JP5633111B2 - Variable magnification optical system and optical apparatus equipped with the variable magnification optical system - Google Patents

Description

The present invention, the variable magnification optical system, and to an optical apparatus including the variable magnification optical system.

  Conventionally, a variable magnification optical system suitable for a photographic camera, an electronic still camera, a video camera, and the like has been proposed (see, for example, Patent Document 1).

JP 2005-121694 A

  However, the conventional variable magnification optical system has a problem that it cannot cope with the problem of aberration fluctuations at the time of short-distance photographing and camera shake correction.

The present invention has been made in view of such a problem, and provides a variable power optical system that has excellent various optical aberrations at the time of short-distance shooting and camera shake correction, and the variable power optical system. It aims at providing the optical instrument provided with.

In order to solve the above-described problem, a variable magnification optical system according to the present invention includes, in order from the object side, a first lens group having a positive refractive power disposed closest to the object side, a second lens group, and a positive lens And a third lens group having a refractive power, and a _Gn lens group having a positive refractive power arranged closest to the image plane side. In zooming, the first lens group and the _Gn lens group are fixed, and the interval between adjacent lens groups changes during zooming, and in focusing, the second lens group and Gth lens group are changed. _At least one lens group arranged between the _n lens groups is configured to move as a focusing lens group.

At this time, a part of the G _n lens unit, a vibration reduction lens group having negative refractive power and moves so as to have an optical axis substantially perpendicular direction component.

At this time, the focal length of the G _n lens unit and FGn, when the focal length of the vibration reduction lens group and FVR, the following expression -3.5 <fGn / fVR <-0.8
To satisfy the conditions.

In the variable magnification optical system, it is preferable that at least two lens groups are provided between the second lens group and the _Gn lens group.

In this variable magnification optical system, the _Gn lens group includes, in order from the object side, a first partial group having a positive refractive power, a second partial group having a negative refractive power, and a positive refractive power. It is preferable that the second partial group is an anti-vibration lens group.

Further, the present zoom lens system, the focal length of the G _n lens unit and FGn, the focal length of the focusing lens group has a FGF, the following formula 0.20 <| fGf / fGn | < 1.00
It is preferable to satisfy the following conditions.

Further, the present zoom lens system, the focal length of the G _n lens unit and FGn, when the focal length of the entire system at the telephoto end state ft, the following formula 0.40 <| fGn | / ft < 1. 00
It is preferable to satisfy the following conditions.

Further, in this variable magnification optical system, when the focal length of the anti-vibration lens group is fVR and the focal length of the entire system in the wide-angle end state is fw, the following expression 0.10 <| fVR | / fw <1.90.
It is preferable to satisfy the following conditions.

The zoom optical system preferably includes, in order from the object side, a first lens group, a second lens group, a third lens group, a fourth lens group, and a _Gn lens group. .

In the variable magnification optical system, it is preferable that the fourth lens group has a positive refractive power.

  An optical apparatus according to the present invention includes any of the above-described variable magnification optical systems.

Variable magnification optical system according to the present invention, and, when forming the optical apparatus including the variable magnification optical system as described above, can be satisfactorily corrected aberrations at the time and image stabilization close object, excellent optical Performance can be obtained.

It is sectional drawing which shows the structure of the variable magnification optical system by 1st Example. FIG. 4A is a diagram illustrating various aberrations in the infinitely focused state in the wide-angle end state according to the first embodiment, FIG. 5A is a diagram illustrating various aberrations in the infinitely focused state in the wide-angle end state, and FIG. FIG. 6 is a meridional lateral aberration diagram when shake correction is performed for a rotational shake of 0.40 ° in the infinitely focused state. FIG. 2A is a diagram illustrating various aberrations in an infinitely focused state in an intermediate focal length state according to the first embodiment, FIG. 3A is a diagram illustrating various aberrations in an infinitely focused state in an intermediate focal length state, and FIG. FIG. 6 is a meridional lateral aberration diagram when shake correction is performed for a 0.30 ° rotational shake in an infinitely focused state in a distance state. FIG. 2A is a diagram illustrating various aberrations in an infinitely focused state in the telephoto end state according to the first embodiment, FIG. 3A is a diagram illustrating various aberrations in an infinitely focused state in the telephoto end state, and FIG. FIG. 6 is a meridional lateral aberration diagram when shake correction is performed for a 0.30 ° rotational shake in the infinite focus state. FIG. 3A is an aberration diagram in a short-distance object focusing state according to the first embodiment, FIG. 3A is an aberration diagram in a short-distance object focusing state in a wide-angle end state, and FIG. FIG. 4C is an aberration diagram in the object in-focus state, and FIG. 4C is an aberration diagram in the near-field object focus state in the telephoto end state. It is sectional drawing which shows the structure of the variable magnification optical system by 2nd Example. FIG. 6A is a diagram illustrating various aberrations in the infinitely focused state in the wide-angle end state according to the second embodiment, FIG. 9A is a diagram illustrating various aberrations in the infinitely focused state in the wide-angle end state, and FIG. FIG. 6 is a meridional lateral aberration diagram when shake correction is performed for a rotational shake of 0.40 ° in the infinitely focused state. FIG. 6A is a diagram illustrating various aberrations in an infinite focus state in an intermediate focal length state according to a second embodiment, FIG. 5A is a diagram illustrating various aberrations in an infinite focus state in a telephoto end state, and FIG. FIG. 6 is a meridional lateral aberration diagram when shake correction is performed with respect to a rotational shake of 0.30 ° in an infinitely focused state. FIG. 6A is a diagram illustrating various aberrations in the infinitely focused state in the telephoto end state according to the second embodiment, FIG. 9A is a diagram illustrating various aberrations in the infinitely focused state in the telephoto end state, and FIG. FIG. 6 is a meridional lateral aberration diagram when shake correction is performed for a 0.30 ° rotational shake in the infinite focus state. FIG. 6A is an aberration diagram in a short-distance object in-focus state according to the second embodiment, FIG. 5A is an aberration diagram in a short-distance object in-focus state in a wide-angle end state, and FIG. FIG. 4C is an aberration diagram in a focused state, and FIG. 4C is an aberration diagram in a short-distance object focused state in a telephoto end state. It is sectional drawing which shows the structure of the variable magnification optical system by 3rd Example. FIG. 7A is a diagram illustrating various aberrations in the infinitely focused state in the wide-angle end state according to the third embodiment, FIG. 9A is a diagram illustrating various aberrations in the infinitely focused state in the wide-angle end state, and FIG. FIG. 6 is a meridional lateral aberration diagram when shake correction is performed for a rotational shake of 0.40 ° in the infinitely focused state. FIG. 6A is a diagram illustrating various aberrations in an infinite focus state in an intermediate focal length state according to the third embodiment, FIG. 5A is a diagram illustrating various aberrations in an infinite focus state in an intermediate focal length state, and FIG. FIG. 6 is a meridional lateral aberration diagram when shake correction is performed for a 0.30 ° rotational shake in an infinitely focused state in a distance state. FIG. 7A is a diagram illustrating various aberrations in the infinitely focused state in the telephoto end state according to the third embodiment, FIG. 9A is a diagram illustrating various aberrations in the infinitely focused state in the telephoto end state, and FIG. FIG. 6 is a meridional lateral aberration diagram when shake correction is performed for a 0.30 ° rotational shake in the infinite focus state. FIG. 10A is an aberration diagram of the third embodiment in a short-distance object focusing state, FIG. 10A is an aberration diagram of a short-distance object focusing state in the wide-angle end state, and FIG. FIG. 4C is an aberration diagram in a focused state, and FIG. 4C is an aberration diagram in a short-distance object focused state in a telephoto end state. It is sectional drawing which shows the structure of the variable magnification optical system by 4th Example. FIG. 10A is a diagram illustrating various aberrations in the infinitely focused state in the wide-angle end state according to the fourth embodiment, FIG. 10A is a diagram illustrating various aberrations in the infinitely focused state in the wide-angle end state, and FIG. FIG. 6 is a meridional lateral aberration diagram when shake correction is performed for a rotational shake of 0.40 ° in the infinitely focused state. FIG. 7A is a diagram illustrating various aberrations in an infinite focus state in an intermediate focal length state according to the fourth embodiment, FIG. 9A is a diagram illustrating various aberrations in an infinite focus state in an intermediate focal length state, and FIG. FIG. 6 is a meridional lateral aberration diagram when shake correction is performed for a 0.30 ° rotational shake in an infinitely focused state in a distance state. FIG. 7A is a diagram illustrating various aberrations in the infinitely focused state in the telephoto end state according to the fourth embodiment, FIG. 9A is a diagram illustrating various aberrations in the infinitely focused state in the telephoto end state, and FIG. FIG. 6 is a meridional lateral aberration diagram when shake correction is performed for a 0.30 ° rotational shake in the infinite focus state. FIG. 10A is an aberration diagram in a short-distance object in-focus state according to the fourth embodiment. FIG. 10A is an aberration diagram in a near-field object in a wide-angle end state. FIG. FIG. 4C is an aberration diagram in a focused state, and FIG. 4C is an aberration diagram in a short-distance object focused state in a telephoto end state. It is sectional drawing which shows the structure of the variable magnification optical system by 5th Example. FIG. 7A is a diagram illustrating various aberrations in the infinitely focused state in the wide-angle end state according to the fifth example, FIG. 9A is a diagram illustrating various aberrations in the infinitely focused state in the wide-angle end state, and FIG. FIG. 6 is a meridional lateral aberration diagram when shake correction is performed for a rotational shake of 0.40 ° in the infinitely focused state. FIG. 6A is a diagram illustrating various aberrations in an infinite focus state in an intermediate focal length state according to a fifth embodiment, FIG. 5A is a diagram illustrating various aberrations in an infinite focus state in an intermediate focal length state, and FIG. FIG. 6 is a meridional lateral aberration diagram when shake correction is performed for a 0.30 ° rotational shake in an infinitely focused state in a distance state. FIG. 10 is a diagram illustrating various aberrations in the infinitely focused state in the telephoto end state according to the fifth embodiment, (a) is various aberration diagrams in the infinitely focused state in the telephoto end state, and (b) is the telephoto end state. FIG. 6 is a meridional lateral aberration diagram when shake correction is performed for a 0.30 ° rotational shake in the infinite focus state. FIG. 10A is an aberration diagram of the near-field object in a focused state according to the fifth embodiment, FIG. 10A is an aberration diagram of the near-field object in a wide-angle end state, and FIG. FIG. 4C is an aberration diagram in a focused state, and FIG. 4C is an aberration diagram in a short-distance object focused state in a telephoto end state. It is sectional drawing which shows the structure of the variable magnification optical system by 6th Example. FIG. 10A is a diagram illustrating various aberrations in the infinitely focused state in the wide-angle end state according to the sixth example, FIG. 10A is a diagram illustrating various aberrations in the infinitely focused state in the wide-angle end state, and FIG. FIG. 6 is a meridional lateral aberration diagram when shake correction is performed for a rotational shake of 0.40 ° in the infinitely focused state. FIG. 10A is a diagram illustrating various aberrations in an infinite focus state in an intermediate focal length state according to the sixth embodiment, FIG. 10A is a diagram illustrating various aberrations in an infinite focus state in an intermediate focal length state, and FIG. FIG. 6 is a meridional lateral aberration diagram when shake correction is performed for a 0.30 ° rotational shake in an infinitely focused state. FIG. 10A is a diagram illustrating various aberrations in the infinitely focused state in the telephoto end state according to the sixth embodiment, FIG. 10A is a diagram illustrating various aberrations in the infinitely focused state in the telephoto end state, and FIG. FIG. 6 is a meridional lateral aberration diagram when shake correction is performed for a 0.30 ° rotational shake in the infinite focus state. FIG. 10A is an aberration diagram of the near-field object focusing state according to the sixth embodiment, FIG. 10A is an aberration diagram of the near-field object focusing state in the wide-angle end state, and FIG. FIG. 4C is an aberration diagram in a focused state, and FIG. 4C is an aberration diagram in a short-distance object focused state in a telephoto end state. 1 shows an electronic still camera equipped with a variable magnification optical system according to the present embodiment, in which (a) is a front view and (b) is a rear view. It is sectional drawing along the AA 'line of Fig.31 (a). It is a flowchart for demonstrating the manufacturing method of the variable magnification optical system which concerns on this embodiment.

