily correct various aberrations by the shift lens group alone. Therefore, it is preferable to set the refractive power of the shift lens group to a positive refractive power so that the aberration correction state of the shift lens group alone can be easily confirmed at the time of manufacturing. If the off-axis light beam that passes through the shift lens group departs from the optical axis, the performance will be greatly degraded at the periphery of the screen during image shift, and it is desirable to dispose the shift lens group near the aperture stop. In particular, in order to reduce the angle between the off-axis light beam entering the shift lens group and the optical axis, a negative lens group is arranged on the object side of the aperture stop, and a shift lens group is arranged on the image side of the aperture stop. Is desirable. From the above, the conditions and conditions are essential.

As described above, the shift amount of the shift lens group required to shift the image by a predetermined amount is determined by the blur coefficient k
Depends on. When the blur coefficient in the wide-angle end state and the focal length of the entire optical system are kw and fw, and the blur coefficient in the telephoto end state and the focal length of the entire optical system are kt and ft, respectively, the blur coefficient ratio K (= k
t / kw) is larger than the zoom ratio Z (= ft / fw), the required lens position control accuracy in the telephoto end state becomes extremely higher than the required lens position control accuracy in the wide angle end state, The lens position control becomes complicated. In addition, since the zooming action is performed only by the lens group arranged on the image side of the shift lens group, the lens system can be downsized while suppressing fluctuations of various aberrations caused by a change in the lens position state. Becomes difficult.

On the other hand, if the blur coefficient ratio K is much smaller than the zoom ratio Z, the lens unit disposed closer to the object side than the shift lens unit has a zooming effect, so that the total length of the lens can be shortened. It is not possible to reduce the size of the lens system by reducing the lens diameter or the like. Therefore, in the present invention, both the suppression of the performance degradation at the time of image shift and the high zoom ratio are achieved by setting the blur coefficient ratio K to an appropriate value with respect to the zoom ratio Z. Is required.

Next, a specific configuration of a variable power optical system which satisfies the above-mentioned conditions (1) and (2) and is suitable for high zooming and downsizing of the lens system will be described. First, a general theory of a variable power optical system suitable for downsizing the lens system will be described. It is known that a telephoto-type refractive power arrangement is effective for reducing the size of a lens system. Therefore, in general, in a variable power optical system aiming at miniaturization, a negative lens group is arranged closest to the image side of the lens system.

The aperture stop is located closer to the object side than the negative lens group. When the lens position changes from the wide-angle end state (the state with the shortest focal length) to the telephoto end state (the state with the longest focal length), the distance between the aperture stop and the negative lens group is reduced and the negative lens is changed. The group is moving to the object side. By narrowing the distance between the aperture stop and the negative lens unit, the off-axis light beam passing through the negative lens unit moves away from the optical axis in the wide-angle end state and approaches the optical axis in the telephoto end state. By moving the negative lens unit toward the object side, the negative lens unit is multiplied (the lateral magnification of the negative lens unit increases at the telephoto end state relative to the wide-angle end state). In this way, fluctuations in off-axis aberrations caused by changes in the lens position state are corrected well, and a certain degree of high magnification is realized.

However, if the back focus is too short in the wide-angle end state, the shadow of dust adhering to the surface near the image plane of the negative lens group is reflected on the film surface. Value. Further, a positive lens group is arranged closest to the object side of the variable power optical system, and the positive lens group is brought closer to the image side in the wide-angle end state to reduce the lens diameter of the positive lens group. Conversely, in the telephoto end state, the overall length of the lens is reduced to some extent by increasing the distance between the positive lens group and the lens group disposed on the image side thereof and strongly converging the light beam by the positive lens group.

Generally, zoom lenses are classified into a two-group type and a multi-group type. Two-group type zoom lens consisting of only variator and compensator,
Not suitable for high magnification. Therefore, a multi-group type is used for a high zoom lens having a zoom ratio exceeding 3 times. Specific examples of a multi-group type zoom lens suitable for miniaturization and high zoom ratio include a positive / negative three-group zoom lens, a positive / negative positive / negative four-group type zoom lens, and a positive / negative positive / negative five-group zoom Lenses, and positive, negative, negative, and negative five-group type zoom lenses are known.

In any of the multi-group type zoom lenses, as described above, the positive lens group is disposed closest to the object side of the lens system, and the negative lens group is disposed closest to the image side. Between one positive lens group (in the case of)
Alternatively, a plurality of lens groups (in the case of 〜) having a positive combined refractive power as a whole are arranged. However, when the lens group moves in the optical axis direction by a very small amount, the lateral magnification of 2
The image plane position moves in relation to the power. Therefore, in the case of the zoom lens of the type (1), when the zoom ratio exceeds 3 times, the lateral magnification of the negative lens unit in the telephoto end state becomes extremely large, and it is difficult to secure a predetermined optical performance. In the zoom lenses of the types (1) to (4), the composite focal length of the lens unit disposed between the positive lens unit and the negative lens unit in the telephoto end state becomes larger than that in the wide-angle end state, and the composite principal point position Moves to the object side, so that an increase in the lateral magnification of the negative lens unit in the telephoto end state is reduced.

In a typical configuration of the present invention, in order from the object side, a first lens group G1 having a positive refractive power, a second lens group G2 having a weak refractive power, and a third lens group G3 having a negative refractive power.
, A fourth lens group G4 having a positive refractive power, and a fifth lens group G5 having a negative refractive power constitute a variable power optical system. And
When the lens position changes from the wide-angle end state to the telephoto end state, the distance between the first lens group G1 and the second lens group G2 increases, and the distance between the second lens group G2 and the third lens group G3 increases. The distance between the third lens group G3 and the fourth lens group G4 decreases, and the distance between the fourth lens group G4 and the fifth lens group G5 decreases.
And the fifth lens group G5 is moved to the object side. Further, a shift lens group is arranged in the fourth lens group G4. With the above configuration, the present invention can achieve a variable-magnification optical system that is small and capable of image shifting with a magnification ratio exceeding 3.5 times.

In particular, in the present invention, high performance and light weight are achieved by making each lens group function so as to satisfy the following conditions [I] to [III]. [I] The lateral magnification of the fifth lens group G5 in the telephoto end state is set to an appropriate value. [II] The principal point position of the first lens group G1 and the principal point position of the second lens group G2 are set to appropriate positions. [III] Clarify the function of the second lens group G2 on aberration correction and the function of the third lens group G3 on aberration correction.

Like the conventional multi-group type zoom lens, the typical configuration of the present invention also has a fifth refractive power of the fifth type.
The lens group G5 is arranged closest to the image. Then, when the lens position state changes from the wide-angle end state to the telephoto end state, the fifth lens group G5 moves to the object side. If the lateral magnification of the fifth lens group G5 in the telephoto end state becomes too large,
The change in the lateral magnification of the fifth lens group G5 from the wide-angle end state to the telephoto end state increases. As a result, fluctuations in off-axis aberrations due to changes in the lens position cannot be satisfactorily suppressed.
Predetermined optical performance cannot be obtained.

Conversely, if the lateral magnification of the fifth lens group G5 in the telephoto end state becomes too small, it occurs in the lens group disposed closer to the object side than the fifth lens group G5 due to a change in the lens position state. The fluctuation of various aberrations increases, and it becomes impossible to obtain predetermined optical performance. In either case, it is possible to secure a predetermined optical performance by using many aspheric surfaces or increasing the number of lenses, but it is impossible to achieve cost reduction and weight reduction. Therefore, it is desirable to set the lateral magnification of the fifth lens group G5 in the telephoto end state to an appropriate value, and the condition [I] is required.

