Zoom optical system, optical apparatus and manufacturing method of zoom optical system

Abstract

To provide a zoom optical system having satisfactory optical performance, an optical apparatus and a manufacturing method of the zoom optical system.SOLUTION: A zoom optical system comprises a plurality of six or more lens groups and the plurality of lens groups consists of a first lens group having positive refractive power and a rear group disposed closer to an image side than the first lens group. In the case of zooming, an interval between the lens groups changes. The first lens group consists of two or less lenses and the rear group includes a first positive lens group having positive refractive power. The lens groups are configured to satisfy the following conditional formulas 7.50<f1 / D1<17.50, 4.00<M1 / D1< 22.00 and 1.00<f1 / fP1<5.00 in which f1 is the focal distance of the first lens group, D1 is the thickness of the first lens group on an optical axis, M1 is the amount of movement of the first lens group in the case of zooming from a wide-angle end state to a telephoto end state, and fP1 is the focal distance of the first positive lens group.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] 2. Description of the Related Art Variable magnification optical systems used in optical devices such as photo cameras, electronic still cameras, and video cameras have been proposed (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2020-170102 A Summary of the Invention

[0004] The variable magnification optical system of the present disclosure has six or more lens groups, the lens groups consisting of a first lens group having positive refractive power and a rear group arranged on the image side of 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: The amount of movement 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 disclosed herein 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 on the image side of 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 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 description of the drawings]

[0006] [Figure 1] FIG. 2 is a cross-sectional view of the variable magnification optical system of the first embodiment when focused on an object at infinity in the wide-angle end state. [Figure 2A] 4A to 4C are diagrams illustrating various aberrations occurring when the variable magnification optical system of the first example 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 occurring 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 occurring 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. [Diagram 3] FIG. 11 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. [Figure 4A] 11A to 11C are diagrams illustrating various aberrations occurring when the variable magnification optical system of the second example is in an intermediate focal length state and is focused on an object at infinity. [Figure 4B] 11A to 11C are diagrams illustrating various aberrations occurring 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] 11A to 11C are diagrams illustrating various aberrations occurring 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. [Diagram 5] FIG. 11 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. [Figure 6A] 13A to 13C are diagrams illustrating various aberrations occurring 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] 13A to 13C are diagrams illustrating various aberrations occurring 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]13A to 13C are diagrams illustrating various aberrations occurring 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. 13 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. [Figure 8A] 13A to 13C are diagrams illustrating various aberrations occurring 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] 13A to 13C are diagrams illustrating various aberrations occurring when the variable magnification optical system of the fourth example is in an intermediate focal length state and is focused on an object at infinity. [Figure 8C] 13A to 13C are diagrams illustrating various aberrations occurring 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. 13 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. [Figure 10A] 13A to 13C are diagrams illustrating various aberrations occurring 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] 13A to 13C are diagrams illustrating various aberrations occurring when the variable magnification optical system of the fifth embodiment is in an intermediate focal length state and is focused on an object at infinity. [Figure 10C] 13A to 13C are diagrams illustrating various aberrations occurring 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. 13 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 occurring when the variable magnification optical system of the sixth example 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 occurring when the variable magnification optical system of the sixth example 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 occurring 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 the seventh embodiment when focused on an object at infinity in the wide-angle end state. [Figure 14A] 13A to 13C are diagrams illustrating various aberrations occurring 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 occurring when the variable magnification optical system of the seventh example 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 occurring 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 the eighth embodiment when focused on an object at infinity in the wide-angle end state. [Figure 16A] 13A to 13C are diagrams illustrating various aberrations occurring when the variable magnification optical system of the eighth example 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 occurring when the variable magnification optical system of the eighth example 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 occurring when the variable magnification optical system of the eighth example 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 embodiment when focused on an object at infinity in the wide-angle end state. [Figure 18A] 13A to 13C are diagrams illustrating various aberrations occurring when the variable magnification optical system of the ninth example 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 the ninth example 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 occurring 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] 4 is a flowchart outlining a method for manufacturing the variable magnification optical system of the present embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

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

[0008] The variable magnification optical system of this embodiment 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 on the image side of 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: (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: The amount of movement of the first lens group when changing magnification from the wide-angle end to the telephoto end

[0009] In the variable magnification optical system of this embodiment, the first lens group is made up of two lenses or less, making it possible to realize a lightweight variable magnification optical system.