  Hereinafter, preferred embodiments of the present application will be described with reference to the drawings. First, as shown in FIG. 1, the variable magnification optical system ZL of the present embodiment includes, 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 negative refractive power, and a fifth lens group G5 having a positive refractive power. In zooming, it is desirable that the first lens group G1 and the fifth lens group G5 are fixed. With this configuration, the zooming mechanism can be simplified, and the size of the lens barrel can be reduced. Further, when the first lens group G1 and the fifth lens group G5 are fixed as described above, the entire length of the variable magnification optical system ZL can be kept constant.

  In focusing, at least one lens group (in this embodiment, the third lens group G3) disposed between the second lens group and the fifth lens group G5 moves as the focusing lens group Gf. Is desirable. The third lens group G3 is suitable for focusing because it has a smaller number of lenses and a smaller outer diameter than the other lens groups. With this configuration, rapid focusing can be performed. Further, there is no change in the overall length due to focusing, and good optical performance can be obtained even when shooting a short-distance object.

  In addition, it is desirable that at least a part of the fifth lens group G5 moves as an anti-vibration lens group so as to have a component in a direction substantially orthogonal to the optical axis. With this configuration, it is possible to prevent vibration with a small-diameter lens group, and it is possible to reduce the size and weight of the camera shake correction mechanism and the size of the lens barrel. The movement having a component in a direction substantially orthogonal to the optical axis is not only to move in a direction orthogonal to the optical axis, but also to move in an oblique direction with respect to the optical axis, Swinging is also included.

  At this time, the fifth lens group G5 includes, in order from the object side, a first partial group G5a having a positive refractive power, a second partial group G5b having a negative refractive power, and a third part having a positive refractive power. It is desirable that the second partial group G5b is an anti-vibration lens group in the configuration having the group G5c. With this configuration, vibration can be prevented with the lens group having the smallest diameter, and the diameter of the lens barrel can be reduced.

Now, conditions for constructing such a variable magnification optical system ZL will be described. First, when the variable magnification optical system ZL has lens groups from the first lens group G1 to the _Gn lens group _Gn , the variable magnification optical system ZL has the focal length of the image stabilizing lens group as fVR. It is desirable that the following conditional expression (1) is satisfied. In this embodiment, since the lens group has a five-group configuration (n = 5), the _Gn lens group _Gn indicates the fifth lens group G5. The anti-vibration lens group indicates a second partial group G5b that constitutes the fifth lens group G5.

−3.5 <fGn / fVR <−0.8 (1)

Conditional expression (1) defines an appropriate focal length of the _Gn lens group _Gn (fifth lens group G5) with respect to the focal length of the image stabilizing lens group (second partial group G5b). Exceeding the upper limit of conditional expression (1) is not preferable because the power of the anti-vibration lens group becomes weak and the shift amount at the time of anti-vibration increases, and the outer diameter of the lens barrel increases. In order to secure the effect of the present embodiment, it is preferable to set the upper limit of conditional expression (1) to −1.0. On the other hand, if the lower limit value of conditional expression (1) is not reached, the power of the anti-vibration lens group becomes strong and the chromatic aberration of magnification becomes large. Also, distortion becomes large. In addition, it is not preferable because performance degradation due to manufacturing errors increases. In order to secure the effect of the present embodiment, it is preferable to set the lower limit of conditional expression (1) to −3.0.

  In addition, it is desirable that the variable magnification optical system ZL satisfies the following conditional expression (2) when the focal length of the focusing lens group Gf (in this embodiment, the third lens group G3) is fGf.

0.20 <| fGf / fGn | <1.00 (2)

Conditional expression (2) defines an appropriate focal length of the focusing lens group Gf (third lens group G3) with respect to the focal length of the _Gn lens group _Gn (fifth lens group G5). If the upper limit value of conditional expression (2) is exceeded, the power of the focusing lens group Gf becomes weak, and the amount of movement of the focusing lens group Gf at the time of focusing becomes large. In order to secure the effect of the present embodiment, it is preferable to set the upper limit of conditional expression (2) to 0.90. On the other hand, if the lower limit value of conditional expression (2) is not reached, the power of the focusing lens group Gf becomes strong, and there is a variation in spherical aberration in the telephoto end state and an image plane variation in the wide-angle end state during focusing. Since it becomes large, it is not preferable. In order to secure the effect of the present embodiment, it is preferable to set the lower limit of conditional expression (2) to 0.35.

  Further, it is desirable that the variable magnification optical system ZL satisfies the following conditional expression (3) when the focal length of the entire system in the telephoto end state is ft.

0.4 <| fGn | / ft <1.0 (3)

Conditional expression (3) defines an appropriate focal length of the _Gn lens group _Gn (fifth lens group G5) with respect to the focal length of the entire system in the telephoto end state. Exceeding the upper limit of conditional expression (3) is not preferable because the power of the _Gn lens group _Gn becomes weak and the optical total length becomes long. In order to secure the effect of the present embodiment, it is preferable to set the upper limit of conditional expression (3) to 0.8. On the other hand, if the lower limit value of conditional expression (3) is not reached, the power of the _Gn lens group _Gn becomes strong, and it becomes difficult to correct spherical aberration and coma at the telephoto end. In order to secure the effect of the present embodiment, it is preferable to set the lower limit of conditional expression (3) to 0.5.

  The variable magnification optical system ZL has the following conditional expression (when the focal length of the anti-vibration lens group (in this embodiment, the second partial group G5b constituting the fifth lens group G5) is fVR: It is desirable to satisfy 4).

0.10 <| fVR | / fw <1.90 (4)

  Conditional expression (4) defines an appropriate focal length of the image stabilizing lens group (second partial group G5b) with respect to the focal length of the entire system in the wide-angle end state. If the upper limit of conditional expression (4) is exceeded, the power of the anti-vibration lens group becomes weak and the amount of shift at the time of anti-vibration increases, which is not preferable because the outer diameter of the lens barrel increases. In order to secure the effect of the present embodiment, it is preferable to set the upper limit of conditional expression (4) to 1.20. On the other hand, if the lower limit value of conditional expression (4) is not reached, the power of the image stabilizing lens group becomes strong, and the Taole variation of the image plane in the wide-angle end state during image stabilization increases. In addition, the optical performance is greatly deteriorated due to a control error during image stabilization, which is not preferable. In order to secure the effect of the present embodiment, it is preferable to set the lower limit of conditional expression (4) to 0.50.