In the wide-angle end state, since the back focus is short, positive distortion is strongly generated in the fifth lens group G5. In the present invention, by setting the combined focal length of the first lens group G1 to the third lens group G3 in the wide-angle end state to a negative value, the refractive power arrangement of the entire optical system is made closer to a symmetric type, and positive distortion is performed. The aberration can be corrected well. In particular, in the present invention, the second lens group G2 is composed of a negative subgroup and a positive subgroup disposed on the image side of the negative subgroup, so that the principal point position of the second lens group G2 (a light beam is incident from the object side). (The principal point position at the time of being moved) is positioned closer to the object side than the first lens group G1, and negative distortion can be effectively generated.

In the telephoto end state, the principal point position of the first lens group G1 (the principal point position when a light beam is incident from the object side) is set in the first lens group G1 or from the first lens group G1. Also, by positioning the lens on the object side, the overall length of the lens can be reduced. Therefore, it is desirable to dispose the positive lens closest to the object side of the first lens group G1. However, when the principal point position of the first lens group G1 is farther away from the first lens group G1 toward the object side, an off-axis light beam passing through the first lens group G1 in the telephoto end state is separated from the optical axis,
The lens diameter becomes large. As described above, the condition [II] is important.

As described above, the fourth lens including the shift lens group
It is desirable to dispose an aperture stop near the lens group G4. In this case, the off-axis light beam passes near the optical axis in the third lens group G3, whereas it passes through the periphery in the second lens group G2. Therefore, the third lens group G3 corrects the axial aberration, and the second lens group G2 corrects the off-axis aberration, so that the second lens group G2 and the third lens group G3 are configured with a small number of lenses. can do. As a result, it is possible to reduce the lens diameter by reducing the weight and the lens thickness, so that the condition [III] is important.

Hereinafter, each conditional expression of the present invention will be described. In the present invention, the following conditional expression (1) is satisfied. 0.3 <fs / fh <0.6 (1) where, fs: focal length of the lens group Gs including the shift lens group fh: focal length of the partial lens group Gh, which is the shift lens group

Conditional expression (1) defines an appropriate range for the ratio of the focal length of the shift lens group Gh to the focal length of the lens group Gs including the shift lens group, and achieves high magnification with a small number of lenses. These are also conditions for suppressing performance degradation during image shifting. When the value exceeds the upper limit of conditional expression (1), the focal length of the shift lens group Gh increases, so that negative spherical aberration generated by the shift lens group alone can be favorably corrected, and the shift can be performed with a small number of lenses. A lens group can be configured. However, the number of lenses in other lens groups other than the shift lens group increases, and it is not possible to achieve weight reduction. Conversely, when the value falls below the lower limit of conditional expression (1),
Since the focal length of the shift lens group Gh becomes small, it becomes difficult to satisfactorily correct negative spherical aberration generated in the shift lens group.

In the present invention, the lens group Ga has a negative refractive power in order to improve the performance and reduce the weight.
It is desirable to satisfy the following conditional expressions (2). 0.4 <(β5t / β5w) / (ft / fw) <0.7 where β5w: lateral magnification of the lens group Ga in the wide-angle end state β5t: lateral magnification of the lens group Ga in the telephoto end state fw: wide-angle end Ft: focal length of the entire optical system in the telephoto end state

Conditional expression (2) defines the change in the lateral magnification of the lens group Ga (that is, the fifth lens group G5 in a typical configuration) disposed on the image side of the lens group Gs including the shift lens group Gh. ing. Exceeding the upper limit of conditional expression (2) is not preferable because the variation in off-axis aberration generated in the lens group Ga increases with a change in the lens position state, making it impossible to achieve high performance. In addition, the lateral magnification of the lens group Ga (the fifth lens group G5) in the telephoto end state becomes large, and it is not preferable because the optical performance is easily deteriorated due to a focus shift due to a lens position control error. Conversely, if the lower limit of conditional expression (2) is exceeded, the lens unit G
a (fifth lens group G5) because the zooming action of the lens group disposed closer to the object side is increased, so that it becomes impossible to configure each lens group constituting the zooming optical system with a small number of lenses. Absent.

In the present invention, in order to reduce the overall length of the lens at the telephoto end and to reduce the size of the lens system, the first lens group G1 having the positive refractive power closest to the object side.
And it is desirable to satisfy the following conditional expressions (3). 0.8 <f1 / (fw · ft) ^1/2 <1.5 (3) where f1: focal length of the first lens group G1

If the value exceeds the upper limit of conditional expression (3), the overall length of the lens is undesirably increased. vice versa,
If the lower limit value of conditional expression (3) is not reached, the off-axis light beam passing through the first lens group G1 in the telephoto end state is separated from the optical axis, and the lens diameter of the first lens group G1 is undesirably increased. .

Further, in the present invention, in order to improve the optical performance in the wide-angle end state and to shorten the entire length of the lens in the telephoto end state, it is disposed between the first lens group G1 and the lens group Gn. It is desirable that the second lens group G2 satisfy the following conditional expression (4). −0.2 <fn / f2 <0.2 (4) where, f2: focal length of the second lens group G2 fn: focal length of the lens group Gn

Conditional expression (4) defines an appropriate range for the ratio between the focal length of the second lens group G2 and the focal length of the lens group Gn (that is, the third lens group G3 in a typical configuration). . If the upper limit of conditional expression (4) is exceeded, the diverging effect of the second lens group G2 will be increased, and the overall length of the lens will be increased in the telephoto end state. Conversely, when the value goes below the lower limit of conditional expression (4), the convergence of the second lens group G2 becomes stronger, and it becomes impossible to obtain a sufficient back focus in the wide-angle end state.

In the variable power optical system disclosed in Japanese Patent Application Laid-Open No. 7-92390, the diverging effect of the second lens group G2 is strong. As a result, when the focal length of the entire optical system in the telephoto end state is lengthened to increase the zoom ratio, it is difficult to shorten the entire length of the lens, which is insufficient in terms of miniaturization. By the way, when the lens group arranged on the image side of the shift lens group is moved as a focusing group to focus on a short-distance object, when the subject position changes, the lateral magnification of the shift lens group is also larger than that of the shift lens group. Also, the lateral magnification of the lens group arranged on the image side changes. For this reason, in the present invention, it is desirable that the lens group disposed closer to the object side than the shift lens group be the focusing group.

In particular, in a lens group apart from the aperture stop S, the height at which an off-axis light beam passes is away from the optical axis, so that a lens group Gn (third lens group G) disposed near the aperture stop S
It is desirable that 3) be a focusing group. In this case, it is desirable to satisfy the following conditional expression (5). 0.2 <(β3t / β3w) / (ft / fw) <0.7 (5) where β3w: lateral magnification of the lens group Gn in the wide-angle end state β3t: lateral magnification of the lens group Gn in the telephoto end state

Conditional expression (5) defines a change in the lateral magnification of the lens group Gn (third lens group G3) accompanying a change in the lens position. Generally, the depth of field in the telephoto end state is smaller than the depth of field in the wide angle end state.
Therefore, the lens position of the focusing group needs to be controlled with higher accuracy in the telephoto end state than in the wide-angle end state. In the present invention, by increasing the amount of movement of the focusing group required to focus on a predetermined short-distance object from the infinity in-focus state in the telephoto end state than in the wide-angle end state, the optical axis direction is increased. The lens position control accuracy is prevented from becoming extremely high in the telephoto end state with respect to the wide angle end state.

The amount of focusing movement (the amount by which the focusing group moves during focusing) is described in Japanese Patent Application Laid-Open No. 7-92390.
As shown in the publication, when the lateral magnification of the focusing group is set to an appropriate value, it can be suppressed to a small value. In the present invention, the lens group Gn (third lens group) which is a focusing group
It is desirable to make the lateral magnification of the lens group G3) close to 0, but the lateral magnification of the lens group Gn (the third lens group G3) is made farther from 0 in the telephoto end state than in the wide angle end state.

If the upper limit of conditional expression (5) is exceeded, the amount of focusing movement in the telephoto end state increases,
A driving mechanism for driving the focusing group is complicated. Conversely, when the value goes below the lower limit of conditional expression (5), the lens position control accuracy required for obtaining the predetermined optical performance becomes higher in the telephoto end state than in the wide-angle end state, and the focusing group in the telephoto end state becomes higher. It is not preferable because the in-focus position of the optical system greatly changes for a small displacement amount.

