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

Abstract

The optical system has, in order from the object side, a first negative lens group having a negative refractive power and a rear group having a plurality of lens groups, and is configured such that the first negative lens group is fixed with respect to the image plane and the interval between adjacent lens groups varies during magnification variation, and the optical system has an aperture stop on the image plane side from the first negative lens group, and is configured such that the distance between adjacent lens groups varies during magnification variation. A second negative lens group disposed adjacent to the image plane side of the aperture stop among the plurality of lens groups included in the rear group has a negative refractive power, and satisfies the following conditional expression: 0.00 < fA / fC [alpha] < 0.30, where fA is the focal length of the first negative lens group, and fC [alpha] is the focal length of the second negative lens group.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to a zoom optical system, an optical apparatus, and a manufacturing method of a zoom optical system. BACKGROUND

[0002] In the past, a zoom optical system used in an optical apparatus such as a camera for photographs, an electronic still camera, a video camera, and the like has been proposed (for example, refer to Patent Literature 1).

[0003] PRIOR ART DOCUMENTS

[0004] PATENT LITERATURE

[0005] Patent Literature 1: Japanese Patent Application Publication No. 2021-196573 SUMMARY

[0006] The zoom optical system of the present disclosure includes, in order from an object side, a first negative lens group having a negative refractive power and a rear group having a plurality of lens groups, at the time of zooming, the first negative lens group is fixed with respect to an image plane, the interval between each of the adjacent lens groups is changed, an aperture stop is provided at the image plane side of the first negative lens group, a second negative lens group, which is one of the plurality of lens groups of the rear group and is disposed adjacent to the image plane side of the aperture stop, has a negative refractive power, and satisfies the following conditional expression: 0.00 < fA / fCα < 0.30 wherein, fA: focal length of the first negative lens group, fCα: focal length of the second negative lens group.

[0007] The zoom optical system of the present disclosure includes, in order from an object side, a first negative lens group having a negative refractive power and a rear group having a plurality of lens groups, at the time of zooming, the first negative lens group is fixed with respect to an image plane, the interval between each of the adjacent lens groups is changed, in the plurality of lens groups of the rear group, a third negative lens group, which is one of the lens groups having a negative refractive power and is disposed on the image plane side of a first positive lens group disposed on the most object side and having a positive refractive power, is disposed on the most object side, and satisfies the following conditional expression: 0.00 < fA / fCβ < 0.30 wherein, fA: focal length of the first negative lens group, fCβ: focal length of the third negative lens group.

[0008] The manufacturing method of the variable magnification optical system of the present disclosure, the variable magnification optical system having a first negative lens group having a negative refractive power and a rear group having a plurality of lens groups in order from an object side, the manufacturing method of the variable magnification optical system including making the variable magnification optical system so as to satisfy, at the time of variable magnification, a condition that the first negative lens group is fixed with respect to an image plane, a distance between adjacent lens groups is changed, an aperture stop is disposed at a position closer to the image plane than the first negative lens group, a second negative lens group having a negative refractive power is disposed adjacent to the image plane side of the aperture stop among the plurality of lens groups of the rear group, and the first negative lens group and the second negative lens group satisfy the following conditional expression: 0.00 < fA / fCα < 0.30 wherein, fA: focal length of the first negative lens group, fCα: focal length of the second negative lens group. BRIEF DESCRIPTION OF DRAWINGS

[0009] Figure 1 is a sectional view of the variable magnification optical system of the first embodiment at the time of focusing on an infinite object in a wide-angle end state.

[0010] Figure 2A is each aberration diagram of the variable magnification optical system of the first embodiment at the time of focusing on an infinite object in a wide-angle end state.

[0011] Figure 2B is each aberration diagram of the variable magnification optical system of the first embodiment at the time of focusing on an infinite object in a telephoto end state.

[0012] Figure 3 is a sectional view of the variable magnification optical system of the second embodiment at the time of focusing on an infinite object in a wide-angle end state.

[0013] Figure 4A is each aberration diagram of the variable magnification optical system of the second embodiment at the time of focusing on an infinite object in a wide-angle end state.

[0014] Figure 4B is each aberration diagram of the variable magnification optical system of the second embodiment at the time of focusing on an infinite object in a telephoto end state.

[0015] Figure 5 is a sectional view of the variable magnification optical system of the third embodiment at the time of focusing on an infinite object in a wide-angle end state.

[0016] Figure 6A is each aberration diagram of the variable magnification optical system of the third embodiment at the time of focusing on an infinite object in a wide-angle end state.

[0017] Figure 6B is each aberration diagram of the variable magnification optical system of the third embodiment at the time of focusing on an infinite object in a telephoto end state. is each aberration diagram of the variable magnification optical system of the third embodiment at the time of focusing on an infinite object in a telephoto end state.

[0018] Figure 7 is a sectional view of the variable magnification optical system of the 4th embodiment when an infinite object in a wide angle end state is focused.

[0019] Figure 8A is each aberration diagram when an infinite object in a wide angle end state is focused for the variable magnification optical system of the 4th embodiment.

[0020] Figure 8B is each aberration diagram when an infinite object in a telephoto end state is focused for the variable magnification optical system of the 4th embodiment.

[0021] Figure 9 is a sectional view of the variable magnification optical system of the 5th embodiment when an infinite object in a wide angle end state is focused.

[0022] Figure 10A is each aberration diagram when an infinite object in a wide angle end state is focused for the variable magnification optical system of the 5th embodiment.

[0023] Figure 10B is each aberration diagram when an infinite object in a telephoto end state is focused for the variable magnification optical system of the 5th embodiment.

[0024] Figure 11 is a sectional view of the variable magnification optical system of the 6th embodiment when an infinite object in a wide angle end state is focused.

[0025] Figure 12A is each aberration diagram when an infinite object in a wide angle end state is focused for the variable magnification optical system of the 6th embodiment.

[0026] Figure 12B is each aberration diagram when an infinite object in a telephoto end state is focused for the variable magnification optical system of the 6th embodiment.

[0027] Figure 13 is a schematic view of a camera equipped with the variable magnification optical system of the present embodiment.

[0028] Figure 14 is a flowchart showing an outline of the 1st manufacturing method of the variable magnification optical system of the present embodiment.

[0029] Figure 15 is a flowchart showing an outline of the 2nd manufacturing method of the variable magnification optical system of the present embodiment. DETAILED DESCRIPTION

[0030] Hereinafter, the variable magnification optical system, the optical apparatus, and the manufacturing method of the variable magnification optical system of the present embodiment will be described.

[0031] The variable magnification optical system of the present embodiment has, in order from the object side, a first negative lens group having a negative refractive power, and a rear group having a plurality of lens groups, at the image plane side of the first negative lens group, has an aperture stop, and has a second negative lens group having a negative refractive power disposed adjacent to the image plane side of the aperture stop among the plurality of lens groups of the rear group, whereby each aberration including spherical aberration at the time of variable magnification can be appropriately corrected. (1-1) 0.00 < fA / fCα < 0.30 wherein, fA: focal length of the first negative lens group fCα: focal length of the second negative lens group

[0032] The variable magnification optical system of the present embodiment has, in order from the object side, a first negative lens group having a negative refractive power, and a rear group having a plurality of lens groups, at the image plane side of the first negative lens group, has an aperture stop, and has a second negative lens group having a negative refractive power disposed adjacent to the image plane side of the aperture stop among the plurality of lens groups of the rear group, whereby each aberration including spherical aberration at the time of variable magnification can be appropriately corrected.

[0033] The conditional expression (1-1) defines the ratio of the focal length of the first negative lens group to the focal length of the second negative lens group. The variable magnification optical system of the present embodiment, by satisfying the conditional expression (1-1), can appropriately correct each aberration including spherical aberration while suppressing the increase in size of the variable magnification optical system.

[0034] In the variable magnification optical system of the present embodiment, if the value of the conditional expression (1-1) exceeds the upper limit value, the refractive power of the first negative lens group is too weak, and the variable magnification optical system is increased in size.

[0035] In the variable magnification optical system of the present embodiment, by setting the upper limit value of the conditional expression (1-1) to 0.30, the effects of the present embodiment can be made more reliable. Further, in order to make the effects of the present embodiment more reliable, it is preferable to set the upper limit value of the conditional expression (1-1) to 0.28, 0.26, 0.25, 0.24, and more preferably to 0.23.

[0036] Further, in the variable magnification optical system of the present embodiment, if the value of the conditional expression (1-1) is lower than the lower limit value, the refractive power of the second negative lens group is too weak, and appropriate correction of each aberration including spherical aberration becomes difficult.

[0037] In the variable magnification optical system of the present embodiment, by setting the lower limit value of the conditional expression (1-1) to 0.00, the effects of the present embodiment can be made more reliable. Further, in order to make the effects of the present embodiment more reliable, it is preferable to set the lower limit value of the conditional expression (1-1) to 0.02, 0.04, 0.06, 0.08, and more preferably to 0.10.

[0038] Further, in the variable magnification optical system of the present embodiment, it is preferable that at least one lens group of the lenses disposed on the image plane side of the 2nd negative lens group moves at the time of focusing.

[0039] In the variable magnification optical system of the present embodiment, by having such a structure, variation of each aberration including spherical aberration at the time of variable magnification is suppressed, and variation of the field angle at the time of focusing (so-called breathing effect) is suppressed.

[0040] Further, the variable magnification optical system of the present embodiment preferably satisfies the following conditional expression. (2-1) 0.90 < MVGCα / MVGE < 1.50 wherein, MVGCα: movement amount of the 2nd negative lens group at the time of variable magnification from the wide angle end to the telephoto end at the time of focusing at infinity MVGE: movement amount of the final negative lens group having a negative refractive power, which is disposed on the most image plane side among the plurality of lens groups possessed by the rear group, at the time of variable magnification from the wide angle end to the telephoto end at the time of focusing at infinity

[0041] The conditional expression (2-1) specifies the ratio of the movement amount of the 2nd negative lens group to the movement amount of the final negative lens group at the time of variable magnification from the wide angle end to the telephoto end at the time of focusing at infinity. The variable magnification optical system of the present embodiment, by satisfying the conditional expression (2-1), the ratio of the movement amount of the 2nd negative lens group to the movement amount of the final negative lens group at the time of variable magnification from the wide angle end to the telephoto end is close to 1, and the image surface curvature can be corrected well in the entire variable magnification region.

[0042] In the variable magnification optical system of the present embodiment, if the value of the conditional expression (2-1) exceeds the upper limit value, it becomes difficult to correct the image surface distortion appropriately in the entire variable magnification region.

[0043] In the variable magnification optical system of the present embodiment, by setting the upper limit value of the conditional expression (2-1) to 1.50, the effect of the present embodiment can be made more reliable. Further, in order to make the effect of the present embodiment more reliable, it is preferable to set the upper limit value of the conditional expression (2-1) to 1.45, 1.40, 1.37, 1.34, and more preferably to 1.30.

[0044] Further, in the variable magnification optical system of the present embodiment, if the value of the conditional expression (2-1) is lower than the lower limit value, it becomes difficult to correct the image surface distortion appropriately in the entire variable magnification region.