  31 and 32 show a configuration of an electronic still camera 1 (hereinafter simply referred to as a camera) as an optical apparatus including the above-described variable magnification optical system ZL. In the camera 1, when a power button (not shown) is pressed, a shutter (not shown) of the photographing lens (variable magnification optical system ZL) is opened, and light from a subject (not shown) is condensed by the variable magnification optical system ZL. The image is formed on an image sensor C (for example, a CCD or a CMOS) disposed on the surface I. The subject image formed on the image sensor C is displayed on the liquid crystal monitor 2 disposed behind the camera 1. The photographer determines the composition of the subject image while looking at the liquid crystal monitor 2, and then presses the release button 3 to photograph the subject image with the image sensor C and records and saves it in a memory (not shown).

  The camera 1 includes an auxiliary light emitting unit 4 that emits auxiliary light when the subject is dark, and a wide (W) when zooming the zoom optical system ZL from the wide-angle end state (W) to the telephoto end state (T). A tele (T) button 5 and function buttons 6 used for setting various conditions of the camera 1 are arranged. The camera 1 may be a so-called single-lens reflex camera including a half mirror, a focusing screen, a pentaprism, an eyepiece optical system, and the like. The variable magnification optical system ZL may be provided in an interchangeable lens that can be attached to and detached from a single-lens reflex camera.

  The contents described below can be appropriately adopted as long as the optical performance is not impaired.

  First, in the above-described explanation and the embodiments described below, a variable magnification optical system ZL having a five-group configuration in which two lens groups arranged closest to the object side are respectively a first lens group G1 and a second lens group G2 is used. Although shown, these two lens groups may be treated as a four-group configuration in which one lens group is used (for example, a fourth embodiment described below). In this case, the object side lens group included in the one lens group is referred to as a front partial lens group, and the image side lens group is referred to as a rear partial lens group.

  Furthermore, the above configuration conditions and the like can be applied to other group configurations such as the 6th group and the 7th group. Specifically, a configuration in which at least one lens having a positive refractive index on the most object side is added, a configuration in which at least one lens having a positive refractive power or a negative refractive power is added on the most image side, A configuration in which three or more lens groups are arranged between the first lens group G1 and the fifth lens group G5 can be mentioned.

  In the above description, the case where the third lens group G3 is used for focusing has been described. However, the present invention is not limited to the third lens group G3, and a single lens group, a plurality of lens groups, or a partial lens group is arranged in the optical axis direction. The focusing lens group Gf may be moved to focus from an infinitely distant object to a close object. In this case, the focusing lens group Gf can be applied to autofocus, and is also suitable for driving a motor for autofocus (such as an ultrasonic motor). In particular, the third lens group G3 is preferably set as the focusing lens group Gf as described above, but the fourth lens group G4 may be used for focusing.

  In the zoom optical system ZL, the lens surface may be an aspherical surface. At this time, any one of an aspheric surface by grinding, a glass mold aspheric surface in which glass is formed into an aspheric shape by a mold, and a composite aspheric surface in which resin is formed in an aspheric shape on the surface of the glass may be used. The lens surface may be a diffractive surface, and the lens may be a gradient index lens (GRIN lens) or a plastic lens.

  The aperture stop S is preferably disposed in the vicinity of the fifth lens group G5 or in the fifth lens group G5. However, the role of the aperture stop S may be substituted by a lens frame without providing a member as the aperture stop S. good. Further, when zooming, by fixing the aperture stop S and the lens disposed on the image side of the aperture stop S, the F-number can be made constant.

  Furthermore, an antireflection film having a high transmittance in a wide wavelength range is applied to each lens surface, thereby reducing flare and ghost and achieving high contrast and high optical performance.

  The zoom optical system ZL of the present embodiment has a focal length in terms of 35 mm film size of about 60 to 80 mm in the wide-angle end state, and about 180 to 400 mm in the telephoto end state, and a zoom ratio of 2 to 2. About 5.

  In the variable magnification optical system ZL of the present embodiment, it is preferable that the first lens group G1 has at least two positive lens components and one negative lens component. In the first lens group G1, it is preferable to dispose lens components in order of negative positive / positive in order from the object side. The first lens group G1 preferably has one cemented lens and two single lenses.

  In the variable magnification optical system ZL of the present embodiment, it is preferable that the second lens group G2 has at least one positive lens component and two negative lens components. In the second lens group G2, it is preferable to dispose lens components in order of negative and positive in order from the object side. Alternatively, the second and third lens components may be bonded together. Further, a negative lens component may be added on the most image side of the second lens group G2.

  In the variable magnification optical system ZL of the present embodiment, it is preferable that the third lens group G3 has at least two positive lens components. The third lens group G3 may be composed of one cemented lens.

  The variable magnification optical system ZL of the present embodiment is preferably configured by one lens component in which the fourth lens group G4 has positive or negative refractive power, but may be configured by using a plurality of lenses.

  In the variable magnification optical system ZL of the present embodiment, as described above, the fifth lens group G5 includes the positive and negative partial lens groups (first partial group G5a, second partial group G5b, and third partial group G5c). And correcting the camera shake (anti-vibration) by moving the second partial group G5b in a direction substantially orthogonal to the optical axis. With this configuration, the diameter of the variable magnification optical system ZL can be reduced. The first partial group G5a has at least one positive lens component, the second partial group G5b group has at least one cemented lens, and the third partial group G5c has at least one negative positive lens component. It is good to have.

  In addition, in order to explain this application in an easy-to-understand manner, the configuration requirements of the embodiment have been described, but it goes without saying that the present application is not limited to this.

  Hereinafter, the outline of the manufacturing method of the variable magnification optical system ZL of this embodiment will be described with reference to FIG. First, each lens is arranged and a lens group is prepared (step S100). Specifically, in this embodiment, for example, in order from the object side, a cemented lens of a negative meniscus lens L11 having a convex surface facing the object side and a positive meniscus lens L12 having a convex surface facing the object side, a biconvex lens L13, and A positive meniscus lens L14 having a convex surface facing the object side is arranged as the first lens group G1, and a negative meniscus lens L21 having a convex surface facing the object side, a biconcave lens L22, and a convex surface facing the object side in order from the object side. A cemented lens with the positive meniscus lens L23 and a negative meniscus lens L24 with a concave surface facing the object side are arranged as a second lens group G2, and in order from the object side, a negative meniscus lens L31 with a convex surface facing the object side A negative meniscus lens L having a cemented lens with a biconvex lens L32 and a biconvex lens L33 to form a third lens group G3 with a concave surface facing the object side. 1 is arranged as a fourth lens group G4, and as a first partial group G5a, a cemented lens of a negative meniscus lens L51 having a convex surface facing the object side and a biconvex lens L52 is arranged in order from the object side, and the second part As a group G5b, a cemented lens of a positive meniscus lens L53 having a concave surface facing the object side and a biconcave lens L54 is disposed in order from the object side, and a convex surface is directed toward the object side in order from the object side as the third subgroup G5c. The fifth lens group G5 includes a cemented lens of the negative meniscus lens L55 and the biconvex lens L56, a positive meniscus lens L57 having a convex surface on the object side, and a negative meniscus lens L58 having a concave surface on the object side. . The variable power optical system ZL is manufactured by arranging the lens groups thus prepared.

  In this case, the first lens group G1 and the fifth lens group G5 are fixed during zooming, and the third lens group G3 moves as the focusing lens group Gf during focusing, and the second partial group G5b is moved. The anti-vibration lens group is arranged so as to move so as to have a component substantially perpendicular to the optical axis (step S200).

  Embodiments of the present application will be described below with reference to the accompanying drawings. FIG. 1, FIG. 6, FIG. 11, FIG. 16, FIG. 21 and FIG. 26 show the refractive power distribution of this variable magnification optical system ZL and the change in the focal length state from the wide-angle end state (W) to the telephoto end state (T). The state of movement of each lens group in is shown. First, the variable magnification optical system ZL according to the first to third, fifth, and sixth examples corresponding to the first aspect of the present invention is shown in FIG. 1, FIG. 6, FIG. 11, FIG. Thus, in order from the object side, the first lens group G1 having positive refractive power, the second lens group G2 having negative refractive power, the third lens group G3 having positive refractive power, and the negative refraction A fourth lens group G4 having power and a fifth lens group G5 having positive refractive power are configured. The fifth lens group G5 includes, in order from the object side, a first partial group G5a having a positive refractive power, a second partial group G5b having a negative refractive power, and a third partial group G5c having a positive refractive power. Consists of In zooming from the wide-angle end state to the telephoto end state, the first lens group G1 and the fifth lens group G5 are fixed, and the third lens group G3 or the fourth lens group G4 is moved along the optical axis. Is used to focus from a long-distance object to a short-distance object, and to perform camera shake correction (anti-vibration) by moving the second partial group G5b of the fifth lens group G5 in a direction substantially orthogonal to the optical axis. It is configured.

  As shown in FIG. 16, the variable magnification optical system ZL according to the fourth example corresponding to the second aspect of the invention includes, in order from the object side, a first lens group G1 having a positive refractive power and a negative refractive power. A second lens group G2 having a positive refractive power, a third lens group G3 having a positive refractive power, and a fourth lens group G4 having a positive refractive power. The first lens group G1 includes, in order from the object side, a front partial lens group G1a having a positive refractive power and a rear partial lens group G1b having a positive refractive power. The fourth lens group G4 includes, in order from the object side, a first partial group G4a having a positive refractive power, a second partial group G4b having a negative refractive power, and a third partial group having a positive refractive power. G4c. When zooming from the wide-angle end state to the telephoto end state, the front lens group G1a and the fourth lens group G4 are fixed, and the third lens group G3 is moved along the optical axis to move the third lens group G3 along the optical axis. It is configured to focus on a distance object and to perform camera shake correction (anti-vibration) by moving the second partial group G4b of the fourth lens group G4 in a direction substantially orthogonal to the optical axis.