[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.

[0011] In the variable magnification optical system of this embodiment, if the value of conditional formula (1) 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 variation.

[0012] In the variable magnification optical system of this embodiment, the effect of this embodiment can be ensured by setting the upper limit value of conditional expression (1) to 55.00. In order to ensure the effect of this embodiment, it is preferable to set the upper limit value 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 formula (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 variation.

[0014] In the variable magnification optical system of this embodiment, the effect of this embodiment can be ensured by setting the lower limit of conditional expression (1) to 7.50. In order to 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 formula (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 variation.

[0017] In the variable magnification optical system of this embodiment, the effect of this embodiment can be ensured by setting the upper limit value of conditional expression (2) to 22.00. In order to ensure the effect of this embodiment, it is preferable to set the upper limit value 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 formula (2) falls below the lower limit, the amount of movement of the first lens group becomes too strong, making it difficult to appropriately suppress fluctuations in various aberrations, including spherical aberration, during magnification change.

[0019] In the variable magnification optical system of this embodiment, the effect of this embodiment can be ensured by setting the lower limit of conditional expression (2) to 4.00. In order to ensure 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), it is possible to appropriately suppress fluctuations in various aberrations, including spherical aberration, during magnification variation.

[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 is satisfied. (3) 2.50 < f1 / (-fN1) < 7.00 however, fN1: focal length of the first negative lens unit

[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.

[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 variation.

[0024] In the variable magnification optical system of this embodiment, the effect of this embodiment can be ensured by setting the upper limit value of conditional expression (3) to 7.00. In order to ensure the effect of this embodiment, it is preferable to set the upper limit value 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 formula (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 variation.

[0026] In the variable magnification optical system of this embodiment, the effect of this embodiment can be ensured by setting the lower limit of conditional expression (3) to 2.50. In order to ensure 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 arranged on the image side of 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.

[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 variation.

[0030] In the variable magnification optical system of this embodiment, the effect of this embodiment can be ensured by setting the upper limit value of conditional expression (4) to 6.50. In order to ensure the effect of this embodiment, it is preferable to set the upper limit value 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 formula (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 variation.

[0032] In the variable magnification optical system of this embodiment, the effect of this embodiment can be more certain by setting the lower limit of conditional expression (4) to 0.05. In order to more certainty of 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 arranged on the image side of 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 unit fN2: focal length of the second negative lens group

[0034] Conditional expression (5) defines the ratio of the focal length of the first negative lens group to 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.

[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 variation.

[0036] In the variable magnification optical system of this embodiment, the upper limit value of conditional expression (5) is set to 1.20, thereby making the effect of this embodiment more certain. In order to make the effect of this embodiment more certain, it is preferable to set the upper limit value 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 formula (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 variation.

[0038] In the variable magnification optical system of this embodiment, the effect of this embodiment can be ensured by setting the lower limit of conditional expression (5) to 0.01. In order to ensure 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 thus can appropriately suppress fluctuations in various aberrations, including spherical aberration, during magnification variation.

[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 satisfies the following conditional expression. (6) 1.00 < f1 / fP1 < 5.00 however, fP1: Focal length of the first positive lens group

[0042] Conditional expression (6) defines the ratio of the focal length of the first lens group to 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.

[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 variation.

[0044] In the variable magnification optical system of this embodiment, the effect of this embodiment can be ensured by setting the upper limit value of conditional expression (6) to 5.00. In order to ensure the effect of this embodiment, it is preferable to set the upper limit value 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 formula (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 variation.

[0046] In the variable magnification optical system of this embodiment, the effect of this embodiment can be ensured by setting the lower limit of conditional expression (6) to 1.00. In order to ensure 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 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 unit

[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 variation.

[0050] In the variable magnification optical system of this embodiment, the effect of this embodiment can be ensured by setting the upper limit value of conditional expression (7) to 5.50. In order to ensure the effect of this embodiment, it is preferable to set the upper limit value 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 variation.

