Variable magnification optical system, optical apparatus, and method for manufacturing variable magnification optical system

Abstract

To provide a variable power optical system having excellent optical performance, an optical apparatus, and a method for manufacturing the variable power optical system.SOLUTION: A variable magnification optical system including six or more lens groups, the plurality of lens groups including a first lens group having a positive refractive power and a rear group disposed on an image side of the first lens group, is configured such that a distance between the lens groups changes during zooming, the first lens group includes two or less lenses, the rear group includes a first positive lens group having a positive refractive power, and the following conditional expressions are both satisfied: 7.50 <f1 / D1 <17.504.00 <M1 / D1 <22.001.00 <f1 / fP1 <5.00, where f1 is a focal distance of the first lens group, D1 is a thickness on an optical axis of the first lens group, M1 is an amount of movement of the first lens group upon zooming from the wide angle end state to the telephoto end state, and is a focal distance of the first positive lens group. fP1.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to a variable magnification optical system, an optical instrument, and a method for manufacturing a variable magnification optical system. [Background technology]

[0002] BACKGROUND ART Variable magnification optical systems have been proposed for use in optical devices such as photographic cameras, electronic still cameras, and video cameras (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2020-170102 Summary of the Invention

[0004] The variable magnification optical system of the present disclosure has six or more lens groups, and the lens groups consist of a first lens group having positive refractive power and a rear group arranged closer to the image than the first lens group, the spacing between each lens group changes during magnification variation, the first lens group consists of two or less lenses, and satisfies both of the following conditional expressions: 7.50 < f1 / D1 < 55.00 4.00 < M1 / D1 < 22.00 however, f1: focal length of the first lens group D1: Thickness of the first lens group on the optical axis M1: Movement distance of the first lens group when changing magnification from the wide-angle end to the telephoto end

[0005] The manufacturing method of a variable magnification optical system of the present disclosure is a manufacturing method of a variable magnification optical system having six or more lens groups, the lens groups being composed of a first lens group having positive refractive power and a rear group arranged closer to the image side than the first lens group, wherein the spacing between each lens group changes during magnification variation, and the first lens group is composed of two or less lenses arranged so as to satisfy both of the following conditional expressions: 7.50 < f1 / D1 < 55.00 4.00 < M1 / D1 < 22.00 however, f1: focal length of the first lens group D1: Thickness of the first lens group on the optical axis M1: Movement distance of the first lens group when changing magnification from the wide-angle end to the telephoto end [Brief explanation of the drawings]

[0006] [Figure 1] FIG. 2 is a cross-sectional view of the variable magnification optical system of the first example when focused on an object at infinity in the wide-angle end state. [Figure 2A] 1A to 1C are diagrams illustrating various aberrations when the variable magnification optical system of Example 1 is in an intermediate focal length state and is focused on an object at infinity. [Figure 2B] 4A to 4C are diagrams illustrating various aberrations when the variable magnification optical system of the first example is in the telephoto end state and is focused on an object at infinity. [Figure 2C] 4A to 4C are diagrams illustrating various aberrations when the variable magnification optical system of the first example is in the wide-angle end state and is focused on an object at infinity. [Figure 3] FIG. 10 is a cross-sectional view of the variable magnification optical system of the second example when focused on an object at infinity in the wide-angle end state. [Figure 4A] 10A to 10C are diagrams illustrating various aberrations when the variable magnification optical system of Example 2 is in an intermediate focal length state and is focused on an object at infinity. [Figure 4B] 10A to 10C are diagrams illustrating various aberrations when the variable magnification optical system of the second example is in the telephoto end state and is focused on an object at infinity. [Figure 4C] 10A to 10C are diagrams illustrating various aberrations when the variable magnification optical system of the second example is in the wide-angle end state and is focused on an object at infinity. [Figure 5] FIG. 10 is a cross-sectional view of the variable magnification optical system of the third example when focused on an object at infinity in the wide-angle end state. [Figure 6A] 10A to 10C are diagrams illustrating various aberrations when the variable magnification optical system of the third example is in the wide-angle end state and is focused on an object at infinity. [Figure 6B] 10A to 10C are diagrams illustrating various aberrations when the variable magnification optical system of the third example is in an intermediate focal length state and is focused on an object at infinity. [Figure 6C]10A to 10C are diagrams illustrating various aberrations when the variable magnification optical system of the third example is in the telephoto end state and is focused on an object at infinity. [Figure 7] FIG. 10 is a cross-sectional view of the variable magnification optical system of the fourth example when focused on an object at infinity in the wide-angle end state. [Figure 8A] 10A to 10C are diagrams illustrating various aberrations when the variable magnification optical system of the fourth example is in the wide-angle end state and is focused on an object at infinity. [Figure 8B] 10A to 10C are diagrams illustrating various aberrations when the variable magnification optical system of Example 4 is in an intermediate focal length state and is focused on an object at infinity. [Figure 8C] 10A to 10C are diagrams illustrating various aberrations when the variable magnification optical system of the fourth example is in the telephoto end state and is focused on an object at infinity. [Figure 9] FIG. 10 is a cross-sectional view of the variable magnification optical system of the fifth example when focused on an object at infinity in the wide-angle end state. [Figure 10A] 10A to 10C are diagrams illustrating various aberrations when the variable magnification optical system of the fifth example is in the wide-angle end state and is focused on an object at infinity. [Figure 10B] 10A to 10C are diagrams illustrating various aberrations when the variable magnification optical system of Example 5 is in an intermediate focal length state and is focused on an object at infinity. [Figure 10C] 10A to 10C are diagrams illustrating various aberrations when the variable magnification optical system of the fifth example is in the telephoto end state and is focused on an object at infinity. [Figure 11] FIG. 10 is a cross-sectional view of the variable magnification optical system of Example 6 when focused on an object at infinity in the wide-angle end state. [Figure 12A] 13A to 13C are diagrams illustrating various aberrations when the variable magnification optical system of Example 6 is in the wide-angle end state and is focused on an object at infinity. [Figure 12B] 13A to 13C are diagrams illustrating various aberrations when the variable magnification optical system of Example 6 is in an intermediate focal length state and is focused on an object at infinity. [Figure 12C] 13A to 13C are diagrams illustrating various aberrations when the variable magnification optical system of the sixth example is in the telephoto end state and is focused on an object at infinity. [Figure 13] FIG. 13 is a cross-sectional view of the variable magnification optical system of Example 7 when focused on an object at infinity in the wide-angle end state. [Figure 14A] 13A to 13C are diagrams illustrating various aberrations when the variable magnification optical system of the seventh example is in the wide-angle end state and is focused on an object at infinity. [Figure 14B]13A to 13C are diagrams illustrating various aberrations when the variable magnification optical system of Example 7 is in an intermediate focal length state and is focused on an object at infinity. [Figure 14C] 13A to 13C are diagrams illustrating various aberrations when the variable magnification optical system of the seventh example is in the telephoto end state and is focused on an object at infinity. [Figure 15] FIG. 13 is a cross-sectional view of the variable magnification optical system of Example 8 when focused on an object at infinity in the wide-angle end state. [Figure 16A] 13A to 13C are diagrams illustrating various aberrations when the variable magnification optical system of Example 8 is in the wide-angle end state and is focused on an object at infinity. [Figure 16B] 13A to 13C are diagrams illustrating various aberrations when the variable magnification optical system of Example 8 is in an intermediate focal length state and is focused on an object at infinity. [Figure 16C] 13A to 13C are diagrams illustrating various aberrations when the variable magnification optical system of Example 8 is in the telephoto end state and is focused on an object at infinity. [Figure 17] FIG. 13 is a cross-sectional view of the variable magnification optical system of the ninth example when focused on an object at infinity in the wide-angle end state. [Figure 18A] 13A to 13C are diagrams illustrating various aberrations when the variable magnification optical system of Example 9 is in the wide-angle end state and is focused on an object at infinity. [Figure 18B] 13A to 13C are diagrams illustrating various aberrations when the variable magnification optical system of Example 9 is in an intermediate focal length state and is focused on an object at infinity. [Figure 18C] 13A to 13C are diagrams illustrating various aberrations when the variable magnification optical system of the ninth example is in the telephoto end state and is focused on an object at infinity. [Figure 19] FIG. 1 is a schematic diagram of a camera equipped with a variable magnification optical system according to an embodiment of the present invention. [Figure 20] 1 is a flowchart showing an outline of a method for manufacturing a variable magnification optical system according to the present embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0007] Hereinafter, a variable magnification optical system, an optical device, and a method for manufacturing a variable magnification optical system according to embodiments of the present application will be described.

[0008] The variable magnification optical system of this embodiment has six or more lens groups, and the lens groups are made up of a first lens group having positive refractive power and a rear group arranged closer to the image than the first lens group, the spacing between each lens group changes during magnification variation, the first lens group is made up of two or less lenses, and satisfies both of the following conditional expressions: (1) 7.50 < f1 / D1 < 55.00 (2) 4.00 < M1 / D1 < 22.00 however, f1: focal length of the first lens group D1: Thickness of the first lens group on the optical axis M1: Movement distance of the first lens group when changing magnification from the wide-angle end to the telephoto end

[0009] The variable magnification optical system of this embodiment can be made lightweight by limiting the first lens group to two or less lenses.

[0010] Conditional expression (1) defines the ratio between the focal length of the first lens group and the thickness of the first lens group on the optical axis. By satisfying conditional expression (1), the variable magnification optical system of this embodiment can appropriately suppress fluctuations in various aberrations, including spherical aberration, during magnification variation.

[0011] In the variable magnification optical system of this embodiment, if the value of conditional expression (1) exceeds the upper limit, the thickness of the first lens group on the optical axis becomes too small, making it difficult to appropriately suppress fluctuations in various aberrations, including spherical aberration, during magnification.

[0012] In the variable magnification optical system of this embodiment, the effect of this embodiment can be more reliably achieved by setting the upper limit of conditional expression (1) to 55.00. In order to further ensure the effect of this embodiment, it is preferable to set the upper limit of conditional expression (1) to 54.50, 54.00, 50.00, 45.00, 40.00, 35.00, 30.00, 17.50, or even 15.00.

[0013] Furthermore, in the variable magnification optical system of this embodiment, if the value of conditional expression (1) falls below the lower limit, the refractive power of the first lens group becomes too strong, making it difficult to appropriately suppress fluctuations in various aberrations, including spherical aberration, during magnification.

[0014] In the variable magnification optical system of this embodiment, the effect of this embodiment can be more reliably achieved by setting the lower limit of conditional expression (1) to 7.50. In order to further ensure the effect of this embodiment, it is preferable to set the lower limit of conditional expression (1) to 8.00, 8.25, 8.50, 8.75, or even 9.00.

[0015] Conditional expression (2) defines the ratio between the amount of movement of the first lens group when changing magnification from the wide-angle end state to the telephoto end state and the thickness of the first lens group on the optical axis. By satisfying conditional expression (2), the variable magnification optical system of this embodiment can appropriately suppress fluctuations in various aberrations, including spherical aberration, when changing magnification.

[0016] In the variable magnification optical system of this embodiment, if the value of conditional expression (2) exceeds the upper limit, the axial thickness of the first lens group becomes too small, making it difficult to appropriately suppress fluctuations in various aberrations, including spherical aberration, during magnification.

[0017] In the variable magnification optical system of this embodiment, the effect of this embodiment can be more reliably achieved by setting the upper limit of conditional expression (2) to 22.00. In order to more reliably achieve the effect of this embodiment, it is preferable to set the upper limit of conditional expression (2) to 21.00, 20.00, 17.50, 15.00, 12.50, 10.00, 8.50, 7.50, or even 6.50.

[0018] Furthermore, in the variable magnification optical system of this embodiment, if the value of conditional expression (2) falls below the lower limit, the amount of movement of the first lens group becomes too large, making it difficult to appropriately suppress fluctuations in various aberrations, including spherical aberration, during magnification.

[0019] In the variable magnification optical system of this embodiment, the effect of this embodiment can be more reliably achieved by setting the lower limit of conditional expression (2) to 4.00. In order to more reliably achieve the effect of this embodiment, it is preferable to set the lower limit of conditional expression (2) to 4.25, 4.50, 4.75, 4.85, 5.00, 5.10, or even 5.25.

[0020] In a variable magnification optical system that satisfies both conditional expressions (1) and (2), fluctuations in various aberrations, including spherical aberration, can be appropriately suppressed when the magnification is changed.

[0021] In the variable magnification optical system of this embodiment, it is preferable that the rear group has a first negative lens unit having negative refractive power, and that the following conditional expression be satisfied: (3) 2.50 < f1 / (-fN1) < 7.00 however, fN1: focal length of the first negative lens group

[0022] Conditional expression (3) defines the ratio between the focal length of the first lens group and the focal length of the first negative lens group. By satisfying conditional expression (3), the variable magnification optical system of this embodiment can appropriately suppress fluctuations in various aberrations, including spherical aberration, during magnification variation.

[0023] In the variable magnification optical system of this embodiment, if the value of conditional expression (3) exceeds the upper limit, the refractive power of the first negative lens group becomes too strong, making it difficult to appropriately suppress fluctuations in various aberrations, including spherical aberration, during magnification.

[0024] In the variable magnification optical system of this embodiment, the effect of this embodiment can be more reliably achieved by setting the upper limit of conditional expression (3) to 7.00. In order to more reliably achieve the effect of this embodiment, it is preferable to set the upper limit of conditional expression (3) to 6.90, 6.75, 6.60, 6.40, or even 6.00.

[0025] Furthermore, in the variable magnification optical system of this embodiment, if the value of conditional expression (3) falls below the lower limit, the refractive power of the first lens group becomes too strong, making it difficult to appropriately suppress fluctuations in various aberrations, including spherical aberration, during magnification.

[0026] In the variable magnification optical system of this embodiment, the effect of this embodiment can be more reliably achieved by setting the lower limit of conditional expression (3) to 2.50. In order to more reliably achieve the effect of this embodiment, it is preferable to set the lower limit of conditional expression (3) to 2.60, 2.75, 2.90, 3.00, 3.10, or even 3.20.

[0027] In addition, in the variable magnification optical system of this embodiment, it is preferable that the rear group has a first negative lens group having negative refractive power and a second negative lens group having negative refractive power that is arranged closer to the image side than the first negative lens group, and that the following formula is satisfied: (4) 0.05 < f1 / (-fN2) < 6.50 however, fN2: focal length of the second negative lens group

[0028] Conditional expression (4) defines the ratio between the focal length of the first lens group and the focal length of the second negative lens group. By satisfying conditional expression (4), the variable magnification optical system of this embodiment can appropriately suppress fluctuations in various aberrations, including spherical aberration, during magnification variation.