In the present invention, as described above, it is desirable to dispose the aperture stop S near the partial lens group Gh, which is a shift lens group. In this case, it is desirable to satisfy the following conditional expression (6). Db / fw <0.2 (6) where Db is a partial lens group Gh that is a shift lens group.
A distance along the optical axis between the surface closest to the aperture stop and the aperture stop S

When the value exceeds the upper limit of conditional expression (6), the difference in height between the on-axis light beam and the off-axis light beam passing through the shift lens group becomes large. As a result, unless the diameter of the shift lens group is increased, fluctuations in various aberrations that occur when an image is shifted by the shift lens group cannot be suppressed. By configuring the shift lens group with a larger number of lenses, it is also possible to suppress variations in various aberrations during image shift. However, in this case,
Not only is the size of the optical system increased, but also the drive mechanism for driving the shift lens group is complicated, which is not preferable.

Next, a description will be given of a method of correcting the fluctuation of the image position, that is, the image blur caused by the optical system. In general, when the optical system and the recording means for recording an image by the optical system are integrally tilted about the principal point position of the optical system (the principal point position when a light beam enters from the object side), the recording means The recording range on the object surface shifts while tilting. Therefore, considering the recording range before the optical system and the recording unit are integrally inclined, the image of the recording range before the inclination is shifted while being inclined on the recording unit. However, when the image magnification is used at the reduction magnification, the inclination amount of the image in the recording range before the inclination on the recording means on the recording means is very small according to the Shine-proof rule. Therefore, when applied to cameras, etc.,
It is considered that the image in the recording range before tilting shifts on the recording means with almost no tilt.

In general, the position of the subject image substantially coincides with the recording means, and when the optical system is blurred, the subject image by the optical system is considered to shift. Assuming that the lens system rotates around the principal point of the lens system, the amount of change in the image position with respect to the blur angle ε of the lens system (the amount of image blur)
δ ′ is represented 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, and the variation δ ′ of the image position is expressed by the following equation (c). δ ′ ≒ f · ε (c) When an image is recorded, if the amount of change δ ′ in the image position becomes large to some extent, it is recorded as image blur.

As the focal length of the optical system increases, the amount of change δ 'of the image position with respect to a predetermined blur angle ε of the optical system increases. Therefore, when the zoom ratio is increased and the focal length in the telephoto end state is increased, image blur is likely to be recorded due to blur of the optical system due to camera shake or the like. To correct the image position fluctuation due to camera shake by compensating the image position fluctuation amount δ ′ due to camera shake or the like by the image shift amount δ due to movement of the shift lens group, the following equation (d) is used. It must be established. δ + δ ′ = 0 (d)

By substituting the equations (a) and (c) into the equation (d), the following equation (e) is obtained. f · ε + kΔ = 0 (e) That is, the shift amount Δ of the shift lens group required to correct the change in the image position due to camera shake or the like is expressed by the following equation (f). Δ = − (f / k) ε (f)

Thus, based on the information on the blur angle ε of the optical system detected by the blur detection system, the information on the focal length of the optical system, and the information on the blur coefficient k,
The required movement amount Δ of the shift lens group (that is, the image blur correction amount) is calculated, and the shift system group is driven by the driving system in the direction perpendicular to the optical axis by the required movement amount Δ, thereby correcting the fluctuation of the image position. can do.

As described above, according to the present invention, it is possible to achieve an anti-shake optical system capable of correcting a change in an image position caused by a shake of the optical system due to a hand shake or the like. However, it is needless to say that the variable power optical system of the present invention is not only applicable to an optical system capable of image shift, but also can achieve sufficiently high optical performance as a normal optical system. . In each of the embodiments described below, a part of the fourth lens group G4 is a shift lens group. However, the lens group including the shift lens group is not particularly limited to the fourth lens group G4. Also, a shift lens group can be provided.

[0054]

Embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 1 is a diagram showing a refractive power distribution of a variable power optical system according to each embodiment of the present invention and a state of movement of each lens group during zooming from a wide-angle end state (W) to a telephoto end state (T). It is. As shown in FIG. 1, the variable power optical system according to each example of the present invention includes, in order from the object side, a first lens group G1 having a positive refractive power and a second lens group having a positive or negative refractive power. The zoom lens includes a group G2, a third lens group G3 having a negative refractive power, a fourth lens group G4 having a positive refractive power, and a fifth lens group G5 having a negative refractive power. Then, at the time of zooming from the wide-angle end state to the telephoto end state, 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 increases. The air gap between the third lens group G3 and the fourth lens group G4 decreases, and the fourth lens group G4 and the fifth lens group G5 increase.
Each lens group is moved to the object side so that the air gap between the lens groups decreases.

In each of the embodiments, the aspherical surface has a height y in the direction perpendicular to the optical axis, a displacement (sag amount) in the optical axis direction at the height y of S (y), and a reference radius of curvature of R. , The conic coefficient is κ, and the n-th order aspherical coefficient is Cn, and is expressed by the following equation (g).

[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 + ··· (g) In each embodiment, the aspherical surface is marked with an asterisk on the right side of the surface number.

[First Embodiment] FIG. 2 is a diagram showing the configuration of a variable power optical system according to a first embodiment of the present invention. In the variable power optical system shown in FIG. 2, the first lens group G1 includes, in order from the object side, a cemented positive lens L1 of a biconvex lens and a negative meniscus lens having a concave surface facing the object side. Also,
The second lens group G2 includes, in order from the object side, a biconcave lens L2.
1 and a biconvex lens L22. Further, the third lens group G3 includes a biconcave lens L3.

The fourth lens group G4 comprises, in order from the object side, a biconvex lens L41, and a cemented positive lens L42 comprising a biconvex lens and a negative meniscus lens having a concave surface facing the object side. Further, the fifth lens group G5 includes, in order from the object side, a positive meniscus lens L having a concave surface facing the object side.
51, a biconcave lens L52, and a negative meniscus lens L53 having a concave surface facing the object side.

The aperture stop S is disposed between the third lens unit G3 and the fourth lens unit G4, and moves together with the fourth lens unit G4 when zooming from the wide-angle end state to the telephoto end state. I do. FIG. 2 shows the positional relationship between the lens groups in the wide-angle end state, and moves on the optical axis along a zoom trajectory indicated by an arrow in FIG. 1 during zooming to the telephoto end state. The image shift is performed by moving the cemented positive lens L42 of the two lens components constituting the fourth lens group G4 in a direction substantially perpendicular to the optical axis to correct a change in the image position due to camera shake or the like. I have. That is, the cemented positive lens L42 forms a partial lens group Gh, which is a shift lens group. Further, focusing is performed by moving the third lens group G3 along the optical axis.

Table 1 below summarizes data values of the first embodiment of the present invention. In Table (1), f is the focal length,
FNO represents the F number, ω represents the half angle of view, Bf represents the back focus, and D0 represents the distance along the optical axis between the object and the surface closest to the object. Furthermore, the surface number indicates the order of the lens surface from the object side along the direction in which the light rays travel,
The refractive index and Abbe number are each d-line (λ = 587.6).
nm).