[0052] In the variable magnification optical system of this embodiment, the effect of this embodiment can be ensured by setting the lower limit of conditional expression (7) to 0.40. In order to ensure 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 arranged on the image side of the first positive lens group.

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

[0055] Moreover, it is 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 of the focal length of the first positive lens group to 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 variation.

[0058] In the variable magnification optical system of this embodiment, the effect of this embodiment can be ensured by setting the upper limit value of conditional expression (8) to 5.50. In order to ensure the effect of this embodiment, it is preferable to set the upper limit value 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 variation.

[0060] In the variable magnification optical system of this embodiment, the effect of this embodiment can be ensured by setting the lower limit of conditional expression (8) to 0.20. In order to ensure 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 thus can appropriately suppress fluctuations in various aberrations, including spherical aberration, during magnification variation.

[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 is satisfied. (9) 1.00 < f1 / fFP < 5.00 however, fFP: focal length of the correct focusing group

[0064] Conditional expression (9) defines the ratio of the focal length of the first lens group to the focal length of the correct 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 adequately 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 ensured by setting the upper limit value of conditional expression (9) to 5.00. In order to ensure the effect of this embodiment, it is preferable to set the upper limit value 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 formula (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 variation.

[0068] In the variable magnification optical system of this embodiment, the effect of this embodiment can be ensured by setting the lower limit of conditional expression (9) to 1.00. In order to ensure 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 is satisfied. (10) -3.50 < fFP / fRPw < 1.00 however, fFP: focal length of the correct focusing group fRPw: The composite focal length at the wide-angle end of the lens group located to the image side of the correct 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 disposed 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 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 its upper limit, the refractive power of the lens group located on the image side of the correct focusing group in the wide-angle end state becomes too strong, making it difficult to adequately 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 ensured by setting the upper limit value of conditional expression (10) to 1.00. In order to ensure the effect of this embodiment, it is preferable to set the upper limit value 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 adequately 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 ensured by setting the lower limit of conditional expression (10) to -3.50. In order to ensure 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 further to -1.50.

[0075] In the variable power 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 is 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 magnification.

[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 adequately 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 ensured by setting the upper limit value of conditional expression (11) to 6.50. In order to ensure the effect of this embodiment, it is preferable to set the upper limit value 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 variation.

[0080] In the variable magnification optical system of this embodiment, the effect of this embodiment can be more certain by setting the lower limit of conditional expression (11) to 0.05. In order to more certainty of 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 power 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 is 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 in the wide-angle end state

[0082] Conditional expression (12) specifies the ratio between the focal length of the negative focusing group and the focal length of the lens group disposed on the image side of 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 appropriately suppressing fluctuations of 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 on the image side of the negative focusing group in the wide-angle end state becomes too strong, making it difficult to adequately 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 ensured by setting the upper limit value of conditional expression (12) to 1.50. In order to ensure the effect of this embodiment, it is preferable to set the upper limit value 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 adequately 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 ensured by setting the lower limit of conditional expression (12) to -35.00. In order to ensure 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 further to -1.00.

[0087] In the variable magnification optical system of this embodiment, it is preferable that the final lens unit, which is located closest to the image side among the lens units in the rear group, 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 of the focal length of the first lens group to 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 change.

[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 change.

[0090] In the variable magnification optical system of this embodiment, the effect of this embodiment can be ensured by setting the upper limit value of conditional expression (13) to 10.00. In order to ensure the effect of this embodiment, it is preferable to set the upper limit value 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 formula (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 variation.

[0092] In the variable magnification optical system of this embodiment, the effect of this embodiment can be ensured by setting the lower limit of conditional expression (13) to 0.50. In order to ensure 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, which is located closest to the image side among the lens groups in the rear group, 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 of the focal length of the first lens group to 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 change.

[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 change.

[0096] In the variable magnification optical system of this embodiment, the effect of this embodiment can be ensured by setting the upper limit value of conditional expression (14) to 3.00. In order to ensure the effect of this embodiment, it is preferable to set the upper limit value 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 formula (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 variation.