[0029] In the variable magnification optical system of this embodiment, if the value of conditional expression (4) exceeds the upper limit, the refractive power of the second negative lens group becomes too strong, making it difficult to appropriately suppress fluctuations in various aberrations, including spherical aberration, during magnification.

[0030] In the variable magnification optical system of this embodiment, the effect of this embodiment can be more reliably achieved by setting the upper limit of conditional expression (4) to 6.50. In order to further ensure the effect of this embodiment, it is preferable to set the upper limit of conditional expression (4) to 6.40, 6.30, 6.25, 6.20, 6.10, 6.00, or even 5.90.

[0031] Furthermore, in the variable magnification optical system of this embodiment, if the value of conditional expression (4) falls below the lower limit, the refractive power of the first lens group becomes too strong, making it difficult to appropriately suppress fluctuations in various aberrations, including spherical aberration, during magnification.

[0032] In the variable magnification optical system of this embodiment, the effect of this embodiment can be more reliably achieved by setting the lower limit of conditional expression (4) to 0.05. In order to more reliably achieve the effect of this embodiment, it is preferable to set the lower limit of conditional expression (4) to 0.08, 0.10, 0.15, 0.25, 0.50, 0.75, 0.90, 1.00, or even 1.25.

[0033] In addition, in the variable magnification optical system of this embodiment, it is preferable that the rear group has a first negative lens group having negative refractive power and a second negative lens group having negative refractive power that is arranged closer to the image side than the first negative lens group, and that the following formula is satisfied: (5) 0.01 < fN1 / fN2 < 1.20 however, fN1: focal length of the first negative lens group fN2: focal length of the second negative lens group

[0034] Conditional expression (5) defines the ratio between the focal length of the first negative lens group and the focal length of the second negative lens group. By satisfying conditional expression (5), the variable magnification optical system of this embodiment can appropriately suppress fluctuations in various aberrations, including spherical aberration, during magnification variation.

[0035] In the variable magnification optical system of this embodiment, if the value of conditional expression (5) exceeds the upper limit, the refractive power of the second negative lens group becomes too strong, making it difficult to appropriately suppress fluctuations in various aberrations, including spherical aberration, during magnification.

[0036] In the variable magnification optical system of this embodiment, the effect of this embodiment can be more reliably achieved by setting the upper limit of conditional expression (5) to 1.20. In order to more reliably achieve the effect of this embodiment, it is preferable to set the upper limit of conditional expression (5) to 1.10, 1.00, 0.95, 0.90, 0.80, 0.70, 0.50, or even 0.45.

[0037] Furthermore, in the variable magnification optical system of this embodiment, if the value of conditional expression (5) falls below the lower limit, the refractive power of the first negative lens group becomes too strong, making it difficult to appropriately suppress fluctuations in various aberrations, including spherical aberration, during magnification.

[0038] In the variable magnification optical system of this embodiment, the effect of this embodiment can be more reliably achieved by setting the lower limit of conditional expression (5) to 0.01. In order to more reliably achieve the effect of this embodiment, it is preferable to set the lower limit of conditional expression (5) to 0.05, 0.10, 0.30, 0.50, or even 0.75.

[0039] In the variable magnification optical system of this embodiment, it is preferable that the first negative lens group is the lens group arranged closest to the object side among the lens groups having negative refractive power in the rear group.

[0040] The variable magnification optical system of this embodiment has such a configuration, and is therefore able to appropriately suppress fluctuations in various aberrations, including spherical aberration, during magnification.

[0041] In the variable magnification optical system of this embodiment, it is preferable that the rear group has a first positive lens group having positive refractive power, and that the following conditional expression be satisfied: (6) 1.00 < f1 / fP1 < 5.00 however, fP1: Focal length of the first positive lens group

[0042] Conditional expression (6) defines the ratio between the focal length of the first lens group and the focal length of the first positive lens group. By satisfying conditional expression (6), the variable magnification optical system of this embodiment can appropriately suppress fluctuations in various aberrations, including spherical aberration, during magnification variation.

[0043] In the variable magnification optical system of this embodiment, if the value of conditional expression (6) exceeds the upper limit, the refractive power of the first positive lens group becomes too strong, making it difficult to appropriately suppress fluctuations in various aberrations, including spherical aberration, during magnification.

[0044] In the variable magnification optical system of this embodiment, the effect of this embodiment can be more reliably achieved by setting the upper limit of conditional expression (6) to 5.00. In order to more reliably achieve the effect of this embodiment, it is preferable to set the upper limit of conditional expression (6) to 4.90, 4.80, 4.75, 4.70, 4.50, 4.25, 4.00, 3.50, or even 3.00.

[0045] Furthermore, in the variable magnification optical system of this embodiment, if the value of conditional expression (6) falls below the lower limit, the refractive power of the first lens group becomes too strong, making it difficult to appropriately suppress fluctuations in various aberrations, including spherical aberration, during magnification.

[0046] In the variable magnification optical system of this embodiment, the effect of this embodiment can be more reliably achieved by setting the lower limit of conditional expression (6) to 1.00. In order to more reliably achieve the effect of this embodiment, it is preferable to set the lower limit of conditional expression (6) to 1.10, 1.25, 1.40, 1.50, or even 1.75.

[0047] In addition, in the variable magnification optical system of this embodiment, it is preferable that the rear group has a first positive lens group having positive refractive power, and a first negative lens group having negative refractive power that is arranged closer to the image side than the first positive lens group, and that the following conditional expression is satisfied: (7) 0.40 < fP1 / (-fN1) < 5.50 however, fP1: Focal length of the first positive lens group fN1: focal length of the first negative lens group

[0048] Conditional expression (7) defines the ratio between the focal length of the first positive lens group and the focal length of the first negative lens group. By satisfying conditional expression (7), the variable magnification optical system of this embodiment can appropriately suppress fluctuations in various aberrations, including spherical aberration, during magnification.

[0049] In the variable magnification optical system of this embodiment, if the value of conditional expression (7) exceeds the upper limit, the refractive power of the first negative lens group becomes too strong, making it difficult to appropriately suppress fluctuations in various aberrations, including spherical aberration, during magnification.

[0050] In the variable magnification optical system of this embodiment, the effect of this embodiment can be more reliably achieved by setting the upper limit of conditional expression (7) to 5.50. In order to more reliably achieve the effect of this embodiment, it is preferable to set the upper limit of conditional expression (7) to 5.40, 5.25, 5.10, 5.00, 4.85, 4.70, 4.50, 4.00, or even 3.75.

[0051] Furthermore, in the variable magnification optical system of this embodiment, if the value of conditional expression (7) falls below the lower limit, the refractive power of the first positive lens group becomes too strong, making it difficult to appropriately suppress fluctuations in various aberrations, including spherical aberration, during magnification.

[0052] In the variable magnification optical system of this embodiment, the effect of this embodiment can be more reliably achieved by setting the lower limit of conditional expression (7) to 0.40. In order to more reliably achieve the effect of this embodiment, it is preferable to set the lower limit of conditional expression (7) to 0.35, 0.50, 0.55, 0.60, 0.65, 0.70, 1.00, 1.25, or even 1.50.

[0053] In addition, in the variable magnification optical system of this embodiment, it is preferable that the rear group has a first positive lens group having positive refractive power, and a second positive lens group having positive refractive power that is arranged closer to the image side than the first positive lens group.

[0054] The variable magnification optical system of this embodiment has such a configuration, and is therefore able to appropriately suppress fluctuations in various aberrations, including spherical aberration, during magnification.

[0055] It is also preferable that the variable magnification optical system of this embodiment satisfies the following conditional expression. (8) 0.20 < fP1 / fP2 < 5.50 however, fP1: Focal length of the first positive lens group fP2: Focal length of the second positive lens group

[0056] Conditional expression (8) defines the ratio between the focal length of the first positive lens group and the focal length of the second positive lens group. By satisfying conditional expression (8), the variable magnification optical system of this embodiment can appropriately suppress fluctuations in various aberrations, including spherical aberration, during magnification.

[0057] In the variable magnification optical system of this embodiment, if the value of conditional expression (8) exceeds the upper limit, the refractive power of the second positive lens group becomes too strong, making it difficult to appropriately suppress fluctuations in various aberrations, including spherical aberration, during magnification.

[0058] In the variable magnification optical system of this embodiment, the effect of this embodiment can be more reliably achieved by setting the upper limit of conditional expression (8) to 5.50. In order to more reliably achieve the effect of this embodiment, it is preferable to set the upper limit of conditional expression (8) to 5.40, 5.25, 5.10, 5.00, 4.95, 4.90, 4.00, 3.50, or even 3.00.

[0059] Furthermore, in the variable magnification optical system of this embodiment, if the value of conditional expression (8) falls below the lower limit, the refractive power of the first positive lens group becomes too strong, making it difficult to appropriately suppress fluctuations in various aberrations, including spherical aberration, during magnification.

[0060] In the variable magnification optical system of this embodiment, the effect of this embodiment can be more reliably achieved by setting the lower limit of conditional expression (8) to 0.20. In order to more reliably achieve the effect of this embodiment, it is preferable to set the lower limit of conditional expression (8) to 0.25, 0.30, 0.35, 0.38, 0.50, or even 0.60.

[0061] In the variable magnification optical system of this embodiment, it is preferable that the first positive lens group is the lens group arranged closest to the object side among the lens groups having positive refractive power in the rear group.

[0062] The variable magnification optical system of this embodiment has such a configuration, and is therefore able to appropriately suppress fluctuations in various aberrations, including spherical aberration, during magnification.

[0063] In the variable magnification optical system of this embodiment, it is preferable that the rear group has a positive focusing group that has positive refractive power and moves along the optical axis during focusing, and that the following conditional expression be satisfied: (9) 1.00 < f1 / fFP < 5.00 however, fFP: focal length of the focusing group

[0064] Conditional expression (9) defines the ratio between the focal length of the first lens group and the focal length of the focusing group. By satisfying conditional expression (9), the variable magnification optical system of this embodiment can appropriately suppress fluctuations in various aberrations, including spherical aberration, during focusing and zooming.

[0065] In the variable magnification optical system of this embodiment, if the value of conditional expression (9) exceeds the upper limit, the refractive power of the focusing group becomes too strong, making it difficult to appropriately suppress fluctuations in various aberrations, including spherical aberration, during focusing.

[0066] In the variable magnification optical system of this embodiment, the effect of this embodiment can be more reliably achieved by setting the upper limit of conditional expression (9) to 5.00. In order to more reliably achieve the effect of this embodiment, it is preferable to set the upper limit of conditional expression (9) to 4.90, 4.75, 4.60, 4.50, 4.40, 4.25, 4.15, 4.00, 3.75, 3.50, 3.25, 3.00, or even 2.75.

[0067] Furthermore, in the variable magnification optical system of this embodiment, if the value of conditional expression (9) falls below the lower limit, the refractive power of the first lens group becomes too strong, making it difficult to appropriately suppress fluctuations in various aberrations, including spherical aberration, during magnification.

[0068] In the variable magnification optical system of this embodiment, the effect of this embodiment can be more reliably achieved by setting the lower limit of conditional expression (9) to 1.00. In order to more reliably achieve the effect of this embodiment, it is preferable to set the lower limit of conditional expression (9) to 1.10, 1.25, 1.40, or even 1.50.

[0069] In the variable magnification optical system of this embodiment, it is preferable that the rear group has a positive focusing group that has positive refractive power and moves along the optical axis during focusing, and that the following conditional expression be satisfied: (10) -3.50 < fFP / fRPw < 1.00 however, fFP: focal length of the focusing group fRPw: The composite focal length at the wide-angle end of the lens group located closer to the image than the focusing group

[0070] Conditional expression (10) defines the ratio between the focal length of the correct focusing group and the combined focal length of the lens group located closer to the image side than the correct focusing group in the wide-angle end state. By satisfying conditional expression (10), the variable magnification optical system of this embodiment can appropriately suppress aberrations such as coma in the wide-angle end state, while also appropriately suppressing fluctuations in aberrations such as spherical aberration during focusing.

[0071] In the variable magnification optical system of this embodiment, if the value of conditional expression (10) exceeds the upper limit, the refractive power of the lens group located closer to the image side than the correct focusing group becomes too strong in the wide-angle end state, making it difficult to appropriately suppress various aberrations, including coma aberration, in the wide-angle end state.

[0072] In the variable magnification optical system of this embodiment, the effect of this embodiment can be more reliably achieved by setting the upper limit of conditional expression (10) to 1.00. In order to more reliably achieve the effect of this embodiment, it is preferable to set the upper limit of conditional expression (10) to 0.90, 0.80, 0.70, 0.60, 0.50, 0.40, or even 0.30.

[0073] Furthermore, in the variable magnification optical system of this embodiment, if the value of conditional expression (10) falls below the lower limit, the refractive power of the focusing group becomes too strong, making it difficult to appropriately suppress fluctuations in various aberrations, including spherical aberration, during focusing.

[0074] In the variable magnification optical system of this embodiment, the effect of this embodiment can be more reliably achieved by setting the lower limit of conditional expression (10) to -3.50. In order to more reliably achieve the effect of this embodiment, it is preferable to set the lower limit of conditional expression (10) to -3.25, -3.15, -3.00, -2.75, -2.50, -2.25, -2.15, -2.00, or even -1.50.

[0075] In the variable magnification optical system of this embodiment, it is preferable that the rear group has a negative focusing group that has negative refractive power and moves along the optical axis during focusing, and that the following conditional expression be satisfied: (11) 0.05 < f1 / (-fFN) < 6.50 however, fFN: Focal length of negative focusing group

[0076] Conditional expression (11) defines the ratio between the focal length of the first lens group and the focal length of the negative focusing group. By satisfying conditional expression (11), the variable magnification optical system of this embodiment can appropriately suppress fluctuations in various aberrations, including spherical aberration, during focusing and zooming.

[0077] In the variable magnification optical system of this embodiment, if the value of conditional expression (11) exceeds the upper limit, the refractive power of the negative focusing group becomes too strong, making it difficult to appropriately suppress fluctuations in various aberrations, including spherical aberration, during focusing.