[0045] In the variable magnification optical system of the present embodiment, by setting the lower limit value of conditional expression (2-1) to 0.90, the effect of the present embodiment can be made more reliable. Further, in order to make the effect of the present embodiment more reliable, it is preferable to set the lower limit value of conditional expression (2-1) to 0.92, 0.94, 0.96, and more preferably to 0.98.

[0046] Further, in the variable magnification optical system of the present embodiment, it is preferable that the 2nd negative lens group has a positive lens Cαp satisfying the following conditional expression. (3-1) 0.020 < PgFCαp - 0.64435 + 0.00168 * νdCαp wherein, PgFCαp: relative partial dispersion of the positive lens Cαp, defined by the following formula when the refractive index of the positive lens Cαp with respect to the g-line is ngCαp, the refractive index of the positive lens Cαp with respect to the F-line is nFCαp, and the refractive index of the positive lens Cαp with respect to the C-line is nCCαp. PgFCαp = (ngCαp - nFCαp) / (nFCαp - nCCαp) νdCαp: Abbe number of the positive lens Cαp with respect to the d-line

[0047] In the variable magnification optical system of the present embodiment, by the 2nd negative lens group having a positive lens Cαp satisfying conditional expression (3-1), the second order dispersion of the magnification chromatic aberration can be well corrected.

[0048] In the variable magnification optical system of the present embodiment, if the value of conditional expression (3-1) is lower than the lower limit value, it becomes difficult to appropriately correct the second order dispersion of the magnification chromatic aberration.

[0049] In the variable magnification optical system of the present embodiment, by setting the lower limit value of conditional expression (3-1) to 0.020, the effect of the present embodiment can be made more reliable. Further, in order to make the effect of the present embodiment more reliable, it is preferable to set the lower limit value of conditional expression (3-1) to 0.022, 0.024, and more preferably to 0.026.

[0050] Further, in the variable magnification optical system of the present embodiment, it is preferable to satisfy the following conditional expression. (4-1) 0.045 < fw / (-fCα) < 0.140 wherein, fw: focal length of the variable magnification optical system at the wide angle end

[0051] The conditional expression (4-1) defines the ratio of the focal length of the variable optical system in the wide-angle end state to the focal length of the second negative lens group. The variable optical system of the present embodiment can appropriately correct various aberrations such as image surface curvature, distortion, spherical aberration, and the like while suppressing an increase in the weight of the variable optical system by satisfying the conditional expression (4-1).

[0052] In the variable optical system of the present embodiment, if the value of the conditional expression (4-1) exceeds the upper limit value, the power of the second negative lens group is too strong, and appropriate correction of various aberrations such as image surface curvature, distortion, and the like becomes difficult.

[0053] In the variable optical system of the present embodiment, the effects of the present embodiment can be made more reliable by setting the upper limit value of the conditional expression (4-1) to 0.140. In addition, in order to make the effects of the present embodiment more reliable, it is preferable to set the upper limit value of the conditional expression (4-1) to 0.135, 0.130, 0.125, and more preferable to set it to 0.122.

[0054] In addition, in the variable optical system of the present embodiment, if the value of the conditional expression (4-1) is lower than the lower limit value, the power of the second negative lens group is too weak, and appropriate correction of various aberrations including spherical aberration becomes difficult. In addition, the lens diameter of the rear group increases, and the weight of the variable optical system increases.

[0055] In the variable optical system of the present embodiment, the effects of the present embodiment can be made more reliable by setting the lower limit value of the conditional expression (4-1) to 0.045. In addition, in order to make the effects of the present embodiment more reliable, it is preferable to set the lower limit value of the conditional expression (4-1) to 0.050, 0.055, 0.058, and more preferable to set it to 0.060.

[0056] In addition, in the variable optical system of the present embodiment, it is preferable that the combined power of the lens group disposed between the first negative lens group and the aperture stop in the wide-angle end state be positive.

[0057] In the variable optical system of the present embodiment, by having such a structure, various aberrations such as image surface curvature and distortion can be well corrected.

[0058] In addition, in the variable optical system of the present embodiment, it is preferable to satisfy the following conditional expression. (5) 0.30 < STLw / TLw < 0.50 wherein, STLw: distance on the optical axis from the aperture stop to the image plane in the wide-angle end state TLw: distance on the optical axis from the most object side lens surface to the image plane in the wide-angle end state

[0059] The conditional expression (5) defines a ratio of a distance on an optical axis from the aperture stop to the image plane to a distance on the optical axis from the most object-ward lens surface to the image plane in the wide-angle end state. The zoom optical system of the present embodiment can appropriately correct various aberrations including coma in the entire zoom region by satisfying the conditional expression (5).

[0060] In the zoom optical system of the present embodiment, if the value of the conditional expression (5) exceeds the upper limit value, the position of the aperture stop is too much toward the object side, and appropriate correction of various aberrations including coma becomes difficult on the wide-angle side at the time of zooming.

[0061] In the zoom optical system of the present embodiment, the effect of the present embodiment can be made more reliable by setting the upper limit value of the conditional expression (5) to 0.50. Further, in order to make the effect of the present embodiment more reliable, it is preferable to set the upper limit value of the conditional expression (5) to 0.48, 0.46, and more preferably to 0.42.

[0062] Further, in the zoom optical system of the present embodiment, if the value of the conditional expression (5) is lower than the lower limit value, the position of the aperture stop is too much toward the image plane side, and appropriate correction of various aberrations including coma becomes difficult on the tele side at the time of zooming.

[0063] In the zoom optical system of the present embodiment, the effect of the present embodiment can be made more reliable by setting the lower limit value of the conditional expression (5) to 0.30. Further, in order to make the effect of the present embodiment more reliable, it is preferable to set the lower limit value of the conditional expression (5) to 0.32, 0.34, 0.36, 0.38, and more preferably to 0.40.

[0064] The zoom optical system of the present embodiment includes, in order from the object side, a first negative lens group having a negative refractive power and a rear group having a plurality of lens groups, at the time of zooming, the first negative lens group is fixed with respect to the image plane, the interval between each of the adjacent lens groups is changed, in the plurality of lens groups included in the rear group, the third negative lens group having a negative refractive power, which is disposed on the image plane side as compared with the first positive lens group disposed on the most object-ward side and having a positive refractive power, is disposed on the most object-ward side, and the following conditional expression is satisfied. (1-2) 0.00 < fA / fCβ < 0.30 wherein, fA: focal length of the first negative lens group fCβ: focal length of the third negative lens group

[0065] The variable magnification optical system of the present embodiment has the first negative lens group having a negative refractive power and a rear group having a plurality of lens groups, and among the plurality of lens groups of the rear group, has the third negative lens group disposed on the most object side among the one or more lens groups having a negative refractive power disposed on the image plane side of the first positive lens group disposed on the most object side and having a positive refractive power, and thus can appropriately correct each aberration including spherical aberration at the time of variable magnification.

[0066] Condition formula (1-2) specifies the ratio of the focal length of the first negative lens group to the focal length of the third negative lens group. The variable magnification optical system of the present embodiment can appropriately correct each aberration including spherical aberration while suppressing the increase in size of the variable magnification optical system by satisfying condition formula (1-2).

[0067] In the variable magnification optical system of the present embodiment, if the value of condition formula (1-2) exceeds the upper limit value, the refractive power of the first negative lens group is too weak, and the variable magnification optical system increases in size.

[0068] In the variable magnification optical system of the present embodiment, by setting the upper limit value of condition formula (1-2) to 0.30, the effect of the present embodiment can be made more reliable. In addition, in order to make the effect of the present embodiment more reliable, it is preferable to set the upper limit value of condition formula (1-2) to 0.28, 0.26, 0.25, 0.24, and more preferably to 0.23.

[0069] In addition, in the variable magnification optical system of the present embodiment, if the value of condition formula (1-2) is lower than the lower limit value, the refractive power of the third negative lens group is too weak, and appropriate correction of each aberration including spherical aberration becomes difficult.

[0070] In the variable magnification optical system of the present embodiment, by setting the lower limit value of condition formula (1-2) to 0.00, the effect of the present embodiment can be made more reliable. In addition, in order to make the effect of the present embodiment more reliable, it is preferable to set the lower limit value of condition formula (1-2) to 0.02, 0.04, 0.06, 0.08, and more preferably to 0.10.

[0071] In addition, in the variable magnification optical system of the present embodiment, it is preferable that at least one lens group among the lenses disposed on the image plane side of the third negative lens group moves at the time of focusing.

[0072] In the variable magnification optical system of the present embodiment, by having such a structure, it is possible to suppress the variation of each aberration including spherical aberration at the time of variable magnification and to suppress the variation of the field angle at the time of focusing (so-called breathing effect).

[0073] In addition, the variable magnification optical system of the present embodiment preferably satisfies the following condition formula. (2-2) 0.90 < MVGCβ / MVGE < 1.50 wherein, MVGCβ: movement amount of the third negative lens group from the wide angle end to the tele end when focusing at infinity MVGE: movement amount of the final negative lens group from the wide angle end to the tele end when focusing at infinity

[0074] The conditional expression (2-2) specifies the ratio of the movement amount of the third negative lens group to the movement amount of the final negative lens group from the wide angle end to the tele end when focusing at infinity. The zoom optical system of the present embodiment can correct the curvature of field well in the entire zoom region by satisfying the conditional expression (2-2), because the ratio of the movement amount of the third negative lens group to the movement amount of the final negative lens group from the wide angle end to the tele end is close to 1.

[0075] In the zoom optical system of the present embodiment, if the value of the conditional expression (2-2) exceeds the upper limit value, it becomes difficult to correct the curvature of field appropriately in the entire zoom region.

[0076] In the zoom optical system of the present embodiment, by setting the upper limit value of the conditional expression (2-2) to 1.50, the effect of the present embodiment can be made more reliable. In order to make the effect of the present embodiment more reliable, it is preferable to set the upper limit value of the conditional expression (2-2) to 1.45, 1.40, 1.37, 1.34, and more preferably to 1.30.

[0077] In the zoom optical system of the present embodiment, if the value of the conditional expression (2-2) is lower than the lower limit value, it becomes difficult to correct the curvature of field appropriately in the entire zoom region.

[0078] In the zoom optical system of the present embodiment, by setting the lower limit value of the conditional expression (2-2) to 0.90, the effect of the present embodiment can be made more reliable. In order to make the effect of the present embodiment more reliable, it is preferable to set the lower limit value of the conditional expression (2-2) to 0.92, 0.94, 0.96, and more preferably to 0.98.

[0079] In the zoom optical system of the present embodiment, it is preferable that the second negative lens group has a positive lens Cβp satisfying the following conditional expression. (3-2) 0.020 < PgFCβp - 0.64435 + 0.00168 * vdCβp wherein, PgFCβp: relative partial dispersion of the positive lens Cβp, defined by the following formula when the refractive index of the positive lens Cβp with respect to the g line is ngCβp, the refractive index of the positive lens Cβp with respect to the F line is nFCβp, and the refractive index of the positive lens Cβp with respect to the C line is nCCβp. PgFCβp = (ngCβp - nFCβp) / (nFCβp - nCCβp) νdCβp: Abbe number of the positive lens Cβp with respect to the d line

[0080] In the variable magnification optical system of the present embodiment, by the third negative lens group having the positive lens Cβp satisfying the conditional expression (3-2), the second-order dispersion of the magnification chromatic aberration can be well corrected.