[0060]

[Table 1] f = 38.81-75.35-125.59-183.37 FNO = 3.88-6.13-8.54-11.00 ω = 29.44-15.51-9.51-6.60 ° Surface number Curvature radius Surface spacing Refractive index Abbe number 1 76.4846 4.270 1.48749 70.45 2 -37.9065 1.381 1.84666 23.83 3 -62.8064 (D3 = variable) 4 -38.7725 1.000 1.83500 42.97 5 25.8577 1.000 6 21.8269 3.767 1.76182 26.55 7 -50.9382 (D7 = variable) 8 -21.0028 1.000 1.80420 46.51 9 305.6880 (D9 = variable) 10 ∞ 1.758 ( Aperture stop S) 11 59.6582 2.512 1.51450 63.05 12 * -24.2827 1.381 13 44.8563 3.767 1.48749 70.45 14 -14.7566 1.000 1.84666 23.83 15 -23.6485 (D15 = variable) 16 -409.2955 3.391 1.75520 27.53 17 -30.3185 0.984 18 -84.3775 1.256 1.83500 42.97 88.8380 5.729 20 -15.2948 1.507 1.80420 46.51 21 -84.9742 (Bf) (Aspherical data) R κ C ₄ 12 plane -24.2827 1.0000 + 1.41918 × 10 ^-5 C ₆ C ₈ C ₁₀ -3.06586 × 10 ^-8 + 5.44479 × 10 ^-10 0.00000 (variable interval in zooming) f 38.8052 75.3505 125.5854 183.3709 D3 1.5070 13.7188 22.8284 28.1015 D7 2 .9290 4.2541 5.3555 6.2791 D9 4.6059 3.2808 2.1794 1.2558 D15 19.9499 11.5156 6.7485 3.8930 Bf 7.9120 28.7151 52.0648 76.3388 (Focus moving distance of the third lens group G3 at the photographing magnification of -1/30) Focal length f 38.8052 75.3505 125.5854 183.3709 D0 1111.3183 2163.1144 3610.6094 5282.6782 Moving amount 0.8858 0.7362 0.7061 0.6938 However, the sign of the moving amount is positive for the movement toward the object side (the moving amount of the cemented positive lens L42 when the image is shifted by 0.01 [rad]) Focal length f 38.8052 75.3505 125.5854 183.3709 Lens movement amount 0.3613 0.4447 0.5335 0.6062 Image shift amount 0.3881 0.7535 1.2560 1.8339 (Values corresponding to conditions) fs = + 20.8950 fh = + 44.8281 f1 = + 96.7562 f2 = −1985.2844 f3 = −24.4039 β5w = +1.2709 β5t = + 3.7446 β3w = −0.2763 β3t = −0.4910 (1) fs / h = 0.466 (2) (β5t / β5w) / (ft / fw) = 0.625 (3) f1 / (fw · ft) 1/2 = 1.147 (4) f3 / f2 = 0.012 (5) (β3t / β3w) / (ft / fw) = 0.376 (6) Db / fw = 0.146

FIGS. 3 to 10 show the d-line (λ = 587.6).
FIG. 7 is a diagram illustrating various aberrations of the first example with respect to (nm). FIG. 3 is a diagram illustrating various aberrations in the infinity in-focus condition in the wide-angle end state (the shortest focal length state), and FIG. 4 is a diagram illustrating various aberrations in the infinity in-focus condition in the first intermediate focal length state. 5 is a diagram of various aberrations in the second intermediate focal length state in an infinity in-focus state, and FIG. 6 is a diagram of various aberrations in a telephoto end state (longest focal length state) in an infinity in-focus state. FIG. 7 is a diagram illustrating various aberrations at a photographing magnification of −1 / 30 × in the wide-angle end state, and FIG. 8 is a photographing magnification of −1 in the first intermediate focal length state.
FIG. 9 is a graph showing various aberrations at a photographing magnification of −1 / 30 × in the second intermediate focal length state, and FIG. 10 is a graph showing various aberrations at a photographing magnification of −1 / 30 × in the telephoto end state. FIG.

FIGS. 11 to 18 are coma aberration diagrams when the image is shifted by 0.01 rad (radian) with respect to the optical axis in the first embodiment. FIG. 11 is a coma aberration diagram in the infinity in-focus state in the wide-angle end state.
FIG. 12 is a coma aberration diagram in the first intermediate focal length state in an infinity in-focus state, FIG. 13 is a coma aberration diagram in the second intermediate focal length state in an infinity in-focus state, and FIG.
FIG. 7 is a coma aberration diagram in an infinity in-focus state in a telephoto end state. FIG. 15 shows the photographing magnification in the wide-angle end state.
FIG. 16 is a coma difference diagram at 1/30 × magnification in a first intermediate focal length state, and FIG. 17 is a coma aberration diagram at 1/30 × magnification in a second intermediate focal length state. FIG. 18 is a coma aberration diagram at 1/30 ×, and FIG. 18 is a coma aberration diagram at a photographing magnification of −1 / 30 × in the telephoto end state. Each of the aberration diagrams in FIGS. 11 to 18 shows that when the cemented positive lens L42 is moved in the positive direction of the image height Y, Y = 15.0,
It shows coma aberrations at 0 and -15.0.

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.

[Second Embodiment] FIG. 19 is a view showing the arrangement of a variable power optical system according to a second embodiment of the present invention. FIG.
In the variable magnification optical system, the first lens group G1 includes, in order from the object side, a cemented positive lens L1 of a biconvex lens and a negative meniscus lens having a concave surface facing the object side. The second lens group G2 includes, in order from the object side, a biconcave lens L21 and a biconvex lens L22. Further, the third lens group G3 includes a biconcave lens L3.

The fourth lens group G4 comprises, in order from the object, a biconvex lens L41 and a cemented positive lens L42 comprising a biconvex lens and a negative meniscus lens having a concave surface facing the object. Further, the fifth lens group G5 includes, in order from the object side, a biconvex lens L51, a biconcave lens L52, and a negative meniscus lens L53 having a concave surface facing the object side.

The aperture stop S is disposed in the fourth lens group G4, and moves integrally with the fourth lens group G4 when changing the magnification from the wide-angle end state to the telephoto end state. FIG. 19 shows the positional relationship of each lens group in the wide-angle end state.
During zooming to the telephoto end state, the lens moves on the optical axis along a zoom trajectory indicated by an arrow in FIG. The image shift is performed by moving the cemented positive lens L42 of the two lens components constituting the fourth lens group G4 in a direction substantially perpendicular to the optical axis to correct a change in the image position due to camera shake or the like. I have. That is, the cemented positive lens L42 forms a partial lens group Gh, which is a shift lens group. Further, the third lens group G3
Is moved along the optical axis to perform focusing.

Table 2 below summarizes the data values of the second embodiment of the present invention. In Table (2), f is the focal length,
FNO represents the F number, ω represents the half angle of view, Bf represents the back focus, and D0 represents the distance along the optical axis between the object and the surface closest to the object. Furthermore, the surface number indicates the order of the lens surface from the object side along the direction in which the light rays travel,
The refractive index and Abbe number are each d-line (λ = 587.6).
nm).

[0068]