[First embodiment]
The variable magnification optical system ZL shown in FIG. 1 shows the configuration of the variable magnification optical system ZL1 according to the first example. When n = 5, that is, the variable magnification optical system ZL1 having a five-group configuration is shown. ing. In the variable magnification optical system ZL1, the first lens group G1 includes, in order from the object side, a cemented lens and a biconvex lens of a negative meniscus lens L11 having a convex surface facing the object side and a positive meniscus lens L12 having a convex surface facing the object side. L13 and a positive meniscus lens L14 having a convex surface facing the object side. The second lens group G2 includes, in order from the object side, a negative meniscus lens L21 having a convex surface facing the object side, a cemented lens of a biconcave lens L22 and a positive meniscus lens L23 having a convex surface facing the object side, and a concave surface facing the object side The negative meniscus lens L24 facing The third lens group G3 includes, in order from the object side, a cemented lens of a negative meniscus lens L31 and a biconvex lens L32 having a convex surface directed toward the object side, and a biconvex lens L33. The fourth lens group G4 includes a negative meniscus lens L41 having a concave surface directed toward the object side. In the fifth lens group G5, the first partial group G5a includes, in order from the object side, a cemented lens of a negative meniscus lens L51 having a convex surface facing the object side and a biconvex lens L52, and the second partial group G5b The third partial group G5c includes, in order from the object side, a negative meniscus lens L55 having a convex surface facing the object side. And a biconvex lens L56, a positive meniscus lens L57 having a convex surface facing the object side, and a negative meniscus lens L58 having a concave surface facing the object side. The aperture stop S is located closest to the object side of the fifth lens group G5 and is included in the first partial group G5a.

  Note that the rotational shake at an angle θ is corrected with a lens having a focal length f of the entire system and an image stabilization coefficient (ratio of the amount of image movement on the imaging surface to the amount of movement of the moving lens group in shake correction) K. In this case, the moving lens group for shake correction may be moved in the direction orthogonal to the optical axis by (f · tan θ) / K (this relationship is the same in the following embodiments). In the wide-angle end state of the first embodiment, the image stabilization coefficient is 1.20 and the focal length is 71.4 (mm). Therefore, the second subgroup for correcting the rotational shake of 0.40 °. The amount of movement of G5b is 0.42 (mm). Further, in the intermediate focal length state of the first embodiment, since the image stabilization coefficient is 1.20 and the focal length is 135.0 (mm), the first for correcting the rotational shake of 0.30 °. The moving amount of the two subgroup G5b is 0.59 (mm). Further, in the telephoto end state of the first embodiment, the image stabilization coefficient is 1.20 and the focal length is 196.0 (mm), so that the second for correcting the rotational shake of 0.30 °. The movement amount of the subgroup G5b is 0.86 (mm).

  Table 1 below lists values of specifications of the first embodiment. In Table 1, f represents a focal length, FNO represents an F number, and ω represents a half angle of view. Furthermore, the surface number is the order of the lens surfaces from the object side along the direction of travel of the light beam, the surface interval is the distance on the optical axis from each optical surface to the next optical surface, and the refractive index and Abbe number are each A value for the d-line (λ = 587.6 nm), Bf indicates a distance (back focus) on the optical axis from the final surface to the image plane I. Here, “mm” is generally used for the focal length, the radius of curvature, the surface interval, and other length units listed in all the following specifications, but the optical system is proportionally enlarged or reduced. However, the same optical performance can be obtained, and the present invention is not limited to this. The radius of curvature of 0.0000 indicates a plane, and the refractive index of air of 1.0000 is omitted. The description of these symbols and the description of the specification table are the same in the following examples.

(Table 1)
Surface number Curvature radius Surface spacing Abbe number Refractive index
1 207.2519 2.0000 32.35 1.850 260
2 77.5141 9.5000 82.52 1.497820
3 461.0795 0.1000
4 96.8810 8.0000 82.52 1.497820
5 -2446.3946 0.1000
6 74.8396 8.0000 65.46 1.603001
7 635.5296 (d1)
8 301.7367 2.2000 42.72 1.834807
9 35.0104 9.1179
10 -83.6050 2.0000 70.41 1.487490
11 42.3925 6.0000 23.78 1.846660
12 647.2222 4.5999
13 -49.2733 2.2000 65.46 1.603001
14 -2747.7138 (d2)
15 350.7655 2.0000 28.46 1.728250
16 91.4253 6.5000 65.46 1.603001
17 -94.5881 0.1000
18 143.9361 5.5000 65.46 1.603001
19 -132.9507 (d3)
20 -84.4304 2.5000 52.31 1.754999
21 -211.8686 (d4)
22 0.0000 1.0000 (Aperture stop S)
23 44.5401 2.0000 32.35 1.850 260
24 30.5381 9.0000 65.46 1.603001
25 -8165.2768 25.0000
26 -197.5962 4.0000 32.35 1.850260
27 -34.4924 2.0000 54.66 1.729157
28 47.2773 5.0000
29 147.5802 2.0000 32.35 1.850 260
30 52.0642 6.0000 82.52 1.497820
31 -60.9696 0.1000
32 37.8007 6.0000 82.52 1.497820
33 394.5473 5.0000
34 -47.6819 2.0000 44.88 1.639300
35 -113.6656 (Bf)

Wide angle end Intermediate focal length Telephoto end
f = 71.40 to 135.00 to 196.00
F.NO = 2.90 to 2.90 to 2.90
ω = 17.12 to 8.94 to 6.14

[Zoom lens group data]
Lens group Focal length 1st lens group 92.254
Second lens group -28.021
Third lens group 64.313
Fourth lens group -187.499
Fifth lens group 111.815

  In the first embodiment, the axial air distance d1 between the first lens group G1 and the second lens group G2, the axial air distance d2 between the second lens group G2 and the third lens group G3, and the third lens group G3. The on-axis air distance d3 between the fourth lens group G4 and the on-axis air distance d4 between the fourth lens group G4 and the fifth lens group G5 changes during zooming. Table 2 below shows variable interval data, Bf, and the total length at each focal length in the wide-angle end state, intermediate focal length state, and telephoto end state of the variable magnification optical system ZL1 according to the first example.

(Table 2)
[Variable interval data]
Wide angle end Intermediate focal length Telephoto end
d1 2.000 23.001 30.816
d2 29.816 15.626 2.943
d3 6.617 14.919 19.787
d4 17.113 2.000 2.000
Bf 58.166 58.166 58.166
Total length 253.180 253.180 253.180

  Table 3 below shows values corresponding to the conditional expressions in the first embodiment. In Table 3, fGn is the focal length of the fifth lens group G5, fw is the focal length of the entire system in the wide-angle end state, fGf is the focal length of the focusing lens group Gf (third lens group G3), fVR is the focal length of the anti-vibration lens group (second partial group G5b), ft is the focal length of the entire system in the telephoto end state, and fn is located closest to the object side among the lens groups having negative refractive power. The focal length of each lens group (second lens group G2) is shown. In the following embodiments, the description of the reference numerals is the same unless otherwise specified.

(Table 3)
(1) fGn / fVR = -1.827
(2) | fGf / fGn | = 0.575
(3) | fGn | /ft=0.570
(4) | fVR | /fw=0.857

  FIG. 2A shows an aberration diagram in the infinite focus state in the wide-angle end state of this first embodiment, and FIG. 3A shows an aberration diagram in the infinite focus state in the intermediate focal length state. FIG. 4A shows an aberration diagram in the infinite focus state in the end state, FIG. 5A shows an aberration diagram in the short distance object focus state in the wide angle end state, and a short distance in the intermediate focal length state. FIG. 5B shows an aberration diagram in the object in-focus state, and FIG. 5C shows an aberration diagram in the near-field object in-focus state in the telephoto end state. Further, FIG. 2B shows a meridional lateral aberration diagram when the shake correction is performed with respect to the rotational shake of 0.40 ° in the infinite focus state at the wide-angle end state in the first embodiment, and FIG. FIG. 3B shows a meridional lateral aberration diagram when shake correction is performed for 0.30 ° rotational shake in the infinite focus state at the intermediate focal length state in the telephoto end state of the first embodiment. FIG. 4B shows a meridional lateral aberration diagram when shake correction is performed with respect to a rotational shake of 0.30 ° in the infinitely focused state.

  In each aberration diagram, FNO is the F number, A is the half field angle, Y is the image height, H0 is the object height, d is the d-line (λ = 587.6 nm), and g is the g-line (λ = 435.6 nm). In the aberration diagrams showing astigmatism, the solid line shows the sagittal image plane, and the broken line shows the meridional image plane. The description of this aberration diagram is the same in the following examples. As is apparent from the respective aberration diagrams, in the first embodiment, it is understood that various aberrations are well corrected in each focal length state from the wide-angle end state to the telephoto end state, and excellent imaging performance is obtained.

