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

Abstract

In order from the object side, the variable magnification optical system comprises a first lens group having a negative refractive power and a subsequent lens group comprising a plurality of lens groups, the subsequent lens group comprising, in order from the object side, a second lens group having a positive refractive power and a third lens group having a positive refractive power, the first lens group being fixed with respect to the image plane during magnification change, the second lens group being fixed with respect to the image plane during magnification change, and the third lens group being fixed with respect to the image plane during magnification change. The variable magnification optical system satisfies the following conditional expression: 1.00 < f2 / f3 < 5.00, where f2 is the focal length of the second lens group, and f3 is the focal length of the third lens group.

Description

Technical Field

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

[0002] Conventionally, a variable magnification optical system used in optical devices such as a camera for photographs, a digital still camera, and a video camera has been proposed (for example, refer to Patent Document 1).

[0003] Prior Art Documents

[0004] Patent Documents

[0005] Patent Document 1: Japanese Unexamined Patent Application Publication No. 2021-196574 Summary of the Invention

[0006] The variable magnification optical system of the present disclosure includes, in order from the object side, a first lens group having a negative optical power and a subsequent lens group having a plurality of lens groups. The subsequent lens group includes, in order from the object side, a second lens group having a positive optical power and a third lens group having a positive optical power. During variable magnification, the first lens group is fixed with respect to the image plane, and the interval between adjacent lens groups changes. The variable magnification optical system satisfies the following conditional expression: 1.00 < f2 / f3 < 5.00 Wherein, f2: Focal length of the second lens group f3: Focal length of the third lens group

[0007] The variable magnification optical system of the present disclosure includes, in order from the object side, a first lens group having a negative optical power and a subsequent lens group having a plurality of lens groups. The subsequent lens group includes a first focusing lens group and a second focusing lens group. The first focusing lens group has a positive optical power and moves during focusing. The second focusing lens group has a negative optical power, is disposed on the image plane side with respect to the first focusing lens group, and moves during focusing. During variable magnification, the first lens group is fixed with respect to the image plane, and the interval between adjacent lens groups changes. The variable magnification optical system satisfies the following conditional expression: 0.70 < fF1 / (-fF2) < 5.00 Wherein, fF1: Focal length of the first focusing lens group, fF2: Focal length of the second focusing lens group.

[0008] The manufacturing method of the zoom optical system of the present disclosure includes configuring a zoom optical system that sequentially includes a first lens group with a negative optical power and a subsequent lens group with multiple lens groups from the object side, where the subsequent lens group includes a second lens group with a positive optical power and a third lens group with a positive optical power from the object side. During zooming, the first lens group is fixed relative to the image plane, and the intervals between adjacent lens groups change. The zoom optical system satisfies the following conditional formula: 1.00 < f2 / f3 < 5.00 Wherein, f2: The focal length of the second lens group, f3: The focal length of the third lens group.

[0009] The manufacturing method of the zoom optical system of the present disclosure includes configuring a zoom optical system that sequentially includes a first lens group with a negative optical power and a subsequent lens group with multiple lens groups from the object side, where the subsequent lens group includes a first focusing lens group and a second focusing lens group. The first focusing lens group has a positive optical power and moves during focusing. The second focusing lens group has a negative optical power, is arranged on the image plane side relative to the first focusing lens group, and moves during focusing. During zooming, the first lens group is fixed relative to the image plane, and the intervals between adjacent lens groups change. The zoom optical system satisfies the following conditional formula: 0.70 < fF1 / (-fF2) < 5.00 Wherein, fF1: The focal length of the first focusing lens group, fF2: The focal length of the second focusing lens group. Description of the Drawings

[0010] Figure 1 is a cross-sectional view of the zoom optical system of the first embodiment during focusing on an infinite object in the wide-angle end state.

[0011] Figure 2 (a) of is various aberration diagrams of the zoom optical system of the first embodiment during focusing on an infinite object in the wide-angle end state, and (b) is various aberration diagrams of the zoom optical system of the first embodiment during focusing on an infinite object in the telephoto end state.

[0012] Figure 3 is a cross-sectional view of the zoom optical system of the second embodiment during focusing on an infinite object in the wide-angle end state.

[0013] Figure 4 (a) of is various aberration diagrams of the zoom optical system of the second embodiment during focusing on an infinite object in the wide-angle end state, and (b) is various aberration diagrams of the zoom optical system of the second embodiment during focusing on an infinite object in the telephoto end state.

[0014] Figure 5 This is a cross-sectional view of the zoom optical system according to the third embodiment when focusing on an infinitely distant object in the wide-angle end state.

[0015] Figure 6 (a) of [the figure] is a diagram of various aberrations when focusing on an infinitely distant object in the wide-angle end state of the zoom optical system according to the third embodiment, (b) is a diagram of various aberrations when focusing on an infinitely distant object in the telephoto end state of the zoom optical system according to the third embodiment, (c) is a diagram of various aberrations when focusing on a nearby object in the wide-angle end state of the zoom optical system according to the third embodiment, and (d) is a diagram of various aberrations when focusing on a nearby object in the telephoto end state of the zoom optical system according to the third embodiment.

[0016] Figure 7 This is a cross-sectional view of the zoom optical system according to the fourth embodiment when focusing on an infinitely distant object in the wide-angle end state.

[0017] Figure 8 (a) of [the figure] is a diagram of various aberrations when focusing on an infinitely distant object in the wide-angle end state of the zoom optical system according to the fourth embodiment, (b) is a diagram of various aberrations when focusing on an infinitely distant object in the telephoto end state of the zoom optical system according to the fourth embodiment, (c) is a diagram of various aberrations when focusing on a nearby object in the wide-angle end state of the zoom optical system according to the fourth embodiment, and (d) is a diagram of various aberrations when focusing on a nearby object in the telephoto end state of the zoom optical system according to the fourth embodiment.

[0018] Figure 9 This is a cross-sectional view of the zoom optical system according to the fifth embodiment when focusing on an infinitely distant object in the wide-angle end state.

[0019] Figure 10 (a) of [the figure] is a diagram of various aberrations when focusing on an infinitely distant object in the wide-angle end state of the zoom optical system according to the fifth embodiment, (b) is a diagram of various aberrations when focusing on an infinitely distant object in the telephoto end state of the zoom optical system according to the fifth embodiment, (c) is a diagram of various aberrations when focusing on a nearby object in the wide-angle end state of the zoom optical system according to the fifth embodiment, and (d) is a diagram of various aberrations when focusing on a nearby object in the telephoto end state of the zoom optical system according to the fifth embodiment.

[0020] Figure 11 This is a schematic diagram of a camera equipped with the zoom optical system of the present embodiment.

[0021] Figure 12 This is a schematic flowchart showing the first manufacturing method of the zoom optical system of the present embodiment.

[0022] Figure 13 This is a schematic flowchart showing the second manufacturing method of the zoom optical system of the present embodiment. Detailed implementation mode

[0023] Hereinafter, a variable magnification optical system, an optical device, and a method for manufacturing the variable magnification optical system according to embodiments of the present application will be described.

[0024] The variable magnification optical system according to the present embodiment includes, in order from the object side, a first lens group having a negative optical power and a subsequent lens group having a plurality of lens groups. The subsequent lens group includes, in order from the object side, a second lens group having a positive optical power and a third lens group having a positive optical power. During variable magnification, the first lens group is fixed with respect to the image plane, and the intervals between adjacent lens groups change. The variable magnification optical system satisfies the following conditional expressions.

[0025] (1) 1.00 < f2 / f3 < 5.00 Wherein, f2: The focal length of the second lens group f3: The focal length of the third lens group

[0026] The variable magnification optical system according to the present embodiment includes a first lens group having a negative optical power and a subsequent lens group having a plurality of lens groups. The subsequent lens group includes, in order from the object side, a second lens group having a positive optical power and a third lens group having a positive optical power. Thus, fluctuations in various aberrations, including spherical aberration during variable magnification, can be suppressed.

[0027] Conditional expression (1) defines the ratio of the focal length of the second lens group to the focal length of the third lens group. By satisfying conditional expression (1), the variable magnification optical system according to the present embodiment can suppress fluctuations in various aberrations, including spherical aberration during variable magnification.

[0028] In the variable magnification optical system according to the present embodiment, if the value of conditional expression (1) exceeds the upper limit value, the optical power of the third lens group becomes too strong, and it is difficult to suppress fluctuations in various aberrations, including spherical aberration during variable magnification.