[Table 2] f = 38.81 to 75.35 to 125.59 to 183.37 FNO = 3.93 to 6.26 to 8.55 to 11.00 ω = 29.50 to 15.48 to 9.48 to 6.58 ° Surface number Curvature radius Surface spacing Refractive index Abbe number 1 84.2784 4.270 1.48749 70.45 2 -36.5885 1.381 1.84666 23.83 3 -60.1436 (D3 = Variable) 4 -32.9779 1.000 1.83500 42.97 5 28.5643 0.879 6 22.4693 3.767 1.76182 26.55 7 -40.8743 (D7 = Variable) 8 -19.4738 1.000 1.83500 42.97 9 249.0346 (D9 = Variable) 10 1.51450 52.512 63.05 11 * -19.0970 1.256 12 ∞ 1.884 (Aperture stop S) 13 33.9949 3.767 1.48749 70.45 14 -15.7174 1.000 1.84666 23.83 15 -25.9351 (D15 = variable) 16 1628.8734 3.391 1.75520 27.53 17 -32.9521 0.242 18 -194.3115 1.256 1.83500 42.97 19 84.9315 6.123 20 -16.7244 1.507 1.80420 46.51 21 -325.1428 (Bf) ( aspheric data) R κ C ₄ 11 surface ^{-19.0970 1.0000 + 1.11017 × 10 -5 C} 6 C 8 C 10 -9.75638 × 10 -9 + 6.25157 × 10 - ¹⁰ 0.00000 (variable interval in zooming) f 38.8046 75.3471 125.5762 183.3269 D3 1.5070 13.1188 23.2186 28.7528 D 7 2.7339 4.1630 5.4403 6.2791 D9 4.8010 3.3719 2.0946 1.2558 D15 21.1065 12.0517 7.1695 3.8930 Bf 7.9110 29.3939 51.6425 76.1403 (Focus moving amount of the third lens group G3 at -1 / 30x magnification) Focal length f 38.8046 75.3471 125.5762 183.3269 D0 1115.0445 2172.7614 3622.1547 5300.8103 Moving amount 0.7174 0.5702 0.5549 0.5358 However, the sign of the moving amount is positive for the movement toward the object side (the moving amount of the cemented positive lens L42 when the image is shifted by 0.01 [rad]) Focal length f 38.8046 75.3471 125.5762 183.3269 Lens shift amount 0.3361 0.4110 0.5020 0.5706 Image shift amount 0.3881 0.7538 1.2558 1.8334 (Conditional value) fs = + 20.3677 fh = + 41.9424 f1 = + 99.492 f2 = + 622.1022 f3 = −21.938 β5w = + 1 .2092 β5t = + 3.4301 β3w = −0.2941 β3t = −0.4264 (1) fs / h = 0.486 (2) (β5t / β5w) / (ft / fw) = 0.600 (3) f1 / (fw · ft) 1/2 = 1.184 (4) f3 / f2 = -0. (5) (β3t / β3w) / (ft / fw) = 0.307 (6) Db / fw = 0.049

FIGS. 20 to 27 show the d-line (λ = 587.
FIG. 9 is a diagram illustrating various aberrations of the second example with respect to 6 nm). FIG.
FIG. 21 is a diagram illustrating various aberrations at the infinity in-focus condition in the wide-angle end state, FIG. 21 is a diagram illustrating various aberrations at the infinity in-focus condition in the first intermediate focal length state, and FIG. 23 is a diagram illustrating various aberrations at the time of focusing on infinity in FIG.
FIG. 4 is a diagram of various aberrations in an infinity in-focus state in a telephoto end state. FIG. 24 shows a photographing magnification of −1 / in the wide-angle end state.
FIG. 25 is a diagram of various aberrations at 30 ×, FIG. 25 is a diagram of various aberrations at a photographing magnification of 1/30 × in the first intermediate focal length state, and FIG.
FIG. 27 is a diagram illustrating various aberrations at 1/30 ×, and FIG. 27 is a diagram illustrating various aberrations at a photographing magnification of −1 / 30 × in the telephoto end state.

FIGS. 28 to 35 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. 28 is a coma aberration diagram in the infinity in-focus state in the wide-angle end state.
FIG. 29 is a coma aberration diagram in the first intermediate focal length state in an infinity in-focus state, FIG. 30 is a coma aberration diagram in the second intermediate focal length state in an infinity in-focus state, and FIG.
FIG. 7 is a coma aberration diagram in an infinity in-focus state in a telephoto end state. FIG. 32 shows a photographing magnification in the wide-angle end state.
FIG. 33 is a coma aberration diagram at 1/30 ×, FIG. 33 is a photograph difference at 1/30 × magnification in a first intermediate focal length state, and FIG. 34 is a photographing magnification− at a second intermediate focal length state. Fig. 35 is a coma aberration diagram at 1 / 30x, and Fig. 35 is a coma aberration diagram at a photographing magnification of -1 / 30x in the telephoto end state. Each of the aberration diagrams in FIGS. 28 to 35 shows that Y = 15.0, when the cemented positive lens L42 is moved in the positive direction of the image height Y,
It shows coma aberrations at 0 and -15.0.

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.

[Third Embodiment] FIG. 36 is a view showing the arrangement of a variable power optical system according to a third embodiment of the present invention. FIG.
In the variable magnification optical system, the first lens group G1 includes, in order from the object side, a cemented positive lens L1 of a biconvex lens and a negative meniscus lens having a concave surface facing the object side. The second lens group G2 includes, in order from the object side, a biconcave lens L21 and a biconvex lens L22. Further, the third lens group G3 includes a biconcave lens L3.

The fourth lens unit G4 comprises, in order from the object side, a cemented positive lens L41 comprising a biconvex lens and a negative meniscus lens having a concave surface facing the object side, and a biconvex lens L42. Further, the fifth lens group G5 includes, in order from the object side, a positive meniscus lens L having a concave surface facing the object side.
51, a biconcave lens L52, and a negative meniscus lens L53 having a concave surface facing the object side.

The aperture stop S is disposed between the third lens group G3 and the fourth lens group G4, and moves together with the fourth lens group G4 when zooming from the wide-angle end state to the telephoto end state. I do. FIG. 36 shows the positional relationship between the lens groups in the wide-angle end state.
Move on the optical axis along the zoom trajectory indicated by the arrow. The image shift is performed by moving the cemented positive lens L41 of the two lens components constituting the fourth lens group G4 in a direction substantially perpendicular to the optical axis, and correcting a change in the image position due to camera shake or the like. I have. That is, the cemented positive lens L41 constitutes a partial lens group Gh, which is a shift lens group. Further, focusing is performed by moving the third lens group G3 along the optical axis.

Table 3 below summarizes data values of the third embodiment of the present invention. In Table (3), f is the focal length,
FNO represents the F number, ω represents the half angle of view, Bf represents the back focus, and D0 represents the distance along the optical axis between the object and the surface closest to the object. Furthermore, the surface number indicates the order of the lens surface from the object side along the direction in which the light rays travel,
The refractive index and Abbe number are each d-line (λ = 587.6).
nm).

[0076]

Table 3 f = 39.14 to 76.00 to 126.67 to 184.96 FNO = 3.88 to 6.18 to 8.71 to 11.03 ω = 28.93 to 15.36 to 9.44 to 6.54 ° Surface number Curvature radius Surface spacing Refractive index Abbe number 1 69.1339 4.307 1.48749 70.45 2 -41.1481 1.393 1.84666 23.83 3 -68.2191 (D3 = variable) 4 -47.9179 1.013 1.83500 42.97 5 21.5600 0.887 6 19.7334 3.420 1.76182 26.55 7 -74.3293 (D7 = variable) 8 -21.2735 1.013 1.65160 58.44 9 190.9490 (D9 = variable) 10 ∞ 1.773 ( Aperture stop S) 11 37.1797 3.800 1.48749 70.45 12 -14.3026 1.013 1.84666 23.83 13 -25.2207 0.633 14 59.8053 2.533 1.51450 63.05 15 * -25.4068 (D15 = variable) 16 -128.2557 3.420 1.75520 27.53 17 -27.1041 0.613 18 -55.9699 1.267 1.80420 46.19 126.6667 6.623 20 -15.1206 1.520 1.80420 46.51 21 -67.9965 (Bf) ( aspheric data) R κ C ₄ 15 surface ^{-25.4068 1.0000 + 2.46520 × 10 -5 C} 6 C 8 C 10 -6.38440 × 10 -8 -5.80820 × 10 ^-10 0.00000 (variable interval in zooming) f 39.1407 76.0020 126.6715 184.9591 D3 1.5200 13.6352 22.0308 28.3806 D7 3.1879 4.4593 5.5276 6.3333 D9 4.4121 3.1407 2.0724 1.2667 D15 19.4714 11.4290 6.9182 3.9639 Bf 7.9845 29.0855 53.5611 77.7300 (Focus moving amount of the third lens group G3 at the photographing magnification of -1/30) Focal length f 39.1407 76.0020 126.6715 184.9591 1999.5 364 5312.4289 Moving amount 1.0935 0.9160 0.8585 0.9134 However, the sign of the moving amount is positive for the movement toward the object side (the moving amount of the cemented positive lens L41 when the image is shifted by 0.01 [rad]) Focal length f 39.1407 76.0020 126.6715 184.9591 Lens 0.3744 0.4590 0.5425 0.6249 Image shift amount 0.3914 0.7602 1.2667 1.8497 (Conditional value) fs = + 21.1286 fh = + 46.4820 f1 = + 93.6994 f2 = −225.0704 f3 = −29.3202 β5w = + 1 0.3305 β5t = + 4.0104 β3w = −0.1992 β3t = −0.4452 (1) fs / f = 0.455 (2) (β5t / β5w) / (ft / fw) = 0.638 (3) f1 / (fw · ft) 1/2 = 1.101 (4) f3 / f2 = 0.130 ( 5) (β3t / β3w) / (ft / fw) = 0.473 (6) Db / fw = 0.045