[0078] In the variable magnification optical system of this embodiment, the effect of this embodiment can be more reliably achieved by setting the upper limit of conditional expression (11) to 6.50. In order to more reliably achieve the effect of this embodiment, it is preferable to set the upper limit of conditional expression (11) to 6.35, 6.20, 6.00, 5.75, 5.50, 5.25, 5.00, 4.50, 4.00, 3.75, or even 3.50.

[0079] Furthermore, in the variable magnification optical system of this embodiment, if the value of conditional expression (11) falls below the lower limit, the refractive power of the first lens group becomes too strong, making it difficult to appropriately suppress fluctuations in various aberrations, including spherical aberration, during magnification.

[0080] In the variable magnification optical system of this embodiment, the effect of this embodiment can be more reliably achieved by setting the lower limit of conditional expression (11) to 0.05. In order to more reliably achieve the effect of this embodiment, it is preferable to set the lower limit of conditional expression (11) to 0.10, 0.50, 1.00, 1.20, 1.50, 1.75, or even 2.00.

[0081] In the variable magnification optical system of this embodiment, it is preferable that the rear group has a negative focusing group that has negative refractive power and moves along the optical axis during focusing, and that the following conditional expression be satisfied: (12) -35.00 < (-fFN) / fRNw < 1.50 however, fFN: Focal length of negative focusing group fRNw: The composite focal length of the lens group located on the image side of the negative focusing group at the wide-angle end.

[0082] Conditional expression (12) defines the ratio between the focal length of the negative focusing group and the focal length of the lens group located closer to the image side than the negative focusing group in the wide-angle end state. By satisfying conditional expression (12), the variable magnification optical system of this embodiment can appropriately suppress aberrations such as coma in the wide-angle end state, while also appropriately suppressing fluctuations in aberrations such as spherical aberration during focusing.

[0083] In the variable magnification optical system of this embodiment, if the value of conditional expression (12) exceeds the upper limit, the refractive power of the lens group located closer to the image side than the negative focusing group becomes too strong in the wide-angle end state, making it difficult to appropriately suppress various aberrations, including coma aberration, in the wide-angle end state.

[0084] In the variable magnification optical system of this embodiment, the effect of this embodiment can be more reliably achieved by setting the upper limit of conditional expression (12) to 1.50. In order to more reliably achieve the effect of this embodiment, it is preferable to set the upper limit of conditional expression (12) to 1.40, 1.25, 1.10, 1.00, 0.90, or even 0.75.

[0085] Furthermore, in the variable magnification optical system of this embodiment, if the value of conditional expression (12) falls below the lower limit, the refractive power of the negative focusing group becomes too strong, making it difficult to appropriately suppress fluctuations in various aberrations, including spherical aberration, during focusing.

[0086] In the variable magnification optical system of this embodiment, the effect of this embodiment can be more reliably achieved by setting the lower limit of conditional expression (12) to -35.00. In order to more reliably achieve the effect of this embodiment, it is preferable to set the lower limit of conditional expression (12) to -32.50, -30.00, -27.50, -25.50, -20.00, -15.00, -10.00, -7.50, -5.00, -2.50, or even -1.00.

[0087] In the variable magnification optical system of this embodiment, it is preferable that the final lens group in the rear group, which is located closest to the image side, has negative refractive power and satisfies the following conditional expression: (13) 0.50 < f1 / (-fR) < 6.50 however, fR: focal length of the final lens group

[0088] Conditional expression (13) defines the ratio between the focal length of the first lens group and the focal length of the final lens group. By satisfying conditional expression (13), the variable magnification optical system of this embodiment can appropriately suppress fluctuations in various aberrations, including spherical aberration, during magnification variation.

[0089] In the variable magnification optical system of this embodiment, if the value of conditional expression (13) exceeds the upper limit, the refractive power of the final lens group becomes too strong, making it difficult to appropriately suppress fluctuations in various aberrations, including coma, during magnification.

[0090] In the variable magnification optical system of this embodiment, the effect of this embodiment can be more reliably achieved by setting the upper limit of conditional expression (13) to 10.00. In order to more reliably achieve the effect of this embodiment, it is preferable to set the upper limit of conditional expression (13) to 9.50, 9.00, 8.75, 7.50, 6.00, or even 5.00.

[0091] Furthermore, in the variable magnification optical system of this embodiment, if the value of conditional expression (13) falls below the lower limit, the refractive power of the first lens group becomes too strong, making it difficult to appropriately suppress fluctuations in various aberrations, including spherical aberration, during magnification.

[0092] In the variable magnification optical system of this embodiment, the effect of this embodiment can be more reliably achieved by setting the lower limit of conditional expression (13) to 0.50. In order to more reliably achieve the effect of this embodiment, it is preferable to set the lower limit of conditional expression (13) to 0.65, 0.75, 1.00, 2.00, 3.00, or even 4.00.

[0093] In the variable magnification optical system of this embodiment, it is preferable that the final lens group in the rear group, which is located closest to the image side, has positive refractive power and satisfies the following conditional expression: (14) 0.01 < f1 / fR < 3.00 however, fR: focal length of the final lens group

[0094] Conditional expression (14) defines the ratio between the focal length of the first lens group and the focal length of the final lens group. By satisfying conditional expression (14), the variable magnification optical system of this embodiment can appropriately suppress fluctuations in various aberrations, including spherical aberration, during magnification variation.

[0095] In the variable magnification optical system of this embodiment, if the value of conditional expression (14) exceeds the upper limit, the refractive power of the final lens group becomes too strong, making it difficult to appropriately suppress fluctuations in various aberrations, including coma, during magnification variation.

[0096] In the variable magnification optical system of this embodiment, the effect of this embodiment can be more reliably achieved by setting the upper limit of conditional expression (14) to 3.00. In order to more reliably achieve the effect of this embodiment, it is preferable to set the upper limit of conditional expression (14) to 2.90, 2.75, 2.50, 2.25, or even 2.10.

[0097] Furthermore, in the variable magnification optical system of this embodiment, if the value of conditional expression (14) falls below the lower limit, the refractive power of the first lens group becomes too strong, making it difficult to appropriately suppress fluctuations in various aberrations, including spherical aberration, during magnification.

[0098] In the variable magnification optical system of this embodiment, the effect of this embodiment can be more reliably achieved by setting the lower limit of conditional expression (14) to 0.01. In order to further ensure the effect of this embodiment, it is preferable to set the lower limit of conditional expression (14) to 0.02, 0.10, 0.20, or even 0.30.

[0099] In the variable magnification optical system of this embodiment, it is preferable that the first lens group has at least one lens that satisfies both of the following conditional expressions. (15) 1.45 < nd1 < 2.10 (16) 20.00 < νd1 < 75.00 however, nd1: refractive index of the lens in the first lens group at the d line νd1: Abbe number of the lens in the first lens group based on the d-line

[0100] Conditional expression (15) defines the refractive index of the lens in the first lens group with respect to the d-line, and conditional expression (16) defines the Abbe number of the lens in the first lens group with respect to the d-line. In the variable magnification optical system of this embodiment, the first lens group has at least one lens that satisfies both conditional expressions (15) and (16), so that various aberrations, including spherical aberration, and chromatic aberration can be effectively corrected in the telephoto end state.

[0101] In the variable magnification optical system of this embodiment, if the value of conditional expression (15) exceeds the upper limit, the refractive power of the final lens group becomes too strong, making it difficult to appropriately suppress fluctuations in various aberrations, including coma, during magnification variation.

[0102] In the variable magnification optical system of this embodiment, the effect of this embodiment can be more reliably achieved by setting the upper limit of conditional expression (15) to 2.10. In order to more reliably achieve the effect of this embodiment, it is preferable to set the upper limit of conditional expression (15) to 2.00, 1.95, 1.90, 1.85, or even 1.80.

[0103] Furthermore, in the variable magnification optical system of this embodiment, if the value of conditional expression (15) falls below the lower limit, the refractive power of the lenses in the first lens group becomes too weak, making it difficult to improve various aberrations, including spherical aberration, in the telephoto end state.

[0104] In the variable magnification optical system of this embodiment, the effect of this embodiment can be more reliably achieved by setting the lower limit of conditional expression (15) to 1.45. In order to more reliably achieve the effect of this embodiment, it is preferable to set the lower limit of conditional expression (15) to 1.47, 1.50, or even 1.55.

[0105] In the variable magnification optical system of this embodiment, if the value of conditional expression (16) exceeds the upper limit, the dispersion of the lenses in the first lens group becomes too small, making it difficult to effectively correct chromatic aberration in the telephoto end state.

[0106] In the variable magnification optical system of this embodiment, the effect of this embodiment can be more reliably achieved by setting the upper limit of conditional expression (16) to 83.00. In order to more reliably achieve the effect of this embodiment, it is preferable to set the upper limit of conditional expression (16) to 82.00, 77.50, 75.00, 72.50, or even 70.00.

[0107] Furthermore, in the variable magnification optical system of this embodiment, if the value of conditional expression (16) falls below the lower limit, the dispersion of the lenses in the first lens group becomes too small, making it difficult to effectively correct chromatic aberration in the telephoto end state.

[0108] In the variable magnification optical system of this embodiment, the effect of this embodiment can be more reliably achieved by setting the lower limit of conditional expression (16) to 20.00. In order to further ensure the effect of this embodiment, it is preferable to set the lower limit of conditional expression (16) to 25.00, 27.50, 30.00, 32.50, or even 34.00.

[0109] It is also preferable that the variable magnification optical system of this embodiment satisfies the following conditional expression. (17) 0.10 < Bfw / fw < 0.95 however, Bfw: Back focus at the wide-angle end of the variable magnification optical system fw: focal length at the wide-angle end of the variable magnification optical system

[0110] Conditional expression (17) defines the ratio between the back focus of the variable magnification optical system in the wide-angle end state and the focal length of the variable magnification optical system in the wide-angle end state. By satisfying conditional expression (17), the variable magnification optical system of this embodiment can effectively correct various aberrations, including coma in the wide-angle end state, while avoiding an increase in the size of the optical system.

[0111] In the variable magnification optical system of this embodiment, if the value of conditional expression (17) exceeds the upper limit, the back focus becomes too long, making it difficult to avoid an increase in the size of the optical system.

[0112] In the variable magnification optical system of this embodiment, the effect of this embodiment can be more reliably achieved by setting the upper limit of conditional expression (17) to 0.95. In order to more reliably achieve the effect of this embodiment, it is preferable to set the upper limit of conditional expression (17) to 0.90, 0.85, 0.80, 0.75, 0.70, 0.65, 0.60, or even 0.55.

[0113] Furthermore, in the variable magnification optical system of this embodiment, if the value of conditional expression (17) falls below the lower limit, the position of the exit pupil becomes too close to the image plane, making it difficult to effectively correct various aberrations, including coma in the wide-angle end state.

[0114] In the variable magnification optical system of this embodiment, the effect of this embodiment can be more reliably achieved by setting the lower limit of conditional expression (17) to 0.10. In order to further ensure the effect of this embodiment, it is preferable to set the lower limit of conditional expression (17) to 0.15, 0.20, 0.25, 0.30, or even 0.35.

[0115] In the variable magnification optical system of this embodiment, it is preferable that the first lens group moves toward the object side when the magnification is changed from the wide-angle end state to the telephoto end state.

[0116] With the variable magnification optical system of this embodiment, by having such a configuration, it is possible to reduce the size of the variable magnification optical system and appropriately suppress fluctuations in various aberrations, including spherical aberration, during magnification.

[0117] In the variable magnification optical system of this embodiment, it is preferable that the first lens group consists of, in order from the object side, a negative lens and a positive lens.

[0118] With the variable magnification optical system of this embodiment, by having such a configuration, it is possible to reduce the weight of the variable magnification optical system and to effectively correct various aberrations, including spherical aberration, in the telephoto end state.

[0119] In the variable magnification optical system of this embodiment, it is preferable that the first lens group is made up of a positive lens.

[0120] With the variable magnification optical system of this embodiment, by having such a configuration, it is possible to reduce the weight of the variable magnification optical system and to effectively correct various aberrations, including spherical aberration, in the telephoto end state.

[0121] In the variable magnification optical system of this embodiment, it is preferable that the rear group has a first focusing group and a second focusing group that each move along the optical axis during focusing.

[0122] With the variable magnification optical system of this embodiment having such a configuration, it is possible to appropriately suppress fluctuations in various aberrations, including spherical aberration, during focusing.

[0123] It is also preferable that the variable magnification optical system of this embodiment satisfies the following conditional expression. (18) 0.20 < |fF1| / |fF2| < 30.00 however, fF1: Focal length of the first focusing group fF2: Focal length of the second focusing group

[0124] Conditional expression (18) defines the ratio between the focal length of the first focusing group and the focal length of the second focusing group. By satisfying conditional expression (18), the variable magnification optical system of this embodiment can appropriately suppress fluctuations in various aberrations, including spherical aberration, during focusing.

[0125] In the variable magnification optical system of this embodiment, if the value of conditional expression (18) exceeds the upper limit, the refractive power of the second focusing group becomes too strong, making it difficult to appropriately suppress fluctuations in various aberrations, including spherical aberration, during focusing.

[0126] In the variable magnification optical system of this embodiment, the effect of this embodiment can be more reliably achieved by setting the upper limit of conditional expression (18) to 30.00. In order to more reliably achieve the effect of this embodiment, it is preferable to set the upper limit of conditional expression (18) to 27.00, 25.00, 10.00, 2.00, 1.95, 1.90, 1.85, 1.80, or even 1.75.

[0127] Furthermore, in the variable magnification optical system of this embodiment, if the value of conditional expression (18) falls below the lower limit, the refractive power of the first focusing group becomes too strong, making it difficult to appropriately suppress fluctuations in various aberrations, including spherical aberration, when the magnification is changed.

[0128] In the variable magnification optical system of this embodiment, the effect of this embodiment can be more reliably achieved by setting the lower limit of conditional expression (18) to 0.20. In order to more reliably achieve the effect of this embodiment, it is preferable to set the lower limit of conditional expression (18) to 0.25, 0.30, 0.35, 0.40, 0.45, or even 0.50.

[0129] In the variable magnification optical system of this embodiment, it is preferable that at least one of the positive lenses in the rear group satisfies the following first dispersion condition: (19) νdP1 < 45.00 however, νdP1: Abbe number of the positive lens in the rear group based on the d-line

[0130] The first dispersion condition (19) defines the Abbe number of the positive lens in the rear group with reference to the d-line. The variable magnification optical system of this embodiment has a positive lens in the rear group that satisfies the first dispersion condition (19), thereby making it possible to effectively correct chromatic aberration.