[0029] In the variable magnification optical system according to the present embodiment, by setting the upper limit value of conditional expression (1) to 5.00, the effects of the present embodiment can be made more reliable. Additionally, in order to make the effects of the present embodiment more reliable, it is preferable to set the upper limit value of conditional expression (1) to 4.50, 4.00, 3.50, 3.00, 2.50, and further to 2.30.

[0030] Furthermore, in the variable magnification optical system according to the present embodiment, if the value of conditional expression (1) is lower than the lower limit value, the optical power of the second lens group becomes too strong, and it is difficult to suppress fluctuations in various aberrations, including spherical aberration during variable magnification.

[0031] In the zoom optical system of the present embodiment, by setting the lower limit value of conditional expression (1) to 1.00, the effects of the present embodiment can be made more reliable. Additionally, in order to make the effects of the present embodiment more reliable, it is preferable to set the lower limit value of conditional expression (1) to 1.20, 1.35, and further to 1.50.

[0032] The zoom optical system of the present embodiment sequentially includes a first lens group having a negative optical power and a subsequent lens group having a plurality of lens groups from the object side. The subsequent lens group includes a first focusing lens group and a second focusing lens group. The first focusing lens group has a positive optical power and moves during focusing. The second focusing lens group has a negative optical power, is disposed on the image plane side with respect to the first focusing lens group, and moves during focusing. During zooming, the first lens group is fixed with respect to the image plane, and the intervals between adjacent lens groups change. The zoom optical system satisfies the following conditional expression.

[0033] (2) 0.70 < fF1 / (-fF2) < 5.00 Wherein, fF1: The focal length of the first focusing lens group fF2: The focal length of the second focusing lens group

[0034] The zoom optical system of the present embodiment includes a first lens group having a negative optical power and a subsequent lens group having a plurality of lens groups. The subsequent lens group includes a second focusing lens group. The second focusing lens group has a negative optical power, is disposed on the image plane side with respect to the first focusing lens group, and moves during focusing. Thereby, fluctuations in various aberrations, such as spherical aberration during focusing, can be suppressed.

[0035] Conditional expression (2) defines the ratio of the focal length of the first focusing lens group to the focal length of the second focusing lens group. By satisfying conditional expression (2), the zoom optical system of the present embodiment can suppress fluctuations in various aberrations, such as spherical aberration during focusing.

[0036] In the zoom optical system of the present embodiment, if the value of conditional expression (2) exceeds the upper limit value, the optical power of the second focusing lens group becomes too strong, and it becomes difficult to suppress fluctuations in various aberrations, such as spherical aberration during focusing.

[0037] In the zoom optical system of the present embodiment, by setting the upper limit value of conditional expression (2) to 5.00, the effects of the present embodiment can be made more reliable. Additionally, in order to make the effects of the present embodiment more reliable, it is preferable to set the upper limit value of conditional expression (2) to 4.50, 4.00, 3.50, 3.00, 2.60, and further to 2.40.

[0038] Further, in the zoom optical system of the present embodiment, if the value of conditional expression (2) is lower than the lower limit value, the optical power of the third focusing lens group becomes too strong, and it is difficult to suppress fluctuations in various aberrations such as spherical aberration during focusing.

[0039] In the zoom optical system of the present embodiment, by setting the lower limit value of conditional expression (2) to 0.70, 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 conditional expression (2) to 0.85, 1.00, 1.15, and further to 1.30.

[0040] Further, in the zoom optical system of the present embodiment, preferably, the subsequent lens group further includes a fourth lens group disposed on the image plane side of the third lens group.

[0041] In the zoom optical system of the present embodiment, by having such a structure, fluctuations in various aberrations such as spherical aberration during zooming can be suppressed.

[0042] Further, in the zoom optical system of the present embodiment, preferably, the subsequent lens group sequentially includes a second lens group having a positive optical power, a third lens group having a positive optical power, and a fourth lens group from the object side.

[0043] In the zoom optical system of the present embodiment, by having such a structure, fluctuations in various aberrations such as spherical aberration during zooming can be suppressed.

[0044] Further, in the zoom optical system of the present embodiment, preferably, the second lens group is the first focusing lens group.

[0045] In the zoom optical system of the present embodiment, by having such a structure, fluctuations in various aberrations such as spherical aberration during focusing can be suppressed.

[0046] Further, in the zoom optical system of the present embodiment, preferably, the following conditional expression is satisfied.

[0047] (3) 0.12 < (-f1) / f2 < 0.95 Wherein, f1: Focal length of the first lens group f2: Focal length of the second lens group

[0048] Conditional expression (3) defines the ratio of the focal length of the first lens group to the focal length of the second lens group. By satisfying conditional expression (3), the zoom optical system of the present embodiment can suppress fluctuations in various aberrations such as coma during zooming.

[0049] In the zoom optical system of the present embodiment, if the value of conditional expression (3) exceeds the upper limit value, the optical power of the second lens group becomes too strong, and it is difficult to suppress the variation of various aberrations led by coma during zooming.

[0050] In the zoom optical system of the present embodiment, by setting the upper limit value of conditional expression (3) to 0.95, the effect of the present embodiment can be made more reliable. Additionally, in order to make the effect of the present embodiment more reliable, it is preferable to set the upper limit value of conditional expression (3) to 0.85, 0.70, 0.60, 0.50, and further to 0.47.

[0051] In addition, in the zoom optical system of the present embodiment, if the value of conditional expression (3) is lower than the lower limit value, the optical power of the first lens group becomes too strong, and it is difficult to suppress the variation of various aberrations led by coma during zooming.

[0052] In the zoom optical system of the present embodiment, by setting the lower limit value of conditional expression (3) to 0.12, the effect of the present embodiment can be made more reliable. Additionally, 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) to 0.15, 0.18, and further to 0.20.

[0053] In addition, in the zoom optical system of the present embodiment, preferably, the following conditional expression is satisfied.

[0054] (4) 0.20 < (-f1) / fw < 2.40 Wherein, f1: Focal length of the first lens group fw: Focal length of the zoom optical system in the wide-angle end state

[0055] Conditional expression (4) defines the ratio of the focal length of the first lens group to the focal length of the zoom optical system in the wide-angle end state. By satisfying conditional expression (4), the zoom optical system of the present embodiment will not be enlarged, and the variation of various aberrations led by coma during zooming can be suppressed.

[0056] In the zoom optical system of the present embodiment, if the value of conditional expression (4) exceeds the upper limit value, the optical power of the first lens group becomes too weak, and the zoom optical system is enlarged. Additionally, it is difficult to suppress the variation of various aberrations led by coma during zooming.

[0057] In the zoom optical system of the present embodiment, by setting the upper limit value of conditional expression (4) to 2.40, the effect of the present embodiment can be made more reliable. Additionally, in order to make the effect of the present embodiment more reliable, it is preferable to set the upper limit value of conditional expression (4) to 2.35, 2.25, 2.20, and further to 2.15.

[0058] Further, in the zoom optical system of the present embodiment, if the value of conditional expression (4) is lower than the lower limit value, the optical power of the first lens group becomes too strong, and it becomes difficult to suppress the variation of various aberrations including coma during zooming.

[0059] In the zoom optical system of the present embodiment, by setting the lower limit value of conditional expression (4) to 0.20, 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 conditional expression (4) to 0.35, 0.50, 0.60, 0.75, 0.80, and further to 0.85.

[0060] Further, in the zoom optical system of the present embodiment, it is preferable to satisfy the following conditional expression.

[0061] (5) 0.10 < |fRF| / |fR| < 1.10 Wherein, fRF: The focal length of the lens group adjacent to the object side of the lens group disposed closest to the image plane side fR: The focal length of the lens group disposed closest to the image plane side

[0062] Conditional expression (5) defines the ratio of the focal length of the lens group adjacent to the object side of the lens group disposed closest to the image plane side to the focal length of the lens group disposed closest to the image plane side. By satisfying conditional expression (5), the zoom optical system of the present embodiment can suppress the variation of various aberrations including coma during zooming.

[0063] In the zoom optical system of the present embodiment, if the value of conditional expression (5) exceeds the upper limit value, the optical power of the lens group disposed closest to the image plane side becomes too strong, and it becomes difficult to suppress the variation of various aberrations including coma during zooming.

[0064] In the zoom optical system of the present embodiment, by setting the upper limit value of conditional expression (5) to 1.10, 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 conditional expression (5) to 1.00, 0.90, 0.80, and further to 0.70.

