Zoom optical system and image capturing device

Abstract

To provide a zoom optical system which is reduced in size and weight and offers good optical performance over an entire zoom range, and to provide an image capturing device equipped with the same.SOLUTION: A zoom optical system is provided, consisting of a first lens group having negative refractive power, a second lens group having positive refractive power, and a succeeding group comprising one or more lens groups, arranged in order from the object side. While zooming, the first lens group moves and a distance between each pair of adjacent lens groups changes. One of the lens groups included in the succeeding group is a focusing lens group configured to move along an optical axis when focusing. The zoom optical system satisfies predetermined conditional expressions.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The technology of the present disclosure relates to a variable magnification optical system and an imaging apparatus. [Background technology]

[0002] 2. Description of the Related Art Conventionally, variable magnification optical systems that can be used in imaging devices such as digital cameras include those described in Patent Documents 1 and 2 below. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Publication No. 2021-162822 [Patent Document 2] JP 2021-086024 A Summary of the Invention [Problem to be solved by the invention]

[0004] There is a demand for variable magnification optical systems that are small and lightweight and that maintain good optical performance over the entire range of magnification, and the level of these demands is increasing year by year.

[0005] The present disclosure provides a variable magnification optical system that is small and lightweight and maintains good optical performance over the entire range of magnification change, and an imaging apparatus that includes this variable magnification optical system. [Means for solving the problem]

[0006] A first aspect of the present disclosure is a variable power optical system comprising, in order from the object side to the image side, a first lens group having negative refractive power, a second lens group having positive refractive power, and a subsequent group including one or more lens groups, wherein, during variable power, the first lens group moves and all intervals between adjacent lens groups change, and one of the lens groups included in the subsequent group is a focusing lens group that moves along an optical axis during focusing, 4.5 <TLw / (ft×tanωt)<8 (1) 0.4 <Bfw / (ft×tanωt)<3 (2) 0.9<(fw×TLw) / ft 2 <3.2 (3) 1.6 <NG1L+0.01×νG1L<2.3 (4) 0.1 <Dsum / (TLw-Bfw)<0.8 (5) The conditional expressions (1), (2), (3), (4), and (5) expressed by the following formulae are satisfied. The symbols in conditional expressions (1), (2), (3), (4), and (5) are defined as follows. The sum of the distance on the optical axis from the lens surface closest to the object in the first lens group to the lens surface closest to the image in the succeeding lens group when focused on an object at infinity at the wide-angle end and the back focus in the air-equivalent distance of the entire system is defined as TLw. The focal length of the entire system when focused on an object at infinity at the telephoto end is defined as ft. The maximum half angle of view when focused on an object at infinity at the telephoto end is defined as ωt. The back focus of the entire system when focused on an object at infinity at the wide-angle end is defined as Bfw. The focal length of the entire system when focused on an object at infinity at the wide-angle end is defined as fw. The refractive index for the d-line and the Abbe number based on the d-line of any lens included in the first lens group are defined as NG1L and νG1L, respectively. The sum of the thicknesses on the optical axis of all lens groups is defined as Dsum.

[0007] A second aspect of the present disclosure provides a variable magnification optical system according to the first aspect, 5.4 <TLw / (ft×tanωt)<7 (1-1) The condition (1-1) is satisfied.

[0008] A third aspect of the present disclosure is a variable magnification optical system according to the first aspect, 0.55 <Bfw / (ft×tanωt)<2 (2-1) The condition (2-1) is satisfied.

[0009] A fourth aspect of the present disclosure is a variable power optical system according to the first aspect, in which, when the thickness on the optical axis of the first lens group is dG1 and the focal length of the first lens group is f1, 0.4 <dG1 / |f1|<2 (6) Condition (6) expressed by the following formula (6) is satisfied.

[0010] A fifth aspect of the present disclosure provides a variable magnification optical system according to the fourth aspect, 0.55 <dG1 / |f1|<1.65 (6-1) The condition (6-1) is satisfied.