[0081] In the variable magnification optical system of the present embodiment, if the value of the conditional expression (3-2) is lower than the lower limit value, it becomes difficult to appropriately correct the second-order dispersion of the magnification chromatic aberration.

[0082] In the variable magnification optical system of the present embodiment, by setting the lower limit value of the conditional expression (3-2) to 0.020, the effect of the present embodiment can be made more reliable. Further, in order to make the effect of the present embodiment more reliable, it is preferable to set the lower limit value of the conditional expression (3-2) to 0.022, 0.024, and more preferably to 0.026.

[0083] Further, in the variable magnification optical system of the present embodiment, it is preferable to satisfy the following conditional expression. (4-2) 0.045 < fw / (-fCβ) < 0.140 wherein, fw: focal length of the variable magnification optical system at the wide angle end

[0084] The conditional expression (4-2) specifies the ratio of the focal length of the variable magnification optical system in the wide angle end state to the focal length of the second negative lens group. The variable magnification optical system of the present embodiment, by satisfying the conditional expression (4-2), can appropriately correct each aberration such as image surface curvature, distortion, spherical aberration, and the like while suppressing an increase in the weight of the variable magnification optical system.

[0085] In the variable magnification optical system of the present embodiment, if the value of the conditional expression (4-2) exceeds the upper limit value, the optical power of the third negative lens group is too strong, and appropriate correction of each aberration such as image surface curvature, distortion, and the like becomes difficult.

[0086] In the variable magnification optical system of this embodiment, by setting the upper limit value of conditional expression (4-2) to 0.140, the effect of this embodiment can be made more reliable. Further, in order to make the effect of this embodiment more reliable, it is preferable to set the upper limit value of conditional expression (4-2) to 0.135, 0.130, 0.125, and more preferably to 0.122.

[0087] Further, in the variable magnification optical system of this embodiment, if the value of conditional expression (4-2) is lower than the lower limit value, the power of the 3rd negative lens group is too weak, and appropriate correction of each aberration including spherical aberration becomes difficult. Further, the lens diameter of the rear group increases, and the weight of the variable magnification optical system increases.

[0088] In the variable magnification optical system of this embodiment, by setting the lower limit value of conditional expression (4-2) to 0.045, the effect of this embodiment can be made more reliable. Further, in order to make the effect of this embodiment more reliable, it is preferable to set the lower limit value of conditional expression (4-2) to 0.050, 0.055, 0.058, and more preferably to 0.060.

[0089] Further, in the variable magnification optical system of this embodiment, it is preferable that the plurality of lens groups possessed by the rear group have a 1st positive lens group disposed closest to the object side and having a positive power, and a 2nd positive lens group disposed adjacent to the image side of the 1st positive lens group and having a positive power, and satisfy the following conditional expression. (6) 1.40 < fB1 / fB2 < 3.00 wherein, fB1: focal length of the 1st positive lens group fB2: focal length of the 2nd positive lens group

[0090] Conditional expression (6) specifies the ratio of the focal length of the 1st positive lens group to the focal length of the 2nd positive lens group. The variable magnification optical system of this embodiment, by satisfying conditional expression (6), can appropriately correct each aberration including spherical aberration, coma, and the like, in the entire region of the variable magnification.

[0091] In the variable magnification optical system of this embodiment, if the value of conditional expression (6) exceeds the upper limit value, the power of the 2nd positive lens group is too strong, and appropriate correction of each aberration including spherical aberration on the tele side at the time of the variable magnification becomes difficult.

[0092] In the variable magnification optical system of this embodiment, by setting the upper limit value of conditional expression (6) to 3.00, the effect of this embodiment can be made more reliable. Further, in order to make the effect of this embodiment more reliable, it is preferable to set the upper limit value of conditional expression (6) to 2.90, 2.80, 2.75, and more preferably to 2.65.

[0093] Further, in the variable magnification optical system of the present embodiment, if the value of the conditional expression (6) is lower than the lower limit value, the power of the first positive lens group is too strong, and appropriate correction of each aberration including coma on the wide angle side at the time of variable magnification becomes difficult.

[0094] In the variable magnification optical system of the present embodiment, by setting the lower limit value of the conditional expression (6) to 1.40, the effect of the present embodiment can be made more reliable. Further, in order to make the effect of the present embodiment more reliable, it is preferable to set the lower limit value of the conditional expression (6) to 1.45, 1.50, 1.55, 1.60, and more preferably to 1.63.

[0095] Further, in the variable magnification optical system of the present embodiment, it is preferable to satisfy the following conditional expression. (7) 1.00 < -fA / fARw < 1.60 wherein, fARw: composite focal length of the rear group at the wide angle end

[0096] The conditional expression (7) specifies the ratio of the focal length of the first negative lens group to the focal length of the rear group in the wide angle end state. The variable magnification optical system of the present embodiment, by satisfying the conditional expression (7), can appropriately correct each aberration including curvature of field, distortion, and the like while suppressing the increase in size of the variable magnification optical system.

[0097] In the variable magnification optical system of the present embodiment, if the value of the conditional expression (7) exceeds the upper limit value, the power of the first negative lens group is too weak, and the variable magnification optical system increases in size.

[0098] In the variable magnification optical system of the present embodiment, by setting the upper limit value of the conditional expression (7) to 1.60, the effect of the present embodiment can be made more reliable. Further, in order to make the effect of the present embodiment more reliable, it is preferable to set the upper limit value of the conditional expression (7) to 1.55, 1.50, 1.48, 1.45, and more preferably to 1.42.

[0099] Further, in the variable magnification optical system of the present embodiment, if the value of the conditional expression (7) is lower than the lower limit value, the power of the first negative lens group is too strong, and appropriate correction of each aberration including curvature of field, distortion, and the like becomes difficult.

[0100] In the variable magnification optical system of the present embodiment, by setting the lower limit value of the conditional expression (7) to 1.00, the effect of the present embodiment can be made more reliable. Further, in order to make the effect of the present embodiment more reliable, it is preferable to set the lower limit value of the conditional expression (7) to 1.03, 1.06, 1.10, 1.13, and more preferably to 1.16.

[0101] Further, in the variable magnification optical system of the present embodiment, it is preferable to satisfy the following conditional expression. (8) 0.50 < fA / fE < 1.20 wherein, fE: focal length of a final negative lens group having a negative refractive power and disposed on the most object side among the plurality of lens groups possessed by the rear group

[0102] Condition (8) specifies the ratio of the focal length of the first negative lens group to the focal length of the final negative lens group. The variable magnification optical system of the present embodiment can appropriately correct various aberrations such as image surface curvature, distortion, and the like while suppressing the increase in size of the variable magnification optical system by satisfying condition (8).

[0103] In the variable magnification optical system of the present embodiment, if the value of condition (8) exceeds the upper limit value, the refractive power of the first negative lens group is too weak, and the variable magnification optical system is large in size.

[0104] In the variable magnification optical system of the present embodiment, by setting the upper limit value of condition (8) to 1.20, the effect of the present embodiment can be made more reliable. In addition, in order to make the effect of the present embodiment more reliable, it is preferable to set the upper limit value of condition (8) to 1.15, 1.10, 1.05, 1.00, and more preferably to 0.98.

[0105] In addition, in the variable magnification optical system of the present embodiment, if the value of condition (8) is lower than the lower limit value, the refractive power of the first negative lens group is too strong, and appropriate correction of various aberrations such as image surface curvature, distortion, and the like becomes difficult.

[0106] In the variable magnification optical system of the present embodiment, by setting the lower limit value of condition (8) to 0.50, the effect of the present embodiment can be made more reliable. In addition, in order to make the effect of the present embodiment more reliable, it is preferable to set the lower limit value of condition (8) to 0.55, 0.60, 0.63, 0.66, and more preferably to 0.68.

[0107] In addition, in the variable magnification optical system of the present embodiment, it is preferable that, at the time of focusing, two lens groups having a positive refractive power among the plurality of lens groups possessed by the rear group move, and the following condition (9) is satisfied. (9) 0.40 < fF1 / fF2 < 1.20 wherein, fF1: focal length of a lens group disposed on the object side among the two lens groups fF2: focal length of a lens group disposed on the image surface side among the two lens groups

[0108] The conditional expression (9) prescribes a ratio of a focal length of the lens group disposed on the object side among the two lens groups which move at the time of focusing and which have positive refractive power, to a focal length of the lens group disposed on the image surface side, among the plurality of lens groups possessed by the rear group. The variable magnification optical system of the present embodiment is able to appropriately correct each aberration such as image surface curvature, coma, and the like at the time of close distance focusing, by satisfying the conditional expression (9).

[0109] In the variable magnification optical system of the present embodiment, if the value of the conditional expression (9) exceeds the upper limit value, the refractive power of the lens group disposed on the object side among the two lens groups is too weak, and appropriate correction of the image surface curvature at the time of close distance focusing becomes difficult.

[0110] In the variable magnification optical system of the present embodiment, by setting the upper limit value of the conditional expression (9) to 1.20, the effects of the present embodiment can be made more reliable. In addition, in order to make the effects of the present embodiment more reliable, it is preferable to set the upper limit value of the conditional expression (9) to 1.15, 1.10, 1.05, 1.00, and more preferably to 0.95.

[0111] In addition, in the variable magnification optical system of the present embodiment, if the value of the conditional expression (9) is lower than the lower limit value, the refractive power of the lens group disposed on the object side among the two lens groups is too strong, and appropriate correction of the coma at the time of close distance focusing becomes difficult.

[0112] In the variable magnification optical system of the present embodiment, by setting the lower limit value of the conditional expression (9) to 0.40, the effects of the present embodiment can be made more reliable. In addition, in order to make the effects of the present embodiment more reliable, it is preferable to set the lower limit value of the conditional expression (9) to 0.44, 0.48, 0.52, 0.56, and more preferably to 0.60.

[0113] In addition, in the variable magnification optical system of the present embodiment, it is preferable to satisfy the following conditional expression. (10) 0.60 < MVF1w / MVF2w < 1.70 wherein, MVF1w: a movement amount of the lens group disposed on the object side among the two lens groups which move at the time of focusing, among the plurality of lens groups possessed by the rear group, at the time of focusing from an infinite distance object to a close distance object in the wide angle end state MVF2w: a movement amount of the lens group disposed on the image surface side among the two lens groups which move at the time of focusing, among the plurality of lens groups possessed by the rear group, at the time of focusing from an infinite distance object to a close distance object in the wide angle end state

[0114] The conditional expression (10) prescribes a ratio of a movement amount of a lens group disposed on the object side to a movement amount of a lens group disposed on the image plane, among the two lens groups that move at the time of focusing, of the plurality of lens groups possessed by the rear group at the time of focusing on a close-range object from an infinite-range object in a wide-angle end state. The variable magnification optical system of the present embodiment is able to appropriately correct various aberrations including image surface curvature by satisfying the conditional expression (10). Furthermore, in the present disclosure, "close-range" refers to the minimum photographing distance.

[0115] In the variable magnification optical system of the present embodiment, if the value of the conditional expression (10) exceeds the upper limit value, it becomes difficult to appropriately correct various aberrations including image surface curvature.