[0131] In the variable magnification optical system of this embodiment, the effect of this embodiment can be more reliably achieved by setting the upper limit of the first dispersion conditional expression (19) to 45.00. In order to further ensure the effect of this embodiment, it is preferable to set the upper limit of the first dispersion conditional expression (19) to 43.00, 40.00, 35.00, 30.00, or even 28.50.

[0132] In the variable magnification optical system of this embodiment, it is preferable that the positive lens satisfying the first dispersion conditional expression (19) is included in the negative lens group having negative refractive power among the lens groups in the rear group.

[0133] With the variable magnification optical system of this embodiment having such a configuration, chromatic aberration can be corrected more effectively.

[0134] In the variable magnification optical system of this embodiment, it is preferable that at least one of the negative lenses in the rear group satisfies the following second dispersion condition: (20) 60.00 < νdN however, νdN: Abbe number of the negative lens in the rear group based on the d-line

[0135] The second dispersion condition (20) defines the Abbe number of the negative lens in the rear group with reference to the d-line. The variable magnification optical system of this embodiment has a negative lens that satisfies the second dispersion condition (20), and thus can effectively correct chromatic aberration.

[0136] In the variable magnification optical system of this embodiment, the effect of this embodiment can be more reliably achieved by setting the lower limit of the second dispersion conditional expression (20) to 60.00. In order to more reliably achieve the effect of this embodiment, it is preferable to set the lower limit of the second dispersion conditional expression (20) to 62.50, 65.00, 67.50, or even 75.00.

[0137] In the variable magnification optical system of this embodiment, it is preferable that the negative lens satisfying the second dispersion conditional expression (20) is included in the final lens group, which is located closest to the image side among the lens groups in the rear group.

[0138] With the variable magnification optical system of this embodiment having such a configuration, chromatic aberration can be corrected more effectively.

[0139] In the variable magnification optical system of this embodiment, it is preferable that at least one of the lens groups in the rear group that has positive refractive power has a positive lens that satisfies the following third dispersion condition: (21) 60.00 < νdP2 however, νdP2: Abbe number of the positive lens in the rear group based on the d-line

[0140] The third dispersion condition (21) defines the Abbe number of the positive lens in the rear group with reference to the d-line. In the variable magnification optical system of this embodiment, the lens group having positive refractive power includes a positive lens that satisfies the third dispersion condition (21), and thus chromatic aberration can be effectively corrected.

[0141] In the variable magnification optical system of this embodiment, the effect of this embodiment can be more reliably achieved by setting the lower limit of the third dispersion conditional expression (21) to 60.00. In order to more reliably achieve the effect of this embodiment, it is preferable to set the lower limit of the third dispersion conditional expression (21) to 62.50, 65.00, 67.50, or even 75.00.

[0142] With the above configuration, it is possible to realize a variable magnification optical system that is small in size and has good imaging performance.

[0143] The optical apparatus of this embodiment has the variable magnification optical system configured as described above, which makes it possible to realize an optical apparatus with excellent optical performance.

[0144] The manufacturing method for a variable magnification optical system of this embodiment is a manufacturing method for a variable magnification optical system having six or more lens groups, the lens groups being composed of a first lens group having positive refractive power and a rear group arranged closer to the image side than the first lens group, wherein the spacing between each lens group changes during magnification variation, and the first lens group is composed of two or less lenses and is arranged so as to satisfy all of the following conditional expressions: (1) 7.50 < f1 / D1 < 55.00 (2) 4.00 < M1 / D1 < 22.00 however, f1: focal length of the first lens group D1: Thickness of the first lens group on the optical axis M1: Movement distance of the first lens group when changing magnification from the wide-angle end to the telephoto end

[0145] By using such a method for manufacturing a variable magnification optical system, it is possible to manufacture a variable magnification optical system having good optical performance.

[0146] (Numerical example) Hereinafter, embodiments of the present invention will be described with reference to the drawings.

[0147] (First Example) FIG. 1 is a cross-sectional view of a variable magnification optical system of the first embodiment when focused on an object at infinity in the wide-angle end state.

[0148] The variable magnification optical system of this embodiment has, in order from the object side, a first lens group G1 having positive refractive power, a second lens group G2 having negative refractive power, an aperture stop S, a third lens group G3 having positive refractive power, a fourth lens group G4 having positive refractive power, a fifth lens group G5 having negative refractive power, and a sixth lens group G6 having negative refractive power.

[0149] The first lens group G1 is composed of, in order from the object side, a cemented positive lens consisting of a negative meniscus lens L1 with a convex surface facing the object side and a positive meniscus lens L2 with a convex surface facing the object side.

[0150] The second lens group G2 is composed of, in order from the object side, a negative meniscus lens L3 with a convex surface facing the object side, a biconcave negative lens L4, a biconvex positive lens L5, and a biconcave negative lens L6.

[0151] The third lens group G3 consists of, in order from the object side, a biconvex positive lens L7, a cemented positive lens formed by cementing a negative meniscus lens L8 with its convex surface facing the object side and a biconvex positive lens L9, and a negative meniscus lens L10 with its concave surface facing the object side.

[0152] The fourth lens group G4 consists of, in order from the object side, a cemented positive lens consisting of a biconvex positive lens L11 and a negative meniscus lens L12 with its concave surface facing the object side, and a cemented positive lens consisting of a negative meniscus lens L13 with its convex surface facing the object side and a biconvex positive lens L14.

[0153] The fifth lens group G5 is composed of, in order from the object side, a cemented negative lens consisting of a biconvex positive lens L15 and a biconcave negative lens L16.

[0154] The sixth lens group G6 is composed of, in order from the object side, a biconcave negative lens L17 and a biconvex positive lens L18.

[0155] On the image plane I, an image pickup element (not shown) made up of a CCD, a CMOS, or the like is disposed.

[0156] The variable magnification optical system of this embodiment focuses by moving the fifth lens group G5 along the optical axis. When focusing on a close object from a state focused on infinity, the fifth lens group G5 is moved from the object side to the image side.

[0157] In the variable magnification optical system of this embodiment, the second lens group G2, the third lens group G3, the fourth lens group G4, the fifth lens group G5, and the sixth lens group G6 correspond to the rear group, and the sixth lens group G6 corresponds to the final lens group. Also, the second lens group G2 corresponds to the first negative lens group, the third lens group G3 corresponds to the first positive lens group, the fourth lens group G4 corresponds to the second positive lens group, and the fifth lens group G5 corresponds to the second negative lens group. Also, the fifth lens group G5 corresponds to the negative focusing group.

[0158] Table 1 below lists the specifications of the variable magnification optical system of this example.

[0159] In Table 1, fw is the focal length of the variable magnification optical system at the wide-angle end, ft is the focal length of the variable magnification optical system at the telephoto end, Fnow is the F-number of the variable magnification optical system at the wide-angle end, and Fnot is the F-number of the variable magnification optical system at the wide-angle end. TL is the total optical length of the variable magnification optical system when focusing on an object at infinity in the wide-angle end, and Bf is the back focal length of the variable magnification optical system.

[0160] In Table 1, m is the order of the optical surface counted from the object side, r is the radius of curvature, d is the surface spacing, nd is the refractive index for the d-line (wavelength 587.6 nm), and νd is the Abbe number for the d-line. A radius of curvature r=∞ indicates a flat surface. In the [Lens Specifications], an optical surface marked with an "*" is an aspheric surface. In the [Lens Specifications], the lenses corresponding to the positive lens P1 in conditional expression (19), the negative lens N in conditional expression (20), and the positive lens P2 in conditional expression (21) are also shown.

[0161] In Table 1, m indicates the optical surface corresponding to the aspherical data, K indicates the conic constant, and A4 to A14 indicate the aspherical coefficients.

[0162] The aspherical surface is expressed by the following formula (a), where y is the height in the direction perpendicular to the optical axis, S(y) is the distance (amount of sag) along the optical axis from the tangent plane of the vertex of each aspherical surface at height y to each aspherical surface, r is the radius of curvature (paraxial radius of curvature) of the reference spherical surface, K is the conic constant, and An is the n-th order aspherical coefficient. In each example, the second order aspherical coefficient A2 is 0. Also, "En" is expressed as "×10 -n " indicates.

[0163] (a) S(y) = (y 2 / r) / { 1 + (1-K×y 2 / r 2 ) 1 / 2} + A4×y 4 + A6×y 6 + A8×y 8 + A10×y 10 + A12×y 12 + A14×y 14

[0164] The units of focal lengths fw, ft, radius of curvature r, and other lengths listed in Table 1 are "mm." However, this is not limited to this, as variable magnification optical systems can achieve the same optical performance whether proportionally enlarged or reduced.

[0165] The symbols in Table 1 described above will be used in the same manner in tables of other embodiments described later.

[0166] (Table 1) [Overall specifications] fw 24.75 ft 193.60 Fnow 4.00 Fnot 6.50 [Lens specifications] mrd nd νd (19) (21) 1) 50.215 2.000 1.903660 31.27 2) 34.572 9.588 1.603000 65.44 3) 1311.519 d3 4) 734.769 1.307 1.953750 32.33 5) 18.756 4.799 6) -48.834 1.129 1.755000 52.33 7) 82.569 0.451 8) 35.539 3.409 1.922860 20.88 P1 9) -55.882 0.297 10) -40.429 1.015 1.816000 46.59 11) 149.588 d11 12> ∞ 2.016 (aperture stop) 13) 45.792 2.740 1.902650 35.72 P1 14) -158.052 0.500 15) 51.626 1.000 2.001000 29.12 16) 25.348 3.645 1.579570 53.74 17) -47.120 1.756 18) -28.990 1.043 1.953750 32.33 19) -180.881 d19 20) 31.325 6.348 1.834810 42.73 P1 21) -46.677 1.000 1.903660 31.27 22) -434.420 0.175 23) 31.122 2.824 1.953750 32.33 24) 15.393 10.000 1.497100 81.49 P2 *25) -46.610 d25 26) 192.398 3.146 1.846660 23.80 P1 27) -50.784 1.017 1.851350 40.13 *28) 33.031 d28 29) -39.648 1.400 1.820800 42.51 *30) 237.062 0.232 31) 46.735 4.880 1.683760 37.57 P1 32) -359.761 Bf [Aspherical data] m K A4 A6 A8 A10 A12 25) 0.0000 3.31E-05 -5.07E-08 7.86E-10 -4.83E-12 1.35E-14 28) 0.0000 -3.68E-06 5.73E-08 -1.75E-10 -8.02E-13 5.32E-15 30) 0.0000 7.67E-06 -1.25E-08 6.72E-11 -1.62E-13 [Focal length data for each group] Group starting plane focal length G1 1 110.64 G2 4 -16.88 G3 13 59.63 G4 20 27.13 G5 26 -47.14 G6 29 -137.34 [Variable Interval Data] Wide-angle end Telephoto end d3 1.969 54.765 d11 17.288 1.166 d19 14.645 1.478 d25 4.685 2.612 d28 8.395 23.634 Bf 11.793 37.548

[0167] FIG. 2A is a diagram showing various aberrations when the variable magnification optical system of Example 1 is in an intermediate focal length state and focused on an object at infinity. FIG. 2B is a diagram showing various aberrations when the variable magnification optical system of Example 1 is in a telephoto end state and focused on an object at infinity. FIG. 2C is a diagram showing various aberrations when the variable magnification optical system of Example 1 is in a wide-angle end state and focused on an object at infinity.

[0168] In each aberration diagram, FNO indicates the F-number, and Y indicates the image height. More specifically, spherical aberration diagrams indicate the F-number value corresponding to the maximum aperture, astigmatism diagrams and distortion diagrams indicate the maximum image height, and coma diagrams indicate the value of each image height. d indicates the d-line, and g indicates the g-line (wavelength 435.8 nm). In astigmatism diagrams, the solid line indicates the sagittal image plane, and the dashed line indicates the meridional image plane. The same symbols as those used in the aberration diagrams of this embodiment are used in the aberration diagrams of other embodiments described below.

[0169] From each aberration diagram, it can be seen that the variable magnification optical system of this embodiment effectively suppresses aberration fluctuations during focusing and magnification change, and has high optical performance.

[0170] (Second Example) FIG. 3 is a cross-sectional view of the variable magnification optical system of the second embodiment when focused on an object at infinity in the wide-angle end state.

[0171] The variable magnification optical system of this embodiment has, in order from the object side, a first lens group G1 having positive refractive power, a second lens group G2 having negative refractive power, an aperture stop S, a third lens group G3 having positive refractive power, a fourth lens group G4 having positive refractive power, a fifth lens group G5 having negative refractive power, and a sixth lens group G6 having negative refractive power.

[0172] The first lens group G1 is composed of a cemented positive lens consisting of, in order from the object side, a negative meniscus lens L1 with a convex surface facing the object side and a positive meniscus lens L2 with a convex surface facing the object side.

[0173] The second lens group G2 is composed of, in order from the object side, a negative meniscus lens L3 with a convex surface facing the object side, a biconcave negative lens L4, a biconvex positive lens L5, and a biconcave negative lens L6.

[0174] The third lens group G3 consists of, in order from the object side, a biconvex positive lens L7, a cemented positive lens formed by cementing a negative meniscus lens L8 with its convex surface facing the object side and a biconvex positive lens L9, and a negative meniscus lens L10 with its concave surface facing the object side.

[0175] The fourth lens group G4 consists of, in order from the object side, a cemented positive lens consisting of a biconvex positive lens L11 and a negative meniscus lens L12 with its concave surface facing the object side, and a cemented positive lens consisting of a negative meniscus lens L13 with its convex surface facing the object side and a biconvex positive lens L14.

[0176] The fifth lens group G5 is composed of, in order from the object side, a cemented negative lens consisting of a biconvex positive lens L15 and a biconcave negative lens L16.

[0177] The sixth lens group G6 is composed of, in order from the object side, a biconcave negative lens L17 and a biconvex positive lens L18.

[0178] On the image plane I, an image pickup element (not shown) made up of a CCD, a CMOS, or the like is disposed.

[0179] The variable magnification optical system of this embodiment focuses by moving the fourth lens group G4 and the fifth lens group G5 along the optical axis. When focusing on a close object from a state focused on infinity, the fourth lens group G4 and the fifth lens group G5 are each moved from the object side to the image side.