[0011] A sixth aspect of the present disclosure is a variable magnification optical system according to the first aspect, wherein the first lens group includes an L1nm lens which is a negative meniscus lens with a convex surface facing the object side and is not cemented, an L1n lens which is a negative lens with a concave surface facing the image side and is not cemented, and an L1p lens which is a positive lens, wherein the L1n lens is disposed adjacent to the image side of the L1nm lens, and the L1p lens is disposed closer to the image side than the L1n lens.

[0012] A seventh aspect of the present disclosure provides a variable power optical system according to the sixth aspect, in which, when the refractive index for the d-line and the Abbe number based on the d-line of a negative lens disposed between the L1nm lens and the L1p lens are NG1n and νG1n, respectively, 1.7 <NG1n+0.01×νG1n<2.16 (7) The negative lens satisfying conditional expression (7) is an L1n lens or a negative lens arranged adjacent to the image side of the L1n lens.

[0013] An eighth aspect of the present disclosure is a variable power optical system according to the seventh aspect, further comprising a negative lens satisfying conditional expression (7): 1.74 <NG1n+0.01×νG1n<2.14 (7-1) The condition (7-1) is satisfied.

[0014] A ninth aspect of the present disclosure is a variable magnification optical system according to the sixth aspect, in which, when the distance on the optical axis between the L1nm lens and the L1n lens is dm and the thickness on the optical axis of the first lens group is dG1, 0.01 <dm / dG1<0.9 (8) The condition (8) is satisfied.

[0015] A tenth aspect of the present disclosure is a variable magnification optical system according to the sixth aspect, wherein the object-side surface of the L1n lens is an aspheric surface in which the refractive power at the position of the maximum effective diameter is shifted in the positive direction compared to the refractive power in the paraxial region.

[0016] An eleventh aspect of the present disclosure is a variable power optical system according to the tenth aspect, wherein the object-side surface of the L1n lens has a concave shape in the paraxial region and a convex shape in the periphery including the position of the maximum effective diameter.

[0017] A twelfth aspect of the present disclosure is a variable power optical system according to the first aspect, in which, when the focal length of the second lens group is f2 and the focal length of the first lens group is f1, 0.3 <f2 / |f1|<5 (9) Condition (9) expressed by the following formula (9) is satisfied.

[0018] A thirteenth aspect of the present disclosure is a variable power optical system according to the twelfth aspect, 0.65 <f2 / |f1|<3 (9-1) The condition (9-1) is satisfied.

[0019] A fourteenth aspect of the present disclosure is a variable power optical system according to the thirteenth aspect, 5.4 <TLw / (ft×tanωt)<7 (1-1) The condition (1-1) is satisfied.

[0020] A fifteenth aspect of the present disclosure is a variable magnification optical system according to the fourteenth aspect, wherein the first lens group includes an L1nm lens which is a negative meniscus lens with a convex surface facing the object side and is not cemented, an L1n lens which is a negative lens with a concave surface facing the image side and is not cemented, and an L1p lens which is a positive lens, wherein the L1n lens is disposed adjacent to the image side of the L1nm lens, and the L1p lens is disposed on the image side of the L1n lens.

[0021] A sixteenth aspect of the present disclosure provides a variable power optical system according to the fifteenth aspect, in which, when the refractive index for the d-line and the Abbe number based on the d-line of a negative lens disposed between the L1nm lens and the L1p lens are NG1n and νG1n, respectively, 1.74 <NG1n+0.01×νG1n<2.14 (7-1) The negative lens satisfying conditional formula (7-1) is an L1n lens or a negative lens arranged adjacent to the image side of the L1n lens.

[0022] A seventeenth aspect of the present disclosure is the variable power optical system of the sixteenth aspect, wherein the first lens group includes, closest to the object side, a positive lens with a convex surface facing the object side.

[0023] An eighteenth aspect of the present disclosure is a variable power optical system according to the sixteenth aspect, 1.82 <NG1L+0.01×νG1L<1.91 (4-1) The condition (4-1) is satisfied.

[0024] A nineteenth aspect of the present disclosure is a variable power optical system according to the sixteenth aspect, wherein, when the thickness of the first lens group on the optical axis is dG1, 0.55 <dG1 / |f1|<1.65 (6-1) The condition (6-1) is satisfied.