[0116] In the variable magnification optical system of the present embodiment, by setting the upper limit value of the conditional expression (10) to 1.70, the effects of the present embodiment can be made more reliable. In addition, in order to make the effects of the present embodiment more reliable, it is preferable to set the upper limit value of the conditional expression (10) to 1.65, 1.60, 1.56, 1.52, and more preferably to 1.48.

[0117] In addition, in the variable magnification optical system of the present embodiment, if the value of the conditional expression (10) is lower than the lower limit value, it becomes difficult to appropriately correct various aberrations including image surface curvature.

[0118] In the variable magnification optical system of the present embodiment, by setting the lower limit value of the conditional expression (10) to 0.60, the effects of the present embodiment can be made more reliable. In addition, in order to make the effects of the present embodiment more reliable, it is preferable to set the lower limit value of the conditional expression (10) to 0.64, 0.68, 0.72, 0.76, and more preferably to 0.80.

[0119] In addition, in the variable magnification optical system of the present embodiment, it is preferable to satisfy the following conditional expression. (11) 0.40 < MVGO / MVGE < 0.80 wherein, MVGE: movement amount of the final negative lens group disposed on the most image plane side and having a negative refractive power, among the plurality of lens groups possessed by the rear group, at the time of variable magnification from the wide-angle end to the telephoto end at the time of focusing on an infinite-range object MVGO: movement amount of the lens group disposed adjacent to the object side of the final negative lens group, among the plurality of lens groups possessed by the rear group, at the time of variable magnification from the wide-angle end to the telephoto end at the time of focusing on an infinite-range object

[0120] The conditional expression (11) specifies a ratio of a movement amount of the final negative lens group to a movement amount of the lens group disposed adjacent to the object side of the final negative lens group when zooming from the wide angle end to the telephoto end at the time of focusing at infinity. The zoom optical system of the present embodiment can appropriately correct each aberration such as coma, magnification chromatic aberration, and the like in the entire zoom region by satisfying the conditional expression (11).

[0121] In the zoom optical system of the present embodiment, if the value of the conditional expression (11) exceeds the upper limit value, the final negative lens group and the lens group adjacent to the object side of the final negative lens group are too close when zooming from the wide angle end to the telephoto end, and thus appropriate correction of each aberration such as coma, magnification chromatic aberration, and the like becomes difficult in the entire zoom region.

[0122] In the zoom optical system of the present embodiment, the effect of the present embodiment can be made more reliable by setting the upper limit value of the conditional expression (11) to 0.80. In addition, in order to make the effect of the present embodiment more reliable, it is preferable to set the upper limit value of the conditional expression (11) to 0.77, 0.75, 0.72, 0.70, and more preferable to set to 0.68.

[0123] In addition, in the zoom optical system of the present embodiment, if the value of the conditional expression (11) is lower than the lower limit value, the final negative lens group and the lens group adjacent to the object side of the final negative lens group are too close when zooming from the wide angle end to the telephoto end, and thus appropriate correction of each aberration such as coma, magnification chromatic aberration, and the like becomes difficult in the entire zoom region.

[0124] In the zoom optical system of the present embodiment, the effect of the present embodiment can be made more reliable by setting the lower limit value of the conditional expression (11) to 0.40. In addition, in order to make the effect of the present embodiment more reliable, it is preferable to set the lower limit value of the conditional expression (11) to 0.42, 0.44, and more preferable to set to 0.46.

[0125] In addition, in the zoom optical system of the present embodiment, it is preferable to satisfy the following conditional expression. (12) 0.40 < BFw / fw < 0.60 wherein, Bfw: back focal distance of the zoom optical system at the wide angle end fw: focal distance of the zoom optical system at the wide angle end

[0126] The conditional expression (12) specifies a ratio of the back focal distance to the focal distance of the zoom optical system at the wide angle end. The zoom optical system of the present embodiment can secure a space for disposing components between the lens disposed closest to the image plane and the image plane while suppressing the enlargement of the zoom optical system by satisfying the conditional expression (12).

[0127] In the variable magnification optical system of the present embodiment, if the value of conditional expression (12) exceeds the upper limit value, the back focal length becomes too large, and the variable magnification optical system becomes large.

[0128] In the variable magnification optical system of the present embodiment, by setting the upper limit value of conditional expression (12) to 0.60, the effect of the present embodiment can be made more reliable. In order to make the effect of the present embodiment more reliable, it is preferable to set the upper limit value of conditional expression (12) to 0.58, 0.56, 0.54, 0.52, and more preferably to 0.50.

[0129] In the variable magnification optical system of the present embodiment, if the value of conditional expression (12) is lower than the lower limit value, the back focal length becomes too small, and it becomes difficult to arrange a member between the lens arranged on the most image surface side and the image surface.

[0130] In the variable magnification optical system of the present embodiment, by setting the lower limit value of conditional expression (12) to 0.40, the effect of the present embodiment can be made more reliable. In order to make the effect of the present embodiment more reliable, it is preferable to set the lower limit value of conditional expression (12) to 0.42, 0.44, and more preferably to 0.46.

[0131] In the variable magnification optical system of the present embodiment, it is preferable to satisfy the following conditional expression. (13) -3.00 < (L1R2+L1R1) / (L1R2-L1R1) < -1.00 wherein, L1R1: radius of curvature of the object side lens surface of the lens arranged on the most object side L1R2: radius of curvature of the image side lens surface of the lens arranged on the most object side

[0132] Conditional expression (13) specifies the shape factor of the lens arranged on the most object side. The variable magnification optical system of the present embodiment can appropriately correct each aberration such as coma, image surface curvature, and the like by satisfying conditional expression (13).

[0133] In the variable magnification optical system of the present embodiment, by setting the upper limit value of conditional expression (13) to -1.00, the effect of the present embodiment can be made more reliable. In order to make the effect of the present embodiment more reliable, it is preferable to set the upper limit value of conditional expression (13) to -1.10, -1.20, -1.30, -1.40, and more preferably to -1.50.

[0134] In the variable magnification optical system of the present embodiment, by setting the lower limit value of conditional expression (13) to -3.00, the effect of the present embodiment can be made more reliable. Further, in order to make the effect of the present embodiment more reliable, it is preferable to set the lower limit value of conditional expression (13) to -2.75, -2.50, -2.25, more preferably to -2.00.

[0135] Further, in the variable magnification optical system of the present embodiment, it is preferable to satisfy the following conditional expression. (14) 0.00 < (LLR2 + LLR1) / (LLR2 - LLR1) < 2.00 wherein, LLR1: radius of curvature of a lens surface on the object side of the lens disposed on the most image surface side LLR2: radius of curvature of a lens surface on the image surface side of the lens disposed on the most image surface side

[0136] Conditional expression (14) specifies the shape factor of the lens disposed on the most image surface side. The variable magnification optical system of the present embodiment, by satisfying conditional expression (14), can appropriately correct each aberration such as coma, image surface curvature, and the like.

[0137] In the variable magnification optical system of the present embodiment, by setting the upper limit value of conditional expression (14) to 2.00, the effect of the present embodiment can be made more reliable. Further, in order to make the effect of the present embodiment more reliable, it is preferable to set the upper limit value of conditional expression (14) to 1.90, 1.80, 1.70, 1.65, more preferably to 1.60.

[0138] In the variable magnification optical system of the present embodiment, by setting the lower limit value of conditional expression (14) to 0.00, the effect of the present embodiment can be made more reliable. Further, in order to make the effect of the present embodiment more reliable, it is preferable to set the lower limit value of conditional expression (14) to 0.20, 0.40, 0.60, 0.80, more preferably to 0.90.

[0139] Further, in the variable magnification optical system of the present embodiment, it is preferable to satisfy the following conditional expression. (15) 68° < 2ωw wherein, 2ωw: total field angle of the variable magnification optical system in the wide angle end state

[0140] Conditional expression (15) specifies the total field angle of the variable magnification optical system in the wide angle end state. The variable magnification optical system of the present embodiment, by satisfying conditional expression (15), can obtain a larger field angle.

[0141] In the variable magnification optical system of the present embodiment, by setting the lower limit value of conditional expression (15) to 68.00°, the effect of the present embodiment can be made more reliable. Further, in order to make the effect of the present embodiment more reliable, it is preferable to set the upper limit value of conditional expression (15) to 72.00°, 75.00°, and more preferably to 80.00°.

[0142] Further, in the variable magnification optical system of the present embodiment, it is preferable to satisfy the following conditional expression. (16) 2ωt < 40° wherein, 2ωt: total field angle of the variable magnification optical system in the tele end state

[0143] Conditional expression (16) specifies the total field angle of the variable magnification optical system in the tele end state. The variable magnification optical system of the present embodiment, by satisfying conditional expression (16), can obtain a larger subject image.

[0144] In the variable magnification optical system of the present embodiment, by setting the upper limit value of conditional expression (16) to 40.00°, the effect of the present embodiment can be made more reliable. Further, in order to make the effect of the present embodiment more reliable, it is preferable to set the upper limit value of conditional expression (16) to 38.00°, 36.00°, and more preferably to 35.00°.

[0145] Further, in the variable magnification optical system of the present embodiment, it is preferable that the movement amount of two lens groups among the plurality of lens groups possessed by the rear group when zooming from the wide end to the tele end at the time of focusing at infinity be equal.

[0146] In the variable magnification optical system of the present embodiment, by having such a structure, the number of components for moving each lens group can be reduced, and thus the weight can be reduced.

[0147] Further, in the variable magnification optical system of the present embodiment, it is preferable that, at the time of zooming and focusing, the lens group disposed on the most image plane side among the plurality of lens groups possessed by the first negative lens group and the rear group be fixed with respect to the image plane.

[0148] In the variable magnification optical system of the present embodiment, by having such a structure, the first negative lens group disposed on the most object side and the lens group disposed on the most image plane side are fixed, and thus reliable engagement to the lens housing can be achieved, and the entry of foreign matter into the optical system can be appropriately suppressed.

[0149] Further, in the variable magnification optical system of the present embodiment, it is preferable to satisfy the following conditional expression. (17) 2.00 < Fnot < 4.00 wherein, Fnot: F number of the variable magnification optical system in the tele end state

[0150] Condition formula (17) defines the F number of the variable magnification optical system in the tele end state. The variable magnification optical system of the present embodiment can ensure brightness in the tele end state and correct various aberrations including spherical aberration well by satisfying condition formula (17).

[0151] In the variable magnification optical system of the present embodiment, the effect of the present embodiment can be made more reliable by setting the upper limit value of condition formula (17) to 4.00. In order to make the effect of the present embodiment more reliable, it is preferable to set the upper limit value of condition formula (17) to 3.50, and more preferable to set it to 3.20.

[0152] In the variable magnification optical system of the present embodiment, the effect of the present embodiment can be made more reliable by setting the lower limit value of condition formula (17) to 2.00. In order to make the effect of the present embodiment more reliable, it is preferable to set the lower limit value of condition formula (17) to 2.20, 2.50, and more preferable to set it to 2.80.

[0153] In the variable magnification optical system of the present embodiment, it is preferable that the plurality of lens groups possessed by the first negative lens group and the rear group are each composed of one or two lens elements. The lens element refers to a single lens or a cemented lens.