[Second Embodiment]
FIG. 6 is a diagram illustrating the configuration of the variable magnification optical system ZL2 according to the second example. When n = 5, that is, the variable magnification optical system ZL2 having a five-group configuration is illustrated. In the variable magnification optical system ZL2 in FIG. 6, the first lens group G1 includes, in order from the object side, a cemented lens of a negative meniscus lens L11 having a convex surface facing the object side and a positive meniscus lens L12 having a convex surface facing the object side. The positive meniscus lens L13 has a convex surface facing the object side, and the positive meniscus lens L14 has a convex surface facing the object side. The second lens group G2 includes, in order from the object side, a negative meniscus lens L21 having a convex surface facing the object side, a cemented lens of a biconcave lens L22 and a positive meniscus lens L23 having a convex surface facing the object side, and a concave surface facing the object side And a negative meniscus lens L25 having a concave surface facing the object side. The third lens group G3 includes, in order from the object side, a cemented lens of a negative meniscus lens L31 and a biconvex lens L32 having a convex surface directed toward the object side, and a biconvex lens L33. The fourth lens group G4 includes a negative meniscus lens L41 having a concave surface directed toward the object side. In the fifth lens group G5, the first partial group G5a is composed of a cemented lens of a biconvex lens L51 and a biconcave lens L52 in order from the object side, and the second partial group G5b is concave on the object side in order from the object side. The third partial group G5c is a cemented lens of a negative meniscus lens L55 and a biconvex lens L56 having a convex surface directed toward the object side in order from the object side. , A biconvex lens L57, and a negative meniscus lens L58 having a concave surface facing the object side. The aperture stop S is located between the first partial group G5a and the second partial group G5b and closest to the image side of the first partial group G5a.

  In the wide angle end state of the second embodiment, the image stabilization coefficient is 1.00 and the focal length is 71.4 (mm). Therefore, the second correction for correcting the rotation shake of 0.40 ° is performed. The moving amount of the two subgroup G5b is 0.50 (mm). Further, in the intermediate focal length state of the second embodiment, the image stabilization coefficient is 1.00 and the focal length is 135.0 (mm), so that the first for correcting the rotational shake of 0.30 °. The moving amount of the two subgroup G5b is 0.71 (mm). Further, in the telephoto end state of the second embodiment, since the image stabilization coefficient is 1.00 and the focal length is 196.0 (mm), the second for correcting the rotational shake of 0.30 °. The movement amount of the subgroup G5b is 1.03 (mm).

  Table 4 below lists values of specifications of the second embodiment.

(Table 4)
Surface number Curvature radius Surface spacing Abbe number Refractive index
1 138.9420 2.0000 32.35 1.850 260
2 74.8515 10.0000 82.52 1.497820
3 499.1083 0.1000
4 86.7613 8.0000 82.52 1.497820
5 437.0393 0.1000
6 84.2569 7.0000 82.52 1.497820
7 938.7139 (d1)
8 384.1157 2.0000 40.94 1.806100
9 35.6165 9.6847
10 -131.1744 2.0000 70.41 1.487490
11 42.3484 4.5000 23.78 1.846660
12 163.1687 5.0588
13 -53.5772 4.0000 22.76 1.808095
14 -32.5969 2.0000 42.72 1.834807
15 -234.9579 (d2)
16 510.9139 2.0000 32.35 1.850 260
17 86.7071 7.0000 65.46 1.603001
18 -83.2647 0.1000
19 103.7337 6.0000 65.46 1.603001
20 -116.8560 (d3)
21 -103.1415 2.5000 42.72 1.834807
22 -342.0133 (d4)
23 58.8589 7.0000 42.72 1.834807
24 -140.2358 2.0000 23.78 1.846660
25 198.9539 3.0000
26 0.0000 20.0000 (Aperture stop S)
27 -183.3956 4.0000 23.78 1.846660
28 -45.0249 2.0000 41.96 1.667551
29 57.8421 5.0000
30 383.3560 2.0000 50.23 1.719995
31 39.1251 7.0000 82.52 1.497820
32 -82.1158 0.1000
33 45.2987 7.0000 82.52 1.497820
34 -153.4974 7.5493
35 -47.9028 2.0000 32.35 1.850260
36 -82.5403 (Bf)

Wide angle end Intermediate focal length Telephoto end
f = 71.40 to 135.00 to 196.00
F.NO = 2.90 to 2.90 to 2.90
ω = 17.09 to 8.94 to 6.14

[Zoom lens group data]
Lens group Focal length 1st lens group 98.419
Second lens group -26.611
Third lens group 59.321
Fourth lens group -177.745
5th lens group 114.057

  In the second embodiment, the axial air distance d1 between the first lens group G1 and the second lens group G2, the axial air distance d2 between the second lens group G2 and the third lens group G3, and the third lens group G3. The on-axis air distance d3 between the fourth lens group G4 and the on-axis air distance d4 between the fourth lens group G4 and the fifth lens group G5 changes during zooming. Table 5 below shows variable interval data, Bf, and the total length at each focal length in the wide-angle end state, intermediate focal length state, and telephoto end state of the variable magnification optical system ZL2 according to the second example.

(Table 5)
[Variable interval data]
Wide angle end Intermediate focal length Telephoto end
d1 2.000 25.437 33.995
d2 24.330 12.566 2.000
d3 4.668 10.865 14.953
d4 21.950 4.080 2.000
Bf 63.539 63.539 63.539
Total length 259.180 259.180 259.180

  Table 6 below shows values corresponding to the conditional expressions in the second embodiment.

(Table 6)
(1) fGn / fVR = -1.399
(2) | fGf / fGn | = 0.520
(3) | fGn | /ft=0.582
(4) | fVR | /fw=1.142

  FIG. 7A shows an aberration diagram in the infinite focus state in the wide-angle end state of this second embodiment, and FIG. 8A shows an aberration diagram in the infinite focus state in the intermediate focal length state. FIG. 9A shows an aberration diagram in the infinite focus state in the end state, FIG. 10A shows an aberration diagram in the short distance object focus state in the wide angle end state, and a short distance in the intermediate focal length state. FIG. 10B shows an aberration diagram in the object in-focus state, and FIG. 10C shows an aberration diagram in the near-field object in-focus state in the telephoto end state. Further, FIG. 7B shows a meridional lateral aberration diagram when the shake correction is performed with respect to the rotational shake of 0.40 ° in the infinitely focused state at the wide-angle end state in the second embodiment. FIG. 8B shows a meridional lateral aberration diagram when the shake correction for the 0.30 ° rotational shake is performed in the infinite focus state at the intermediate focal length state in FIG. 8B, and in the telephoto end state of the second embodiment. FIG. 9B shows a meridional lateral aberration diagram when shake correction is performed with respect to rotational shake of 0.30 ° in the infinitely focused state. As is apparent from these respective aberration diagrams, in the second example, it is understood that various aberrations are satisfactorily corrected in each focal length state from the wide-angle end state to the telephoto end state, and excellent imaging performance is obtained.

[Third embodiment]
FIG. 11 is a diagram illustrating the configuration of the variable magnification optical system ZL3 according to the third example. When n = 5, that is, the variable magnification optical system ZL3 having a five-group configuration is illustrated. In the variable magnification optical system ZL3 of FIG. 11, the first lens group G1 includes, in order from the object side, a cemented lens of a negative meniscus lens L11 having a convex surface facing the object side and a positive meniscus lens L12 having a convex surface facing the object side. The positive meniscus lens L13 has a convex surface facing the object side, and the positive meniscus lens L14 has a convex surface facing the object side. The second lens group G2 includes, in order from the object side, a negative meniscus lens L21 having a convex surface facing the object side, a cemented lens of a biconcave lens L22 and a positive meniscus lens L23 having a convex surface facing the object side, and a concave surface facing the object side And a negative meniscus lens L25 having a concave surface facing the object side. The third lens group G3 includes, in order from the object side, a positive meniscus lens L31 having a concave surface facing the object side, and a cemented lens of a negative meniscus lens L32 having a convex surface facing the object side and a biconvex lens L33. The fourth lens group G4 includes a negative meniscus lens L41 having a concave surface directed toward the object side. In the fifth lens group G5, the first partial group G5a includes, in order from the object side, a biconvex lens L51 and a positive meniscus lens L52 having a convex surface facing the object side. The second partial group G5b is formed from the object side. In order, it is composed of a cemented lens of a positive meniscus lens L53 and a biconcave lens L54 having a concave surface facing the object side, and a negative meniscus lens L55 having a convex surface facing the object side, and the third subgroup G5c is in order from the object side. , A biconvex lens L56, a biconvex lens L57, and a negative meniscus lens L58 having a concave surface facing the object side. The aperture stop S is located closest to the object side of the fifth lens group G5 and is included in the first partial group G5a.

  In the wide angle end state of the third embodiment, the image stabilization coefficient is 1.30 and the focal length is 71.4 (mm). The moving amount of the two subgroup G5b is 0.38 (mm). Further, in the intermediate focal length state of the third embodiment, the image stabilization coefficient is 1.30 and the focal length is 135.0 (mm), so that the first for correcting the rotational shake of 0.30 °. The moving amount of the two subgroup G5b is 0.54 (mm). Further, in the telephoto end state of the third embodiment, since the image stabilization coefficient is 1.30 and the focal length is 196.0 (mm), the second for correcting the rotational shake of 0.30 °. The movement amount of the subgroup G5b is 0.79 (mm).

  Table 7 below shows values of specifications of the third embodiment.