[0025] A twentieth aspect of the present disclosure is a variable power optical system according to the nineteenth aspect, 0.75 <dG1 / |f1|<1.35 (6-2) The condition (6-2) is satisfied.

[0026] A twenty-first aspect of the present disclosure provides a variable magnification optical system according to the nineteenth aspect, in which, when the distance on the optical axis between the L1nm lens and the L1n lens is dm, 0.01 <dm / dG1<0.9 (8) The condition (8) is satisfied.

[0027] A twenty-second aspect of the present disclosure is the variable power optical system of the nineteenth aspect, wherein the first lens group is made up of four or less lenses.

[0028] A 23rd aspect of the present disclosure is a variable magnification optical system according to the 19th aspect, in which the object-side surface of the L1n lens is an aspheric surface in which the refractive power at the position of the maximum effective diameter is shifted in the positive direction compared to the refractive power in the paraxial region.

[0029] A twenty-fourth aspect of the present disclosure is a variable power optical system according to the first aspect, wherein, when the focal length of the first lens group is f1, 0.45 <fw / |f1|<2 (10) Condition (10) expressed by the following formula is satisfied.

[0030] A 25th aspect of the present disclosure is a variable power optical system according to the first aspect, wherein the first lens group includes an L1nm lens which is a negative meniscus lens that is not cemented and has a convex surface facing the object side, and where the paraxial radius of curvature of the object side surface of the L1nm lens is Rf and the paraxial radius of curvature of the image side surface of the L1nm lens is Rr, 1<(Rf+Rr) / (Rf-Rr)<7 (11) satisfies conditional expression (11) expressed by:

[0031] A 26th aspect of the present disclosure is a variable magnification optical system according to the first aspect, wherein a vibration reduction group that moves in a direction intersecting the optical axis during image blur correction is disposed on the image side of the first lens group, and when the focal length of the vibration reduction group is fois, 0.3 <ft / |fois|<4 (12) The condition (12) is satisfied.

[0032] A 27th aspect of the present disclosure is a variable power optical system according to the first aspect, wherein, when the focal length of the focusing lens group is ffoc, 0.3 <ft / |ffoc|<3 (13) The condition (13) is satisfied.

[0033] A 28th aspect of the present disclosure provides a variable power optical system according to the first aspect, in which an Lr lens is disposed closer to the image side than the focusing lens group, and the refractive index for the d-line and the Abbe number based on the d-line of the Lr lens are defined as Nr and νr, respectively: 1.7 <Nr+0.01×νr<2.16 (14) The condition (14) is satisfied.

[0034] A twenty-ninth aspect of the present disclosure is an imaging device including the variable magnification optical system according to any one of the first to twenty-eighth aspects.

[0035] In addition, in this specification, "consisting of" and "consisting of" are intended to mean that, in addition to the listed components, the following may be included: a lens that has substantially no refractive power, optical elements other than lenses such as an aperture, a filter, and a cover glass, and mechanical parts such as a lens flange, a lens barrel, an image sensor, and an image stabilization mechanism.

[0036] In this specification, a "group having positive refractive power" means that the group as a whole has positive refractive power. Similarly, a "group having negative refractive power" means that the group as a whole has negative refractive power. A "lens having positive refractive power" and a "positive lens" are synonymous. A "lens having negative refractive power" and a "negative lens" are synonymous. In this specification, a "group" is not limited to a configuration consisting of multiple lenses, and may be a configuration consisting of only one lens.

[0037] In this specification, the term "whole system" refers to a variable magnification optical system. The "focal length" used in the conditional expressions is a paraxial focal length. The "distance on the optical axis" used in the conditional expressions is a geometric distance unless otherwise specified. The values ​​used in the conditional expressions are values ​​based on the d-line when focused on an object at infinity unless otherwise specified. The radius of curvature, sign of refractive power, and surface shape of lenses including aspheric surfaces are those in the paraxial region unless otherwise specified. The sign of the paraxial radius of curvature is positive for a surface with a convex shape facing the object side, and negative for a surface with a convex shape facing the image side. Effect of the Invention