[0180] In the variable magnification optical system of this embodiment, the second lens group G2, the third lens group G3, the fourth lens group G4, the fifth lens group G5, and the sixth lens group G6 correspond to the rear group, and the sixth lens group G6 corresponds to the final lens group. Also, the second lens group G2 corresponds to the first negative lens group, the third lens group G3 corresponds to the first positive lens group, the fourth lens group G4 corresponds to the second positive lens group, and the fifth lens group G5 corresponds to the second negative lens group. Also, the fourth lens group G4 corresponds to the first focusing group and the positive focusing group, and the fifth lens group G5 corresponds to the second focusing group and the negative focusing group.

[0181] Table 2 below lists the values ​​of the specifications of the variable magnification optical system of this example.

[0182] (Table 2) [Overall specifications] fw 24.75 ft 193.60 Fnow 4.00 Fnot 6.50 [Lens specifications] mrd nd νd (19) (21) 1) 50.215 2.000 1.903660 31.27 2) 34.572 9.588 1.603000 65.44 3) 1311.519 d3 4) 734.769 1.307 1.953750 32.33 5) 18.756 4.799 6) -48.834 1.129 1.755000 52.33 7) 82.569 0.451 8) 35.539 3.409 1.922860 20.88 P1 9) -55.882 0.297 10) -40.429 1.015 1.816000 46.59 11) 149.588 d11 12> ∞ 2.016 (aperture stop) 13) 45.792 2.740 1.902650 35.72 P1 14) -158.052 0.500 15) 51.626 1.000 2.001000 29.12 16) 25.348 3.645 1.579570 53.74 17) -47.120 1.756 18) -28.990 1.043 1.953750 32.33 19) -180.881 d19 20) 31.325 6.348 1.834810 42.73 P1 21) -46.677 1.000 1.903660 31.27 22) -434.420 0.175 23) 31.122 2.824 1.953750 32.33 24) 15.393 10.000 1.497100 81.49 P2 *25) -46.610 d25 26) 192.398 3.146 1.846660 23.80 P1 27) -50.784 1.017 1.851350 40.13 *28) 33.031 d28 29) -39.648 1.400 1.820800 42.51 *30) 237.062 0.232 31) 46.735 4.880 1.683760 37.57 P1 32) -359.761 Bf [Aspherical data] m K A4 A6 A8 A10 A12 25) 0.0000 3.31E-05 -5.07E-08 7.86E-10 -4.83E-12 1.35E-14 28) 0.0000 -3.68E-06 5.73E-08 -1.75E-10 -8.02E-13 5.32E-15 30) 0.0000 7.67E-06 -1.25E-08 6.72E-11 -1.62E-13 [Focal length data for each group] Group starting plane focal length G1 1 110.64 G2 4 -16.88 G3 13 59.63 G4 20 27.13 G5 26 -47.14 G6 29 -137.34 [Variable Interval Data] Wide-angle end Telephoto end d3 1.969 54.765 d11 17.288 1.166 d19 14.645 1.478 d25 4.685 2.612 d28 8.395 23.634 Bf 11.793 37.548

[0183] FIG. 4A is a diagram showing various aberrations when the variable magnification optical system of Example 2 is focused on an object at infinity in the intermediate focal length state, FIG. 4B is a diagram showing various aberrations when the variable magnification optical system of Example 2 is focused on an object at infinity in the telephoto end state, and FIG. 4C is a diagram showing various aberrations when the variable magnification optical system of Example 2 is focused on an object at infinity in the wide-angle end state.

[0184] From each aberration diagram, it can be seen that the variable magnification optical system of this embodiment effectively suppresses aberration fluctuations during focusing and magnification change, and has high optical performance.

[0185] (Third Example) FIG. 5 is a cross-sectional view of the variable magnification optical system of the third embodiment when focused on an object at infinity in the wide-angle end state.

[0186] The variable magnification optical system of this embodiment has, in order from the object side, a first lens group G1 having positive refractive power, a second lens group G2 having negative refractive power, an aperture stop S, a third lens group G3 having positive refractive power, a fourth lens group G4 having positive refractive power, a fifth lens group G5 having negative refractive power, a sixth lens group G6 having negative refractive power, and a seventh lens group G7 having positive refractive power.

[0187] The first lens group G1 is composed of, in order from the object side, a cemented positive lens consisting of a negative meniscus lens L1 with a convex surface facing the object side and a positive meniscus lens L2 with a convex surface facing the object side.

[0188] The second lens group G2 consists of, in order from the object side, a negative meniscus lens L3 with a convex surface facing the object side, a cemented positive lens consisting of a biconcave negative lens L4 and a positive meniscus lens L5 with a convex surface facing the object side, and a negative meniscus lens L6 with a concave surface facing the object side.

[0189] The third lens group G3 is composed of, in order from the object side, a positive meniscus lens L7 with a convex surface facing the object side, and a positive meniscus lens L8 with a convex surface facing the object side.

[0190] The fourth lens group G4 consists of, in order from the object side, a cemented positive lens consisting of a negative meniscus lens L9 with a convex surface facing the object side and a positive meniscus lens L10 with a convex surface facing the object side, a cemented negative lens consisting of a biconvex positive lens L11 and a negative meniscus lens L12 with a concave surface facing the object side, and a biconvex positive lens L13.

[0191] The fifth lens group G5 is composed of, in order from the object side, a positive meniscus lens L14 with its concave surface facing the object side, and a negative biconcave lens L15.

[0192] The sixth lens group G6 is made up of a biconcave negative lens L16.

[0193] The seventh lens group G7 is made up of a positive meniscus lens L17 with its convex surface facing the object side.

[0194] On the image plane I, an image pickup element (not shown) made up of a CCD, a CMOS, or the like is disposed.

[0195] The variable magnification optical system of this embodiment focuses by moving the fifth lens group G5 and the sixth lens group G6 along the optical axis. When focusing on a close object from a state focused on infinity, the fifth lens group G5 and the sixth lens group G6 are each moved from the object side to the image side.

[0196] In the variable magnification optical system of this embodiment, the second lens group G2, the third lens group G3, the fourth lens group G4, the fifth lens group G5, the sixth lens group G6, and the seventh lens group G7 correspond to the rear group, and the seventh lens group G7 corresponds to the final lens group. Also, the second lens group G2 corresponds to the first negative lens group, the third lens group G3 corresponds to the first positive lens group, the fourth lens group G4 corresponds to the second positive lens group, and the fifth lens group G5 corresponds to the second negative lens group. Also, the fifth lens group G5 corresponds to the first focusing group, the sixth lens group G6 corresponds to the second focusing group, and the fifth lens group G5 and the sixth lens group G6 correspond to the negative focusing group.

[0197] Table 3 below lists the specifications of the variable magnification optical system of this example.

[0198] (Table 3) [Overall specifications] fw 28.00 ft 194.00 Fnow 4.37 Fnot 6.57 [Lens specifications] mrd nd νd (19) (20) (21) 1) 63.743 2.000 1.749500 35.25 2) 40.141 10.350 1.593190 67.90 3) 9735.642 d3 * 4) 158.701 1.500 1.773870 47.25 * 5) 22.089 5.915 6) -167.771 1.000 1.497820 82.57 N 7) 20.719 4.566 1.850000 27.03 P1 8) 79.584 2.363 9) -46.857 1.000 1.834810 42.73 10) -393.371 d10 11> ∞ 2.000 (aperture stop) *12) 25.238 2.790 1.592450 66.92 P2 13) 59.114 0.200 14) 26.374 2.366 1.617720 49.81 15) 38.522 d15 16) 23.189 2.580 1.902650 35.77 17) 13.857 5.703 1.497820 82.57 P2 18) 693.648 1.004 19) 752.104 4.789 1.517420 52.20 20) -18.856 1.000 2.000690 25.46 21) -60.570 0.200 *22) 443.772 4.473 1.517420 52.20 23) -23.063 d23 24) -308.609 5.485 1.945944 17.98 25) -37.228 1.504 26) -58.034 1.000 1.834000 37.18 27) 84.476 d27 *28) -39.484 1.500 1.773870 47.25 29) 108.384 d29 30) 38.120 2.261 1.834000 37.18 31) 43.033 Bf [Aspherical surface] m K A4 A6 A8 A10 4) 0.0000 7.29E-07 2.06E-08 -4.49E-11 2.79E-14 5) 0.0000 2.28E-06 3.23E-08 4.83E-11 2.02E-13 12) 0.0000 -9.41E-06 -1.09E-09 4.05E-11 -1.20E-13 22) 0.0000 -3.09E-05 2.57E-08 -7.88E-12 3.97E-13 28) 0.0000 -6.15E-06 -1.61E-08 3.82E-11 -1.85E-14 [Focus distance of each group] Group initial focal distance G1 1 127.24 G2 4 -21.51 G3 12 45.92 G4 16 42.44 G5 24 -980.13 G6 28 -37.23 G7 30 331.08 [Variable Interval Data] Wide-angle end Telephoto end d3 2.000 51.261 d10 25.674 2.000 d15 9.525 2.000 d23 3.205 2.269 d27 5.176 5.639 d29 4.174 37.020 Bf 13.579 36.718

[0199] FIG. 6A is a diagram showing various aberrations when the variable magnification optical system of Example 3 is focused on an object at infinity in the wide-angle end state, FIG. 3B is a diagram showing various aberrations when the variable magnification optical system of Example 6 is focused on an object at infinity in the intermediate focal length state, and FIG. 3C is a diagram showing various aberrations when the variable magnification optical system of Example 6 is focused on an object at infinity in the telephoto end state.

[0200] From each aberration diagram, it can be seen that the variable magnification optical system of this embodiment effectively suppresses aberration fluctuations during focusing and magnification change, and has high optical performance.

[0201] (Fourth Example) FIG. 7 is a cross-sectional view of the variable magnification optical system of the fourth embodiment when focused on an object at infinity in the wide-angle end state.

[0202] The variable magnification optical system of this embodiment has, in order from the object side, a first lens group G1 having positive refractive power, a second lens group G2 having negative refractive power, an aperture stop S, a third lens group G3 having positive refractive power, a fourth lens group G4 having negative refractive power, a fifth lens group G5 having positive refractive power, a sixth lens group G6 having positive refractive power, and a seventh lens group G7 having negative refractive power.

[0203] The first lens group G1 is composed of, in order from the object side, a cemented positive lens consisting of a negative meniscus lens L1 with its convex surface facing the object side and a biconvex positive lens L2.

[0204] The second lens group G2 is composed of, in order from the object side, a biconcave negative lens L3, a biconcave negative lens L4, a biconvex positive lens L5, and a biconcave negative lens L6.

[0205] The third lens group G3 is composed of, in order from the object side, a biconvex positive lens L7, and a cemented negative lens formed by cementing a negative meniscus lens L8 with its convex surface facing the object side and a positive meniscus lens L9 with its convex surface facing the object side.

[0206] The fourth lens group G4 is composed of, in order from the object side, a biconvex positive lens L10, a cemented negative lens consisting of a biconcave negative lens L11 and a positive meniscus lens L12 with its convex surface facing the object side.

[0207] The fifth lens group G5 is composed of, in order from the object side, a cemented positive lens consisting of a negative meniscus lens L13 with a convex surface facing the object side and a positive meniscus lens L14 with a convex surface facing the object side.

[0208] The sixth lens group G6 is made up of a biconvex positive lens L15.

[0209] The seventh lens group G7 is composed of, in order from the object side, a biconcave negative lens L16, a biconvex positive lens L17, and a plano-concave negative lens L18 with its concave surface facing the object side.

[0210] On the image plane I, an image pickup element (not shown) made up of a CCD, a CMOS, or the like is disposed.

[0211] The variable magnification optical system of this embodiment focuses by moving the fifth lens group G5 and the sixth lens group G6 along the optical axis. When focusing on a close object from a state focused on infinity, the fifth lens group G5 and the sixth lens group G6 are each moved from the image side to the object side.

[0212] In the variable magnification optical system of this embodiment, the second lens group G2, the third lens group G3, the fourth lens group G4, the fifth lens group G5, the sixth lens group G6, and the seventh lens group G7 correspond to the rear group, and the seventh lens group G7 corresponds to the final lens group. Also, the second lens group G2 corresponds to the first negative lens group, the third lens group G3 corresponds to the first positive lens group, the fourth lens group G4 corresponds to the second negative lens group, and the fifth lens group G5 corresponds to the second positive lens group. Also, the fifth lens group G5 corresponds to the first focusing group, the sixth lens group G6 corresponds to the second focusing group, and the fifth lens group G5 and the sixth lens group G6 correspond to the positive focusing group.

[0213] Table 4 below lists the specifications of the variable magnification optical system of this example.

[0214] (Table 4) [Overall specifications] fw 24.70 ft 233.00 Fnow 4.50 Fnot 6.57 [Lens specifications] mrd nd νd (19) (21) 1) 59.540 1.800 1.902650 35.77 2) 41.859 11.321 1.593190 67.90 3) -1956.315 d3 * 4) -379.614 1.500 1.773870 47.25 5) 21.088 6.883 6) -118.229 1.000 1.950000 29.37 7) 89.211 0.200 8) 38.887 5.729 1.860740 23.08 P1 9) -55.015 1.189 10) -34.049 1.000 1.816000 46.59 11) 19309.949 d11 12> ∞ 2.000 (aperture stop) *13) 23.950 5.797 1.592450 66.92 P2 14) -162.098 0.200 15) 35.893 1.000 1.834810 42.73 16) 22.737 2.714 1.592700 35.27 P1 17) 30.251 d17 18) 26.148 5.048 1.593190 67.90 P2 19) -98.728 1.059 20) -84.013 1.000 2.000690 25.46 21) 20.844 4.119 1.593190 67.90 22) 163.041 d22 23) 23.630 1.000 1.902650 35.77 24) 12.909 6.589 1.728250 28.38 25) 150.766 d25 26) 48.329 2.746 1.548141 45.78 P1 *27) -404.148 d27 28) -65.371 1.000 1.816000 46.59 29) 26.189 0.850 30) 34.959 6.023 1.688930 31.16 P1 31) -33.122 1.371 *32) -22.123 1.300 1.773870 47.25 33) ∞ Bf [Aspherical data] m K A4 A6 A8 A10 4) 0.0000 2.64E-06 -1.77E-09 5.14E-12 -3.69E-15 13) 0.0000 -1.00E-05 -3.09E-09 -1.67E-11 -9.99E-15 27) 0.0000 2.31E-05 -1.32E-09 -3.88E-11 -1.96E-12 32) 0.0000 6.59E-06 1.96E-08 -1.08E-10 5.11E-13 [Focal length data for each group] Group starting plane focal length G1 1 122.62 G2 4 -21.74 G3 13 41.87 G4 18 -326.91 G5 23 48.34 G6 26 78.92 G7 28 -25.48 [Variable Interval Data] Wide-angle end Telephoto end d3 2.000 51.859 d11 33.722 2.003 d17 9.826 2.000 d22 2.157 3.750 d25 2.446 6.907 d27 3.087 2.700 Bf 11.455 67.126

[0215] FIG. 8A is a diagram showing various aberrations when the variable magnification optical system of Example 4 is in the wide-angle end state and focused on an object at infinity, FIG. 8B is a diagram showing various aberrations when the variable magnification optical system of Example 4 is in the intermediate focal length state and focused on an object at infinity, and FIG. 8C is a diagram showing various aberrations when the variable magnification optical system of Example 4 is in the telephoto end state and focused on an object at infinity.