FIGS. 37 to 44 show the d-line (λ = 587.
FIG. 9 is a diagram illustrating various aberrations of the third example with respect to (6 nm). FIG.
FIG. 38 is a diagram showing various aberrations at the infinity in-focus condition in the wide-angle end state, FIG. 38 is a diagram showing various aberrations at the infinity in-focus condition in the first intermediate focal length condition, and FIG. 40 is a diagram illustrating various aberrations at the time of focusing on infinity in FIG.
FIG. 4 is a diagram of various aberrations in an infinity in-focus state in a telephoto end state. FIG. 41 shows a photographing magnification of −1 / in the wide-angle end state.
42 is a diagram of various aberrations at 30 ×, FIG. 42 is a diagram of various aberrations at a photographing magnification of 1/30 × in the first intermediate focal length state, and FIG. 43 is a photographing magnification− of the photographing magnification in the second intermediate focal length state.
44 are graphs showing various aberrations at 1 / 30x, and FIG. 44 is a graph showing various aberrations at a photographing magnification of -1 / 30x in the telephoto end state.

FIGS. 45 to 52 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. 45 is a coma aberration diagram at the infinity in-focus condition in the wide-angle end state.
FIG. 46 is a coma aberration diagram in an infinity in-focus condition in a first intermediate focal length state, FIG. 47 is a coma aberration diagram in an infinity in-focus condition in a second intermediate focal length condition, and FIG.
FIG. 7 is a coma aberration diagram in an infinity in-focus state in a telephoto end state. FIG. 49 shows the photographing magnification in the wide-angle end state.
FIG. 50 is a coma aberration diagram at 1/30 ×, FIG. 50 is a photographing difference at 1/30 × magnification in a first intermediate focal length state, and FIG. 51 is a photographing magnification− at a second intermediate focal length state. Fig. 52 is a coma aberration diagram at 1 / 30x, and Fig. 52 is a coma aberration diagram at a photographing magnification of -1 / 30x in the telephoto end state. Each of the aberration diagrams in FIGS. 45 to 52 shows that when the cemented positive lens L41 is moved in the positive direction of the image height Y, Y = 15.0,
It shows coma aberrations at 0 and -15.0.

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.

[Fourth Embodiment] FIG. 53 is a diagram showing the configuration of a variable power optical system according to a fourth embodiment of the present invention. FIG.
In the variable magnification optical system, the first lens group G1 includes, in order from the object side, a cemented positive lens L1 of a biconvex lens and a negative meniscus lens having a concave surface facing the object side. The second lens group G2 includes, in order from the object side, a biconcave lens L21 and a biconvex lens L22. Further, the third lens group G3 includes a biconcave lens L3.

The fourth lens group G4 comprises, in order from the object side, a cemented positive lens L41 comprising a biconvex lens and a negative meniscus lens having a concave surface facing the object side, and a biconvex lens L42. Further, the fifth lens group G5 includes, in order from the object side, a positive meniscus lens L having a concave surface facing the object side.
51, a biconcave lens L52, and a negative meniscus lens L53 having a concave surface facing the object side.

The aperture stop S is disposed between the third lens unit G3 and the fourth lens unit G4, and moves together with the fourth lens unit G4 when zooming from the wide-angle end state to the telephoto end state. I do. FIG. 53 shows the positional relationship between the lens groups in the wide-angle end state.
Move on the optical axis along the zoom trajectory indicated by the arrow. The image shift is performed by moving the cemented positive lens L41 of the two lens components constituting the fourth lens group G4 in a direction substantially perpendicular to the optical axis, and correcting a change in the image position due to camera shake or the like. I have. That is, the cemented positive lens L41 constitutes a partial lens group Gh, which is a shift lens group. Further, focusing is performed by moving the third lens group G3 along the optical axis.

Table 4 below summarizes the data values of the fourth embodiment of the present invention. In Table (4), f is the focal length,
FNO represents the F number, ω represents the half angle of view, Bf represents the back focus, and D0 represents the distance along the optical axis between the object and the surface closest to the object. Furthermore, the surface number indicates the order of the lens surface from the object side along the direction in which the light rays travel,
The refractive index and Abbe number are each d-line (λ = 587.6).
nm).

[0084]

Table 4 f = 39.14-76.00-126.67-185.60 FNO = 3.88-6.18-8.71-11.03 ω = 28.90-15.36-9.44-6.51 ° Surface number Curvature radius Surface spacing Refractive index Abbe number 1 73.1567 4.307 1.48749 70.45 2 -39.1087 1.393 1.84666 23.83 3 -64.5503 (D3 = variable) 4 -46.5542 1.013 1.83500 42.97 5 21.4634 0.887 6 19.8299 3.420 1.76182 26.55 7 -73.2670 (D7 = variable) 8 -22.7369 1.013 1.77250 49.61 9 436.3215 (D9 = variable) 10 ∞ 1.773 ( Aperture stop S) 11 39.1568 3.800 1.48749 70.45 12 -14.4724 1.013 1.84666 23.83 13 -25.6533 0.633 14 60.5646 2.533 1.51450 63.05 15 * -24.9534 (D15 = variable) 16 -295.5822 3.420 1.72825 28.31 17 -27.7080 0.760 18 -57.5935 1.267 1.80420 46.51 19 126.6667 5.827 20 -15.4450 1.520 1.80420 46.51 21 -89.3643 (Bf) ( aspheric data) R κ C ₄ 15 surface ^{-24.9534 1.0000 + 2.48433 × 10 -5 C} 6 C 8 C 10 + 4.04532 × 10 -8 -2.85972 × 10 ^-10 0.00000 (variable interval in zooming) f 39.1404 76.0013 126.6695 185.6034 D3 1.5200 13.6819 22.0757 28.6921 D7 3.1692 4.2974 5.3942 6.3333 D9 4.4308 3.3026 2.2058 1.2667 D15 20.7598 11.9921 7.2574 4.1800 Bf 7.9804 29.6382 54.4074 78.3845 (Focus moving distance of the third lens group G3 at the photographing magnification of -1/30) Focal length f 39.1404 76.0013 126.6695 185.6034 173 5319.9470 Moving amount 1.0788 0.9104 0.8502 0.9276 However, the sign of the moving amount is positive for the movement toward the object side (the moving amount of the cemented positive lens L41 when the image is shifted by 0.01 [rad]) Focal length f 39.1404 76.0013 126.6695 185.6034 Lens 0.3907 0.4768 0.5636 0.6548 Image shift amount 0.3915 0.7600 1.2667 1.8563 (Conditional value) fs = + 21.3628 fh = + 48.4896 f1 = + 94.8466 f2 = −318.1155 f3 = −27.9483 β5w = + 1 .2896 β5t = + 3.8874 β3w = −0.2353 β3t = −0.4866 (1) fs / f = 0.441 (2) (β5t / β5w) / (ft / fw) = 0.639 (3) f1 / (fw · ft) 1/2 = 1.113 (4) f3 / f2 = 0.088 ( 5) (β3t / β3w) / (ft / fw) = 0.436 (6) Db / fw = 0.045

FIGS. 54 to 61 show d-line (λ = 587.
FIG. 10 is a diagram illustrating various aberrations of the fourth example with respect to (6 nm). FIG.
FIG. 55 is a diagram illustrating various aberrations at the infinity in-focus condition in the wide-angle end state, FIG. 55 is a diagram illustrating various aberrations at the infinity in-focus condition in the first intermediate focal length condition, and FIG. 57 are graphs showing various aberrations at an infinity in-focus condition in FIG.
FIG. 4 is a diagram of various aberrations in an infinity in-focus state in a telephoto end state. FIG. 58 shows a photographing magnification of −1 / in the wide-angle end state.
FIG. 59 is a diagram of various aberrations at a magnification of 30 ×, FIG. 59 is a diagram of various aberrations at a photographing magnification of 1/30 × in a first intermediate focal length state, and FIG.
FIG. 61 is a diagram illustrating various aberrations at 1/30 ×, and FIG. 61 is a diagram illustrating various aberrations at a photographing magnification of −1 / 30 × in the telephoto end state.