[0065] Further, in the zoom optical system of the present embodiment, if the value of conditional expression (5) is lower than the lower limit value, the optical power of the lens group adjacent to the object side of the lens group disposed closest to the image plane side becomes too strong, and it becomes difficult to suppress the variation of various aberrations including coma during zooming.

[0066] In the zoom optical system of the present embodiment, by setting the lower limit value of conditional expression (5) to 0.10, the effects of the present embodiment can be made more reliable. Additionally, to make the effects of the present embodiment more reliable, it is preferable to set the lower limit value of conditional expression (5) to 0.15, and further to 0.20.

[0067] Furthermore, in the zoom optical system of the present embodiment, it is preferable to satisfy the following conditional expression.

[0068] (6) 0.15 < BFw / fw < 1.10 Wherein, BFw: The back focal length of the zoom optical system at infinity focus in the wide-angle end state fw: The focal length of the zoom optical system in the wide-angle end state

[0069] Conditional expression (6) defines the ratio of the back focal length of the zoom optical system at infinity focus in the wide-angle end state to the focal length of the zoom optical system in the wide-angle end state. By satisfying conditional expression (6), the zoom optical system of the present embodiment can well correct various aberrations such as coma at infinity focus in the wide-angle end state.

[0070] In the zoom optical system of the present embodiment, if the value of conditional expression (6) exceeds the upper limit value, then in the wide-angle end state, the back focal length becomes larger relative to the focal length, and it is difficult to well correct various aberrations such as coma at infinity focus in the wide-angle end state.

[0071] In the zoom optical system of the present embodiment, by setting the upper limit value of conditional expression (6) to 1.10, the effects of the present embodiment can be made more reliable. Additionally, to make the effects of the present embodiment more reliable, it is preferable to set the upper limit value of conditional expression (6) to 1.00, 0.95, and further to 0.90.

[0072] Furthermore, in the zoom optical system of the present embodiment, if the value of conditional expression (6) is lower than the lower limit value, then in the wide-angle end state, the back focal length becomes smaller relative to the focal length, and it is difficult to well correct various aberrations such as coma at infinity focus in the wide-angle end state.

[0073] In the zoom optical system of the present embodiment, by setting the lower limit value of conditional expression (6) to 0.15, the effects of the present embodiment can be made more reliable. Additionally, to make the effects of the present embodiment more reliable, it is preferable to set the lower limit value of conditional expression (6) to 0.20, 0.25, 0.30, 0.35, and further to 0.40.

[0074] Furthermore, in the zoom optical system of the present embodiment, it is preferable to provide an aperture stop between the third lens group and the fourth lens group.

[0075] In the zoom optical system of the present embodiment, by having such a structure, the zoom optical system is not enlarged, and various aberrations such as coma when focusing at infinity in the wide-angle end state can be corrected well.

[0076] In addition, in the zoom optical system of the present embodiment, it is preferable to satisfy the following conditional expression.

[0077] (7) 0.40 < Dwa / Dwb < 2.50 Wherein, Dwa: The distance from the object-side most surface of the first lens group to the aperture stop in the wide-angle end state Dwb: The distance from the aperture stop to the image plane in the wide-angle end state

[0078] The conditional expression (7) defines the ratio of the distance from the object-side most surface of the first lens group to the aperture stop to the distance from the aperture stop to the image plane. By satisfying the conditional expression (7), the zoom optical system of the present embodiment can correct various aberrations such as spherical aberration when focusing at infinity in the wide-angle end state well.

[0079] In the zoom optical system of the present embodiment, if the value of the conditional expression (7) exceeds the upper limit value, the distance from the object-side most surface of the first lens group to the aperture stop and the distance from the aperture stop to the image plane become too large, so it is difficult to correct various aberrations such as spherical aberration when focusing at infinity in the wide-angle end state well.

[0080] In the zoom optical system of the present embodiment, by setting the upper limit value of the conditional expression (7) to 2.50, 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 upper limit value of the conditional expression (7) to 2.25, 2.10, 2.00, 1.85, and further to 1.70.

[0081] In addition, in the zoom optical system of the present embodiment, if the value of the conditional expression (7) is lower than the lower limit value, the distance from the aperture stop to the image plane becomes too large, so it is difficult to correct various aberrations such as spherical aberration when focusing at infinity in the wide-angle end state well.

[0082] In the zoom optical system of the present embodiment, by setting the lower limit value of the conditional expression (7) to 0.40, 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 the conditional expression (7) to 0.50, 0.65, 0.80, 0.95, 1.10, and further to 1.20.

[0083] In addition, in the zoom optical system of the present embodiment, preferably, the following conditional expressions are satisfied.

[0084] (8) 0.01 < fwa / |fwb| < 0.30 Wherein, fwa: The combined focal length from the lens closest to the object side of the first lens group to the lens adjacent to the object side of the aperture stop in the wide-angle end state fwb: The combined focal length from the lens adjacent to the image plane side of the aperture stop to the lens closest to the image plane side in the wide-angle end state

[0085] Conditional expression (8) defines the ratio of the combined focal length from the lens closest to the object side of the first lens group to the lens adjacent to the object side of the aperture stop and the combined focal length from the lens adjacent to the image plane side of the aperture stop to the lens closest to the image plane side. By satisfying conditional expression (8), the zoom optical system of the present embodiment can well correct various aberrations such as spherical aberration when focusing at infinity in the wide-angle end state.

[0086] In the zoom optical system of the present embodiment, if the value of conditional expression (8) exceeds the upper limit value, the optical power from the lens adjacent to the image plane side of the aperture stop to the lens closest to the image plane side becomes too large, so it is difficult to well correct various aberrations such as spherical aberration when focusing at infinity in the wide-angle end state.

[0087] In the zoom optical system of the present embodiment, by setting the upper limit value of conditional expression (8) 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 conditional expression (8) to 0.25, 0.20, 0.17, and further to 0.14.

[0088] In addition, in the zoom optical system of the present embodiment, if the value of conditional expression (8) is lower than the lower limit value, the optical power from the lens closest to the object side of the first lens group to the lens adjacent to the object side of the aperture stop becomes too large, so it is difficult to well correct various aberrations such as spherical aberration when focusing at infinity in the wide-angle end state.

[0089] In the zoom optical system of the present embodiment, by setting the lower limit value of conditional expression (8) to 0.01, 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 conditional expression (8) to 0.02, 0.03, and further to 0.04.

[0090] In addition, in the zoom optical system of the present embodiment, preferably, the following conditional expressions are satisfied.

[0091] (9) 1.00 < MWF1 / MWF2 < 15.00 wherein MWF1: The movement amount of the first focusing lens group when focusing from an infinitely distant object to a near - distance object in the wide - angle end state MWF2: The movement amount of the second focusing lens group when focusing from an infinitely distant object to a near - distance object in the wide - angle end state

[0092] The conditional expression (9) defines the ratio of the movement amount of the first focusing lens group to the movement amount of the second focusing lens group when focusing from an infinitely distant object to a near - distance object in the wide - angle end state. Here, the near - distance refers to the distance at which the photographic magnification becomes 1 / 30. By satisfying the conditional expression (9), the zoom optical system of the present embodiment can suppress the variation of various aberrations such as coma during focusing in the wide - angle end state.

[0093] In the zoom optical system of the present embodiment, if the value of the conditional expression (9) exceeds the upper limit value, the movement amount of the first focusing lens group becomes too large, so it is difficult to suppress the variation of various aberrations such as coma during focusing in the wide - angle end state.

[0094] In the zoom optical system of the present embodiment, by setting the upper limit value of the conditional expression (9) to 15.00, the effect of the present embodiment can be made more reliable. Additionally, 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 (9) to 12.50, 11.00, 10.00, 8.50, 7.00, and further to 6.50.

[0095] In addition, in the zoom optical system of the present embodiment, if the value of the conditional expression (9) is lower than the lower limit value, the movement amount of the second lens group becomes too large, so it is difficult to suppress the variation of various aberrations such as coma during focusing in the wide - angle end state.

[0096] In the zoom optical system of the present embodiment, by setting the lower limit value of the conditional expression (9) to 1.00, the effect of the present embodiment can be made more reliable. Additionally, 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 (9) to 1.50, 2.00, 2.50, 3.00, 3.50, and further to 3.80.

[0097] In addition, in the zoom optical system of the present embodiment, preferably, the following conditional expression is satisfied.