(Table 7)
Surface number Curvature radius Surface spacing Abbe number Refractive index
1 150.1075 2.2000 28.69 1.795041
2 77.1608 9.5000 82.52 1.497820
3 756.3684 0.1000
4 82.5453 8.0000 82.52 1.497820
5 581.7849 0.0000
6 73.1642 8.0000 82.52 1.497820
7 427.5813 (d1)
8 214.3299 2.0000 42.72 1.834807
9 33.7853 12.1976
10 -109.2380 2.0000 82.52 1.497820
11 39.0214 6.0000 23.78 1.846660
12 220.3271 4.2950
13 -55.0435 4.0000 25.68 1.784723
14 -31.3217 2.0000 42.72 1.834807
15 -1128.7256 (d2)
16 -4413.9629 4.0000 37.95 1.723420
17 -90.7104 0.1000
18 74.5140 2.0000 22.79 1.808090
19 42.9390 9.0000 65.46 1.603001
20 -133.3513 (d3)
21 -90.0000 2.5000 23.78 1.846660
22 -222.6096 (d4)
23 0.0000 2.0000 (Aperture stop S)
24 181.5274 4.0000 82.52 1.497820
25 -226.9093 0.1000
26 42.1406 4.0000 82.52 1.497820
27 81.5898 17.0000
28 -5404.9164 4.0000 28.46 1.728250
29 -46.9905 1.6000 53.71 1.579570
30 64.5686 3.5000
31 1040.8030 1.6000 55.52 1.696797
32 57.6196 5.0000
33 329.9937 4.5000 82.52 1.497820
34 -56.0769 1.1857
35 41.0985 6.0000 82.52 1.497820
36 -1567.9225 4.0871
37 -49.0618 2.0000 23.78 1.846660
38 -109.7403 (Bf)

Wide angle end Intermediate focal length Telephoto end
f = 71.40 to 135.00 to 196.00
F.NO = 2.90 to 2.90 to 2.90
ω = 16.97 to 8.90 to 6.12

[Zoom lens group data]
Lens group Focal length 1st lens group 87.956
Second lens group -24.084
Third lens group 55.399
4th lens group -180.000
5th lens group 110.905

  In the third example, the axial air gap d1 between the first lens group G1 and the second lens group G2, the axial air gap d2 between the second lens group G2 and the third lens group G3, and the third lens group G3. The on-axis air distance d3 between the fourth lens group G4 and the on-axis air distance d4 between the fourth lens group G4 and the fifth lens group G5 changes during zooming. Table 8 below shows variable interval data, Bf, and the total length at each focal length in the wide-angle end state, intermediate focal length state, and telephoto end state of the variable magnification optical system ZL3 according to the third example.

(Table 8)
[Variable interval data]
Wide angle end Intermediate focal length Telephoto end
d1 2.089 21.088 27.934
d2 24.923 12.762 2.000
d3 5.167 11.520 15.477
d4 16.232 3.041 3.000
Bf 60.304 60.304 60.304
Total length 247.180 247.180 247.180

  Table 9 below shows values corresponding to the conditional expressions in the third embodiment.

(Table 9)
(1) fGn / fVR = -1.953
(2) | fGf / fGn | = 0.500
(3) | fGn | /ft=0.566
(4) | fVR | /fw=0.795

  FIG. 12A shows an aberration diagram in the infinite focus state in the wide-angle end state of this third embodiment, and FIG. 13A shows an aberration diagram in the infinite focus state in the intermediate focal length state. FIG. 14A shows an aberration diagram in the infinite focus state in the end state, FIG. 15A shows an aberration diagram in the short distance object focus state in the wide angle end state, and a short distance in the intermediate focal length state. FIG. 15B shows an aberration diagram in the object in-focus state, and FIG. 15C shows an aberration diagram in the short-distance object in-focus state in the telephoto end state. FIG. 12B shows a meridional lateral aberration diagram when the shake correction is performed for the 0.40 ° rotational shake in the infinitely focused state at the wide-angle end state in the third embodiment. FIG. FIG. 13B shows a meridional lateral aberration diagram when the shake correction is performed for the 0.30 ° rotational shake in the infinite focus state at the intermediate focal length state in FIG. 13B, and in the telephoto end state of the third embodiment. FIG. 14B shows a meridional lateral aberration diagram when shake correction is performed for 0.30 ° rotational shake in the infinite focus state. As is apparent from these aberration diagrams, in the third embodiment, it is understood that various aberrations are well corrected in each focal length state from the wide-angle end state to the telephoto end state, and excellent imaging performance is obtained. .

[Fourth embodiment]
FIG. 16 is a diagram illustrating the configuration of the variable magnification optical system ZL4 according to the fourth example. When n = 4, that is, the variable magnification optical system ZL4 having a four-group configuration is illustrated. In the fourth example, “the front lens group G1a of the first lens group G1” corresponds to the “first lens group having a positive refractive power disposed on the most object side” described above. The rear lens group G1b of one lens group G1 corresponds to the “second lens group arranged on the image plane side of the first lens group” described above, and the “fourth lens group G4” corresponds to the “most image”. the equivalent to G _n lens unit "," the second lens group G2 and the third lens group G3 "was above" the second lens group the G _n lens having a positive refractive power disposed on the side This corresponds to “at least one lens group disposed between the groups”. In the variable magnification optical system ZL4 of FIG. 16, the front lens group G1a of the first lens group G1 includes, in order from the object side, a cemented lens of a negative meniscus lens L11 having a convex surface facing the object side and a biconvex lens L12, and The rear lens group G1b includes, in order from the object side, a cemented lens of a negative meniscus lens L14 having a convex surface facing the object side and a positive meniscus lens L15 having a convex surface facing the object side. The The second lens group G2 includes, in order from the object side, a negative meniscus lens L21 having a convex surface facing the object side, a cemented lens of a biconcave lens L22 and a positive meniscus lens L23 having a convex surface facing the object side, and a concave surface facing the object side The negative meniscus lens L24 facing The third lens group G3 includes, in order from the object side, a positive meniscus lens L31 having a concave surface directed toward the object side, and a cemented lens of a biconvex lens L32 and a biconcave lens L33. In the fourth lens group G4, the first partial group G4a includes, in order from the object side, a positive meniscus lens L41 having a convex surface facing the object side, and a positive meniscus lens L42 having a convex surface facing the object side. The subgroup G4b is composed of a cemented lens of a positive meniscus lens L43 having a concave surface facing the object side and a biconcave lens L44 in order from the object side, and the third subgroup G4c is composed of a biconvex lens L45, both lenses in order from the object side. The lens includes a convex lens L46 and a negative meniscus lens L47 having a concave surface facing the object side. The aperture stop S is located closest to the object side of the fourth lens group G4 and is included in the first partial group G4a.

  In the wide angle end state of the fourth embodiment, the image stabilization coefficient is 1.00 and the focal length is 71.4 (mm). The moving amount of the two subgroup G4b is 0.50 (mm). Further, in the intermediate focal length state of the fourth embodiment, the image stabilization coefficient is 1.00 and the focal length is 135.0 (mm), so that the first for correcting the rotational shake of 0.30 °. The moving amount of the two subgroup G4b is 0.71 (mm). Further, in the telephoto end state of the fourth embodiment, since the image stabilization coefficient is 1.00 and the focal length is 196.0 (mm), the second for correcting the rotational shake of 0.30 °. The movement amount of the subgroup G4b is 1.03 (mm).

  Table 10 below lists values of specifications of the fourth embodiment.

(Table 10)
Surface number Curvature radius Surface spacing Abbe number Refractive index
1 1045.9991 2.0000 37.16 1.834000
2 97.1615 11.0000 82.52 1.497820
3 -456.3712 0.1000
4 101.1567 9.0000 82.52 1.497820
5 -557.8689 (d1)
6 74.2367 2.0000 39.58 1.804398
7 51.0499 11.0000 49.78 1.617720
8 486.7171 (d2)
9 1114.6545 2.0000 42.72 1.834807
10 36.6691 7.8157
11 -80.7935 2.0000 70.41 1.487490
12 39.9085 5.5000 23.78 1.846660
13 431.9436 3.9771
14 -53.1722 2.0000 65.46 1.603001
15 434.1583 (d3)
16 -242.6876 4.0000 28.69 1.795041
17 -60.5190 0.1000
18 65.5165 8.0000 65.46 1.603001
19 -63.3283 2.0000 23.78 1.846660
20 290.8761 (d4)
21 0.0000 2.0000 (Aperture stop S)
22 54.2771 4.0000 82.52 1.497820
23 155.7161 0.1000
24 49.4783 3.0000 82.52 1.497820
25 79.4482 20.0000
26 -135.1336 4.0000 23.78 1.846660
27 -38.1621 2.0000 35.91 1.664460
28 60.6022 5.0000
29 105.0514 5.0000 82.52 1.497820
30 -95.4182 7.0498
31 81.3474 6.0000 82.52 1.497820
32 -92.9849 2.7410
33 -40.2997 2.0000 32.35 1.850 260
34 -82.0021 (Bf)

Wide angle end Intermediate focal length Telephoto end
f = 71.40 to 135.00 to 196.00
F.NO = 2.91 to 2.91 to 2.91
ω = 16.90-8.81-6.05

[Zoom lens group data]
Lens group Focal length front lens group 229.571
Rear lens group 165.806
Second lens group -26.418
Third lens group 76.245
Fourth lens group 110.040

  In the fourth example, the axial air distance d1 between the front partial lens group G1a and the rear partial lens group G1b of the first lens group G1, and the axial air distance d2 between the rear partial lens group G1b and the second lens group G2. The on-axis air distance d3 between the second lens group G2 and the third lens group G3 and the on-axis air distance d4 between the third lens group G3 and the fourth lens group G4 change during zooming. Table 11 below shows variable interval data, Bf, and the total length at each focal length in the wide-angle end state, the intermediate focal length state, and the telephoto end state of the zoom optical system ZL4 according to the fourth example.