FIGS. 62 to 69 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. 62 is a coma aberration diagram at the infinity in-focus condition in the wide-angle end state.
63 is a coma aberration diagram at the infinity in-focus condition in the first intermediate focal length state, FIG. 64 is a coma aberration diagram at the infinity in-focus condition in the second intermediate focal length condition, and FIG.
FIG. 7 is a coma aberration diagram in an infinity in-focus state in a telephoto end state. FIG. 66 shows a photographing magnification in the wide-angle end state.
FIG. 67 is a coma aberration diagram at 1/30 ×, FIG. 67 is a coma difference diagram at 1/30 × magnification at a first intermediate focal length state, and FIG. 68 is a photographing magnification− at a second intermediate focal length state. Fig. 69 is a coma aberration diagram at 1 / 30x, and Fig. 69 is a coma aberration diagram at a photographing magnification of -1 / 30x in the telephoto end state. Each of the aberration diagrams in FIGS. 62 to 69 shows that Y = 15.0, when the cemented positive lens L41 is moved in the positive direction of the image height Y,
It shows coma aberrations at 0 and -15.0.

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.

[0088]

As described above, according to the present invention,
It is possible to realize a variable-magnification optical system that is small, has high performance, and has a zoom ratio of about 5 and is suitable for high zooming and capable of image shifting. It goes without saying that the introduction of a plurality of aspherical surfaces into the lens unit of the variable power optical system can further increase the aperture, increase the power, and reduce the size.

[Brief description of the drawings]

FIG. 1 is a diagram showing a refractive power distribution of a variable power optical system according to each embodiment of the present invention and a state of movement of each lens group during zooming from a wide-angle end state (W) to a telephoto end state (T). It is.

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

FIG. 3 is a diagram illustrating various aberrations of the first example in a focused state at infinity in a wide-angle end state.

FIG. 4 is a diagram illustrating various aberrations of the first example in a first intermediate focal length state in an infinity in-focus state;

FIG. 5 is a diagram illustrating various aberrations of the first example in a second intermediate focal length state in an infinity in-focus state;

FIG. 6 is a diagram illustrating various aberrations of the first example at a telephoto end in an infinity in-focus state;

FIG. 7 is a photographing magnification-1 in the wide-angle end state of the first embodiment.
It is a graph of various aberrations at / 30 time.

FIG. 8 is a diagram illustrating various aberrations at a magnification of −1/30 in the first intermediate focal length state of the first example.

FIG. 9 is a diagram illustrating various aberrations at a magnification of −1/30 in the second intermediate focal length state of the first example.

FIG. 10 shows a photographing magnification in the telephoto end state of the first embodiment.
It is a some-aberration figure at 1/30 time.

FIG. 11 is a coma aberration diagram at the time of image shifting in an infinity in-focus state in a wide-angle end state according to the first example.

FIG. 12 is a coma aberration diagram at the time of image shift in an infinity in-focus state in a first intermediate focal length state of the first example.

FIG. 13 is a coma aberration diagram at the time of image shift in an infinity in-focus state in the second intermediate focal length state of the first example.

FIG. 14 is a coma aberration diagram at the time of image shift in an infinity in-focus condition in the telephoto end state of the first embodiment.

FIG. 15 is a photographing magnification in the wide-angle end state of the first embodiment.
It is a coma aberration figure at the time of image shift at 1/30 time.

FIG. 16 is a coma aberration diagram when the image is shifted at a photographing magnification of −1/30 in the first intermediate focal length state of the first example.

FIG. 17 is a coma aberration diagram when the image is shifted at a photographing magnification of −1/30 in the second intermediate focal length state of the first example.

FIG. 18 shows a photographing magnification of the first embodiment in a telephoto end state.
It is a coma aberration figure at the time of image shift at 1/30 time.

FIG. 19 is a diagram showing a configuration of a variable power optical system according to Example 2 of the present invention.

FIG. 20 is a diagram illustrating various aberrations of the second example in a state at infinity in a wide-angle end state.

FIG. 21 is a diagram illustrating various aberrations of the second example in a first intermediate focal length state in an infinity in-focus state;

FIG. 22 is a diagram illustrating various aberrations of the second example in a second intermediate focal length state in an infinity in-focus state;

FIG. 23 is a diagram illustrating various aberrations of the second example at a telephoto end in an infinity in-focus condition;

FIG. 24 shows a photographing magnification in the wide-angle end state according to the second embodiment.
It is a some-aberration figure at 1/30 time.

FIG. 25 is a diagram illustrating various aberrations at a magnification of −1/30 in the first intermediate focal length state of the second example.

FIG. 26 is a diagram illustrating various aberrations at a magnification of −1/30 in the second intermediate focal length state according to the second example;

FIG. 27 shows a photographing magnification in the telephoto end state of the second embodiment.
It is a some-aberration figure at 1/30 time.

FIG. 28 is a coma aberration diagram at the time of image shift in an infinity in-focus condition in the wide-angle end state according to the second example.

FIG. 29 is a coma aberration diagram at the time of image shift in an infinity in-focus state in the first intermediate focal length state of the second example.

FIG. 30 is a coma aberration diagram at the time of image shift in an infinity in-focus condition in a second intermediate focal length state of the second example.

FIG. 31 is a coma aberration diagram at the time of image shift in an infinity in-focus condition in the telephoto end state of the second embodiment.

FIG. 32 shows a photographing magnification in the wide-angle end state according to the second embodiment.
It is a coma aberration figure at the time of image shift at 1/30 time.

FIG. 33 is a coma aberration diagram when an image is shifted at a photographing magnification of −1/30 in the first intermediate focal length state according to the second embodiment.

FIG. 34 is a coma aberration diagram at the time of image shift at a photographing magnification of −1/30 in the second intermediate focal length state of the second example.

FIG. 35 shows a photographing magnification of the second embodiment in a telephoto end state.
It is a coma aberration figure at the time of image shift at 1/30 time.

FIG. 36 is a diagram showing a configuration of a variable power optical system according to Example 3 of the present invention.

FIG. 37 is a diagram illustrating various aberrations of the third example in a focused state at infinity in a wide-angle end state.

FIG. 38 is a diagram illustrating various aberrations of the third example in a first intermediate focal length state in an infinity in-focus state;

FIG. 39 is a diagram illustrating various aberrations of the third example in a second intermediate focal length state in an infinity in-focus state;

FIG. 40 is a diagram illustrating various aberrations of the third example at a telephoto end in an infinity in-focus condition;

FIG. 41 shows a photographing magnification in the wide-angle end state according to the third embodiment.
It is a some-aberration figure at 1/30 time.

FIG. 42 is a diagram illustrating various aberrations at a magnification of −1/30 in the first intermediate focal length state of the third example.

FIG. 43 is a diagram illustrating various aberrations at a photographing magnification of −1/30 in the second intermediate focal length state of the third example.

FIG. 44 shows a photographing magnification in the telephoto end state of the third embodiment.
It is a some-aberration figure at 1/30 time.