[0154] Generally, in a variable magnification optical system in which the lens group closest to the object side is fixed, the movement amount of each lens group cannot be sufficiently ensured at the time of variable magnification, and aberration correction becomes difficult. In the variable magnification optical system of the present embodiment, the lens groups are set to a plurality, and the relative positions of the plurality of lens groups are changed, so that each aberration at the time of variable magnification can be corrected well while the lens group closest to the object side is set to be fixed. In the variable magnification optical system of the present embodiment, by making each lens group composed of one or two lens elements, the manufacturing error within the lens group can be reduced.

[0155] With the above structure, a variable magnification optical system that is small in size and has good imaging performance can be realized.

[0156] The optical apparatus of the present embodiment has the variable magnification optical system having the above structure. Thereby, an optical apparatus having good optical performance can be realized.

[0157] The manufacturing method of the zoom optical system of the present embodiment includes: configuring a zoom optical system sequentially provided from an object side with a first negative lens group having a negative refractive power and a rear group having a plurality of lens groups, in zooming, the first negative lens group is fixed with respect to an image plane, the interval between adjacent lens groups changes, an aperture stop is disposed at the image plane side of the first negative lens group, a second negative lens group having a negative refractive power is disposed adjacent to the image plane side of the aperture stop among the plurality of lens groups of the rear group, and the following conditional expression is satisfied. (1-1) 0.00 < fA / fCa < 0.30 wherein, fA: focal length of the first negative lens group fCa: focal length of the second negative lens group

[0158] The manufacturing method of the zoom optical system of the present embodiment includes: configuring a zoom optical system sequentially provided from an object side with a first negative lens group having a negative refractive power and a rear group having a plurality of lens groups, in zooming, the first negative lens group is fixed with respect to an image plane, the interval between adjacent lens groups changes, a third negative lens group having a negative refractive power is disposed at the most object side among one or more lens groups having a negative refractive power disposed at the image plane side of a first positive lens group having a positive refractive power disposed at the most object side among the plurality of lens groups of the rear group, and the following conditional expression is satisfied. (1-2) 0.00 < fA / fCβ < 0.30 wherein, fA: focal length of the first negative lens group fCβ: focal length of the third negative lens group

[0159] By the manufacturing method of the optical system, a zoom optical system having good optical performance can be manufactured.

[0160] (Numerical Example)

[0161] Hereinafter, the embodiment of the present application will be described based on the drawings.

[0162] (First Embodiment)

[0163] Figure 1 is a sectional view of the zoom optical system of the first embodiment at the time of focusing on an infinite distance object in a wide angle end state.

[0164] The zoom optical system of the present embodiment sequentially has, from the object side, a first lens group G1 having a negative refractive power, a second lens group G2 having a positive refractive power, a third lens group G3 having a positive refractive power, a fourth lens group G4 having a negative refractive power, a fifth lens group G5 having a positive refractive power, a sixth lens group G6 having a positive refractive power, and a seventh lens group G7 having a negative refractive power.

[0165] The first lens group G1 is composed of, in order from the object side, a negative meniscus lens L1 whose convex surface faces the object side, and a negative meniscus lens L2 whose convex surface faces the object side, and a positive meniscus lens L3 whose concave surface faces the object side.

[0166] The second lens group G2 is composed of a positive biconvex lens L4 and a negative biconcave lens L5.

[0167] The third lens group G3 is composed of a negative meniscus lens L6 whose convex surface faces the object side, and a positive biconvex lens L7.

[0168] The fourth lens group G4 is composed of, in order from the object side, an aperture stop S, a negative biconcave lens L8, and a positive biconvex lens L9.

[0169] The fifth lens group G5 is composed of a positive biconvex lens L10 and a negative meniscus lens L11 whose concave surface faces the object side.

[0170] The sixth lens group G6 is composed of a positive meniscus lens L12 whose concave surface faces the object side.

[0171] The seventh lens group G7 is composed of a negative meniscus lens L13 whose concave surface faces the object side.

[0172] On the image plane I, a photographing element (not shown) composed of a CCD or a CMOS or the like is disposed.

[0173] In the variable magnification optical system of the present embodiment, when zooming from the wide-angle end state to the telephoto end state, the first lens group G1 is fixed with respect to the image plane I, and each of the groups from the second lens group G2 to the seventh lens group G7 moves along the optical axis toward the object side. Thus, in the variable magnification optical system of the present embodiment, when zooming from the wide-angle end state to the telephoto end state, the interval between adjacent lens groups among the first lens group G1 to the seventh lens group G7 changes.

[0174] The variable magnification optical system of the present embodiment performs focusing by moving the fifth lens group G5 and the sixth lens group G6 along the optical axis, respectively. In the case of focusing on a close-range object from a state of focusing on infinity, the fifth lens group G5 and the sixth lens group G6 move from the image plane side to the object side, respectively.

[0175] In the variable magnification optical system of the present embodiment, the first lens group G1 corresponds to the first negative lens group, the second lens group G2 to the seventh lens group G7 correspond to the plurality of lens groups possessed by the rear group. The fourth lens group G4 corresponds to the second negative lens group, and also corresponds to the third negative lens group. The positive lens L9 corresponds to the positive lens Cαp, and also corresponds to the positive lens Cβp. The fifth lens group G5 corresponds to the first positive lens group, the sixth lens group G6 corresponds to the second positive lens group. The seventh lens group G7 corresponds to the final negative lens group.

[0176] In the following Table 1, values of the parameters of the variable magnification optical system of the present embodiment are described.

[0177] In [Overall Parameters], fW indicates the focal length of the entire system in the wide-angle end state, fT indicates the focal length of the entire system in the telephoto end state, FnoW indicates the F number in the wide-angle end state, FnoT indicates the F number in the telephoto end state, Y indicates the maximum image height, TL indicates the distance from the most object side lens surface to the image plane, BfW indicates the back focal length in the wide-angle end state, BfT indicates the back focal length in the telephoto end state, 2ωw indicates the full field angle (degrees) in the wide-angle end state, and 2ωt indicates the full field angle (degrees) in the telephoto end state.

[0178] In [Lens Parameters], m indicates the serial number of the optical surface counted from the object side, r indicates the curvature radius, d indicates the surface interval, nd indicates the refractive index for the d line (wavelength 587.6 nm), and νd indicates the Abbe number for the d line. The curvature radius r = ∞ indicates a plane. In addition, in [Lens Parameters], the optical surface to which an "*" is attached indicates an aspherical surface.

[0179] In [Aspherical Surface Data], m indicates the optical surface corresponding to the aspherical surface data, K indicates the conic constant, and A4 to A12 indicate the aspherical coefficients.

[0180] In [Aspherical Surface Data], m indicates the optical surface corresponding to the aspherical surface data, K indicates the conic constant, and A4 to A12 indicate the aspherical coefficients. -n

[0181] (a) S(y) = (y 2 / r) / {1 + (1 - K x y 2 / r 2 ) 1 / 2} + A4 x y4+ A6 x y6+ A8 x y8+ A10 x y 10 +A12 x y​12

[0182] The focal lengths fW and fT, the curvature radius r, and other lengths described in Table 1 are in units of "mm". However, since the same optical performance can be obtained even if the optical system is scaled up or scaled down, the units are not limited to this.

[0183] The symbols of Table 1 described above are also used in the tables of other embodiments described later.

[0184] (Table 1)

[0185] [Overall Parameters]

[0186] [Lens Parameters]

[0187] [Aspherical Surface Data]

[0188] [Each Group Focal Length Data]

[0189] [Variable Interval Data]

[0190] Figure 2A is each aberration diagram at the time of focusing on an infinite object in the wide-angle end state of the variable magnification optical system of the first embodiment, Figure 2B is each aberration diagram at the time of focusing on an infinite object in the telephoto end state of the variable magnification optical system of the first embodiment.

[0191] In each aberration diagram, FNO indicates the F value, and Y indicates the image height. Specifically, in the spherical aberration diagram, the value of the F value corresponding to the maximum aperture is shown, in the astigmatism diagram and the distortion diagram, the maximum value of the image height is shown, and in the coma diagram, the value of each image height is shown. 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 surface, and the broken line indicates the tangential image surface. In each aberration diagram of other embodiments described later, the same symbols as those of each aberration diagram of the present embodiment are used.

[0192] As is clear from each aberration diagram, the variable magnification optical system of the present embodiment corrects each aberration well and has high optical performance.

[0193] (Second Embodiment)

[0194] Figure 3 is a sectional view of the variable magnification optical system of the second embodiment at the time of focusing on an infinite object in the wide-angle end state.

[0195] The variable magnification optical system of the present embodiment has, in order from the object side, a first lens group G1 having negative refractive power, a second lens group G2 having positive 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 positive refractive power, a sixth lens group G6 having positive refractive power, and a seventh lens group G7 having negative refractive power.

[0196] The first lens group G1 is composed of, in order from the object side, a meniscus-shaped negative lens L1 with the convex surface facing the object side, and a biconcave-shaped negative lens L2 and a meniscus-shaped positive lens L3 with the convex surface facing the object side.

[0197] The second lens group G2 is composed of a biconvex-shaped positive lens L4 and a biconcave-shaped negative lens L5.

[0198] The third lens group G3 is composed of, in order from the object side, a meniscus-shaped positive lens L6 with the convex surface facing the object side, and a meniscus-shaped negative lens L7 with the convex surface facing the object side and a biconvex-shaped positive lens L8.

[0199] The fourth lens group G4 is composed of, in order from the object side, an aperture stop S, a biconcave-shaped negative lens L9, and a biconvex-shaped positive lens L10.

[0200] The fifth lens group G5 is composed of a biconvex-shaped positive lens L11 and a meniscus-shaped negative lens L12 with the concave surface facing the object side.

[0201] The sixth lens group G6 is composed of a meniscus-shaped positive lens L13 with the concave surface facing the object side.

[0202] The seventh lens group G7 is composed of a meniscus-shaped negative lens L14 with the concave surface facing the object side.

[0203] On the image plane I, a photographing element (not shown) composed of a CCD or a CMOS or the like is disposed.

[0204] In the variable magnification optical system of the present embodiment, when zooming from the wide-angle end state to the telephoto end state, the first lens group G1 is fixed with respect to the image plane I, and each of the groups from the second lens group G2 to the seventh lens group G7 moves along the optical axis toward the object side. Thus, in the variable magnification optical system of the present embodiment, when zooming from the wide-angle end state to the telephoto end state, the interval between adjacent lens groups among the first lens group G1 to the seventh lens group G7 changes.

[0205] The variable magnification optical system of this embodiment performs focusing by moving the 5th lens group G5 and the 6th lens group G6 along the optical axis, respectively. In the case of focusing on a close-range object from a state of focusing on an infinite-range object, the 5th lens group G5 and the 6th lens group G6 are moved from the image plane side to the object side, respectively.

[0206] In the variable magnification optical system of this embodiment, the 1st lens group G1 corresponds to the 1st negative lens group, and the 2nd lens group G2 to the 7th lens group G7 correspond to the multiple lens groups possessed by the rear group. The 4th lens group G4 corresponds to the 2nd negative lens group, and also to the 3rd negative lens group. The positive lens L10 corresponds to the positive lens Cαp, and also to the positive lens Cβp. The 5th lens group G5 corresponds to the 1st positive lens group, and the 6th lens group G6 corresponds to the 2nd positive lens group. The 7th lens group G7 corresponds to the final negative lens group.