  Here, in the variable magnification optical system ZL4 of the fourth example, the front partial lens group G1a and the rear partial lens group G1b can move independently during zooming. Specifically, in the zoom optical system ZL4, the position of the front lens group G1a on the optical axis is fixed during zooming, and the rear lens group G1b moves to the image plane side. In this case, it can be said that the variable magnification optical system ZL4 has a five-group configuration. Further, in the variable magnification optical system ZL4 having the five-group configuration, the fourth lens group as counted from the object side moves during focusing.

(Table 11)
[Variable interval data]
Wide angle end Intermediate focal length Telephoto end
d1 2.000 8.560 10.000
d2 2.000 24.609 32.890
d3 25.910 14.258 3.000
d4 29.722 12.206 13.743
Bf 61.103 61.103 61.103
Total length 256.119 256.119 256.119

  Table 12 below shows values corresponding to the conditional expressions in the fourth embodiment. In the fourth embodiment, in the sign of the value corresponding to the conditional expression, fGn represents the focal length of the fourth lens group G4, and fVR represents the focal length of the image stabilizing lens group (second partial group G4b). Yes. The description of the other symbols is the same as that of the first embodiment.

(Table 12)
(1) fGn / fVR = -1.382
(2) | fGf / fGn | = 0.693
(3) | fGn | /ft=0.561
(4) | fVR | /fw=1.115

  FIG. 17A shows an aberration diagram in the infinite focus state in the wide-angle end state of this fourth embodiment, and FIG. 18A shows an aberration diagram in the infinite focus state in the intermediate focal length state. FIG. 19A shows an aberration diagram in the infinite focus state in the end state, FIG. 20A shows an aberration diagram in the near object focus state in the wide angle end state, and FIG. 20A shows the short distance in the intermediate focal length state. FIG. 20B shows an aberration diagram in the object in-focus state, and FIG. 20C shows an aberration diagram in the near-field object in-focus state in the telephoto end state. Further, FIG. 17B shows a meridional lateral aberration diagram when the shake correction is performed with respect to the rotational shake of 0.40 ° in the infinitely focused state at the wide-angle end state in the fourth example, and FIG. 17B shows the fourth example. FIG. 18B shows a meridional lateral aberration diagram when shake correction is performed for 0.30 ° rotational shake in the infinite focus state at the intermediate focal length state in FIG. 18B, and in the telephoto end state of the fourth embodiment. FIG. 19B shows a meridional lateral aberration diagram when shake correction is performed with respect to a rotational shake of 0.30 ° in the infinite focus state.

[Fifth embodiment]
FIG. 21 is a diagram showing a configuration of a variable magnification optical system ZL5 according to the fifth example. When n = 5, that is, a variable magnification optical system ZL5 having a five-group configuration is shown. In the variable magnification optical system ZL5 of FIG. 21, the first lens group G1 includes, in order from the object side, a cemented lens of a negative meniscus lens L11 having a convex surface facing the object side and a biconvex lens L12, a biconvex lens L13, and an object It comprises a positive meniscus lens L14 having a convex surface on the side. The second lens group G2 includes, in order from the object side, a negative meniscus lens L21 having a convex surface facing the object side, a cemented lens of a biconcave lens L22 and a positive meniscus lens L23 having a convex surface facing the object side, and a concave surface facing the object side The negative meniscus lens L24 facing The third lens group G3 includes, in order from the object side, a cemented lens of a positive meniscus lens L31 having a convex surface facing the object side and a negative meniscus lens L32 having a convex surface facing the object side. The fourth lens group G4 includes, in order from the object side, a positive meniscus lens L41 having a concave surface directed toward the object side, and a cemented lens of a biconvex lens L42 and a biconcave lens L43. In the fifth lens group G5, the first partial group G5a includes a positive meniscus lens L51 having a convex surface directed toward the object side, and the second partial group G5b includes, in order from the object side, a biconvex lens L52 and a biconcave lens L53. The third partial group G5c includes, in order from the object side, a biconvex lens L55, a biconvex lens L56, and a negative meniscus lens L57 having a concave surface facing the object side. Composed. The aperture stop S is located closest to the object side of the fifth lens group G5 and is included in the first partial group G5a.

  In the wide-angle end state of the fifth embodiment, the image stabilization coefficient is 1.00 and the focal length is 71.4 (mm). The moving amount of the two subgroup G5b is 0.50 (mm). Further, in the intermediate focal length state of the fifth embodiment, the image stabilization coefficient is 1.00 and the focal length is 135.0 (mm), so that the first for correcting the rotational shake of 0.30 °. The moving amount of the two subgroup G5b is 0.71 (mm). Further, in the telephoto end state of the fifth embodiment, since the image stabilization coefficient is 1.00 and the focal length is 196.0 (mm), the second for correcting the rotational shake of 0.30 °. The movement amount of the subgroup G5b is 1.03 (mm).

  Table 13 below provides values of specifications of the fifth embodiment.

(Table 13)
Surface number Curvature radius Surface spacing Abbe number Refractive index
1 547.8686 2.0000 32.35 1.850 260
2 127.0457 9.0000 82.52 1.497820
3 -387.4049 0.1000
4 101.3137 8.0000 82.52 1.497820
5 -1800.9098 0.1000
6 66.1166 8.0000 82.52 1.497820
7 235.5025 (d1)
8 106.3241 2.0000 37.16 1.834000
9 30.3987 12.4957
10 -72.3427 2.0000 70.41 1.487490
11 37.6638 5.5000 23.78 1.846660
12 303.0536 4.1346
13 -44.9339 2.0000 65.46 1.603001
14 -1269.0712 (d2)
15 59.3815 4.0000 47.93 1.717004
16 227.8818 2.0000 42.72 1.834807
17 63.6840 (d3)
18 -274.5014 4.0000 42.24 1.799520
19 -75.2662 0.1000
20 74.6839 8.0000 65.46 1.603001
21 -55.3310 2.0000 32.35 1.850 260
22 4084.7965 (d4)
23 0.0000 2.0000 (Aperture stop S)
24 51.4321 5.0000 82.52 1.497820
25 2335.6701 20.0000
26 213.2867 4.0000 23.78 1.846660
27 -57.2867 1.5000 31.07 1.688931
28 116.1082 2.5000
29 -213.4066 1.5000 46.47 1.582670
30 57.4789 5.0000
31 146.7888 4.0000 69.98 1.518601
32 -72.6641 0.6223
33 84.7129 9.0000 52.31 1.517420
34 -32.2458 2.0000 32.35 1.850260
35 -265.8952 (Bf)

Wide angle end Intermediate focal length Telephoto end
f = 71.40 to 135.00 to 196.00
F.NO = 2.91 to 2.91 to 2.91
ω = 16.69 to 8.79 to 6.06

[Zoom lens group data]
Lens Group Focal Length First Lens Group 93.218
Second lens group -26.822
Third lens group 59448.564
Fourth lens group 86.438
5th lens group 119.455

  In the fifth embodiment, the axial air gap d1 between the first lens group G1 and the second lens group G2, the axial air gap d2 between the second lens group G2 and the third lens group G3, and the third lens group G3. The on-axis air distance d3 between the fourth lens group G4 and the on-axis air distance d4 between the fourth lens group G4 and the fifth lens group G5 changes during zooming. Table 14 below shows variable interval data, Bf, and the total length at each focal length in the wide-angle end state, the intermediate focal length state, and the telephoto end state of the variable magnification optical system ZL5 according to the fifth example.

(Table 14)
[Variable interval data]
Wide angle end Intermediate focal length Telephoto end
d1 2.683 24.724 32.437
d2 24.804 16.117 2.000
d3 9.527 4.934 5.838
d4 17.138 8.376 13.875
Bf 72.476 72.476 72.476
Total length 259.180 259.180 259.180

  Table 15 below shows values corresponding to the conditional expressions in the fifth embodiment.

(Table 15)
(1) fGn / fVR = -1.412
(2) | fGf / fGn | = 0.724
(3) | fGn | /ft=0.609
(4) | fVR | /fw=1.185

  FIG. 22A shows an aberration diagram in the infinite focus state in the wide-angle end state of this fifth embodiment, and FIG. 23A shows an aberration diagram in the infinite focus state in the intermediate focal length state. FIG. 24A shows an aberration diagram in the infinitely focused state in the end state, FIG. 25A shows an aberration diagram in the near-distance object focused state in the wide-angle end state, and FIG. FIG. 25B shows an aberration diagram in the object in-focus state, and FIG. 25C shows an aberration diagram in the near-field object in-focus state in the telephoto end state. Further, FIG. 22B shows a meridional lateral aberration diagram when the shake correction is performed with respect to the rotational shake of 0.40 ° in the infinite focus state at the wide-angle end state in the fifth embodiment, and FIG. 22B shows the fifth embodiment. FIG. 23 (b) shows a meridional lateral aberration diagram when shake correction is performed for 0.30 ° rotational shake in the infinite focus state at the intermediate focal length state of FIG. 23, and in the telephoto end state of the fifth embodiment. FIG. 24B shows a meridional lateral aberration diagram when shake correction is performed with respect to a rotational shake of 0.30 ° in the infinitely focused state. As is apparent from these respective aberration diagrams, in this fifth embodiment, it is understood that various aberrations are satisfactorily corrected in each focal length state from the wide-angle end state to the telephoto end state, and excellent imaging performance is obtained. .