[0038] According to the present disclosure, it is possible to provide a variable magnification optical system that is small and lightweight and maintains good optical performance over the entire range of magnification, and an imaging device that includes this variable magnification optical system. [Brief description of the drawings]

[0039] [Figure 1] 1A and 1B correspond to the variable magnification optical system of Example 1, and are diagrams showing a cross-sectional view of the configuration of a variable magnification optical system according to one embodiment and a movement locus. [Diagram 2] FIG. 2 is a cross-sectional view of the configuration of the variable magnification optical system in FIG. 1, and is also a diagram for explaining symbols in conditional expressions. [Diagram 3] FIG. 4 is a diagram for explaining the position of the maximum effective diameter. [Figure 4] 3A to 3C are diagrams showing various aberrations in the variable magnification optical system of Example 1. [Diagram 5] 11A and 11B are diagrams showing a cross-sectional view and a movement locus of a variable magnification optical system according to a second embodiment. [Figure 6] 6A to 6C are diagrams showing various aberrations in the variable magnification optical system of Example 2. [Figure 7] 11A and 11B are diagrams showing a cross-sectional view and a movement locus of a variable magnification optical system according to a third embodiment. [Figure 8] 11A to 11C are diagrams showing various aberrations in the variable magnification optical system of Example 3. [Figure 9] 13A and 13B are diagrams showing a cross-sectional view and a movement locus of a variable magnification optical system according to a fourth embodiment. [Figure 10] 11A to 11C are diagrams showing various aberrations in the variable magnification optical system of Example 4. [Figure 11] 13A and 13B are diagrams showing a cross-sectional view and a movement locus of a variable magnification optical system according to a fifth embodiment. [Figure 12] 13A to 13C are diagrams showing various aberrations in the variable magnification optical system of Example 5. [Figure 13] 13A and 13B are diagrams showing a cross-sectional view and a movement locus of a variable magnification optical system according to a sixth embodiment. [Figure 14] 13A to 13C are diagrams showing various aberrations in the variable magnification optical system of Example 6. [Figure 15] 13A and 13B are diagrams showing a cross-sectional view and a movement locus of a variable magnification optical system according to a seventh embodiment. [Figure 16] 13A to 13C are diagrams showing various aberrations in the variable magnification optical system of Example 7. [Figure 17] 13A and 13B are diagrams showing a cross-sectional view and a movement locus of a variable magnification optical system according to an eighth embodiment. [Figure 18] 13A to 13C are diagrams showing various aberrations in the variable magnification optical system of Example 8. [Figure 19] 13A and 13B are diagrams showing a cross-sectional view and a movement locus of a variable magnification optical system according to a ninth embodiment. [Figure 20] 13A to 13C are diagrams showing various aberrations in the variable magnification optical system of Example 9. [Figure 21] 13A and 13B are diagrams showing a cross-sectional view and a movement locus of a variable magnification optical system according to a tenth embodiment. [Figure 22] 23A to 23C are diagrams showing various aberrations in the variable magnification optical system of Example 10. [Diagram 23] 13A and 13B are diagrams showing a cross-sectional view and a movement locus of a variable magnification optical system according to an eleventh embodiment. [Figure 24] 13A to 13C are diagrams showing various aberrations in the variable magnification optical system of Example 11. [Diagram 25] 13A and 13B are diagrams showing a cross-sectional view and a movement locus of a variable magnification optical system according to a twelfth embodiment. [Figure 26] 16A to 16C are diagrams showing various aberrations in the variable magnification optical system of Example 12. [Figure 27] 13A and 13B are diagrams showing a cross-sectional view and a movement locus of a variable magnification optical system according to a thirteenth embodiment. [Figure 28] 23A to 23C are diagrams showing various aberrations in the variable magnification optical system of Example 13. [Figure 29] 13A and 13B are diagrams showing a cross-sectional view and a movement locus of a variable magnification optical system according to a fourteenth embodiment. [Diagram 30] 23A to 23C are diagrams showing various aberrations in the variable magnification optical system of Example 14. [Diagram 31] 15A and 15B are diagrams showing a cross-sectional view and a movement locus of a variable magnification optical system according to a fifteenth embodiment. [Diagram 32] 23A to 23C are diagrams showing various aberrations in the variable magnification optical system of Example 15. [Diagram 33] 23A and 23B are diagrams showing a cross-sectional view and a movement locus of the variable magnification optical system of Example 16. [Diagram 34] 23A to 23C are diagrams showing various aberrations in the variable magnification optical system of Example 16. [Diagram 35] 23A and 23B are diagrams showing a cross-sectional view and a movement locus of the variable magnification optical system of Example 17. [Diagram 36] 21A to 21C are diagrams showing various aberrations in the variable magnification optical system of Example 17. [Figure 37] 23A and 23B are diagrams showing a cross-sectional view and a movement locus of the variable magnification optical system of Example 18. [Figure 38] 23A to 23C are diagrams showing various aberrations in the variable magnification optical system of Example 18. [Figure 39] 23A and 23B are diagrams showing a cross-sectional view and a movement locus of the variable magnification optical system of Example 19. [Diagram 40] 23A to 23C are diagrams showing various aberrations in the variable magnification optical system of Example 19. [Diagram 41] 23A and 23B are diagrams showing a cross-sectional view and a movement locus of the variable magnification optical system according to the twentieth embodiment. [Diagram 42] 23A to 23C are diagrams showing various aberrations in the variable magnification optical system of Example 20. [Diagram 43] 1 is a perspective view of the front side of an imaging device according to an embodiment. [Diagram 44] FIG. 2 is a perspective view of the rear side of the imaging device according to the embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0040] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings.