[0207] In Table 2 below, the values of the parameters of the variable magnification optical system of this embodiment are described.

[0208] (Table 2)

[0209] [Overall Parameters]

[0210] [Parameters of Lenses]

[0211] [Aspherical Surface Data]

[0212] [Data of Focal Length of Each Group]

[0213] [Data of Variable Spacing]

[0214] Figure 4A is each aberration diagram at the time of focusing on an infinite-range object in the wide-angle end state of the variable magnification optical system of the 2nd embodiment, Figure 4B is each aberration diagram at the time of focusing on an infinite-range object in the telephoto end state of the variable magnification optical system of the 2nd embodiment.

[0215] As is clear from the each aberration diagram, the variable magnification optical system of this embodiment well corrects each aberration, and has high optical performance.

[0216] (3rd Embodiment)

[0217] Figure 5 is a sectional view of the variable magnification optical system of the 3rd embodiment at the time of focusing on an infinite-range object in the wide-angle end state.

[0218] The variable magnification optical system of the present embodiment has, in order from the object side, a first lens group G1 having negative refractive power, a second lens group G2 having positive 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 positive refractive power, a sixth lens group G6 having positive refractive power, and a seventh lens group G7 having negative refractive power.

[0219] The first lens group G1 is composed of, in order from the object side, a meniscus-shaped negative lens L1 having a convex surface toward the object side, and a meniscus-shaped negative lens L2 having a convex surface toward the object side and a meniscus-shaped positive lens L3 having a convex surface toward the object side.

[0220] The second lens group G2 is composed of a biconvex-shaped positive lens L4 and a biconcave-shaped negative lens L5.

[0221] The third lens group G3 is composed of a meniscus-shaped negative lens L6 having a convex surface toward the object side and a biconvex-shaped positive lens L7.

[0222] The fourth lens group G4 is composed of, in order from the object side, an aperture stop S, a biconcave-shaped negative lens L8 and a meniscus-shaped positive lens L9 having a convex surface toward the object side, and a meniscus-shaped positive lens L10 having a convex surface toward the object side.

[0223] The fifth lens group G5 is composed of a biconvex-shaped positive lens L11 and a meniscus-shaped negative lens L12 having a concave surface toward the object side.

[0224] The sixth lens group G6 is composed of a meniscus-shaped positive lens L13 having a concave surface toward the object side.

[0225] The seventh lens group G7 is composed of a meniscus-shaped negative lens L14 having a concave surface toward the object side.

[0226] On the image plane I, a photographing element (not shown) composed of a CCD or a CMOS or the like is disposed.

[0227] In the variable magnification optical system of the present embodiment, when zooming from the wide-angle end state to the telephoto end state, the first lens group G1 is fixed with respect to the image plane I, and each of the groups from the second lens group G2 to the seventh lens group G7 moves along the optical axis toward the object side. Thus, in the variable magnification optical system of the present embodiment, when zooming from the wide-angle end state to the telephoto end state, the interval between adjacent lens groups among the first lens group G1 to the seventh lens group G7 changes.

[0228] The variable magnification optical system of this embodiment performs focusing by moving the 5th lens group G5 and the 6th lens group G6 along the optical axis, respectively. In the case of focusing on a close-range object from a state of focusing on an infinite-range object, the 5th lens group G5 and the 6th lens group G6 are moved from the image plane side to the object side, respectively.

[0229] In the variable magnification optical system of this embodiment, the 1st lens group G1 corresponds to the 1st negative lens group, and the 2nd lens group G2 to the 7th lens group G7 correspond to the multiple lens groups possessed by the rear group. The 4th lens group G4 corresponds to the 2nd negative lens group, and also to the 3rd negative lens group. The positive lens L10 corresponds to the positive lens Cαp, and also to the positive lens Cβp. The 5th lens group G5 corresponds to the 1st positive lens group, and the 6th lens group G6 corresponds to the 2nd positive lens group. The 7th lens group G7 corresponds to the final negative lens group.

[0230] In Table 3 below, the values of the parameters of the variable magnification optical system of this embodiment are described.

[0231] (Table 3)

[0232] [Overall Parameters]

[0233] [Parameters of Lenses]

[0234] [Aspherical Surface Data]

[0235] [Data of Focal Length of Each Group]

[0236] [Data of Variable Spacing]

[0237] Figure 6A is each aberration diagram at the time of focusing on an infinite-range object in the wide-angle end state of the variable magnification optical system of the 3rd embodiment, Figure 6B is each aberration diagram at the time of focusing on an infinite-range object in the telephoto end state of the variable magnification optical system of the 3rd embodiment.

[0238] As is clear from the each aberration diagram, the variable magnification optical system of this embodiment corrects each aberration well, and has high optical performance.

[0239] (4th Embodiment)

[0240] Figure 7 is a sectional view of the variable magnification optical system of the 4th embodiment at the time of focusing on an infinite-range object in the wide-angle end state.

[0241] The variable magnification optical system of the present embodiment has, in order from the object side, a first lens group G1 having negative refractive power, a second lens group G2 having positive 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 positive refractive power, a sixth lens group G6 having positive refractive power, and a seventh lens group G7 having negative refractive power.

[0242] The first lens group G1 is composed of, in order from the object side, a meniscus-shaped negative lens L1 having a convex surface toward the object side, and a meniscus-shaped negative lens L2 having a convex surface toward the object side and a meniscus-shaped positive lens L3 having a convex surface toward the object side.

[0243] The second lens group G2 is composed of a biconvex-shaped positive lens L4 and a biconcave-shaped negative lens L5.

[0244] The third lens group G3 is composed of a meniscus-shaped negative lens L6 having a convex surface toward the object side and a biconvex-shaped positive lens L7.

[0245] The fourth lens group G4 is composed of, in order from the object side, an aperture stop S, a biconcave-shaped negative lens L8, and a biconvex-shaped positive lens L9.

[0246] The fifth lens group G5 is composed of a biconvex-shaped positive lens L10 and a meniscus-shaped negative lens L11 having a concave surface toward the object side.

[0247] The sixth lens group G6 is composed of a meniscus-shaped positive lens L12 having a concave surface toward the object side.

[0248] The seventh lens group G7 is composed of a meniscus-shaped negative lens L13 having a concave surface toward the object side.

[0249] On the image plane I, a photographing element (not shown) composed of a CCD or a CMOS or the like is disposed.

[0250] In the variable magnification optical system of the present embodiment, when zooming from the wide-angle end state to the telephoto end state, the first lens group G1 is fixed with respect to the image plane I, the second lens group G2, the third lens group G3, the fifth lens group G5, and the sixth lens group G6 are moved toward the object side along the optical axis respectively, and the fourth lens group G4 and the seventh lens group G7 are moved toward the object side along the optical axis in conjunction. Thus, in the variable magnification optical system of the present embodiment, when zooming from the wide-angle end state to the telephoto end state, the interval between adjacent lens groups among the first lens group G1 to the seventh lens group G7 changes.

[0251] The variable magnification optical system of this embodiment performs focusing by moving the 5th lens group G5 and the 6th lens group G6 along the optical axis, respectively. In the case of focusing on a close-range object from a state of focusing on an infinite-range object, the 5th lens group G5 and the 6th lens group G6 are moved from the image plane side to the object side, respectively.

[0252] In the variable magnification optical system of this embodiment, the 1st lens group G1 corresponds to the 1st negative lens group, and the 2nd lens group G2 to the 7th lens group G7 correspond to the multiple lens groups possessed by the rear group. The 4th lens group G4 corresponds to the 2nd negative lens group, and also to the 3rd negative lens group. The positive lens L9 corresponds to the positive lens Cαp, and also to the positive lens Cβp. The 5th lens group G5 corresponds to the 1st positive lens group, and the 6th lens group G6 corresponds to the 2nd positive lens group. The 7th lens group G7 corresponds to the final negative lens group.

[0253] In Table 4 below, the values of the parameters of the variable magnification optical system of this embodiment are described.

[0254] (Table 4)

[0255] [Overall Parameters]

[0256] [Parameters of Lenses]

[0257] [Aspherical Surface Data]

[0258] [Data of Focal Length of Each Group]

[0259] [Data of Variable Spacing]

[0260] Figure 8A is each aberration chart at the time of focusing on an infinite-range object in the wide-angle end state of the variable magnification optical system of the 4th embodiment, Figure 8B is each aberration chart at the time of focusing on an infinite-range object in the telephoto end state of the variable magnification optical system of the 4th embodiment.

[0261] As is clear from the each aberration chart, the variable magnification optical system of this embodiment corrects each aberration well, and has high optical performance.

[0262] (5th Embodiment)

[0263] Figure 9 is a sectional view of the variable magnification optical system of the 5th embodiment at the time of focusing on an infinite-range object in the wide-angle end state.

[0264] The variable magnification optical system of the present embodiment has, in order from the object side, a first lens group G1 having negative refractive power, a second lens group G2 having positive 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 positive refractive power, a sixth lens group G6 having positive refractive power, a seventh lens group G7 having negative refractive power, and an eighth lens group G8 having positive refractive power.

[0265] The first lens group G1 is composed of, in order from the object side, a meniscus-shaped negative lens L1 having a convex surface toward the object side, and a meniscus-shaped negative lens L2 having a convex surface toward the object side and a meniscus-shaped positive lens L3 having a convex surface toward the object side.

[0266] The second lens group G2 is composed of a biconvex-shaped positive lens L4 and a biconcave-shaped negative lens L5.

[0267] The third lens group G3 is composed of a meniscus-shaped negative lens L6 having a convex surface toward the object side and a biconvex-shaped positive lens L7.

[0268] The fourth lens group G4 is composed of, in order from the object side, an aperture stop S, a biconcave-shaped negative lens L8, and a biconvex-shaped positive lens L9.

[0269] The fifth lens group G5 is composed of a biconvex-shaped positive lens L10 and a meniscus-shaped negative lens L11 having a concave surface toward the object side.

[0270] The sixth lens group G6 is composed of a meniscus-shaped positive lens L12 having a concave surface toward the object side.

[0271] The seventh lens group G7 is composed of a meniscus-shaped negative lens L13 having a concave surface toward the object side.

[0272] The eighth lens group G8 is composed of a biconvex-shaped positive lens L14.

[0273] On the image plane I, a photographing element (not shown) composed of a CCD or a CMOS or the like is disposed.

[0274] In the variable magnification optical system of the present embodiment, when zooming from the wide-angle end state to the telephoto end state, the first lens group G1 and the eighth lens group G8 are fixed with respect to the image plane I, and each of the groups from the second lens group G2 to the seventh lens group G7 moves along the optical axis toward the object side. Thus, in the variable magnification optical system of the present embodiment, when zooming from the wide-angle end state to the telephoto end state, the interval between adjacent lens groups among the first lens group G1 to the eighth lens group G8 changes.

[0275] The variable magnification optical system of this embodiment performs focusing by moving the 5th lens group G5 and the 6th lens group G6 along the optical axis, respectively. In the case of focusing on a close-range object from a state of focusing on an infinite-range object, the 5th lens group G5 and the 6th lens group G6 are moved from the image plane side to the object side, respectively.