[Sixth embodiment]
FIG. 26 is a diagram illustrating the configuration of the variable magnification optical system ZL6 according to the sixth example. When n = 5, that is, the variable magnification optical system ZL6 having a five-group configuration is illustrated. In the variable magnification optical system ZL6 of FIG. 26, the first lens group G1 includes, in order from the object side, a cemented lens of a negative meniscus lens L11 having a convex surface facing the object side and a biconvex lens L12, a biconvex lens L13, and an object It comprises a positive meniscus lens L14 having a convex surface on the side. The second lens group G2 includes, in order from the object side, a negative meniscus lens L21 having a convex surface facing the object side, a cemented lens of a biconcave lens L22 and a positive meniscus lens L23 having a convex surface facing the object side, and a concave surface facing the object side And a negative meniscus lens L25 having a concave surface facing the object side. The third lens group G3 includes, in order from the object side, a positive meniscus lens L31 having a concave surface facing the object side, and a cemented lens of a negative meniscus lens L32 having a convex surface facing the object side and a biconvex lens L33. The fourth lens group G4 includes a negative meniscus lens L41 having a concave surface directed toward the object side. In the fifth lens group G5, the first partial group G5a includes, in order from the object side, a biconvex lens L51 and a positive meniscus lens L52 having a convex surface facing the object side. The second partial group G5b is formed from the object side. In order, the lens is composed of a cemented lens of a biconvex lens L53 and a biconcave lens L54, and a negative meniscus lens L55 having a convex surface facing the object side. And a negative meniscus lens L58 having a concave surface directed toward the object side. The aperture stop S is located between the first partial group G5a and the second partial group G5b and closest to the image side of the first partial group G5a.

  In the sixth embodiment, in the wide-angle end state, the image stabilization coefficient is 1.30 and the focal length is 71.4 (mm). The moving amount of the two subgroup G5b is 0.38 (mm). Further, in the intermediate focal length state of the sixth embodiment, the image stabilization coefficient is 1.30 and the focal length is 135.0 (mm), and therefore the first for correcting the rotational shake of 0.30 °. The moving amount of the two subgroup G5b is 0.54 (mm). Further, in the telephoto end state of the sixth embodiment, the image stabilization coefficient is 1.30 and the focal length is 196.0 (mm), so that the second for correcting the rotational shake of 0.30 °. The movement amount of the subgroup G5b is 0.79 (mm).

  Table 16 below provides values of specifications of the sixth embodiment.

(Table 16)
Surface number Curvature radius Surface spacing Abbe number Refractive index
1 381.3020 2.5000 28.69 1.795041
2 106.4250 8.8000 82.52 1.497820
3 -1149.1256 0.1000
4 98.2127 8.5000 82.52 1.497820
5 -1919.4180 0.1000
6 66.6347 8.5000 82.52 1.497820
7 293.0617 (d1)
8 228.7827 2.1000 46.62 1.816000
9 33.2041 10.0000
10 -117.4258 2.1000 70.41 1.487490
11 37.9960 6.2000 23.78 1.846660
12 287.5696 4.2000
13 -53.8038 3.3000 25.43 1.805181
14 -38.9730 2.1000 46.62 1.816000
15 -2687.3318 (d2)
16 -1365.0388 3.8000 44.78 1.743997
17 -93.5331 0.1000
18 77.7004 2.4000 23.78 1.846660
19 47.7610 8.8000 65.46 1.603001
20 -130.8829 (d3)
21 -90.0052 2.5000 23.78 1.846660
22 -222.5672 (d4)
23 156.5810 3.8000 82.52 1.497820
24 -223.4996 0.1000
25 48.3764 4.0000 82.52 1.497820
26 104.4479 6.6000
27 0.0000 15.4000 (Aperture stop S)
28 629.9782 3.8000 28.46 1.728250
29 -55.4480 1.6000 53.71 1.579570
30 55.4345 4.0000
31 482.0258 1.6000 39.57 1.804400
32 58.8315 4.0000
33 182.5454 5.0000 82.52 1.497820
34 -61.2108 0.1000
35 40.0944 6.5000 82.52 1.497820
36 -880.4337 4.7500
37 -53.2131 2.0000 32.35 1.850 260
38 -148.8412 (Bf)

Wide angle end Intermediate focal length Telephoto end
f = 71.40 to 135.00 to 196.00
F.NO = 2.89 to 2.89 to 2.89
ω = 16.96 to 8.90 to 6.12

[Zoom lens group data]
Lens group Focal length 1st lens group 92.597
Second lens group -26.083
Third lens group 57.143
Fourth lens group -180.041
Fifth lens group 111.174

  In the sixth example, the axial air distance d1 between the first lens group G1 and the second lens group G2, the axial air distance d2 between the second lens group G2 and the third lens group G3, and the third lens group G3. The on-axis air distance d3 between the fourth lens group G4 and the on-axis air distance d4 between the fourth lens group G4 and the fifth lens group G5 changes during zooming. Table 17 below shows variable interval data, Bf, and the total length at each focal length in the wide-angle end state, the intermediate focal length state, and the telephoto end state of the variable magnification optical system ZL6 according to the sixth example.

(Table 17)
[Variable interval data]
Wide angle end Intermediate focal length Telephoto end
d1 2.054 23.103 30.776
d2 25.896 13.196 2.011
d3 5.289 12.530 16.871
d4 19.899 4.308 3.480
Bf 53.787 53.787 53.787
Total length 246.275 246.275 246.275

  Table 18 below shows values corresponding to the conditional expressions in the sixth embodiment.

(Table 18)
(1) fGn / fVR = −2.095
(2) | fGf / fGn | = 0.511
(3) | fGn | /ft=0.568
(4) | fVR | /fw=0.744

  FIG. 27A shows an aberration diagram in the infinite focus state in the wide-angle end state of this sixth embodiment, and FIG. 28A shows an aberration diagram in the infinite focus state in the intermediate focal length state. FIG. 29A shows an aberration diagram in the infinite focus state in the end state, FIG. 30A shows an aberration diagram in the short distance object focus state in the wide angle end state, and FIG. 30A shows the short distance in the intermediate focal length state. FIG. 30B shows an aberration diagram in the object in-focus state, and FIG. 30C shows an aberration diagram in the near-field object in-focus state in the telephoto end state. FIG. 27B shows a meridional lateral aberration diagram when the shake correction is performed for the 0.40 ° rotational shake in the infinitely focused state at the wide-angle end state in the sixth embodiment. FIG. 28 (b) shows a meridional lateral aberration diagram when shake correction is performed with respect to a rotational shake of 0.30 ° in the infinite focus state at the intermediate focal length state of FIG. 28, and in the telephoto end state of the sixth embodiment. FIG. 29 (b) shows a meridional lateral aberration diagram when shake correction is performed with respect to a rotational shake of 0.30 ° in the infinite focus state. As is apparent from these respective aberration diagrams, in the sixth embodiment, it is understood that various aberrations are satisfactorily corrected in each focal length state from the wide-angle end state to the telephoto end state, and excellent imaging performance is obtained. .

ZL (ZL1 to ZL6) Variable power optical system G1 First lens group G2 Second lens group G3 Third lens group G4 Fourth lens group G4a First partial group G4b Second partial group G4c Third partial group G5 Fifth lens group G5a First partial group G5b Second partial group G5c Third partial group S Aperture stop 1 Electronic still camera (optical equipment)

Claims (9)

In order from the object side, a first lens group having a positive refractive power disposed closest to the object side, a second lens group, and a third lens group having a positive refractive power,
A _Gn lens group having a positive refractive power and arranged closest to the image plane side;
At the time of zooming, the first lens group and the _Gn lens group are fixed,
The interval between the lens groups adjacent to each other changes during zooming,
At the time of focusing, at least one lens group disposed between the second lens group and the _Gn lens group moves as a focusing lens group,
Moving the anti-vibration lens group having a negative refractive power, which is a part of the _Gn lens group, so as to have a component substantially perpendicular to the optical axis;
Wherein the focal length of the G _n lens unit and FGn, the focal length of the vibration reduction lens group and the FVR, the following expression -3.5 <fGn / fVR <-0.8
Variable magnification optical system that satisfies the above conditions. Wherein between the second lens group and the third G _n lens unit, zooming optical system according to claim 1 having at least two lens groups. The _Gn lens group is in order from the object side.
A first subgroup having positive refractive power;
A second subgroup having negative refractive power;
A third subgroup having a positive refractive power,
Variable-power optical system according to claim 1 or 2, wherein the second sub group is the vibration reduction lens group. Wherein the focal length of the G _n lens unit and FGn, when the focal length of the focusing lens group and FGF, the following formula 0.20 <| fGf / fGn | < 1.00
The variable magnification optical system as described in any one of Claims 1-3 which satisfy | fills these conditions. The focal length of the first G _n lens unit and FGn, when the focal length of the entire system at the telephoto end state ft, the following formula 0.40 <| fGn | / ft < 1.00
The zoom lens system according to any one of claims 1 to 4, which satisfies the following condition. When the focal length of the anti-vibration lens group is fVR and the focal length of the entire system in the wide-angle end state is fw, the following expression 0.10 <| fVR | / fw <1.90.
The zoom lens system according to any one of claims 1 to 5, which satisfies the following condition. From the object side,
The first lens group;
The second lens group;
The third lens group;
A fourth lens group;
Variable-power optical system according to any one of claims 1 to 6 having a said first G _n lens unit. The zoom optical system according to claim 7 , wherein the fourth lens group has a negative refractive power. Optical apparatus including the variable magnification optical system according to any one of claims 1-8.

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