[0216] From each aberration diagram, it can be seen that the variable magnification optical system of this embodiment effectively suppresses aberration fluctuations during focusing and magnification change, and has high optical performance.

[0217] (Fifth Example) FIG. 9 is a cross-sectional view of the variable magnification optical system of the fifth embodiment when focused on an object at infinity in the wide-angle end state.

[0218] The variable magnification optical system of this embodiment has, in order from the object side, a first lens group G1 having positive refractive power, a second lens group G2 having negative refractive power, a third lens group G3 having positive refractive power, a fourth lens group G4 having positive refractive power, a fifth lens group G5 having negative refractive power, and a sixth lens group G6 having positive refractive power.

[0219] The first lens group G1 is composed of, in order from the object side, a cemented positive lens consisting of a negative meniscus lens L1 with its convex surface facing the object side and a biconvex positive lens L2.

[0220] The second lens group G2 is composed of, in order from the object side, a cemented negative lens of a biconcave negative lens L3 and a positive meniscus lens L4 with its convex surface facing the object side, and a biconcave negative lens L5.

[0221] The third lens group G3 is made up of a biconvex positive lens L6.

[0222] The fourth lens group G4 is composed of, in order from the object side, a cemented positive lens of a biconvex positive lens L7 and a biconcave negative lens L8, a biconvex positive lens L9, and an aperture stop S.

[0223] The fifth lens group G5 is composed of, in order from the object side, a cemented negative lens consisting of a positive meniscus lens L10 with a convex surface facing the object side and a negative meniscus lens L11 with a convex surface facing the object side.

[0224] The sixth lens group G6 is composed of, in order from the object side, a biconvex positive lens L12 and a biconcave negative lens L13.

[0225] On the image plane I, an image pickup element (not shown) made up of a CCD, a CMOS, or the like is disposed.

[0226] The variable magnification optical system of this embodiment focuses by moving the third lens group G3 and the fifth lens group G5 along the optical axis. When focusing on a close object from a state focused on infinity, the third lens group G3 is moved from the object side to the image side, and the fifth lens group G5 is moved from the image side to the object side.

[0227] In the variable magnification optical system of this embodiment, the second lens group G2, the third lens group G3, the fourth lens group G4, the fifth lens group G5, and the sixth lens group G6 correspond to the rear group, and the sixth lens group G6 corresponds to the final lens group. Also, the second lens group G2 corresponds to the first negative lens group, the third lens group G3 corresponds to the first positive lens group, the fourth lens group G4 corresponds to the second positive lens group, and the fifth lens group G5 corresponds to the second negative lens group. Also, the third lens group G3 corresponds to the first focusing group and the positive focusing group, and the fifth lens group G5 corresponds to the second focusing group and the negative focusing group.

[0228] Table 5 below lists the specifications of the variable magnification optical system of this example.

[0229] (Table 5) [Overall specifications] fw 72.10 ft 292.00 Fnow 4.58 Fnot 6.61 [Lens specifications] mrd nd νd (19) (21) 1) 93.405 1.700 1.620040 36.40 2) 42.616 9.246 1.593490 67.00 3) -447.133 d3 4) -103.511 1.300 1.683760 37.64 5) 20.714 4.645 1.846660 23.80 P1 6) 115.440 1.781 7) -68.341 1.400 1.804000 46.60 8) 70.521 d8 9) 125.904 3.704 1.593490 67.00 P2 10) -55.136 d10 11) 40.554 5.120 1.497820 82.57 P2 12) -50.483 1.300 1.834000 37.18 13) 158.692 0.352 14) 61.264 3.021 1.516800 64.13 P2 15) -380.539 1.336 16> ∞ d16 (aperture stop) 17) 16.841 4.019 1.516800 64.13 P2 18) 103.211 1.000 1.834810 42.73 19) 17.184 d19 20) 36.185 4.666 1.647690 33.72 P1 21) -30.124 1.591 22) -26.250 1.200 1.772500 49.62 23) 57.120 Bf [Focal length data for each group] Group starting plane focal length G1 1 137.15 G2 4 -33.71 G3 9 65.10 G4 11 98.06 G5 17 -97.80 G6 20 3777.12 [Variable Interval Data] Wide-angle end Telephoto end d3 3.000 57.438 d8 32.058 2.647 d10 10.781 15.109 d16 13.747 14.331 d19 19.107 19.820 Bf 38.890 67.593

[0230] FIG. 10A is a diagram showing various aberrations when the variable magnification optical system of Example 5 is focused on an object at infinity in the wide-angle end state, FIG. 10B is a diagram showing various aberrations when the variable magnification optical system of Example 5 is focused on an object at infinity in the intermediate focal length state, and FIG. 10C is a diagram showing various aberrations when the variable magnification optical system of Example 5 is focused on an object at infinity in the telephoto end state.

[0231] From each aberration diagram, it can be seen that the variable magnification optical system of this embodiment effectively suppresses aberration fluctuations during focusing and magnification change, and has high optical performance.

[0232] (Sixth Example) FIG. 11 is a cross-sectional view of the variable magnification optical system of the sixth embodiment when focused on an object at infinity in the wide-angle end state.

[0233] The variable magnification optical system of this embodiment has, in order from the object side, a first lens group G1 having positive refractive power, a second lens group G2 having negative refractive power, a third lens group G3 having positive refractive power, a fourth lens group G4 having positive refractive power, a fifth lens group G5 having negative refractive power, and a sixth lens group G6 having positive refractive power.

[0234] The first lens group G1 is composed of, in order from the object side, a cemented positive lens consisting of a negative meniscus lens L1 with its convex surface facing the object side and a biconvex positive lens L2.

[0235] The second lens group G2 is composed of, in order from the object side, a cemented negative lens of a biconcave negative lens L3 and a positive meniscus lens L4 with its convex surface facing the object side, and a biconcave negative lens L5.

[0236] The third lens group G3 is made up of a biconvex positive lens L6.

[0237] The fourth lens group G4 is composed of, in order from the object side, a cemented negative lens of a biconvex positive lens L7 and a biconcave negative lens L8, a biconvex positive lens L9, and an aperture stop S.

[0238] The fifth lens group G5 is composed of, in order from the object side, a cemented negative lens consisting of a positive meniscus lens L10 with a convex surface facing the object side and a negative meniscus lens L11 with a convex surface facing the object side.

[0239] The sixth lens group G6 is composed of, in order from the object side, a biconvex positive lens L12 and a biconcave negative lens L13.

[0240] On the image plane I, an image pickup element (not shown) made up of a CCD, a CMOS, or the like is disposed.

[0241] The variable magnification optical system of this embodiment focuses by moving the third lens group G3 along the optical axis. When focusing on a close object from a state focused on infinity, the third lens group G3 is moved from the object side to the image side.

[0242] In the variable magnification optical system of this embodiment, the second lens group G2, the third lens group G3, the fourth lens group G4, the fifth lens group G5, and the sixth lens group G6 correspond to the rear group, and the sixth lens group G6 corresponds to the final lens group. Also, the second lens group G2 corresponds to the first negative lens group, the third lens group G3 corresponds to the first positive lens group, the fourth lens group G4 corresponds to the second positive lens group, and the fifth lens group G5 corresponds to the second negative lens group. Also, the third lens group G3 corresponds to the positive focusing group.

[0243] Table 6 below lists the specifications of the variable magnification optical system of this example.

[0244] (Table 6) [Overall specifications] fw 72.10 ft 292.00 Fnow 4.58 Fnot 6.57 [Lens specifications] mrd nd νd (19) (21) 1) 92.970 1.700 1.620040 36.40 2) 43.346 9.131 1.593490 67.00 3) -462.480 d3 4) -100.059 1.300 1.683760 37.64 5) 20.916 4.670 1.846660 23.80 P1 6) 121.589 1.756 7) -71.192 1.400 1.804000 46.60 8) 67.069 d8 9) 106.891 3.779 1.593490 67.00 P2 10) -58.234 d10 11) 43.138 5.112 1.497820 82.57 P2 12) -47.949 1.300 1.834000 37.18 13) 142.876 0.200 14) 52.297 3.255 1.516800 64.13 P2 15) -331.307 1.309 16> ∞ d16 (Open-mouth twist) 17) 15.447 4.036 1.487490 70.32 P2 18) 58.875 1.000 1.816000 46.59 19) 15.196 d19 20) 27.012 5.563 1.639800 34.55 P1 21) -31.106 1.109 22) -28.302 1.200 1.816000 46.59 23) 42.508 Bf [Data on focal distance for each group] Group initial face focal distance G1 1 137.16 G2 4 -33.63 G3 9 64.06 G4 11 98.59 G5 17 -88.07 G6 20 1085.47 [Variable Interval Data] Wide-angle end Telephoto end d3 3.000 57.365 d8 32.338 2.626 d10 10.055 15.204 d16 13.438 16.164 d19 19.352 24.524 Bf 38.520 60.623

[0245] FIG. 12A is a diagram showing various aberrations when the variable magnification optical system of Example 6 is focused on an object at infinity in the wide-angle end state, FIG. 12B is a diagram showing various aberrations when the variable magnification optical system of Example 6 is focused on an object at infinity in the intermediate focal length state, and FIG. 12C is a diagram showing various aberrations when the variable magnification optical system of Example 6 is focused on an object at infinity in the telephoto end state.

[0246] From each aberration diagram, it can be seen that the variable magnification optical system of this embodiment effectively suppresses aberration fluctuations during focusing and magnification change, and has high optical performance.

[0247] (Seventh Example) FIG. 13 is a cross-sectional view of the variable magnification optical system of the seventh embodiment when focused on an object at infinity in the wide-angle end state.

[0248] The variable magnification optical system of this embodiment has, in order from the object side, a first lens group G1 having positive refractive power, a second lens group G2 having negative refractive power, a third lens group G3 having positive refractive power, a fourth lens group G4 having negative refractive power, a fifth lens group G5 having negative refractive power, and a sixth lens group G6 having positive refractive power.

[0249] The first lens group G1 is composed of, in order from the object side, a cemented positive lens consisting of a negative meniscus lens L1 with its convex surface facing the object side and a biconvex positive lens L2.

[0250] The second lens group G2 consists of, in order from the object side, a negative meniscus lens L3 with a convex surface facing the object side, a biconvex positive lens L4, a biconcave negative lens L5, and a negative meniscus lens L6 with a concave surface facing the object side.

[0251] The third lens group G3 consists of, in order from the object side, a cemented positive lens of a negative meniscus lens L7 with a convex surface facing the object side and a biconvex positive lens L8, a cemented positive lens of a biconvex positive lens L9 and a biconcave negative lens L10, an aperture stop S, a cemented negative lens of a negative meniscus lens L11 with a convex surface facing the object side and a positive meniscus lens L12 with a convex surface facing the object side, and a biconvex positive lens L13.

[0252] The fourth lens group G4 is composed of, in order from the object side, a positive meniscus lens L14 with its concave surface facing the object side, and a negative biconcave lens L15.

[0253] The fifth lens group G5 is made up of a negative meniscus lens L16 with its concave surface facing the object side.

[0254] The sixth lens group G6 is made up of a biconvex positive lens L17.

[0255] On the image plane I, an image pickup element (not shown) made up of a CCD, a CMOS, or the like is disposed.

[0256] The variable magnification optical system of this embodiment focuses by moving the fourth lens group G4 and the fifth lens group G5 along the optical axis. When focusing on a close object from a state focused on infinity, the fourth lens group G4 and the fifth lens group G5 are each moved from the object side to the image side.

[0257] In the variable magnification optical system of this embodiment, the second lens group G2, the third lens group G3, the fourth lens group G4, the fifth lens group G5, and the sixth lens group G6 correspond to the rear group, and the sixth lens group G6 corresponds to the final lens group. Also, the second lens group G2 corresponds to the first negative lens group, the third lens group G3 corresponds to the first positive lens group, the fourth lens group G4 corresponds to the second negative lens group, and the sixth lens group G6 corresponds to the second positive lens group. Also, the fourth lens group G4 corresponds to the first focusing group, the fifth lens group G5 corresponds to the second focusing group, and the fourth lens group G4 and the fifth lens group G5 correspond to the negative focusing group.

[0258] Table 7 below lists the specifications of the variable magnification optical system of this example.