[0276] In the variable magnification optical system of this embodiment, the 1st lens group G1 corresponds to the 1st negative lens group, and the 2nd lens group G2 to the 8th lens group G8 correspond to the plurality of lens groups possessed by the rear group. The 4th lens group G4 corresponds to the 2nd negative lens group, and also corresponds to the 3rd negative lens group. The positive lens L9 corresponds to the positive lens Cαp, and also corresponds to the positive lens Cβp. The 5th lens group G5 corresponds to the 1st positive lens group, and the 6th lens group G6 corresponds to the 2nd positive lens group. The 7th lens group G7 corresponds to the final negative lens group.

[0277] In Table 5 below, the values of the parameters of the variable magnification optical system of this embodiment are described.

[0278] (Table 5)

[0279] [Overall Parameters]

[0280] [Overall Parameters]

[0281] [Overall Parameters]

[0282] [Overall Parameters]

[0283] [Overall Parameters]

[0284] Figure 10A is each aberration diagram at the time of focusing on an infinite-range object in the wide-angle end state of the variable magnification optical system of the 5th embodiment, Figure 10B is each aberration diagram at the time of focusing on an infinite-range object in the telephoto end state of the variable magnification optical system of the 5th embodiment.

[0285] As is clear from the each aberration diagram, the variable magnification optical system of this embodiment corrects each aberration well, and has high optical performance.

[0286] (6th Embodiment)

[0287] Figure 11 is a sectional view of the variable magnification optical system of the 6th embodiment at the time of focusing on an infinite-range object in the wide-angle end state.

[0288] The variable magnification optical system of the present embodiment has, in order from the object side, a first lens group G1 having negative 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, a sixth lens group G6 having positive refractive power, a seventh lens group G7 having positive refractive power, and an eighth lens group G8 having negative refractive power.

[0289] The first lens group G1 is composed of a meniscus-shaped negative lens L1 whose convex surface faces the object side.

[0290] The second lens group G2 is composed of a meniscus-shaped negative lens L2 whose convex surface faces the object side and a meniscus-shaped positive lens L3 whose convex surface faces the object side.

[0291] The third lens group G3 is composed of a biconvex-shaped positive lens L4 and a biconcave-shaped negative lens L5.

[0292] The fourth lens group G4 is composed of a meniscus-shaped negative lens L6 whose convex surface faces the object side and a biconvex-shaped positive lens L7.

[0293] The fifth lens group G5 is composed of, in order from the object side, an aperture stop S, a biconcave-shaped negative lens L8, and a biconvex-shaped positive lens L9.

[0294] The sixth lens group G6 is composed of a biconvex-shaped positive lens L10 and a meniscus-shaped negative lens L11 whose concave surface faces the object side.

[0295] The seventh lens group G7 is composed of a meniscus-shaped positive lens L12 whose concave surface faces the object side.

[0296] The eighth lens group G8 is composed of a meniscus-shaped negative lens L13 whose concave surface faces the object side.

[0297] On the image plane I, a photographing element (not shown) composed of a CCD or a CMOS or the like is disposed.

[0298] In the variable magnification optical system of the present embodiment, when zooming from the wide-angle end state to the telephoto end state, the first lens group G1 is fixed with respect to the image plane I, and each of the groups from the second lens group G2 to the eighth lens group G8 moves along the optical axis toward the object side. Thus, in the variable magnification optical system of the present embodiment, when zooming from the wide-angle end state to the telephoto end state, the interval between adjacent lens groups among the first lens group G1 to the eighth lens group G8 changes.

[0299] The variable magnification optical system of this embodiment performs focusing by moving the 6th lens group G6 and the 7th lens group G7 along the optical axis, respectively. In the case of focusing on a close-range object from a state of focusing on an infinite-range object, the 6th lens group G6 and the 7th lens group G7 are moved from the image plane side to the object side, respectively.

[0300] In the variable magnification optical system of this embodiment, the 1st lens group G1 corresponds to the 1st negative lens group, and the 2nd lens group G2 to the 8th lens group G8 correspond to the plurality of lens groups possessed by the rear group. The 5th lens group G5 corresponds to the 2nd negative lens group, and also corresponds to the 3rd negative lens group. The positive lens L9 corresponds to the positive lens Cαp, and also corresponds to the positive lens Cβp. The 6th lens group G6 corresponds to the 1st positive lens group, and the 7th lens group G7 corresponds to the 2nd positive lens group. The 8th lens group G8 corresponds to the final negative lens group.

[0301] In Table 6 below, values of the parameters of the variable magnification optical system of this embodiment are described.

[0302] (Table 6)

[0303] [Overall Parameters]

[0304] [Parameters of Lenses]

[0305] [Aspherical Surface Data]

[0306] [Data of Focal Length of Each Group]

[0307] [Data of Variable Spacing]

[0308] Figure 12A is a graph of each aberration at the time of focusing on an infinite-range object in the wide-angle end state of the variable magnification optical system of the 6th embodiment, Figure 12B is a graph of each aberration at the time of focusing on an infinite-range object in the telephoto end state of the variable magnification optical system of the 6th embodiment.

[0309] As is clear from the graphs of each aberration, the variable magnification optical system of this embodiment corrects each aberration well, and has high optical performance.

[0310] With each of the above embodiments, a variable magnification optical system having good optical performance can be realized.

[0311] Hereinafter, the corresponding values of the conditional expressions of each embodiment are shown.

[0312] fw is the focal length of the variable magnification optical system at the wide angle end, and BFw is the back focal length of the variable magnification optical system at the wide angle end. TLw is the distance on the optical axis from the most object- side lens surface to the image plane in the wide angle end state, and STLw is the distance on the optical axis from the aperture stop to the image plane in the wide angle end state. Fnot is the F number of the variable magnification optical system in the tele end state, 2ωw is the total field angle of the variable magnification optical system in the wide angle end state, and 2ωt is the total field angle of the variable magnification optical system in the tele end state.

[0313] fA is the focal length of the first negative lens group, and fARw is the composite focal length of the rear group at the wide angle end. fB1 is the focal length of the first positive lens group, and fB2 is the focal length of the second positive lens group. fCα is the focal length of the second negative lens group, and fCβ is the focal length of the third negative lens group. fF1 is the focal length of the lens group disposed on the object side among the two lens groups that move at the time of focusing and have positive refractive power, and fF2 is the focal length of the lens group disposed on the image side among the two lens groups. fE is the focal length of the final negative lens group.

[0314] PgFCαp is the relative partial dispersion of the positive lens Cαp, and νdCαp is the Abbe number of the positive lens Cαp with respect to the d line. PgFCβp is the relative partial dispersion of the positive lens Cβp, and νdCβp is the Abbe number of the positive lens Cβp with respect to the d line. In addition, when the refractive index of the lens X with respect to the g line is ngX, the refractive index of the lens X with respect to the F line is nFX, and the refractive index of the lens X with respect to the C line is nCX, the relative partial dispersion PgFX of the lens X is defined by (ngX - nFX) / (nFX - nCX).

[0315] L1R1 is the radius of curvature of the lens surface on the object side of the lens disposed on the most object- side, and L1R2 is the radius of curvature of the lens surface on the image side of the lens. LLR1 is the radius of curvature of the lens surface on the object side of the lens disposed on the most image- side, and LLR2 is the radius of curvature of the lens surface on the image side of the lens.

[0316] MVGCa is the movement amount of the second negative lens group when zooming from the wide angle end to the telephoto end at the time of focusing on infinity, and MVGCp is the movement amount of the third negative lens group when zooming from the wide angle end to the telephoto end at the time of focusing on infinity. MF1w is the movement amount of the lens group disposed on the object side among the two lens groups that move at the time of focusing and have positive power when focusing on a close object from an object at infinity in the wide angle end state, and MF2w is the movement amount of the lens group disposed on the image side among the two lens groups when focusing on a close object from an object at infinity in the wide angle end state. MVGO is the movement amount of the lens group disposed adjacent to the object side of the final negative lens group when zooming from the wide angle end to the telephoto end at the time of focusing on infinity, and MVGE is the movement amount of the final negative lens group when zooming from the wide angle end to the telephoto end at the time of focusing on infinity.

[0317] [Conditional Expression Corresponding Values]

[0318] The above-described embodiments show one specific example of the present application, but the present application is not limited to these embodiments. The following can be appropriately adopted within a range that does not affect the optical performance of the zoom optical system of the embodiments of the present application.

[0319] In the zoom optical system of the present embodiment, the third negative lens group can not have an aperture stop. In addition, the position of the aperture stop in the zoom optical system of the present embodiment is not limited to the position of the aperture stop S in the zoom optical systems of the above-described embodiments.

[0320] The zoom optical system of the present embodiment can not have an optical member such as a filter between the most image plane side lens surface and the image plane.

[0321] The zoom optical system of the present embodiment can have a shake correction lens group that corrects image blur due to hand shake by moving in a manner having a component perpendicular to the optical axis. The shake correction lens group can be a lens group or a partial lens group composed of one or more lens components included in the lens group.

[0322] In the zoom optical system of the present embodiment, the lens surface can be formed as a spherical surface or a plane, or can be formed as an aspherical surface. When the lens surface is a spherical surface or a plane, lens processing and assembly adjustment become easy, and degradation of optical performance due to errors in processing and assembly adjustment can be prevented, and thus is preferable. In addition, when the lens surface is a spherical surface or a plane, degradation of drawing performance at the time of image plane shift is less, and thus is preferable.

[0323] When the lens surface is an aspherical surface, the aspherical surface can be formed by polishing of glass or by molding of glass using a mold having an aspherical shape, or can be formed on the surface of resin bonded to the surface of glass. In addition, in the variable magnification optical system of the present embodiment, the lens surface can also be provided as a diffractive surface, and the lens can also be provided as a refractive index distribution type lens (GRIN lens) or a plastic lens.

[0324] Next, based on Figure 13 A camera provided with the variable magnification optical system of the present embodiment will be described.

[0325] Figure 13 is a schematic view of a camera provided with the variable magnification optical system of the present embodiment.

[0326] The camera 1 is a so-called mirrorless camera provided with the optical system of the above-described first embodiment as a photographing lens 2.

[0327] In the camera 1, light from an object (subject) not shown is condensed by the photographing lens 2 to reach a photographing element 3. The photographing element 3 converts the light from the subject into image data. When a photographer presses a release button not shown, the image data is stored in a memory not shown. In this way, the photographer can perform photographing of a subject based on the camera 1.

[0328] Here, the variable magnification optical system of the above-described 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. Furthermore, even a camera configured to mount the variable magnification optical systems of the above-described second to sixth embodiments as the photographing lens 2 can achieve the same effects as the camera 1.

[0329] Finally, based on Figure 14 and Figure 15 a manufacturing method of the variable magnification optical system of the present embodiment will be described.

[0330] Figure 14 is a flowchart showing an outline of the first manufacturing method of the variable magnification optical system of the present embodiment. Figure 14 The first manufacturing method of the variable magnification optical system of the present embodiment shown includes the following steps S11-S15.

[0331] Step S11: A first negative lens group and a rear group including a plurality of lens groups are prepared.

[0332] Step S12: The first negative lens group is fixed with respect to an image plane, and the interval between each of the adjacent lens groups is changed during variable magnification.