[0041] FIG. 1 shows a cross-sectional view of the configuration and light beam of a variable magnification optical system according to an embodiment of the present disclosure, and a movement trajectory. In FIG. 1, the upper row labeled "Wide" shows the wide-angle end state, and the lower row labeled "Tele" shows the telephoto end state. In FIG. 1, the light beams are an axial light beam at the wide-angle end and a light beam with a maximum half angle of view ωw, and an axial light beam at the telephoto end and a light beam with a maximum half angle of view ωt. FIG. 2 shows a cross-sectional view of the configuration of the variable magnification optical system of FIG. 1 at the wide-angle end. In FIGS. 1 and 2, a state in which an object at infinity is focused is shown, with the left side being the object side and the right side being the image side. The examples shown in FIGS. 1 and 2 correspond to the variable magnification optical system of Example 1 described later. The following description will be mainly made with reference to FIG. 1, and FIG. 2 will be referred to as necessary.

[0042] The variable magnification optical system of the present disclosure comprises, in order from the object side to the image side along the optical axis Z, a first lens group G1 having negative refractive power, a second lens group G2 having positive refractive power, and a subsequent group GR including one or more lens groups. During magnification change, the first lens group G1 moves, and all the intervals between the adjacent lens groups change. This configuration is advantageous in suppressing various aberrations throughout the entire range of magnification change.

[0043] In particular, making the first lens group G1 a group having negative refractive power is advantageous for obtaining a wide angle of view. Making the first lens group G1 a group having negative refractive power and making the second lens group G2 a group having positive refractive power is advantageous for suppressing various aberrations. Making the second lens group G2 a group having positive refractive power is advantageous for suppressing aberration fluctuations during zooming, since the height from the optical axis Z of the light ray incident on the subsequent group GR can be reduced.

[0044] In this specification, a group whose distance in the optical axis direction between adjacent groups changes when the magnification is changed is defined as one lens group. When the magnification is changed, the distance between adjacent lenses in one lens group does not change. In other words, a "lens group" is a component of a variable magnification optical system, and is a part including at least one lens separated by an air gap that changes when the magnification is changed. When the magnification is changed, each lens group is moved or fixed. A "lens group" may include a component other than a lens that does not have a refractive power, such as an aperture stop St.