[0259] (Table 7) [Overall specifications] fw 72.10 ft 292.00 Fnow 4.49 Fnot 6.21 [Lens specifications] mrd nd νd (19) (21) 1) 103.381 1.800 1.612660 44.46 2) 56.049 7.558 1.497000 81.73 3) -417.833 d3 4) 1940.418 1.700 1.728250 28.38 5) 44.522 0.200 6) 40.999 5.800 1.805180 25.45 P1 7) -98.495 0.975 8) -90.753 1.300 1.719990 50.27 9) 49.210 5.010 10) -50.325 1.200 1.804000 46.60 11) -103.290 d11 12) 74.439 1.200 1.801000 34.92 13) 34.335 5.843 1.640000 60.20 14) -89.952 1.500 15) 33.118 5.468 1.487490 70.31 16) -71.039 1.300 1.806100 40.97 17) 150.553 1.732 18> ∞ 17.417 (aperture stop) 19) 58.020 1.200 1.834000 37.18 20) 24.956 4.220 1.516800 64.14 P2 21) 248.482 0.200 22) 95.637 2.538 1.801000 34.92 P1 23) -243.668 d23 24) -178.276 2.420 1.805180 25.45 P1 25) -42.169 2.338 26) -42.123 1.000 1.772500 49.62 27) 49.172 d27 28) -20.209 1.300 1.806100 40.97 29) -33.231 d29 30) 133.070 4.831 1.683760 37.64 P1 31) -133.074 Bf [Focal length data for each group] Group starting plane focal length G1 1 198.62 G2 4 -54.01 G3 12 42.61 G4 24 -54.29 G5 28 -66.96 G6 30 98.03 [Variable Interval Data] Wide-angle end Telephoto end d3 2.000 80.188 d11 56.188 2.000 d23 2.073 3.714 d27 19.599 17.958 d29 1.892 28.542 Bf 28.519 29.869

[0260] FIG. 14A is a diagram showing various aberrations when the variable magnification optical system of Example 7 is focused on an object at infinity in the wide-angle end state, FIG. 14B is a diagram showing various aberrations when the variable magnification optical system of Example 7 is focused on an object at infinity in the intermediate focal length state, and FIG. 14C is a diagram showing various aberrations when the variable magnification optical system of Example 7 is focused on an object at infinity in the telephoto end state.

[0261] From each aberration diagram, it can be seen that the variable magnification optical system of this embodiment effectively suppresses aberration fluctuations during focusing and magnification change, and has high optical performance.

[0262] (Eighth Example) FIG. 15 is a cross-sectional view of the variable magnification optical system of Example 8 when focused on an object at infinity in the wide-angle end state.

[0263] The variable magnification optical system of this embodiment has, in order from the object side, a first lens group G1 having positive refractive power, a second lens group G2 having positive refractive power, a third lens group G3 having negative refractive power, a fourth lens group G4 having positive refractive power, a fifth lens group G5 having negative refractive power, a sixth lens group G6 having negative refractive power, and a seventh lens group G7 having positive refractive power.

[0264] The first lens group G1 is composed of, in order from the object side, a cemented positive lens consisting of a negative meniscus lens L1 with its convex surface facing the object side and a biconvex positive lens L2.

[0265] The second lens group G2 is made up of a biconvex positive lens L3.

[0266] The third lens group G3 is composed of, in order from the object side, a biconcave negative lens L4, a biconvex positive lens L5, a biconcave negative lens L6, and a biconcave negative lens L7.

[0267] The fourth lens group G4 consists of, in order from the object side, a cemented positive lens of a negative meniscus lens L8 with a convex surface facing the object side and a biconvex positive lens L9, a cemented positive lens of a biconvex positive lens L10 and a biconcave negative lens L11, an aperture stop S, a cemented positive lens of a negative meniscus lens L12 with a convex surface facing the object side and a positive meniscus lens L13 with a convex surface facing the object side, and a positive meniscus lens L14 with a convex surface facing the object side.

[0268] The fifth lens group G5 is composed of, in order from the object side, a positive meniscus lens L15 with its concave surface facing the object side, and a negative biconcave lens L16.

[0269] The sixth lens group G6 is made up of a negative meniscus lens L17 with its concave surface facing the object side.

[0270] The seventh lens group G7 is made up of a biconvex positive lens L18.

[0271] On the image plane I, an image pickup element (not shown) made up of a CCD, a CMOS, or the like is disposed.

[0272] The variable magnification optical system of this embodiment focuses by moving the fifth lens group G5 and the sixth lens group G6 along the optical axis. When focusing on a close object from a state focused on infinity, the fifth lens group G5 and the sixth lens group G6 are each moved from the object side to the image side.

[0273] In the variable magnification optical system of this embodiment, the second lens group G2, the third lens group G3, the fourth lens group G4, the fifth lens group G5, the sixth lens group G6, and the seventh lens group G7 correspond to the rear group, and the seventh lens group G7 corresponds to the final lens group. Also, the second lens group G2 corresponds to the first positive lens group, the third lens group G3 corresponds to the first negative lens group, the fourth lens group G4 corresponds to the second positive lens group, and the fifth lens group G5 corresponds to the second negative lens group. Also, the fifth lens group G5 corresponds to the first focusing group, the sixth lens group G6 corresponds to the second focusing group, and the fifth lens group G5 and the sixth lens group G6 correspond to the negative focusing group.

[0274] Table 8 below lists the specifications of the variable magnification optical system of this example.

[0275] (Table 8) [Overall specifications] fw 72.10 ft 291.99 Fnow 4.63 Fnot 6.45 [Lens specifications] mrd nd νd (19) (21) 1) 50.215 2.000 1.903660 31.27 1) 110.903 1.800 1.612660 44.46 2) 54.570 6.966 1.497000 81.73 3) -8459.724 d3 4) 389.676 3.198 1.593490 67.00 P2 5) -170.170 d5 6) -80.023 1.700 1.834000 37.18 7) 128.334 0.200 8) 62.764 5.800 1.805180 25.45 P1 9) -104.722 0.200 10) -239.601 1.300 1.593490 67.00 11) 64.821 2.975 12) -115.403 1.200 1.804000 46.60 13) 106.788 d13 14) 69.826 1.200 1.801000 34.92 15) 32.742 6.159 1.640000 60.20 P2 16) -98.985 1.500 17) 32.137 5.379 1.487490 70.31 P2 18) -82.765 1.300 1.806100 40.97 19) 187.891 1.821 20> ∞ 14.671 (aperture stop) 21) 42.155 1.200 1.834000 37.18 22) 20.994 4.480 1.516800 64.14 P2 23) 145.744 0.200 24) 86.627 2.095 1.801000 34.92 P1 25) 326.609 d25 26) -283.549 2.410 1.805180 25.45 P1 27) -42.139 2.354 28) -39.853 1.000 1.772500 49.62 29) 41.741 d29 30) -20.381 1.300 1.806100 40.97 31) -29.284 d31 32) 146.035 4.576 1.683760 37.64 33) -146.063 Bf [Aspherical data] m K A4 A6 A8 A10 A12 25) 0.0000 3.31E-05 -5.07E-08 7.86E-10 -4.83E-12 1.35E-14 28) 0.0000 -3.68E-06 5.73E-08 -1.75E-10 -8.02E-13 5.32E-15 30) 0.0000 7.67E-06 -1.25E-08 6.72E-11 -1.62E-13 [Focal length data for each group] Group starting plane focal length G1 1 287.74 G2 4 200.00 G3 6 -42.96 G4 14 41.02 G5 26 -49.36 G6 30 -88.96 G7 32 107.48 [Variable Interval Data] Wide-angle end Telephoto end d3 1.000 54.911 d5 2.049 27.612 d13 55.563 2.000 d25 2.292 3.990 d29 19.287 17.589 d31 2.709 30.614 Bf 28.515 28.611

[0276] FIG. 16A is a diagram showing various aberrations when the variable magnification optical system of Example 8 is focused on an object at infinity in the wide-angle end state, FIG. 16B is a diagram showing various aberrations when the variable magnification optical system of Example 8 is focused on an object at infinity in the intermediate focal length state, and FIG. 16C is a diagram showing various aberrations when the variable magnification optical system of Example 8 is focused on an object at infinity in the telephoto end state.

[0277] From each aberration diagram, it can be seen that the variable magnification optical system of this embodiment effectively suppresses aberration fluctuations during focusing and magnification change, and has high optical performance.

[0278] (Ninth Example) FIG. 17 is a cross-sectional view of the variable magnification optical system of Example 9 when focused on an object at infinity in the wide-angle end state.

[0279] The variable magnification optical system of this embodiment has, in order from the object side, a first lens group G1 having positive refractive power, a second lens group G2 having negative refractive power, a third lens group G3 having positive refractive power, an aperture stop S, a fourth lens group G4 having negative refractive power, a fifth lens group G5 having positive refractive power, a sixth lens group G6 having positive refractive power, and a seventh lens group G7 having negative refractive power.

[0280] The first lens group G1 is made up of a biconvex positive lens L1.

[0281] The second lens group G2 consists of, in order from the object side, a cemented positive lens consisting of a positive meniscus lens L2 with a convex surface facing the object side and a positive meniscus lens L3 with a convex surface facing the object side; a cemented negative lens consisting of a negative meniscus lens L4 with a convex surface facing the object side and a negative meniscus lens L5 with a convex surface facing the object side; a negative meniscus lens L6 with a convex surface facing the object side; and a cemented negative lens consisting of a positive meniscus lens L7 with a concave surface facing the object side and a biconcave negative lens L8.

[0282] The third lens group G3 consists of, in order from the object side, a cemented positive lens consisting of a biconvex positive lens L9 and a negative meniscus lens L10 with its concave surface facing the object side, a cemented negative lens consisting of a negative meniscus lens L11 with its convex surface facing the object side and a positive meniscus lens L12 with its convex surface facing the object side, and a positive meniscus lens L13 with its convex surface facing the object side.

[0283] The fourth lens group G4 is composed of, in order from the object side, a biconvex positive lens L14 and a negative meniscus lens L15 with its convex surface facing the object side.

[0284] The fifth lens group G5 is composed of, in order from the object side, a cemented positive lens consisting of a positive meniscus lens L16 having a convex surface facing the object side and a positive meniscus lens L17 having a convex surface facing the object side.

[0285] The sixth lens group G6 is made up of a positive meniscus lens L18 with its convex surface facing the object side.

[0286] The seventh lens group G7 consists of, in order from the object side, a biconvex positive lens L19, a cemented negative lens consisting of a biconcave negative lens L20 and a biconvex positive lens L21, and a negative meniscus lens L22 with its convex surface facing the object side.

[0287] On the image plane I, an image pickup element (not shown) made up of a CCD, a CMOS, or the like is disposed.

[0288] The variable magnification optical system of this embodiment focuses by moving the fifth lens group G5 and the sixth lens group G6 along the optical axis. When focusing on a close object from a state focused on infinity, the fifth lens group G5 and the sixth lens group G6 are each moved from the image side to the object side.

[0289] In the variable magnification optical system of this embodiment, the second lens group G2, the third lens group G3, the fourth lens group G4, the fifth lens group G5, the sixth lens group G6, and the seventh lens group G7 correspond to the rear group, and the seventh lens group G7 corresponds to the final lens group. Also, the second lens group G2 corresponds to the first negative lens group, the third lens group G3 corresponds to the first positive lens group, the fourth lens group G4 corresponds to the second negative lens group, and the fifth lens group G5 corresponds to the second positive lens group. Also, the fifth lens group G5 corresponds to the first focusing group, the sixth lens group G6 corresponds to the second focusing group, and the fifth lens group G5 and the sixth lens group G6 correspond to the positive focusing group.

[0290] Table 9 below lists the specifications of the variable magnification optical system of this example.

[0291] (Table 9) [Overall specifications] fw 205.00 ft 683.00 Fnow 6.30 Fnot 8.00 [Lens specifications] mrd nd νd (19) (21) 1) 282.304 8.619 1.518600 69.89 2) -1633.247 d2 3) 71.894 8.200 1.688930 31.16 P1 4) 713.201 2.000 1.719990 50.27 5) 1550.228 1.500 6) 218.910 1.700 1.801000 34.92 7) 194.026 3.400 1.805180 25.45 8) 153.211 2.400 9) 647.598 1.700 1.762000 40.11 10) 71.876 5.689 11) -272.927 4.600 1.603420 38.03 P1 12) -79.620 1.400 1.744000 44.81 13) 200.459 d13 14) 123.134 8.211 1.593190 67.90 P2 15) -90.441 1.700 1.902650 35.77 16) -200.512 1.200 17) 105.179 1.700 1.953750 32.33 18) 43.357 8.307 1.497820 82.57 P2 19) 322.659 0.300 20) 54.955 4.500 1.744000 44.81 P1 21) 110.542 d21 22> ∞ 4.000 (aperture stop) 23) 70.798 5.930 1.625880 35.72 P1 24) -204.931 0.795 25) 23072.958 1.700 1.883000 40.66 26) 46.606 d26 27) 90.300 2.279 1.677900 50.67 28) 118.675 1.711 1.850260 32.35 P1 29) 166.913 d29 30) 75.383 2.670 1.738000 32.26 31) 705.367 d31 32) 607.612 2.517 1.582670 46.48 33) -162.694 1.703 34) -168.514 1.700 1.696800 55.52 35) 48.407 4.347 1.688930 31.16 P1 36) -1458.581 1.700 37) 473.287 1.700 1.883000 40.66 38) 41.575 Bf [Focal length data for each group] Group starting plane focal length G1 1 464.85 G2 3 -144.07 G3 14 102.52 G4 23 -163.34 G5 27 253.50 G6 30 114.16 G7 32 -54.49 [Variable Interval Data] Wide-angle end Telephoto end d2 4.000 174.000 d13 92.124 3.000 d21 16.841 12.922 d26 9.152 107.086 d29 1.500 9.376 d31 16.068 3.300 Bf 89.891 89.891

[0292] Figure 18A is a diagram showing various aberrations when the variable magnification optical system of Example 9 is focused on an object at infinity in the wide-angle end state, Figure 18B is a diagram showing various aberrations when the variable magnification optical system of Example 9 is focused on an object at infinity in the intermediate focal length state, and Figure 18C is a diagram showing various aberrations when the variable magnification optical system of Example 9 is focused on an object at infinity in the telephoto end state.

[0293] From each aberration diagram, it can be seen that the variable magnification optical system of this embodiment effectively suppresses aberration fluctuations during focusing and magnification change, and has high optical performance.

[0294] According to each of the above-described embodiments, a variable magnification optical system having good optical performance can be realized.

[0295] The values ​​corresponding to the conditional expressions in each example are shown below.

[0296] f1 is the focal length of the first lens group, D1 is the axial thickness of the first lens group, and M1 is the amount of movement of the first lens group when changing magnification from the wide-angle end to the telephoto end. fN1 is the focal length of the first negative lens group, fN2 is the focal length of the second negative lens group, fP1 is the focal length of the first positive lens group, and fP2 is the focal length of the second positive lens group. fFP is the focal length of the positive focusing group, and fRPw is the combined focal length of the lens group located closer to the image than the positive focusing group in the wide-angle end. fFN is the focal length of the negative focusing group, and fRNw is the combined focal length of the lens group located closer to the image than the negative focusing group in the wide-angle end. fR is the focal length of the final lens group. nd1 is the refractive index of the lens in the first lens group at the d-line, and νd1 is the Abbe number of the lens in the first lens group based on the d-line. Bfw is the back focal length of the variable magnification optical system in the wide-angle end state, and fw is the focal length of the variable magnification optical system in the wide-angle end state. fF1 is the focal length of the first focusing group, and fF2 is the focal length of the second focusing group. νdP1 is the Abbe number based on the d-line of the positive lens in the rear group, νdN is the Abbe number based on the d-line of the negative lens in the rear group, and νdP2 is the Abbe number based on the d-line of the positive lens in the rear group.