[0098] (10) 0.70 < MTF1 / MTF2 < 10.00 wherein MTF1: The movement amount of the first focusing lens group when focusing from an infinitely distant object to a near - distance object in the telephoto end state MTF2: Movement amount of the second focusing lens group when focusing from an infinitely distant object to a close object in the telephoto end state

[0099] Conditional expression (10) defines the ratio of the movement amount of the first focusing lens group to the movement amount of the second focusing lens group when focusing from an infinitely distant object to a close object in the telephoto end state. By satisfying conditional expression (10), the zoom optical system of the present embodiment can suppress variations in various aberrations such as coma during focusing in the telephoto end state.

[0100] In the zoom optical system of the present embodiment, if the value of conditional expression (10) exceeds the upper limit value, the movement amount of the first focusing lens group becomes too large, and thus it is difficult to suppress variations in various aberrations such as coma during focusing in the telephoto end state.

[0101] In the zoom optical system of the present embodiment, by setting the upper limit value of conditional expression (10) to 10.00, the effects of the present embodiment can be made more reliable. Additionally, to make the effects of the present embodiment more reliable, it is preferable to set the upper limit value of conditional expression (10) to 9.00, 7.50, 5.00, 3.50, and further to 2.80.

[0102] Furthermore, in the zoom optical system of the present embodiment, if the value of conditional expression (10) is lower than the lower limit value, the movement amount of the second lens group becomes too large, and thus it is difficult to suppress variations in various aberrations such as coma during focusing in the telephoto end state.

[0103] In the zoom optical system of the present embodiment, by setting the lower limit value of conditional expression (10) to 0.70, the effects of the present embodiment can be made more reliable. Additionally, to make the effects of the present embodiment more reliable, it is preferable to set the lower limit value of conditional expression (10) to 0.85, 1.00, 1.25, 1.50, and further to 1.80.

[0104] Moreover, in the zoom optical system of the present embodiment, preferably, the following conditional expression is satisfied.

[0105] (11) 0.60 < βWF1 / βWF2 < 10.00 where βWF1: Lateral magnification of the first focusing lens group when focusing on an infinitely distant object in the wide-angle end state βWF2: Lateral magnification of the second focusing lens group when focusing on an infinitely distant object in the wide-angle end state

[0106] The conditional expression (11) defines the ratio of the lateral magnification of the first focusing lens group to the lateral magnification of the second focusing lens group when focusing on an infinitely distant object in the wide-angle end state. By satisfying the conditional expression (11), the zoom optical system of the present embodiment can suppress the variation of various aberrations including coma during focusing in the wide-angle end state.

[0107] In the zoom optical system of the present embodiment, if the value of the conditional expression (11) exceeds the upper limit value, the lateral magnification of the first focusing lens group when focusing on an infinitely distant object in the wide-angle end state becomes too large, so it is difficult to suppress the variation of various aberrations including coma during focusing in the wide-angle end state.

[0108] In the zoom optical system of the present embodiment, by setting the upper limit value of the conditional expression (11) to 10.00, 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 upper limit value of the conditional expression (11) to 8.50, 7.00, 5.00, and further to 4.00.

[0109] 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 lateral magnification of the second focusing lens group when focusing on an infinitely distant object in the wide-angle end state becomes too large, so it is difficult to suppress the variation of various aberrations including coma during focusing in the wide-angle end state.

[0110] In the zoom optical system of the present embodiment, by setting the lower limit value of the conditional expression (11) to 0.60, 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 the conditional expression (11) to 0.90, 1.00, 1.25, 1.50, 1.70, and further to 1.80.

[0111] In addition, in the zoom optical system of the present embodiment, preferably, the following conditional expression is satisfied.

[0112] (12) 0.20 < βTF1 / βTF2 < 5.00 Wherein, βWT1: The lateral magnification of the first focusing lens group when focusing on an infinitely distant object in the telephoto end state βWT2: The lateral magnification of the second focusing lens group when focusing on an infinitely distant object in the telephoto end state

[0113] The conditional expression (12) defines the ratio of the lateral magnification of the first focusing lens group to the lateral magnification of the second focusing lens group when focusing on an infinitely distant object in the telephoto end state. By satisfying the conditional expression (12), the zoom optical system of the present embodiment can suppress the variation of various aberrations including coma during focusing in the telephoto end state.

[0114] In the zoom optical system of the present embodiment, if the value of conditional expression (12) exceeds the upper limit value, the lateral magnification of the first focusing lens group when focusing on an infinitely distant object in the telephoto end state becomes too large. Therefore, it is difficult to suppress fluctuations in various aberrations such as coma during focusing in the telephoto end state.

[0115] In the zoom optical system of the present embodiment, by setting the upper limit value of conditional expression (12) to 5.00, the effects of the present embodiment can be made more reliable. Additionally, in order to make the effects of the present embodiment more reliable, it is preferable to set the upper limit value of conditional expression (12) to 4.00, 3.00, 2.50, 2.00, and further to 1.40.

[0116] In addition, in the zoom optical system of the present embodiment, if the value of conditional expression (12) is lower than the lower limit value, the lateral magnification of the second focusing lens group when focusing on an infinitely distant object in the telephoto end state becomes too large. Therefore, it is difficult to suppress fluctuations in various aberrations such as coma during focusing in the telephoto end state.

[0117] In the zoom optical system of the present embodiment, by setting the lower limit value of conditional expression (12) to 0.20, the effects of the present embodiment can be made more reliable. Additionally, in order to make the effects of the present embodiment more reliable, it is preferable to set the lower limit value of conditional expression (12) to 0.35, 0.50, 0.65, and further to 0.80.

[0118] In addition, in the zoom optical system of the present embodiment, preferably, the following conditional expression is satisfied.

[0119] (13) 0.50 < Gw / Gt < 1.50 Where, Gw: The distance from the lens surface closest to the object side of the zoom optical system to the center of gravity position of the zoom optical system in the wide-angle end state Gt: The distance from the lens surface closest to the object side of the zoom optical system to the center of gravity position of the zoom optical system in the telephoto end state

[0120] Conditional expression (13) defines the ratio of the distance from the lens surface closest to the object side of the zoom optical system to the center of gravity position of the zoom optical system in the wide-angle end state to the distance from the lens surface closest to the object side of the zoom optical system to the center of gravity position of the zoom optical system in the telephoto end state. By satisfying conditional expression (13), the change in the center of gravity position during zooming in the zoom optical system of the present embodiment becomes smaller, and high operability can be obtained.

[0121] In the zoom optical system of the present embodiment, when the conditional expression (13) is not satisfied, the change in the center-of-gravity position during zooming becomes large, which impairs the operability.

[0122] In the zoom optical system of the present embodiment, by setting the upper limit value of the conditional expression (13) to 1.50, the effects of the present embodiment can be made more reliable. Additionally, 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 (13) to 1.48, 1.45, and further to 1.40.

[0123] In the zoom optical system of the present embodiment, by setting the lower limit value of the conditional expression (13) to 0.50, the effects of the present embodiment can be made more reliable. Additionally, 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 (13) to 0.60, 0.75, 0.90, and further to 1.00.

[0124] Additionally, in the zoom optical system of the present embodiment, preferably, the following conditional expression is satisfied.

[0125] (14) 37.00° < ωw where ωw: The half field of view angle of the zoom optical system in the wide-angle end state

[0126] The conditional expression (14) defines the half field of view angle of the zoom optical system in the wide-angle end state. By satisfying the conditional expression (14), the zoom optical system of the present embodiment can image a subject in a relatively large range on the image plane.

[0127] In the zoom optical system of the present embodiment, by setting the lower limit value of the conditional expression (14) to 37.00°, the effects of the present embodiment can be made more reliable. Additionally, 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 (14) to 39.00°, and further to 42.00°.

[0128] Additionally, in the zoom optical system of the present embodiment, preferably, the following conditional expression is satisfied.

[0129] (15) ωt < 44.00° where ωt: The half field of view angle of the zoom optical system in the telephoto end state

[0130] The conditional expression (15) defines the half field of view angle of the zoom optical system in the telephoto end state. By satisfying the conditional expression (15), the zoom optical system of the present embodiment can image a relatively distant subject larger on the image plane.

[0131] In the zoom optical system of the present embodiment, by setting the upper limit value of conditional expression (15) to 44.00°, the effects of the present embodiment can be made more reliable. Additionally, to make the effects of the present embodiment more reliable, it is preferable to set the upper limit value of conditional expression (15) to 42.00°, 33.00°, 18.00°, and further to 14.00°.

[0132] With the above structure, a zoom optical system that is small-sized and has good imaging performance can be achieved.