[0098] In the variable magnification optical system of this embodiment, the effect of this embodiment can be ensured by setting the lower limit of conditional expression (14) to 0.01. In order to 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 for the d line of the lens in the first lens group νd1: Abbe number of the lens in the first lens group based on the d line

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

[0101] In the variable magnification optical system of this embodiment, if the value of conditional formula (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 change.

[0102] In the variable magnification optical system of this embodiment, the effect of this embodiment can be ensured by setting the upper limit value of conditional expression (15) to 2.10. In order to ensure the effect of this embodiment, it is preferable to set the upper limit value 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 formula (15) falls below the lower limit, the refractive power of the lenses in the first lens group becomes too weak, making it difficult to correct 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 ensured by setting the lower limit of conditional expression (15) to 1.45. In order to ensure 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, when 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 satisfactorily 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 ensured by setting the upper limit value of conditional expression (16) to 83.00. In order to ensure the effect of this embodiment, it is preferable to set the upper limit value 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 satisfactorily 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 ensured by setting the lower limit of conditional expression (16) to 20.00. In order to 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] Moreover, it is 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 of the variable magnification optical system at the wide-angle end

[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 ensured by setting the upper limit value of conditional expression (17) to 0.95. In order to ensure the effect of this embodiment, it is preferable to set the upper limit value 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 formula (17) falls below the lower limit, the position of the exit pupil becomes too close to the image plane, making it difficult to satisfactorily 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 ensured by setting the lower limit of conditional expression (17) to 0.10. In order to 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 appropriately suppress fluctuations in various aberrations, including spherical aberration, during magnification change while making the variable magnification optical system more compact.

[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 satisfactorily 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 satisfactorily correct various aberrations including spherical aberration in the telephoto end state.

[0121] In the variable power 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] Moreover, it is 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 of the focal length of the first focusing group to 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 formula (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 ensured by setting the upper limit value of conditional expression (18) to 30.00. In order to ensure the effect of this embodiment, it is preferable to set the upper limit value 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 formula (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, during magnification variation.

[0128] In the variable magnification optical system of this embodiment, the effect of this embodiment can be ensured by setting the lower limit of conditional expression (18) to 0.20. In order to ensure 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 based on 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), and thus can effectively correct chromatic aberration.

[0131] In the variable magnification optical system of this embodiment, the effect of this embodiment can be ensured by setting the upper limit value of the first dispersion conditional formula (19) to 45.00. In order to ensure the effect of this embodiment, it is preferable to set the upper limit value of the first dispersion conditional formula (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 condition (19) is included in a 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, by having such a configuration, chromatic aberration can be corrected more satisfactorily.

[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 respect 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 ensured by setting the lower limit of the second dispersion conditional formula (20) to 60.00. In order to ensure the effect of this embodiment, it is preferable to set the lower limit of the second dispersion conditional formula (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 condition (20) is included in the final lens group that 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, by having such a configuration, chromatic aberration can be corrected more satisfactorily.

[0139] In the variable power 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 based on the d-line. In the variable magnification optical system of this embodiment, the lens group having positive refractive power has a positive lens that satisfies the third dispersion condition (21), so that 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 formula (21) to 60.00. In order to further ensure the effect of this embodiment, it is preferable to set the lower limit of the third dispersion conditional formula (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 device of this embodiment has the variable magnification optical system configured as described above, which makes it possible to realize an optical device 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, and the spacing between each lens group changes during magnification variation. 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 a 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 consisting of 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) constituted by a CCD, a CMOS, or the like is disposed.

[0156] In the variable magnification optical system of this embodiment, focusing is performed 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. 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. The fifth lens group G5 corresponds to the negative focusing group.

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

[0159] In Table 1, fw is the focal length of the variable magnification optical system in the wide-angle end state, ft is the focal length of the variable magnification optical system in the telephoto end state, Fnow is the F-number of the variable magnification optical system in the wide-angle end state, Fnot is the F-number of the variable magnification optical system in the wide-angle end state, TL is the total optical length of the variable magnification optical system when focusing on an object at infinity in the wide-angle end state, and Bf is the back focus 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 addition, in [Lens specifications], an optical surface marked with an "*" indicates that it is an aspheric surface. In addition, in [Lens specifications], lenses corresponding to the positive lens P1 in conditional formula (19), the negative lens N in conditional formula (20), and the positive lens P2 in conditional formula (21) are shown.