[0297] [Conditional expression corresponding value] Conditional Expression | Example 1 2 3 4 5 (1)f1 / D1 : 9.548 9.548 10.302 9.345 12.530 (2)M1 / D1 : 5.387 5.387 5.957 5.461 5.423 (3)f1 / (-fN1) : 6.554 6.554 5.914 5.639 4.069 (4)f1 / (-fN2) : 2.347 2.347 0.130 0.375 1.402 (5)fN1 / fN2 : 0.358 0.358 0.022 0.067 0.345 (6)f1 / fP1 : 1.855 1.855 2.771 2.929 2.107 (7)fP1 / (-fN1) : 3.532 3.532 2.134 1.926 1.931 (8)fP1 / fP2 : 2.198 2.198 1.082 0.866 0.664 (9)f1 / fFP : - 4.078 - 2.537 2.107 1.554 (10)fFP / fRPw : - -0.795 - -1.110 0.284 -3.098 (11)f1 / (-fFN) : 2.347 2.347 0.130 - 1.402 (12)(-fFN) / fRNw : -0.343 -0.343 -23.612 - 0.026 (13)f1 / (-fR) : 0.806 0.806 - 4.813 - (14)f1 / fR : - - 0.384 - 0.036 (15)nd1 : 1.603 1.603 1.750 1.903 1.620 1.593 1.593 1.593 (16)νd1 : 65.44 65.44 35.25 35.77 36.40 67.90 67.90 67.00 (17)Bfw / fw : 0.476 0.476 0.485 0.464 0.539 (18)|fF1| / |fF2| : - 0.575 26.324 0.612 0.666 (19)νdP1 : 20.88 20.88 27.03 23.08 23.80 35.72 35.72 35.27 33.72 42.73 42.73 45.78 23.80 23.80 31.16 37.57 37.57 (20)νdN: - - 82.57 - - (21)νdP2 : 81.49 81.49 66.92 66.92 67.00 82.57 67.90 82.57 64.13 64.13

[0298] Conditional Expression | Example 6 7 8 9 (1)f1 / D1 : 12.664 21.226 32.826 53.933 (2)M1 / D1 : 5.522 5.557 6.150 19.724 (3)f1 / (-fN1) : 4.079 3.677 6.699 3.227 (4)f1 / (-fN2) : 1.557 3.659 5.830 2.846 (5)fN1 / fN2 : 0.382 0.995 0.870 0.882 (6)f1 / fP1 : 2.141 4.661 1.439 4.534 (7)fP1 / (-fN1) : 1.905 0.789 4.656 0.712 (8)fP1 / fP2 : 0.650 0.435 4.876 0.404 (9)f1 / fFP: 2.141 - - 1.834 4.072 (10)fFP / fRPw : 0.244 - - -1.283 -2.095 (11)f1 / (-fFN) : - 3.659 5.830 - 2.966 3.235 (12)(-fFN) / fRNw : - -0.213 -0.062 - 0.683 0.828 (13)f1 / (-fR) : - - - 8.531 (14)f1 / fR : 0.126 2.026 2.677 - (15)nd1 : 1.620 1.613 1.613 1.519 1.593 1.497 1.497 (16)νd1 : 36.40 44.46 44.46 69.89 67.00 81.73 81.73 (17)Bfw / fw : 0.534 0.396 0.396 0.438 (18)|fF1| / |fF2| : - 0.811 0.555 2.221 (19)νdP1 : 23.80 25.45 25.45 31.16 34.55 34.92 34.92 38.03 25.45 25.45 44.81 37.64 35.72 32.35 31.16 (20)νdN: - - - - (21)νdP2 : 67.00 64.14 67.00 67.90 82.57 60.20 82.57 64.13 70.31 70.32 64.14

[0299] The above examples are merely examples of the present invention, and the present invention is not limited to these. The following content can be appropriately adopted within the scope that does not impair the optical performance of the variable magnification optical system of the embodiment of the present application.

[0300] In addition, the lens surfaces of the lenses constituting the variable magnification optical systems of the above examples may be coated with an anti-reflection coating that has high transmittance over a wide wavelength range, thereby reducing flare and ghosting and achieving high-contrast optical performance.

[0301] Next, a camera equipped with the variable magnification optical system of this embodiment will be described with reference to FIG. FIG. 19 is a schematic diagram of a camera equipped with the variable magnification optical system of this embodiment.

[0302] The camera 1 is a so-called mirrorless camera with interchangeable lenses, which is provided with the variable magnification optical system according to the first embodiment as the photographic lens 2.

[0303] In camera 1, light from an object (subject) (not shown) is collected by photographic lens 2 and reaches image sensor 3. Image sensor 3 converts the light from the subject into image data. The image data is displayed on electronic viewfinder 4. This allows a photographer with their eye positioned at eyepoint EP to observe the subject.

[0304] Furthermore, when the photographer presses a release button (not shown), the image data is stored in a memory (not shown). In this way, the photographer can use the camera 1 to photograph a subject.

[0305] Here, the variable magnification optical system of the first embodiment mounted on the camera 1 as the photographic lens 2 is a variable magnification optical system with good optical performance. Therefore, the camera 1 can achieve good optical performance. Note that even if a camera is constructed that mounts the variable magnification optical system of any of the second to ninth embodiments as the photographic lens 2, the same effects as those of the camera 1 can be achieved.

[0306] Finally, an outline of a method for manufacturing the variable magnification optical system of this embodiment will be explained with reference to Fig. 20. Fig. 20 is a flowchart showing an outline of the method for manufacturing the variable magnification optical system of this embodiment.

[0307] The first manufacturing method of the variable magnification optical system of this embodiment shown in FIG. 20 includes the following steps S1 to S4.

[0308] Step S1: Six or more lens groups are prepared, each of which includes a first lens group having positive refractive power and a rear lens group disposed closer to the image side than the first lens group.

[0309] Step S2: When the magnification is changed, the spacing between the lens groups is changed.

[0310] Step S3: The first lens group is composed of two or less lenses.

[0311] Step S4: The variable magnification optical system is made to satisfy all of the following conditions. (1) 7.50 < f1 / D1 < 55.00 (2) 4.00 < M1 / D1 < 22.00 however, f1: focal length of the first lens group D1: Thickness of the first lens group on the optical axis M1: Movement distance of the first lens group when changing magnification from the wide-angle end to the telephoto end

[0312] According to the manufacturing method of the variable magnification optical system of this embodiment, it is possible to manufacture a variable magnification optical system having good imaging performance.

[0313] It should be understood that those skilled in the art can make various changes, substitutions and alterations thereto without departing from the spirit and scope of the present invention. [Explanation of symbols]

[0314] S aperture stop I image plane 1 camera 2. Shooting lens 3. Image sensor

Claims

1. a plurality of lens groups of six or more, each of which comprises a first lens group having positive refractive power and a rear lens group disposed closer to the image side than the first lens group; When changing magnification, the spacing between each lens group changes, the first lens group is composed of two or less lenses, the rear group includes a first negative lens group arranged closest to the object among the lens groups having negative refractive power in the rear group, a second negative lens group arranged closest to the object among the lens groups having negative refractive power arranged closer to the image than the first negative lens group, and a negative focusing group having negative refractive power and moving along the optical axis during focusing, the final lens group located closest to the image side among the lens groups in the rear group has negative refractive power; A variable magnification optical system that satisfies both of the following conditions: 7.50 < f1 / D1 < 55.00 3.10 < f1 / (-fN1) < 7.00 0.50 < f1 / (-fR) < 6.50 0.01 < fN1 / fN2 < 1.10 -35.00 < (-fFN) / fRNw < 1.50 however, f1: focal length of the first lens group D1: Axial thickness of the first lens group fN1: focal length of the first negative lens unit fR: focal length of the final lens group fN2: focal length of the second negative lens unit fFN: focal length of the negative focusing group fRNw: composite focal length in the wide-angle end state of the lens group arranged on the image side of the negative focusing group

2. 2. The variable magnification optical system according to claim 1, wherein the following condition is satisfied: 4.00 < M1 / D1 < 22.00 however, M1: Amount of movement of the first lens group when changing magnification from the wide-angle end state to the telephoto end state

3. 3. The variable magnification optical system according to claim 1, wherein the following condition is satisfied: 0.05 < f1 / (-fN2) < 6.50 however, fN2: focal length of the second negative lens unit

4. the rear group includes a first positive lens group that is disposed closest to the object side among lens groups having positive refractive power in the rear group, 4. A variable magnification optical system according to claim 1, which satisfies the following condition: 1.00 < f1 / fP1 < 5.00 however, fP1: focal length of the first positive lens group

5. the rear group includes a first positive lens group that is disposed closest to the object among the lens groups having positive refractive power in the rear group and that is disposed closer to the object than the first negative lens group, 4. A variable magnification optical system according to claim 1, which satisfies the following condition: 0.40 < fP1 / (-fN1) < 5.50 however, fP1: focal length of the first positive lens unit

6. The variable magnification optical system according to any one of claims 1 to 3, wherein the rear group comprises: a first positive lens group that is arranged closest to the object among the lens groups having positive refractive power in the rear group; and a second positive lens group that is arranged closest to the object among the lens groups having positive refractive power that are arranged closer to the image side than the first positive lens group.

7. 7. The variable magnification optical system according to claim 6, which satisfies the following condition: 0.20 < fP1 / fP2 < 5.50 however, fP1: focal length of the first positive lens unit fP2: focal length of the second positive lens unit

8. the rear group includes a positive focusing group that has positive refractive power and moves along the optical axis during focusing; 8. A variable magnification optical system according to claim 1, which satisfies the following condition: 1.00 < f1 / fFP < 5.00 however, fFP: focal length of the focusing group

9. the rear group includes a positive focusing group that has positive refractive power and moves along the optical axis during focusing; 9. A variable magnification optical system according to claim 1, which satisfies the following condition: -3.50 < fFP / fRPw < 1.00 however, fFP: focal length of the focusing group fRPw: composite focal length in the wide-angle end state of the lens group arranged on the image side of the focusing group

10. 10. A variable magnification optical system according to claim 1, which satisfies the following condition: 0.05 < f1 / (-fFN) < 6.50

11. 11. The variable magnification optical system according to claim 1, wherein the first lens group has at least one lens that satisfies both of the following conditional expressions: 1<f<1 / ... 1.45 < nd1 < 2.10 20.00 < νd1 < 75.00 however, nd1: refractive index of the lens in the first lens group with respect to the d line νd1: Abbe number of the lens in the first lens group based on the d line

12. 12. A variable magnification optical system according to claim 1, which satisfies the following condition: 0.10 < Bfw / fw < 0.95 however, Bfw: back focus of the variable magnification optical system in the wide-angle end state fw: focal length of the variable magnification optical system in the wide-angle end state

13. 13. The variable magnification optical system according to claim 1, wherein the first lens group moves toward the object side when varying magnification from the wide-angle end state to the telephoto end state.

14. 14. The variable magnification optical system according to claim 1, wherein the first lens group is made up of, in order from the object side, a negative lens and a positive lens.

15. 15. The variable magnification optical system according to claim 1, wherein the first lens group is made up of a positive lens.

16. 16. A variable magnification optical system according to claim 1, wherein the rear group comprises a first focusing group and a second focusing group that each move along the optical axis during focusing.

17. 17. The variable magnification optical system according to claim 16, which satisfies the following condition: 0.20 < | fF1 | / | fF2 | < 30.00 however, fF1: focal length of the first focusing group fF2: focal length of the second focusing group

18. 18. A variable magnification optical system according to claim 1, wherein at least one of the positive lenses in the rear group satisfies the following first dispersion condition: ##EQU1## where .gtoreq. ... νdP < 45.00 however, νdP: Abbe number of the positive lens in the rear group based on the d-line

19. 19. The variable magnification optical system according to claim 18, wherein the positive lens satisfying the first dispersion condition is included in a negative lens group having negative refractive power among the lens groups in the rear group.

20. 20. The variable magnification optical system according to claim 1, wherein at least one of the negative lenses in the rear group satisfies the following second dispersion condition: ##EQU1## where .gtoreq. ... 60.00 < νdN however, νdN: Abbe number of the negative lens in the rear group based on the d line

21. 21. The variable magnification optical system according to claim 20, wherein the negative lens satisfying the second dispersion condition is included in the final lens group located closest to the image side among the lens groups in the rear group.

22. 22. A variable magnification optical system according to claim 1, wherein at least one of the lens groups in the rear group that has a positive refractive power has a positive lens that satisfies the following third dispersion condition: ##EQU1## where .gtoreq..times ... 60.00 < νdP however, νdP: Abbe number of the positive lens in the rear group based on the d-line

23. An optical instrument comprising a variable magnification optical system according to any one of claims 1 to 22.

24. A method for manufacturing a variable magnification optical system having six or more lens groups, the lens groups comprising a first lens group having positive refractive power and a rear lens group disposed closer to an image side than the first lens group, When changing magnification, the spacing between each lens group changes, the first lens group is composed of two or less lenses, the rear group includes a first negative lens group that is located closest to the object among the lens groups having negative refractive power in the rear group, a second negative lens group that is located closer to the image than the first negative lens group and has negative refractive power, and a negative focusing group that has negative refractive power and moves along the optical axis during focusing, the final lens group located closest to the image side among the lens groups in the rear group has negative refractive power; A manufacturing method for a variable magnification optical system in which the lenses are arranged so as to satisfy both of the following conditions: 7.50 < f1 / D1 < 55.00 3.10 < f1 / (-fN1) < 7.00 0.50 < f1 / (-fR) < 6.50 0.01 < fN1 / fN2 < 1.10 -35.00 < (-fFN) / fRNw < 1.50 however, f1: focal length of the first lens group D1: Axial thickness of the first lens group fN1: focal length of the first negative lens unit fR: focal length of the final lens group fN2: focal length of the second negative lens unit fFN: focal length of the negative focusing group fRNw: composite focal length in the wide-angle end state of the lens group arranged on the image side of the negative focusing group

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