[0045] As an example, each group of the variable magnification optical system shown in FIG. 1 is configured as follows. The first lens group G1 is composed of four lenses, lenses L11 to L14, in order from the object side to the image side. The second lens group G2 is composed of a lens L21, an aperture stop St, and lenses L22 to L23, in order from the object side to the image side. The subsequent lens group GR is composed of one lens group. The subsequent lens group GR is composed of a third lens group G3, which is composed of one lens, lens L31. Note that the aperture stop St shown in FIG. 1 does not indicate the size or shape, but indicates the position on the optical axis.

[0046] In the example of Fig. 1, when changing magnification, the first lens group G1, the second lens group G2, and the third lens group G3 move along the optical axis Z while changing the intervals between the adjacent lens groups. In Fig. 1, between the upper and lower diagrams, solid arrows indicate the schematic movement trajectories of each lens group when changing magnification from the wide-angle end to the telephoto end.

[0047] 1 is merely an example, and various modifications of the variable power optical system of the present disclosure are possible without departing from the spirit and scope of the present disclosure. Preferred and possible configurations of the variable power optical system of the present disclosure are described below.

[0048] The first lens group G1 may be configured to include a positive lens with a convex surface facing the object side, which is advantageous for correcting spherical aberration at the telephoto end.

[0049] The first lens group G1 may be configured to include four or less lenses, which can suppress various aberrations while preventing the first lens group G1 from becoming large.

[0050] The first lens group G1 preferably includes an L1nm lens, which is a negative meniscus lens with a convex surface facing the object side, an L1n lens, which is a negative lens with a concave surface facing the image side, and an L1p lens, which is a positive lens. The L1n lens is preferably disposed adjacent to the image side of the L1nm lens, and the L1p lens is disposed closer to the image side than the L1n lens. The L1p lens may be disposed adjacent to the image side of the L1n lens, and may not be disposed adjacent to the image side of the L1n lens as long as it is located closer to the image side than the L1n lens. When the first lens group G1 includes the L1nm lens, the L1n lens, and the L1p lens of the above-mentioned preferred configuration, it is advantageous to correct distortion and curvature of field, especially at the wide-angle end. In the example of FIG. 1, the lens L12 corresponds to the L1nm lens, the lens L13 corresponds to the L1n lens, and the lens L14 corresponds to the L1p lens.

[0051] The object-side surface of the L1n lens may be configured to be an aspheric surface whose refractive power at the position of the maximum effective diameter is shifted in the positive direction compared to its refractive power in the paraxial region, which is advantageous for correcting distortion aberration.

[0052] Here, the "position of the maximum effective diameter" in this specification will be described with reference to FIG. 3. FIG. 3 is an explanatory diagram. In FIG. 3, the left side is the object side, and the right side is the image side. FIG. 3 shows an on-axis light beam Xa and an off-axis light beam Xb passing through a lens Lx. In the example of FIG. 3, a light beam Xb1, which is an upper light beam of the off-axis light beam Xb, is a light beam that passes through the outermost side. The "outside" here means the radial outside with the optical axis Z as the center, that is, the side away from the optical axis Z. In this specification, the position of the intersection between this outermost light beam and the lens surface is the position Px of the maximum effective diameter. Also, twice the distance from the position Px of the maximum effective diameter to the optical axis Z is the effective diameter ED of the object-side surface of the lens Lx. In the example of FIG. 3, the upper light beam of the off-axis light beam Xb is a light beam that passes through the outermost side, but which light beam passes through the outermost side varies depending on the optical system.

[0053] In addition, in this specification, "the refractive power at the position of the maximum effective diameter is shifted in the positive direction compared to the refractive power in the paraxial region" has the following meaning based on the sign of the refractive power. When the surface has positive refractive power in both the paraxial region and the position of the maximum effective diameter, it means that the surface has a stronger positive refractive power at the position of the maximum effective diameter compared to the paraxial region. When the surface has negative refractive power in both the paraxial region and the position of the maximum effective diameter, it means that the surface has a weaker negative refractive power at the position of the maximum effective diameter compared to the paraxial region. When the surface has refractive powers of opposite signs in the paraxial region and the position of the maximum effective diameter, it means that the surface has negative refractive power in the paraxial region and positive refractive power at the position of the maximum effective diameter.