[0133] The optical device of the present embodiment has a zoom optical system with the above structure. Thus, an optical device with good optical performance can be achieved.

[0134] The manufacturing method of the zoom optical system of the present embodiment includes configuring a zoom optical system that sequentially includes a first lens group with a negative optical power and subsequent lens groups with multiple lens groups from the object side, where the subsequent lens groups sequentially include a second lens group with a positive optical power and a third lens group with a positive optical power from the object side. During zooming, the first lens group is fixed relative to the image plane, and the intervals between adjacent lens groups change. The zoom optical system satisfies the following conditional expressions.

[0135] (1) 1.00 < f2 / f3 < 5.00 Where, f2: The focal length of the second lens group f3: The focal length of the third lens group

[0136] The manufacturing method of the zoom optical system of the present embodiment includes configuring a zoom optical system that sequentially includes a first lens group with a negative optical power and subsequent lens groups with multiple lens groups from the object side, where the subsequent lens groups include a first focusing lens group and a second focusing lens group. The first focusing lens group has a positive optical power and moves during focusing. The second focusing lens group has a negative optical power, is disposed on the image plane side relative to the first focusing lens group, and moves during focusing. During zooming, the first lens group is fixed relative to the image plane, and the intervals between adjacent lens groups change. The zoom optical system satisfies the following conditional expressions.

[0137] (2) 0.70 < fF1 / (-fF2) < 5.00 Where, fF1: The focal length of the first focusing lens group fF2: The focal length of the second focusing lens group

[0138] Through such a manufacturing method of the optical system, a zoom optical system with good optical performance can be manufactured.

[0139] (Numerical Example)

[0140] Hereinafter, embodiments of the present application will be described with reference to the drawings.

[0141] (First Embodiment)

[0142] Figure 1 FIG. 8 is a cross-sectional view of the zoom optical system according to the first embodiment when focusing on an infinite object in the wide-angle end state.

[0143] The zoom optical system of the present embodiment sequentially includes a first lens group G1 having a negative optical power, a second lens group G2 having a positive optical power, a third lens group G3 having a positive optical power, a fourth lens group G4 having a negative optical power, a fifth lens group G5 having a positive optical power, and a sixth lens group G6 having a negative optical power from the object side.

[0144] The first lens group G1 is sequentially composed of a meniscus-shaped negative lens L11 with a convex surface facing the object side, a biconcave negative lens L12, and a cemented negative lens formed by joining a meniscus-shaped positive lens L13 with a convex surface facing the object side from the object side.

[0145] The second lens group G2 is composed of a cemented positive lens formed by joining a biconvex positive lens L21 and a biconcave negative lens L22.

[0146] The third lens group G3 is composed of a cemented positive lens formed by joining a meniscus-shaped negative lens L31 with a convex surface facing the object side and a biconvex positive lens L32.

[0147] The fourth lens group G4 is sequentially composed of an aperture stop S, a biconcave negative lens L41, and a meniscus-shaped positive lens L42 with a convex surface facing the object side from the object side.

[0148] The fifth lens group G5 is sequentially composed of a cemented positive lens formed by joining a biconvex positive lens L51 and a biconcave negative lens L52, and a meniscus-shaped positive lens L53 with a concave surface facing the object side from the object side.

[0149] The sixth lens group G6 is sequentially composed of a biconcave negative lens L61 and a meniscus-shaped positive lens L62 with a concave surface facing the object side from the object side.

[0150] On the image plane I, an imaging element (not shown) composed of a CCD, a CMOS, or the like is arranged.

[0151] The zoom optical system of the present embodiment performs focusing by moving the fifth lens group G5 along the optical axis. When focusing on a near object from the state of focusing on infinity, the fifth lens group G5 moves from the image plane side toward the object side.

[0152] The values of the parameters of the zoom optical system of the present embodiment are shown in Table 1 below.

[0153] In [overall parameters], TL represents the distance from the lens surface closest to the object side to the image plane, fw represents the focal length of the entire system in the wide-angle end state, ft represents the focal length of the entire system in the telephoto end state, FNOw represents the F-number in the wide-angle end state, FNOt represents the F-number in the telephoto end state, ωw represents the half field of view angle (degrees) in the wide-angle end state, ωt represents the half field of view angle (degrees) in the telephoto end state, and Y represents the maximum image height.

[0154] In [lens parameters], m represents the order of the optical surface counted from the object side, r represents the radius of curvature, d represents the surface interval, nd represents the refractive index for the d-line (wavelength 587.6 nm), and νd represents the Abbe number for the d-line. A radius of curvature r = ∞ represents a plane. Additionally, in [lens parameters], the optical surfaces with an asterisk (*) attached indicate aspherical surfaces.

[0155] In [aspherical data], m represents the optical surface corresponding to the aspherical data, K represents the conic constant, and A4 - A12 represent the aspherical coefficients.

[0156] When the height in the direction perpendicular to the optical axis is set as y, the distance along the optical axis (recess amount) from the tangent plane of each aspherical surface at the vertex of height y to each aspherical surface is set as S(y), the radius of curvature of the reference sphere (paraxial radius of curvature) is set as r, the conic constant is set as K, and the aspherical coefficient of the nth order is set as An, the aspherical surface is represented by the following formula (a). Additionally, in each embodiment, the aspherical coefficient A2 of the second order is 0. Also, "E-n" represents "×10 -n ".

[0157] (a) S(y)= (y 2 / r) / {1 + (1-K×y 2 / r 2 ) 1 / 2} + A4×y 4 + A6×y 6 + A8×y 8 +A10×y 10 + A12×y 12

[0158] The units of the focal lengths fw and ft, the radius of curvature r, and other lengths described in Table 1 are "mm". However, equivalent optical performance can be obtained even if the optical system is scaled up or down, so it is not limited to this.

[0159] The symbols in Table 1 described above are also used in the tables of other embodiments described later.

[0160] (Table 1)

[0161] [Overall parameters]

[0162] [Lens parameters]

[0163]

[0164] [Aspherical data]

[0165] [Focal length data for each group]

[0166] [Variable interval data]

[0167] Figure 2 The (a) of is the aberration diagrams when focusing on an infinitely distant object in the wide-angle end state of the zoom optical system of the first embodiment. Figure 2 The (b) of is the aberration diagrams when focusing on an infinitely distant object in the telephoto end state of the zoom optical system of the first embodiment.

[0168] In each aberration diagram, FNO represents the F-number, and Y represents the image height. Specifically, in the spherical aberration diagram, the value of the F-number 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 values of each image height are shown. D represents the d-line, and g represents the g-line (wavelength 435.8 nm). In the astigmatism diagram, the solid line represents the sagittal image plane, and the dashed line represents the meridional image plane. The same symbols as those in the aberration diagrams of this embodiment are also used in the aberration diagrams of other embodiments described later.

[0169] From the aberration diagrams, it can be seen that the zoom optical system of this embodiment appropriately corrects various aberrations and has high optical performance.

[0170] (Second embodiment)

[0171] Figure 3 is a cross-sectional view of the zoom optical system of the second embodiment when focusing on an infinitely distant object in the wide-angle end state.

[0172] The zoom optical system of this embodiment sequentially includes a first lens group G1 having a negative optical power, a second lens group G2 having a positive optical power, a third lens group G3 having a positive optical power, a fourth lens group G4 having a negative optical power, a fifth lens group G5 having a positive optical power, and a sixth lens group G6 having a negative optical power from the object side.

[0173] The first lens group G1 is composed of a cemented negative lens formed by a meniscus-shaped negative lens L11 with its convex surface facing the object side, a biconcave negative lens L12, and a meniscus-shaped positive lens L13 with its convex surface facing the object side, in that order from the object side.

[0174] The second lens group G2 is composed of a cemented positive lens formed by a biconvex positive lens L21 and a biconcave negative lens L22.

[0175] The third lens group G3 is composed of a cemented positive lens formed by a meniscus-shaped negative lens L31 with its convex surface facing the object side and a biconvex positive lens L32.

[0176] The fourth lens group G4 is composed of an aperture stop S, a biconcave negative lens L41, and a meniscus-shaped positive lens L42 with its convex surface facing the object side, in that order from the object side.

[0177] The fifth lens group G5 is composed of a cemented positive lens formed by a biconvex positive lens L51 and a meniscus-shaped negative lens L52 with its concave surface facing the object side, and a meniscus-shaped positive lens L53 with its concave surface facing the object side, in that order from the object side.

[0178] The sixth lens group G6 is composed of a biconcave negative lens L61 and a biconvex positive lens L62, in that order from the object side.