FIG. 45 is a coma aberration diagram at the time of image shift in an infinity in-focus condition in the wide-angle end state according to the third example.

FIG. 46 is a coma aberration diagram at the time of image shift in an infinity in-focus state in the first intermediate focal length state of the third example.

FIG. 47 is a coma aberration diagram at the time of image shift in an infinity in-focus state in the second intermediate focal length state of the third example.

FIG. 48 is a coma aberration diagram at the time of image shift in an infinity in-focus condition in the telephoto end state of the third embodiment.

FIG. 49—Photographing magnification in the wide-angle end state according to the third embodiment—
It is a coma aberration figure at the time of image shift at 1/30 time.

FIG. 50 is a coma aberration diagram at the time of image shift at a photographing magnification of −1/30 in the first intermediate focal length state of the third example.

FIG. 51 is a coma aberration diagram at the time of image shift at a photographing magnification of −1/30 in the second intermediate focal length state of the third example.

FIG. 52 is a photographing magnification in the telephoto end state of the third embodiment.
It is a coma aberration figure at the time of image shift at 1/30 time.

FIG. 53 is a diagram showing a configuration of a variable power optical system according to Example 4 of the present invention.

FIG. 54 is a diagram illustrating various aberrations of the fourth example in an infinity in-focus condition in a wide-angle end state;

FIG. 55 is a diagram illustrating various aberrations of the fourth example in a first intermediate focal length state in an infinity in-focus state;

FIG. 56 is a diagram illustrating various aberrations of the fourth example in a second intermediate focal length state in an infinity in-focus state;

FIG. 57 is a diagram illustrating various aberrations of the fourth example in a telephoto end state in an infinity in-focus state;

FIG. 58—Photographing magnification in the wide-angle end state of the fourth embodiment—
It is a some-aberration figure at 1/30 time.

FIG. 59 is a diagram illustrating various aberrations at a photographing magnification of −1 / 30 × in the first intermediate focal length state of the fourth example.

FIG. 60 is a diagram illustrating various aberrations at a photographing magnification of −1 / 30 × in the second intermediate focal length state of the fourth example.

FIG. 61 shows a photographing magnification of the fourth embodiment in a telephoto end state.
It is a some-aberration figure at 1/30 time.

FIG. 62 is a coma aberration diagram at the time of image shift in an infinity in-focus condition in the wide-angle end state according to the fourth embodiment.

FIG. 63 is a coma aberration diagram at the time of image shift in an infinity in-focus condition in the first intermediate focal length state of the fourth example.

FIG. 64 is a coma aberration diagram at the time of image shift in an infinity in-focus state in the second intermediate focal length state of the fourth example.

FIG. 65 is a coma aberration diagram at the time of image shift in an infinity in-focus condition in the telephoto end state of the fourth embodiment.

FIG. 66—Photographing magnification in the wide-angle end state of the fourth embodiment—
It is a coma aberration figure at the time of image shift at 1/30 time.

FIG. 67 is a coma aberration diagram when an image is shifted at an imaging magnification of −1/30 in the first intermediate focal length state in the fourth example.

FIG. 68 is a coma aberration diagram at the time of image shift at a photographing magnification of −1/30 in the second intermediate focal length state of the fourth example.

FIG. 69 shows a photographing magnification in the telephoto end state of the fourth embodiment.
It is a coma aberration figure at the time of image shift at 1/30 time.

[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 (9)

[Claims] 1. A lens group Gs having a positive refractive power, a lens group Gn having a negative refractive power disposed adjacent to an object side of the lens group Gs, and an image side of the lens group Gs adjacent to an image side of the lens group Gs. When the lens position state changes from the wide-angle end state to the telephoto end state, the air gap between the lens group Gn and the lens group Gs decreases, and the lens group Gs The air gap with the lens group Ga changes, the lens group Gs has at least two partial lens groups, and one of the at least two partial lens groups is substantially perpendicular to the optical axis. , The image is shifted along a direction substantially perpendicular to the optical axis. When the focal length of the lens group Gs is fs and the focal length of the partial lens group Gh is fh, 0.3 <Fs / Image shiftable variable magnification optical system characterized by satisfying the condition of h <0.6. 2. The variable-magnification optical system according to claim 1, wherein an aperture stop S is provided in the lens group Gs or adjacent to the lens group Gs. 3. The lens group Ga has a negative refractive power, and when the lens position state changes from the wide-angle end state to the telephoto end state, the lens group Ga moves to the object side, and the lens group Ga in the wide-angle end state The lateral magnification of the lens group Ga is β5w, and the lateral magnification of the lens group Ga in the telephoto end state is β5w.
5t, and the focal length of the entire optical system in the wide-angle end state is f
w, and the focal length of the entire optical system in the telephoto end state is f
3. The image-shifting variable power optical system according to claim 1, wherein the following condition is satisfied: 0.4 <(β5t / β5w) / (ft / fw) <0.7. . 4. A first lens group G1 having a positive refractive power and disposed closest to the object side, wherein a focal length of the first lens group G1 is f1, and a focal length of the entire optical system in a wide-angle end state. Where fw is fw and the focal length of the entire optical system in the telephoto end state is ft, and the following condition is satisfied: 0.8 <f1 / (fw · ft) ^1/2 <1.5. The variable power optical system according to any one of claims 1 to 3, wherein the variable power optical system is capable of image shift. 5. The first lens group G1 moves toward the object side when the lens position changes from the wide-angle end state to the telephoto end state, and is disposed between the first lens group G1 and the lens group Gn. -0.2 <fn / f2 <0.2, where f2 is the focal length of the second lens group G2 and fn is the focal length of the second lens group G2. The image-shifting variable power optical system according to claim 4, wherein the condition is satisfied. 6. A focusing on a short-distance object is performed by moving one of the lens groups arranged closer to the object side than the lens group Gs along the optical axis. The variable-power optical system capable of image shifting according to claim 1. 7. Focusing on a short-distance object is performed by moving the lens group Gn along the optical axis, a lateral magnification of the lens group Gn in a wide-angle end state is set to β3w, and The lateral magnification of the lens group Gn is β
3t, and the focal length of the entire optical system in the wide-angle end state is f
w, and the focal length of the entire optical system in the telephoto end state is f
7. The image shiftable device according to claim 1, wherein a condition of 0.2 <(β3t / β3w) / (ft / fw) <0.7 is satisfied. Variable magnification optical system. 8. The distance along the optical axis between the surface closest to the aperture stop of the partial lens group Gh and the aperture stop S is Db.
Where fo is the focal length of the entire optical system in the wide-angle end state.
The variable power optical system according to claim 2, wherein the following condition is satisfied: Db / fw <0.2. 9. A first lens group G1 having a positive refractive power, a second lens group G2 having a positive or negative refractive power, and a third lens having a negative refractive power in order from the object side. A group G3, a fourth lens group G4 having a positive refractive power, and a fifth lens group G5 having a negative refractive power. When the lens position changes from the wide-angle end state to the telephoto end state, One lens group G1 and the second lens group G2
, The air gap between the second lens group G2 and the third lens group G3 increases, the air gap between the third lens group G3 and the fourth lens group G4 decreases,
At least the first lens group G is configured to reduce the air gap between the fourth lens group G4 and the fifth lens group G5.
1 and the fifth lens group G5 move toward the object side, and by moving a part of the fourth lens group G4 in a direction substantially perpendicular to the optical axis, along the direction substantially perpendicular to the optical axis. The lateral magnification of the fifth lens group G5 in the wide-angle end state by β
5w, the lateral magnification of the fifth lens group G5 in the telephoto end state is β5t, the focal length of the entire optical system in the wide-angle end state is fw, and the focal length of the entire optical system in the telephoto end state is ft. An image-shifting zoom optical system characterized by satisfying a condition of 0.4 <(β5t / β5w) / (ft / fw) <0.7.