[0054] The object-side surface of the L1n lens may be configured to be concave in the paraxial region and convex in the peripheral portion including the position of the maximum effective diameter, which is advantageous for correcting curvature of field.

[0055] The L1nm lens or the L1n lens may be configured as a composite aspherical lens. In this case, it is advantageous for suppressing various aberrations. A composite aspherical lens has the advantages of being less expensive than a molded aspherical lens made of glass alone, and being more environmentally resistant than an aspherical lens made of resin alone.

[0056] In this specification, a compound aspherical lens refers to a lens in which a lens (e.g., a spherical lens) and an aspherical film formed on the lens are integrally configured to function as a single aspherical lens as a whole. In most compound aspherical lenses, the lens (e.g., a spherical lens) on which the film is formed is made of glass, and the film is made of resin. In this specification, a compound aspherical lens is not considered a cemented lens, but is treated as a single lens that is not cemented, that is, a single lens.

[0057] When the first lens group G1 includes the above-mentioned L1n lens, as shown in the following Examples 6 and 7, an L2nm lens, which is a negative meniscus lens with a convex surface facing the object side, may be arranged on the image side of the L1n lens. In this case, it is advantageous for correcting the curvature of field. The object side surface of the L2nm lens may be configured to be an aspheric surface in which the refractive power at the position of the maximum effective diameter is shifted in the negative direction compared to the refractive power in the paraxial region. In this case, it is more advantageous for correcting the curvature of field. The L2nm lens is preferably arranged in the first lens group G1. The L2nm lens may be arranged adjacent to the image side of the L1n lens.

[0058] In this specification, "the refractive power at the position of the maximum effective diameter is shifted in the negative direction compared to the refractive power in the paraxial region" has the following meaning based on the sign of the refractive power. When the surface has negative refractive power in both the paraxial region and the position of the maximum effective diameter, it means that the surface has a stronger negative refractive power at the position of the maximum effective diameter compared to the paraxial region. When the surface has positive refractive power in both the paraxial region and the position of the maximum effective diameter, it means that the surface has a weaker positive refractive power at the position of the maximum effective diameter compared to the paraxial region. When the surface has refractive powers of opposite signs in the paraxial region and the position of the maximum effective diameter, it means that the surface has a positive refractive power in the paraxial region and a negative refractive power at the position of the maximum effective diameter.

[0059] The variable magnification optical system of the present disclosure preferably has a focusing function. For example, one of the lens groups included in the subsequent group GR may be configured to be a focusing lens group that moves along the optical axis Z during focusing. Focusing is performed by moving the focusing lens group. In the example of FIG. 1, the focusing lens group is composed of the third lens group G3. The brackets and left and right arrows attached to the third lens group G3 in the lower diagram of FIG. 1 indicate that the third lens group G3 is a focusing lens group and the direction in which it moves when focusing from an object at infinity to a nearest object. Note that the focusing lens group functions over the entire range of magnification including the wide-angle end state, but in FIG. 1, the above arrows are only written in the lower diagram to avoid cluttering the diagram.

[0060] The focusing lens group may be configured to consist of one lens or one cemented lens, which is advantageous for increasing the focusing speed since it is easy to make the focusing lens group small and lightweight.

[0061] In addition, the variable magnification optical system of the present disclosure preferably has an image blur correction function. For example, a vibration-proof group that moves in a direction intersecting the optical axis Z during image blur correction may be arranged on the image side of the first lens group G1. Image blur correction is performed by the movement of the vibration-proof group. In the example of FIG. 1, the vibration-proof group is made up of lens L21. The parentheses and downward arrow attached to lens L21 in the lower diagram of FIG. 1 indicate that lens L21 is the vibration-proof group. Note that the vibration-proof group functions over the entire range of magnification, including the wide-angle end state, but in FIG. 1, the arrow is only written in the lower diagram to avoid complication.