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

[0162] An aspheric 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 along the optical axis from the tangent plane of the apex of each aspheric surface at height y to each aspheric surface, r is the radius of curvature (paraxial radius of curvature) of the reference sphere, K is the conic constant, and An is the n-th order aspheric coefficient. Note that in each embodiment, the second order aspheric coefficient A2 is 0. Also, "En" is expressed as "×10 -n ".

[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 focal lengths fw, ft, the radius of curvature r, and other lengths listed in Table 1 are in units of "mm." However, this is not limited to this because the same optical performance can be obtained with a variable magnification optical system even if the magnification is proportionally enlarged or reduced.

[0165] The symbols in Table 1 described above are 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) 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 [Aspheric 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 focused on an object at infinity in the intermediate focal length state, FIG. 2B is a diagram showing various aberrations when the variable magnification optical system of Example 1 is focused on an object at infinity in the telephoto end state, and FIG. 2C is a diagram showing various aberrations when the variable magnification optical system of Example 1 is focused on an object at infinity in the wide-angle end state.

[0168] In each aberration diagram, FNO indicates the F-number and Y indicates the image height. In detail, the spherical aberration diagram indicates the F-number value corresponding to the maximum aperture, the astigmatism diagram and the distortion diagram indicate the maximum image height, and the coma diagram indicates the value of each image height. d indicates the d-line and g indicates the g-line (wavelength 435.8 nm). In the astigmatism diagram, 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 various aberration diagrams of the present embodiment are used in the various aberration diagrams of other embodiments described later.

[0169] It can be seen from each aberration diagram 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 made up of a cemented positive lens including, 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 consisting of 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) constituted by a CCD, a CMOS, or the like is disposed.

[0179] In the variable magnification optical system of this embodiment, focusing is performed 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. 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. 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 embodiment.

[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) 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 [Aspheric 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 the second embodiment 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 the second embodiment 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 the second embodiment is focused on an object at infinity in the wide-angle end state.

[0184] It can be seen from each aberration diagram 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 a concave surface facing the object side, and a biconcave negative lens L15.

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

[0193] The seventh lens group G7 is composed 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) constituted by a CCD, a CMOS, or the like is disposed.

[0195] In the variable magnification optical system of this embodiment, focusing is performed 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. 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. 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 values ​​of the specifications of the variable magnification optical system of this embodiment.

[0198] (Table 3) [Overall specifications] fw28.00 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 the third embodiment 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 the sixth embodiment 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 the sixth embodiment is focused on an object at infinity in the telephoto end state.

[0200] It can be seen from each aberration diagram 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 a 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 includes, in order from the object side, a biconvex positive lens L7, and a cemented negative lens consisting of a negative meniscus lens L8 with a convex surface facing the object side and a positive meniscus lens L9 with a 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 composed of a biconvex positive lens L15.

[0209] The seventh lens group G7 includes, 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) constituted by a CCD, a CMOS or the like is disposed.

[0211] In the variable magnification optical system of this embodiment, focusing is performed 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. 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. 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 values ​​of the specifications of the variable magnification optical system of this embodiment.

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

[0216] It can be seen from each aberration diagram 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 a 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 consisting 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 composed 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) constituted by a CCD, a CMOS or the like is disposed.

[0226] In the variable magnification optical system of this embodiment, focusing is performed 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. 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. 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 values ​​of the specifications of the variable magnification optical system of this embodiment.

[0229] (Table 5) [Overall specifications] fw72.10 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] It can be seen from each aberration diagram 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 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 a 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 consisting 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 composed 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) constituted by 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. 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. The third lens group G3 corresponds to the positive focusing group.

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

[0244] (Table 6) [Overall specifications] fw72.10 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 aperture) 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 [Focal length data for each group] Group Starting surface Focal length 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] It can be seen from each aberration diagram 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 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 a 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 a concave surface facing the object side, and a biconcave negative lens L15.

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

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

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

[0256] In the variable magnification optical system of this embodiment, focusing is performed 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. 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. 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 values ​​of the specifications of the variable magnification optical system of this embodiment.