[0333] Step S13: An aperture stop is disposed at a position on the image plane side of the first negative lens group.

[0334] Step S14: The 2nd negative lens group among the plurality of lens groups possessed by the rear group is disposed adjacent to the image plane side of the aperture stop.

[0335] Step S15: The variable magnification optical system is caused to satisfy the following conditional expression. (1-1) 0.00 < fA / fCa < 0.30 wherein, fA: focal length of the 1st negative lens group fCa: focal length of the 2nd negative lens group

[0336] Figure 15 is a flowchart showing an outline of the 2nd manufacturing method of the variable magnification optical system of the present embodiment. Figure 15 The 2nd manufacturing method of the variable magnification optical system of the present embodiment shown in the figure includes the following steps S21-S25.

[0337] Step S21: The 1st negative lens group and the subsequent lens group including a plurality of lens groups are prepared.

[0338] Step S22: The 1st negative lens group is fixed with respect to the image plane and the interval between the adjacent lens groups is changed at the time of variable magnification.

[0339] Step S23: Among the plurality of lens groups possessed by the rear group, the 3rd negative lens group among one or more lens groups having a negative refractive power disposed on the image plane side is disposed on the most object side compared to the 1st positive lens group disposed on the most object side and having a positive refractive power.

[0340] Step S24: The variable magnification optical system is caused to satisfy the following conditional expression. (1-2) 0.00 < fA / fCp < 0.30 wherein, fA: focal length of the 1st negative lens group fCp: focal length of the 3rd negative lens group

[0341] According to these manufacturing methods of the variable magnification optical system of the present embodiment, an optical system having good imaging performance can be manufactured.

[0342] Those skilled in the art will understand that various changes, substitutions and modifications can be made without departing from the spirit and scope of the present disclosure.

[0343] Explanation of Reference Numerals

[0344] S aperture stop

[0345] I image plane

[0346] 1 camera

[0347] 2 photographic lens

[0348] 3 Taking element

Claims

1. A zoom optical system, wherein, The zoom optical system, starting from the object side, sequentially includes a first negative lens group with negative optical power and a rear group with multiple lens groups. During zooming, the first negative lens group remains fixed relative to the image plane, while the spacing between adjacent lens groups changes. An aperture stop is provided on the image plane side, which is closer to the first negative lens group. The second negative lens group, which is arranged adjacent to the image plane side of the aperture stop among the multiple lens groups in the rear group, has negative optical power. The zoom optical system satisfies the following condition: 0.00 < fA / fCα < 0.30 in, fA: The focal length of the first negative lens group. fCα: The focal length of the second negative lens group.

2. The zoom optical system according to claim 1, wherein, Compared to the second negative lens group, at least one of the lenses disposed on the image plane side moves during focusing.

3. The zoom optical system according to claim 1 or 2, wherein, The zoom optical system satisfies the following condition: 0.90 < MVGCα / MVGE < 1.50 in, MVGCα: The amount of movement of the second negative lens group when zooming from the wide-angle end to the telephoto end at infinity focus. MVGE: The amount of movement of the final negative lens group, which is located closest to the image plane and has negative optical power, among the multiple lens groups of the rear group when zooming from the wide-angle end to the telephoto end during infinity focusing.

4. The zoom optical system according to any one of claims 1 to 3, wherein, The second negative lens group has a positive lens Cαp that satisfies the following condition: 0.020<PgFCαp-0.64435+0.00168*νdCαp in, PgFCαp: The relative partial dispersion of the positive lens Cαp, defined by the following formula when the refractive index of the positive lens Cαp with respect to the g line is set to ngCαp, the refractive index of the positive lens Cαp with respect to the F line is set to nFCαp, and the refractive index of the positive lens Cαp with respect to the C line is set to nCCαp, i.e. PgFCαp=(ngCαp-nFCαp) / (nFCαp-nCCαp) νdCαp: The Abbe number of the positive lens Cαp with reference to the d line.

5. The zoom optical system according to any one of claims 1 to 4, wherein, The zoom optical system satisfies the following condition: 0.045<fw / (-fCα)<0.140 in, fw: The focal length of the zoom optical system at the wide-angle end.

6. The zoom optical system according to any one of claims 1 to 5, wherein, The combined optical power of the lens group positioned between the first negative lens group and the aperture stop is positive at the wide-angle end.

7. The zoom optical system according to any one of claims 1 to 6, wherein, The zoom optical system satisfies the following condition: 0.30 < STLw / TLw < 0.50 in, STLw: The distance along the optical axis from the aperture stop to the image plane in the wide-angle end state. TLw: The distance along the optical axis from the lens surface closest to the object to the image plane in the wide-angle state.

8. A zoom optical system, wherein, The zoom optical system, starting from the object side, sequentially includes a first negative lens group with negative optical power and a rear group with multiple lens groups. During zooming, the first negative lens group remains fixed relative to the image plane, while the spacing between adjacent lens groups changes. Among the multiple lens groups in the rear group, compared to the first positive lens group, which is positioned closest to the object and has positive optical power, the third negative lens group, which is positioned on the image plane side and has negative optical power, is positioned closest to the object. The zoom optical system satisfies the following condition: 0.00 < fA / fCβ < 0.30 in, fA: The focal length of the first negative lens group. fCβ: The focal length of the third negative lens group.

9. The zoom optical system according to claim 8, wherein, Compared to the third negative lens group, at least one of the lenses disposed on the image plane side moves during focusing.

10. The zoom optical system according to claim 8 or 9, wherein, The zoom optical system satisfies the following condition: 0.90 < MVGCβ / MVGE < 1.50 in, MVGCβ: The amount of movement of the third negative lens group when zooming from the wide-angle end to the telephoto end at infinity focus. MVGE: The amount of movement of the final negative lens group, which is located closest to the image plane and has negative optical power, among the multiple lens groups of the rear group when zooming from the wide-angle end to the telephoto end during infinity focusing.

11. The zoom optical system according to any one of claims 8 to 10, wherein, The third negative lens group has a positive lens Cβp that satisfies the following condition: 0.020<PgFCβp-0.64435+0.00168*νdCβp in, PgFCβp: The relative partial dispersion of the positive lens Cβp, defined by the following formula when the refractive index of the positive lens Cβp with respect to the g line is set to ngCβp, the refractive index of the positive lens Cβp with respect to the F line is set to nFCβp, and the refractive index of the positive lens Cβp with respect to the C line is set to nCCβp, i.e. PgFCβp=(ngCβp-nFCβp) / (nFCβp-nCCβp) νdCβp: The Abbe number of the positive lens Cβp relative to the d-line.

12. The zoom optical system according to any one of claims 8 to 11, wherein, The zoom optical system satisfies the following condition: 0.045<fw / (-fCβ)<0.140 in, fw: The focal length of the zoom optical system at the wide-angle end.

13. The zoom optical system according to any one of claims 1 to 12, wherein, The rear group comprises a plurality of lens groups, including a first positive lens group disposed closest to the object side and having positive optical power, and a second positive lens group disposed adjacent to the image plane side of the first positive lens group and having positive optical power, and satisfying the following condition: 1.40 < fB1 / fB2 < 3.00 in, fB1: The focal length of the first positive lens group. fB2: The focal length of the second positive lens group.

14. The zoom optical system according to any one of claims 1 to 13, wherein, The zoom optical system satisfies the following condition: 1.00 < -fA / fARw < 1.60 in, fARw: The composite focal length of the rear group at the wide-angle end.

15. The zoom optical system according to any one of claims 1 to 14, wherein, The zoom optical system satisfies the following condition: 0.50 < fA / fE < 1.20 in, fE: The focal length of the final negative lens group among the multiple lens groups of the rear group, which is located closest to the image side and has negative optical power.

16. The zoom optical system according to any one of claims 1 to 15, wherein, During focusing, two lens groups with positive optical power among the multiple lens groups in the rear group move. The zoom optical system satisfies the following condition: 0.40 < fF1 / fF2 < 1.20 in, fF1: The focal length of the lens group positioned on the object side of the two lens groups. fF2: The focal length of the lens group located on the image plane side of the two lens groups.

17. The zoom optical system according to any one of claims 1 to 16, wherein, The zoom optical system satisfies the following condition: 0.60 < MVF1w / MVF2w < 1.70 in, MVF1w: In wide-angle mode, when focusing from an object at infinity to a closer object, the amount of movement of the lens group located on the object side among the two lens groups that move during focusing in the rear group of multiple lens groups. MVF2w: The amount of movement of the lens group located on the image plane side among the two lens groups that move during focusing when focusing from an object at infinity to a closer object in the wide-angle end state.

18. The zoom optical system according to any one of claims 1 to 17, wherein, The zoom optical system satisfies the following condition: 0.40 < MVGO / MVGE < 0.80 in, MVGE: The amount of movement of the final negative lens group, which is located closest to the image plane and has negative optical power, among the multiple lens groups in the rear group when zooming from the wide-angle end to the telephoto end during infinity focusing. MVGO: The amount of movement of a lens group that is adjacent to the object side of the final negative lens group when zooming from the wide-angle end to the telephoto end during infinity focusing.

19. The zoom optical system according to any one of claims 1 to 18, wherein, The zoom optical system satisfies the following condition: 0.40 < BFw / fw < 0.60 in, Bfw: Back focal length of the zoom optical system at the wide-angle end. fw: The focal length of the zoom optical system at the wide-angle end.

20. The zoom optical system according to any one of claims 1 to 19, wherein, The zoom optical system satisfies the following condition: -3.00<(L1R2+L1R1) / (L1R2-L1R1)<-1.00 in, L1R1: The radius of curvature of the lens surface on the object side of the lens positioned closest to the object. L1R2: The radius of curvature of the lens surface on the image plane side of the lens positioned closest to the object.

21. The zoom optical system according to any one of claims 1 to 20, wherein, The zoom optical system satisfies the following condition: 0.00<(LLR2+LLR1) / (LLR2-LLR1)<2.00 in, LLR1: The radius of curvature of the lens surface on the object side of the lens located closest to the image plane. LLR2: The radius of curvature of the lens surface on the image plane side of the lens positioned closest to the image plane.

22. The zoom optical system according to any one of claims 1 to 21, wherein, The zoom optical system satisfies the following condition: 68°<2ωw in, 2ωw: The full field of view of the zoom optical system in the wide-angle state.

23. The zoom optical system according to any one of claims 1 to 22, wherein, The zoom optical system satisfies the following condition: 2ωt<40° in, 2ωt: The full field of view of the zoom optical system in the telephoto state.

24. An optical device comprising the optical system according to any one of claims 1 to 23.

25. A method for manufacturing a zoom optical system, wherein the zoom optical system comprises, sequentially from the object side, a first negative lens group having negative optical power and a rear group having multiple lens groups, wherein, During zooming, the first negative lens group remains fixed relative to the image plane, while the spacing between adjacent lens groups changes. An aperture stop is disposed on the image plane side relative to the first negative lens group. The second negative lens group, having negative optical power, is arranged adjacent to the image plane side of the aperture stop among the multiple lens groups in the rear group. The following condition must be satisfied: 0.00 < fA / fCα < 0.30 in, fA: The focal length of the first negative lens group. fCα: The focal length of the second negative lens group.

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