[0179] On the image plane I, an imaging element (not shown) composed of a CCD, a CMOS, or the like is arranged.

[0180] In the variable magnification optical system of this embodiment, focusing is performed by moving the fifth lens group G5 along the optical axis. When focusing from an infinite focus state to a close object, the fifth lens group G5 moves from the image plane side toward the object side.

[0181] The values of the parameters of the variable magnification optical system of this embodiment are described in Table 2 below.

[0182] (Table 2)

[0183] [Overall parameters]

[0184] [Lens parameters]

[0185]

[0186] [Aspherical data]

[0187] [Focal length data for each group]

[0188] [Variable interval data]

[0189] Figure 4 (a) is the aberration diagrams when focusing on an infinitely distant object in the wide-angle end state of the zoom optical system of the second embodiment. Figure 4 (b) is the aberration diagrams when focusing on an infinitely distant object in the telephoto end state of the zoom optical system of the second embodiment.

[0190] From the aberration diagrams, it can be seen that the zoom optical system of this embodiment appropriately corrects various aberrations and has high optical performance.

[0191] (Third Embodiment)

[0192] Figure 5 is a cross-sectional view of the zoom optical system of the third embodiment when focusing on an infinitely distant object in the wide-angle end state.

[0193] The zoom optical system of this embodiment sequentially includes a first lens group G1 with a negative focal power, a second lens group G2 with a positive focal power, a third lens group G3 with a positive focal power, a fourth lens group G4 with a positive focal power, a fifth lens group G5 with a negative focal power, and a sixth lens group G6 with a positive focal power from the object side.

[0194] The first lens group G1 is composed of a meniscus-shaped negative lens L11 with its convex surface facing the object side, a biconcave negative lens L12, and a biconcave negative lens L13 and a meniscus-shaped positive lens L14 with its convex surface facing the object side, which are joined to form a negative lens from the object side.

[0195] The second lens group G2 is composed of a biconvex positive lens L21.

[0196] The third lens group G3 is composed of a meniscus-shaped positive lens L31 with its convex surface facing the object side, a meniscus-shaped positive lens L32 with its convex surface facing the object side, and a meniscus-shaped negative lens L33 with its convex surface facing the object side and a biconvex positive lens L34, which are joined to form a positive lens from the object side.

[0197] The fourth lens group G4 is composed of an aperture stop S, a biconcave negative lens L41, a meniscus-shaped positive lens L42 with its concave surface facing the object side and a meniscus-shaped negative lens L43 with its concave surface facing the object side, which are joined to form a negative lens, a biconvex positive lens L44, a meniscus-shaped negative lens L45 with its convex surface facing the object side and a meniscus-shaped positive lens L46 with its convex surface facing the object side, which are joined to form a negative lens, and a biconvex positive lens L47 from the object side.

[0198] The fifth lens group G5 is composed of a cemented negative lens formed by a meniscus-shaped positive lens L51 with its concave surface facing the object side and a biconcave negative lens L52.

[0199] The sixth lens group G6 is composed of a meniscus-shaped positive lens L61 with its convex surface facing the object side.

[0200] On the image plane I, an imaging element (not shown) made of a CCD, a CMOS, or the like is disposed.

[0201] The zoom optical system of this embodiment performs focusing by moving the second lens group G2 and the fifth lens group G5 along the optical axis. When focusing from an infinite focus state to a close object, the second lens group G2 moves from the object side toward the image side, and the fifth lens group G5 moves from the image side toward the object side.

[0202] In the zoom optical system of this embodiment, the second lens group G2 corresponds to the first focusing lens group, and the fifth lens group G5 corresponds to the second focusing lens group.

[0203] The values of the parameters of the zoom optical system of this embodiment are described in Table 3 below.

[0204] (Table 3)

[0205] [Overall parameters]

[0206] [Lens parameters]

[0207]

[0208]

[0209] [Aspherical data]

[0210] [Focal length data of each group]

[0211] [Variable interval data]

[0212] Figure 6 (a) of is the aberration diagrams when focusing on an infinite object in the wide-angle end state of the zoom optical system of the third embodiment, Figure 6 (b) of is the aberration diagrams when focusing on an infinite object in the telephoto end state of the zoom optical system of the third embodiment, Figure 6(c) shows aberration diagrams during focusing on a nearby object in the wide-angle end state of the zoom optical system according to the third embodiment. Figure 6 (d) shows aberration diagrams during focusing on a nearby object in the telephoto end state of the zoom optical system according to the third embodiment.

[0213] From the aberration diagrams, it can be seen that the zoom optical system of this embodiment appropriately corrects various aberrations and has high optical performance.

[0214] (Fourth Embodiment)

[0215] Figure 7 is a cross-sectional view of the zoom optical system according to the fourth embodiment during focusing on an infinitely distant object in the wide-angle end state.

[0216] The zoom optical system of this embodiment sequentially includes a first lens group G1 having a negative optical power, a second lens group G2 having a positive optical power, a third lens group G3 having a positive optical power, a fourth lens group G4 having a positive optical power, a fifth lens group G5 having a negative optical power, and a sixth lens group G6 having a positive optical power from the object side.

[0217] The first lens group G1 is sequentially composed of a meniscus-shaped negative lens L11 with the convex surface facing the object side, a biconcave negative lens L12, and a combined negative lens formed by joining a biconcave negative lens L13 and a biconvex positive lens L14 from the object side.

[0218] The second lens group G2 is composed of a biconvex positive lens L21.

[0219] The third lens group G3 is sequentially composed of a meniscus-shaped positive lens L31 with the convex surface facing the object side, and a combined positive lens formed by joining a meniscus-shaped negative lens L32 with the convex surface facing the object side and a biconvex positive lens L33 from the object side.

[0220] The fourth lens group G4 is sequentially composed of an aperture stop S, a combined negative lens formed by joining a biconcave negative lens L41 and a biconvex positive lens L42, a biconvex positive lens L43, a combined negative lens formed by joining a meniscus-shaped negative lens L44 with the convex surface facing the object side and a meniscus-shaped positive lens L45 with the convex surface facing the object side, and a biconvex positive lens L46 from the object side.

[0221] The fifth lens group G5 is composed of a combined negative lens formed by joining a meniscus-shaped positive lens L51 with the concave surface facing the object side and a biconcave negative lens L52.

[0222] The sixth lens group G6 is composed of a biconvex positive lens L61.

[0223] On the image plane I, an imaging element (not shown) composed of a CCD or CMOS, etc. is arranged.

[0224] The zoom optical system of this embodiment performs focusing by moving the second lens group G2 and the fifth lens group G5 along the optical axis. When focusing from an infinite focus state to a close object, the second lens group G2 moves from the object side toward the image plane side, and the fifth lens group G5 moves from the image plane side toward the object side.

[0225] In the zoom optical system of this embodiment, the second lens group G2 corresponds to the first focusing lens group, and the fifth lens group G5 corresponds to the second focusing lens group.

[0226] The values of the parameters of the zoom optical system of this embodiment are listed in Table 4 below.

[0227] (Table 4)

[0228] [Overall parameters]

[0229] [Lens parameters]

[0230]

[0231] [Aspherical data]

[0232] [Focal length data for each group]

[0233] [Variable interval data]

[0234] Figure 8 (a) of is the aberration diagrams when focusing on an infinite object in the wide-angle end state of the zoom optical system of the fourth embodiment, Figure 8 (b) of is the aberration diagrams when focusing on an infinite object in the telephoto end state of the zoom optical system of the fourth embodiment, Figure 8 (c) of is the aberration diagrams when focusing on a close object in the wide-angle end state of the zoom optical system of the fourth embodiment, Figure 8 (d) of is the aberration diagrams when focusing on a close object in the telephoto end state of the zoom optical system of the fourth embodiment.

[0235] From the aberration diagrams, it can be seen that the zoom optical system of this embodiment appropriately corrects various aberrations and has high optical performance.

[0236] (The fifth embodiment)

[0237] Figure 9Cross-sectional view of the zoom optical system according to the fifth embodiment when focusing on an infinitely distant object in the wide-angle end state.

[0238] The zoom optical system of this embodiment sequentially includes a first lens group G1 having a negative optical power, a second lens group G2 having a positive optical power, a third lens group G3 having a positive optical power, a fourth lens group G4 having a negative optical power, and a fifth lens group G5 having a positive optical power from the object side.