[0259] (Table 7) [Overall specifications] fw72.10 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] It can be seen from each aberration diagram 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 sectional view of the variable magnification optical system of the eighth embodiment 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 a 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 includes, 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 a concave surface facing the object side, and a biconcave negative lens L16.

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

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

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

[0272] In the variable magnification optical system of this embodiment, focusing is performed 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. 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. 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 values ​​of the specifications of the variable magnification optical system of this embodiment.

[0275] (Table 8) [Overall specifications] fw72.10 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) 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 [Aspheric 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] It can be seen from each aberration diagram 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 sectional view of the variable magnification optical system of the ninth embodiment 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 made up 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 made up 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 made up 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 including 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 composed of a positive meniscus lens L18 with its convex surface facing the object side.

[0286] The seventh lens group G7 consists of, 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) constituted by a CCD, a CMOS, or the like is disposed.

[0288] In the variable magnification optical system of this embodiment, focusing is performed 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. 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. 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 values ​​of the specifications of the variable magnification optical system of this embodiment.

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

[0293] It can be seen from each aberration diagram 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 embodiments, a variable magnification optical system having good optical performance can be realized.

[0295] Values ​​corresponding to the conditional expressions in each embodiment are shown below.

[0296] f1 is the focal length of the first lens group, D1 is the thickness of the first lens group on the optical axis, and M1 is the amount of movement of the first lens group when changing magnification from the wide-angle end state to the telephoto end state. 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 composite focal length in the wide-angle end state of the lens group arranged on the image side of the positive focusing group. fFN is the focal length of the negative focusing group, and fRNw is the composite focal length in the wide-angle end state of the lens group arranged on the image side of the negative focusing group. fR is the focal length of the final lens group. nd1 is the refractive index of the lens in the first lens group with respect to the d-line, and νd1 is the Abbe number based on the d-line of the lens in the first lens group. Bfw is the back focus in the wide-angle end state of the variable magnification optical system, and fw is the focal length in the wide-angle end state of the variable magnification optical system. 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 formula | 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 formula | 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 show specific examples of the present invention, and the present invention is not limited thereto. The following contents can be appropriately adopted within a range 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 system of each of the above embodiments may be coated with an anti-reflection coating having a high transmittance over a wide wavelength range, thereby reducing flare and ghosting and achieving optical performance with high contrast.

[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 of an interchangeable lens type that is provided with the variable magnification optical system according to the first embodiment as the photographing lens 2.

[0303] In camera 1, light from an object (subject) (not shown) is collected by photographing 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 his or her 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 manner, the photographer can use the camera 1 to photograph the subject.

[0305] Here, the variable magnification optical system of the first embodiment mounted on the camera 1 as the photographing lens 2 is a variable magnification optical system having 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 photographing lens 2, the same effects as 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 described with reference to Fig. 20. Fig. 20 is a flow chart showing an outline of the method for manufacturing the variable magnification optical system of this embodiment.

[0307] A first manufacturing method for 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 group disposed closer to the image side than the first lens group.

[0309] Step S2: The spacing between each lens group is changed during magnification change.

[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: The amount of movement 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, the plurality of lens groups being composed of a first lens group having a 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 positive lens group having a positive refractive power, A variable magnification optical system that satisfies both of the following conditions: 7.50 < f1 / D1 < 17.50 4.00 < M1 / D1 < 22.00 1.00 < f1 / fP1 < 5.00 however, f1: focal length of the first lens group D1: thickness of the first lens group on the optical axis M1: the movement amount of the first lens group when changing the magnification from the wide-angle end state to the telephoto end state fP1: focal length of the first positive lens group

2. the rear group includes a first negative lens group having negative refractive power, 2. The variable magnification optical system according to claim 1, which satisfies the following condition: 2.50 < f1 / (-fN1) < 7.00 however, fN1: focal length of the first negative lens unit

3. the rear group includes a first negative lens group having negative refractive power, and a second negative lens group having negative refractive power and disposed closer to the image side than the first negative lens group, 3. The variable magnification optical system according to claim 1, wherein the following formula 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 negative lens group having negative refractive power, and a second negative lens group having negative refractive power and disposed closer to the image side than the first negative lens group, 4. The variable magnification optical system according to claim 1, which satisfies the following formula: 0.01 < fN1 / fN2 < 1.20 however, fN1: focal length of the first negative lens unit fN2: focal length of the second negative lens unit

5. 5. The variable magnification optical system according to claim 2, wherein the first negative lens group is a lens group arranged closest to the object side among the lens groups having negative refractive power in the rear group.

6. the rear group includes a first negative lens group having negative refractive power and disposed closer to the image side than the first positive lens group, 6. 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 fN1: focal length of the first negative lens unit

7. 7. The variable magnification optical system according to claim 1, wherein the rear group has a second positive lens group having positive refractive power, the second positive lens group being arranged closer to the image side than the first positive lens group.

8. 8. The variable magnification optical system according to claim 7, 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

9. 9. The variable magnification optical system according to claim 1, wherein the first positive lens group is a lens group arranged closest to the object side among the lens groups having positive refractive power in the rear group.

10. the rear group includes a positive focusing group that has a positive refractive power and moves along the optical axis during focusing; 10. 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

11. the rear group includes a positive focusing group that has a positive refractive power and moves along the optical axis during focusing; 11. 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: the composite focal length in the wide-angle end state of the lens group disposed on the image side of the correct focusing group

12. the rear group includes a negative focusing group having negative refractive power and moving along the optical axis during focusing; 12. A variable magnification optical system according to claim 1, which satisfies the following condition: 0.05 < f1 / (-fFN) < 6.50 however, fFN: focal length of the negative focusing group

13. the rear group includes a negative focusing group having negative refractive power and moving along the optical axis during focusing; 13. A variable magnification optical system according to claim 1, which satisfies the following condition: -35.00 < (-fFN) / fRNw < 1.50 however, fFN: focal length of the negative focusing group fRNw: the composite focal length in the wide-angle end state of the lens group disposed on the image side of the negative focusing group

14. Among the lens groups in the rear group, the final lens group arranged closest to the image side has negative refractive power, 14. A variable magnification optical system according to claim 1, which satisfies the following condition: 0.50 < f1 / (-fR) < 6.50 however, fR: focal length of the final lens group

15. Among the lens groups in the rear group, the final lens group arranged closest to the image side has positive refractive power, 14. A variable magnification optical system according to claim 1, which satisfies the following condition: 0.01 < f1 / fR < 3.00 however, fR: focal length of the final lens group

16. 16. The variable magnification optical system according to claim 1, wherein the first lens group has at least one lens that satisfies all of the following conditional expressions: 1<x<1, 2<x<1, 3<x<1, 4<x<1, 5<x<1, 6<x<1, 7<x<1, 8<x<1, 9<x<1, 10<x<1, 11<x<1, 12<x<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

17. 17. 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

18. 18. 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.

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

20. The variable magnification optical system according to any one of claims 1 to 19, wherein the first lens group is made up of a positive lens.

21. 21. A variable power optical system according to claim 1, wherein the rear group comprises a first focusing group and a second focusing group each of which moves along the optical axis during focusing.

22. 22. The variable magnification optical system according to claim 21, 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

23. 23. The 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## νdP < 45.00 however, νdP: Abbe number based on the d line of the positive lens in the rear group

24. 24. The variable magnification optical system according to claim 23, 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.

25. 25. 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## 60.00 < vdN however, νdN: Abbe number of the negative lens in the rear group based on the d line

26. 26. The variable magnification optical system according to claim 25, wherein the negative lens satisfying the second dispersion condition is included in a final lens group that is disposed closest to the image side among the lens groups in the rear group.

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

28. An optical instrument comprising a variable magnification optical system according to any one of claims 1 to 27.

29. A method for manufacturing 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 disposed closer to an image side than the first lens group, comprising: 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 positive lens group having a positive 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 conditional expressions: 7.50 < f1 / D1 < 17.50 4.00 < M1 / D1 < 22.00 1.00 < f1 / fP1 < 5.00 however, f1: focal length of the first lens group D1: thickness of the first lens group on the optical axis M1: the amount of movement of the first lens group when changing magnification from the wide-angle end state to the telephoto end state fP1: focal length of the first positive lens group

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