[0239] The first lens group G1 is sequentially composed of a meniscus-shaped negative lens L11 with a convex surface facing the object side, a meniscus-shaped positive lens L12 with a concave surface facing the object side, a biconcave-shaped negative lens L13, and a cemented negative lens formed by a meniscus-shaped positive lens L14 with a convex surface facing the object side from the object side.

[0240] The second lens group G2 is composed of a biconvex-shaped positive lens L21.

[0241] The third lens group G3 sequentially includes a meniscus-shaped positive lens L31 with a convex surface facing the object side, a cemented positive lens formed by a meniscus-shaped negative lens L32 with a convex surface facing the object side and a biconvex-shaped positive lens L33, an aperture stop S, a biconcave-shaped negative lens L34, a cemented negative lens formed by a meniscus-shaped positive lens L35 with a concave surface facing the object side and a biconcave-shaped negative lens L36, a biconvex-shaped positive lens L37, a cemented positive lens formed by a meniscus-shaped negative lens L38 with a convex surface facing the object side and a biconvex-shaped positive lens L39, and a biconvex-shaped positive lens L310 from the object side.

[0242] The fourth lens group G4 is composed of a cemented negative lens formed by a meniscus-shaped positive lens L41 with a concave surface facing the object side and a biconcave-shaped negative lens L42.

[0243] The fifth lens group G5 is composed of a meniscus-shaped positive lens L51 with a convex surface facing the object side.

[0244] On the image plane I, an imaging element (not shown) composed of a CCD or a CMOS, etc. is disposed.

[0245] The zoom optical system of this embodiment performs focusing by moving the second lens group G2 and the fourth lens group G4 along the optical axis. When focusing on a near object from the state of focusing on infinity, the second lens group G2 moves from the object side toward the image side, and the fourth lens group G4 moves from the image side toward the object side.

[0246] In the zoom optical system of this embodiment, the second lens group G2 corresponds to the first focusing lens group, and the fourth lens group G4 corresponds to the second focusing lens group.

[0247] The values of the parameters of the zoom optical system of this embodiment are described in Table 5 below.

[0248] (Table 5)

[0249] [Overall parameters]

[0250] [Lens parameters]

[0251]

[0252]

[0253] [Aspherical data]

[0254] [Focal length data for each group]

[0255] [Variable interval data]

[0256] Figure 10 (a) of is the aberration diagram when focusing on an infinite object in the wide-angle end state of the zoom optical system of the fifth embodiment, Figure 10 (b) of is the aberration diagram when focusing on an infinite object in the telephoto end state of the zoom optical system of the fifth embodiment, Figure 10 (c) of is the aberration diagram when focusing on a close object in the wide-angle end state of the zoom optical system of the fifth embodiment, Figure 10 (d) of is the aberration diagram when focusing on a close object in the telephoto end state of the zoom optical system of the fifth embodiment.

[0257] From the aberration diagrams, it can be seen that the zoom optical system of this embodiment appropriately corrects various aberrations and has high optical performance.

[0258] According to the above embodiments, a zoom optical system with good optical performance can be realized.

[0259] Hereinafter, the conditional corresponding values of each embodiment are shown.

[0260] fw is the focal length of the zoom optical system in the wide-angle end state, and BFw is the back focal length of the zoom optical system when focusing at infinity in the wide-angle end state.

[0261] f1 is the focal length of the first lens group, f2 is the focal length of the second lens group, and f3 is the focal length of the third lens group. fF1 is the focal length of the first focusing lens group, and fF2 is the focal length of the second focusing lens group. fRF is the focal length of the lens group adjacent to the object side of the lens group disposed closest to the image plane side, and fR is the focal length of the lens group disposed closest to the image plane side. fwa is the combined focal length from the lens closest to the object side of the first lens group to the lens adjacent to the object side of the aperture stop in the wide-angle end state, and fwb is the combined focal length from the lens adjacent to the image plane side of the aperture stop to the lens closest to the image plane side in the wide-angle end state.

[0262] Dwa is the distance from the surface closest to the object side of the first lens group to the aperture stop in the wide-angle end state, and Dwb is the distance from the aperture stop to the image plane in the wide-angle end state.

[0263] MWF1 is the movement amount of the first focusing lens group when focusing from an infinite object to a close object in the wide-angle end state, and MWF2 is the movement amount of the second focusing lens group when focusing from an infinite object to a close object in the wide-angle end state. MTF1 is the movement amount of the first focusing lens group when focusing from an infinite object to a close object in the telephoto end state, and MTF2 is the movement amount of the second focusing lens group when focusing from an infinite object to a close object in the telephoto end state.

[0264] βWF1 is the lateral magnification of the first focusing lens group when focusing on an infinite object in the wide-angle end state, and βWF2 is the lateral magnification of the second focusing lens group when focusing on an infinite object in the wide-angle end state. βTF1 is the lateral magnification of the first focusing lens group when focusing on an infinite object in the telephoto end state, and βTF2 is the lateral magnification of the second focusing lens group when focusing on an infinite object in the telephoto end state.

[0265] Gw is the distance from the lens surface closest to the object side of the zoom optical system to the center of gravity position of the zoom optical system in the wide-angle end state, and Gt is the distance from the lens surface closest to the object side of the zoom optical system to the center of gravity position of the zoom optical system in the telephoto end state. ωw is the half field angle of the zoom optical system in the wide-angle end state, and ωt is the half field angle of the zoom optical system in the telephoto end state.

[0266] [Conditional formula corresponding value]

[0267] The above embodiments represent a specific example of the present invention, and the present invention is not limited thereto. The following content can be appropriately adopted within the range that does not impair the optical performance of the zoom optical system of the embodiment of the present application.

[0268] In the zoom optical system of the present embodiment, the fourth lens group may 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 embodiments.

[0269] The zoom optical system of the present embodiment may also have an optical member such as a filter between the lens surface closest to the image plane side and the image plane.

[0270] The zoom optical system of the present embodiment may also have an anti-shake lens group that corrects image blur caused by hand shake by moving in a direction having a component perpendicular to the optical axis. The anti-shake lens group may be a lens group or a partial lens group composed of one or more lens components included in the lens group.

[0271] In the zoom optical system of the present embodiment, the lens surface may be formed by a spherical surface or a plane surface, or may be formed by an aspherical surface. When the lens surface is a spherical surface or a plane surface, lens processing and assembly adjustment become easy, and deterioration of optical performance caused by errors in processing and assembly adjustment can be prevented, so it is preferable. In addition, when the lens surface is a spherical surface or a plane surface, deterioration of the drawing performance during image plane shift is small, so it is preferable.

[0272] When the lens surface is an aspherical surface, the aspherical surface may be formed by grinding a glass or using a glass mold having an aspherical shape, or may be formed on the surface of a resin bonded to the glass surface. In addition, in the zoom optical system of the present embodiment, the lens surface may be a diffractive surface, and the lens may also be a gradient-index lens (GRIN lens) or a plastic lens.

[0273] Next, based on Figure 11 A camera including the zoom optical system of the present embodiment will be described.

[0274] Figure 11 is a schematic diagram of a camera having the zoom optical system of the present embodiment.

[0275] The camera 1 is a so-called mirrorless camera with interchangeable lenses that includes the optical system of the above-described first embodiment as the photographic lens 2.

[0276] In the camera 1, light from an object (subject) (not shown) is condensed by the photographic lens 2 and reaches the imaging element 3. The imaging element 3 converts the light from the subject into image data. When the photographer presses a release button (not shown), the image data is stored in a memory (not shown). In this way, the photographer can photograph the subject using the camera 1.

[0277] Here, the zoom optical system of the first embodiment mounted as the photographic lens 2 on the camera 1 is a zoom optical system having good optical performance. Therefore, the camera 1 can achieve good optical performance. In addition, even for a camera in which the zoom optical systems of the second to fifth embodiments are mounted as the photographic lens 2, the same effects as those of the camera 1 can be obtained.

[0278] Finally, based on Figure 12 and Figure 13 a schematic of the manufacturing method of the zoom optical system of the present embodiment will be described.

[0279] Figure 12 is a flowchart showing the schematic of the first manufacturing method of the zoom optical system of the present embodiment. Figure 12 The first manufacturing method of the zoom optical system of the present embodiment shown includes the following steps S11 - S13.

[0280] Step S11: Prepare the first lens group and the subsequent lens groups including the second lens group and the third lens group.

[0281] Step S12: During zooming, fix the first lens group relative to the image plane and vary the intervals between adjacent lens groups.

[0282] Step S13: Make the zoom optical system satisfy the following conditional expression.

[0283] (1) 1.00 < f2 / f3 < 5.00 where f2: the focal length of the second lens group f3: the focal length of the third lens group

[0284] Figure 13 is a flowchart showing the schematic of the second manufacturing method of the zoom optical system of the present embodiment. Figure 13 The second manufacturing method of the zoom optical system of the present embodiment shown includes the following steps S21 - S23.

[0285] Step S21: Prepare the first lens group and the subsequent lens groups including the first focusing lens group and the second focusing lens group.

[0286] Step S22: During zooming, fix the first lens group relative to the image plane and vary the intervals between adjacent lens groups.

[0287] Step S23: Make the zoom optical system satisfy the following conditional expression.

[0288] (2) 0.70 < fF1 / (-fF2) < 5.00 where fF1: the focal length of the first focusing lens group fF2: Focal length of the second focusing lens group

[0289] According to these manufacturing methods of the zoom optical system of the present embodiment, an optical system with good imaging performance can be manufactured.

[0290] It should be understood that those skilled in the art can make various changes, substitutions and modifications to it without departing from the spirit and scope of the present disclosure.

[0291] Reference numeral description

[0292] S Aperture stop

[0293] I Image plane

[0294] 1 Camera

[0295] 2 Photographic lens

[0296] 3 Imaging element

Claims

1. A variable magnification optical system, wherein, the variable magnification optical system sequentially includes a first lens group having a negative optical power and a subsequent lens group having a plurality of lens groups from the object side, the subsequent lens group sequentially includes a second lens group having a positive optical power and a third lens group having a positive optical power from the object side, during variable magnification, the first lens group is fixed relative to the image plane, and the intervals between adjacent lens groups change, the variable magnification optical system satisfies the following conditional formula: 1.00 < f2 / f3 < 5.00 wherein, f2: the focal length of the second lens group, f3: the focal length of the third lens group.

2. A variable magnification optical system, wherein, the variable magnification optical system sequentially includes a first lens group having a negative optical power and a subsequent lens group having a plurality of lens groups from the object side, the subsequent lens group includes a first focusing lens group and a second focusing lens group. The first focusing lens group has a positive optical power and moves during focusing. The second focusing lens group has a negative optical power, is disposed on the image plane side with respect to the first focusing lens group, and moves during focusing, during variable magnification, the first lens group is fixed relative to the image plane, and the intervals between adjacent lens groups change, the variable magnification optical system satisfies the following conditional formula: 0.70 < fF1 / (-fF2) < 5.00 wherein, fF1: the focal length of the first focusing lens group, fF2: the focal length of the second focusing lens group.

3. The variable magnification optical system according to claim 1, wherein, the subsequent lens group further includes a fourth lens group disposed on the image plane side of the third lens group.

4. The variable magnification optical system according to claim 2, wherein, the subsequent lens group sequentially includes a second lens group having a positive optical power, a third lens group having a positive optical power, and a fourth lens group from the object side.

5. The variable magnification optical system according to claim 4, wherein, the second lens group is the first focusing lens group.

6. The variable magnification optical system according to any one of claims 1, 3 to 5, wherein, the variable magnification optical system satisfies the following conditional formula: 0.12 < (-f1) / f2 < 0.95 wherein, f1: the focal length of the first lens group, f2: the focal length of the second lens group.

7. The variable magnification optical system according to any one of claims 1 to 6, wherein, the variable magnification optical system satisfies the following conditional formula: 0.20 < (-f1) / fw < 2.40 wherein, f1: the focal length of the first lens group, fw: the focal length of the variable magnification optical system in the wide-angle end state.

8. The variable magnification optical system according to any one of claims 1 to 7, wherein, the variable magnification optical system satisfies the following conditional formula: 0.10 < |fRF| / |fR| < 1.10 wherein, fRF: the focal length of the lens group adjacent to the object side of the lens group disposed closest to the image plane, fR: the focal length of the lens group disposed closest to the image plane.

9. The variable magnification optical system according to any one of claims 1 to 8, wherein, the variable magnification optical system satisfies the following conditional formula: 0.15 < BFw / fw < 1.10 Wherein, BFw: the back focal length of the zoom optical system during infinite focus in the wide-angle end state, fw: the focal length of the zoom optical system in the wide-angle end state.

10. The zoom optical system according to claim 3 or 4, Wherein, The zoom optical system has an aperture stop between the third lens group and the fourth lens group.

11. The zoom optical system according to claim 10, Wherein, The zoom optical system satisfies the following conditional formula: 0.40 < Dwa / Dwb < 2.50 Wherein, Dwa: the distance from the object-side most surface of the first lens group to the aperture stop in the wide-angle end state, Dwb: the distance from the aperture stop to the image plane in the wide-angle end state.

12. The zoom optical system according to claim 10 or 11, Wherein, The zoom optical system satisfies the following conditional formula: 0.01 < fwa / |fwb| < 0.30 Wherein, fwa: the combined focal length from the object-side most lens of the first lens group to the lens adjacent to the object side of the aperture stop in the wide-angle end state, fwb: the combined focal length from the lens adjacent to the image side of the aperture stop to the image-side most lens in the wide-angle end state.

13. The zoom optical system according to claim 2, 4 or 5, Wherein, The zoom optical system satisfies the following conditional formula: 1.00 < MWF1 / MWF2 < 15.00 Wherein, MWF1: the moving amount of the first focusing lens group when focusing from an infinite object to a close object in the wide-angle end state, MWF2: the moving amount of the second focusing lens group when focusing from an infinite object to a close object in the wide-angle end state.

14. The zoom optical system according to claim 2, 4, 5 or 13, Wherein, The zoom optical system satisfies the following conditional formula: 0.70 < MTF1 / MTF2 < 10.00 Wherein, MTF1: the moving amount of the first focusing lens group when focusing from an infinite object to a close object in the telephoto end state, MTF2: the moving amount of the second focusing lens group when focusing from an infinite object to a close object in the telephoto end state.

15. The zoom optical system according to claim 2, 4, 5, 13 or 14, Wherein, The zoom optical system satisfies the following conditional formula: 0.60 < βWF1 / βWF2 < 10.00 Wherein, βWF1: the lateral magnification of the first focusing lens group during infinite focus in the wide-angle end state, βWF2: the lateral magnification of the second focusing lens group during infinite focus in the wide-angle end state.

16. The zoom optical system according to claim 2, 4, 5, 13, 14 or 15, Wherein, The zoom optical system satisfies the following conditional formula: 0.20 < βTF1 / βTF2 < 5.00 Wherein, βWT1: the lateral magnification of the first focusing lens group during infinite focus in the telephoto end state, βWT2: The lateral magnification of the second focusing lens group when focusing on an infinitely distant object in the telephoto end state.

17. The zoom optical system according to any one of claims 1 to 16, wherein, the zoom optical system satisfies the following conditional expression: 0.50 < Gw / Gt < 1.50 wherein, Gw: The distance from the lens surface closest to the object side of the zoom optical system to the center of gravity position of the zoom optical system in the wide-angle end state, Gt: The distance from the lens surface closest to the object side of the zoom optical system to the center of gravity position of the zoom optical system in the telephoto end state.

18. An optical device having the zoom optical system according to any one of claims 1 to 17.

19. A method for manufacturing a zoom optical system, wherein, a zoom optical system having a first lens group with a negative optical power and subsequent lens groups with multiple lens groups in sequence from the object side is configured such that, the subsequent lens groups include a second lens group with a positive optical power and a third lens group with a positive optical power in sequence from the object side, during zooming, the first lens group is fixed relative to the image plane, and the intervals between adjacent lens groups change, the zoom optical system satisfies the following conditional expression: 1.00 < f2 / f3 < 5.00 wherein, f2: The focal length of the second lens group, f3: The focal length of the third lens group.

20. A method for manufacturing a zoom optical system, wherein, a zoom optical system having a first lens group with a negative optical power and subsequent lens groups with multiple lens groups in sequence from the object side is configured such that, the subsequent lens groups include a first focusing lens group and a second focusing lens group. The first focusing lens group has a positive optical power and moves during focusing. The second focusing lens group has a negative optical power, is arranged on the image plane side relative to the first focusing lens group, and moves during focusing, during zooming, the first lens group is fixed relative to the image plane, and the intervals between adjacent lens groups change, the zoom optical system satisfies the following conditional expression: 0.70 < fF1 / (-fF2) < 5.00 wherein, fF1: The focal length of the first focusing lens group, fF2: The focal length of the second focusing lens group.

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