[0062] The vibration-proof group may be configured to be composed of all lenses included in the second lens group G2. By using the second lens group G2, which has a relatively low light ray height, as the vibration-proof group, it is advantageous to reduce the size and weight of the vibration-proof group. When the second lens group G2 includes both a positive lens and a negative lens, it is advantageous to suppress the variation of chromatic aberration during image blur correction. The vibration-proof group may be configured to be composed of one lens closest to the object side of the second lens group G2. By using one lens as the vibration-proof group, it is more advantageous to reduce the size and weight of the vibration-proof group. By arranging the vibration-proof group closest to the object side of the second lens group G2, it is easy to secure a space for installing a vibration-proof mechanism.

[0063] The number of lenses included in the variable magnification optical system of the present disclosure may be configured to be equal to or greater than 8 and equal to or less than 12. In this case, it is advantageous for reducing the size and weight of the entire optical system.

[0064] Next, preferred and possible configurations for the conditional expressions of the variable magnification optical system of the present disclosure will be described. In the following description of the conditional expressions, in order to avoid redundant explanations, the same symbols are used for elements with the same definitions, and redundant explanations of the symbols are omitted. In addition, in the following, in order to avoid redundant explanations, the "variable magnification optical system of the present disclosure" will also be simply referred to as the "variable magnification optical system."

[0065] It is preferable that the variable magnification optical system satisfies the following conditional expression (1). Here, TLw is the sum of the distance on the optical axis from the lens surface closest to the object in the first lens group G1 to the lens surface closest to the image in the succeeding group GR when the lens is focused on an object at infinity at the wide-angle end, and the back focus in the air equivalent distance of the entire system. ft is the focal length of the entire system when the lens is focused on an object at infinity at the telephoto end. ωt is the maximum half angle of view when the lens is focused on an object at infinity at the telephoto end. tan is the tangent. TLw is the total optical length when the lens is focused on an object at infinity at the wide-angle end. As an example, FIG. 2 shows the total optical length TLw. By making sure that the corresponding value of conditional expression (1) is not equal to or less than the lower limit, it is advantageous to suppress various aberrations over the entire range of the variable magnification. By making sure that the corresponding value of conditional expression (1) is not equal to or more than the upper limit, it is advantageous to reduce the size of the entire optical system. 4.5 <TLw / (ft×tanωt)<8 (1)

[0066] In order to obtain better characteristics, the lower limit of conditional expression (1) is more preferably set to 5, more preferably 5.3, even more preferably 5.4, even more preferably 5.6, and even more preferably 5.7. In order to obtain better characteristics, the upper limit of conditional expression (1) is more preferably set to 7.5, even more preferably 7.2, even more preferably 7, even more preferably 6.9, and even more preferably 6.8. For example, it is more preferable that the variable magnification optical system satisfies the following conditional expression (1-1). 5.4 <TLw / (ft×tanωt)<7 (1-1)

[0067] It is preferable that the variable magnification optical system satisfies the following conditional expression (2). Here, the back focus in the air-equivalent distance of the entire system when focused on an object at infinity at the wide-angle end is Bfw. The back focus in the air-equivalent distance is the air-equivalent distance on the optical axis from the lens surface closest to the image side of the variable magnification optical system to the image surface Sim. As an example, FIG. 2 shows the above-mentioned back focus Bfw. By making the corresponding value of conditional expression (2) equal to or greater than the lower limit, the above-mentioned back focus Bfw does not become too short, which makes it easy to attach a mount exchange mechanism. By making the corresponding value of conditional expression (2) equal to or greater than the upper limit, the above-mentioned back focus Bfw does not become too long, which makes it easy to make the device compact. 0.4 <Bfw / (ft×tanωt)<3 (2)

[0068] In order to obtain better characteristics, the lower limit of conditional expression (2) is more preferably 0.45, even more preferably 0.5, even more preferably 0.55, and even more preferably 0.6. In order to obtain better characteristics, the upper limit of conditional expression (2) is more preferably 2.5, even more preferably 2.2, even more preferably 2, and even more preferably 1.8. For example, it is more preferable that the variable magnification optical system satisfies the following conditional expression (2-1). 0.55 <Bfw / (ft×tanωt)<2 (2-1)

[0069] It is preferable that the variable magnification optical system satisfies the following conditional expression (3). Here, fw is the focal length of the entire system when focused on an object at infinity at the wide-angle end. By ensuring that the corresponding value of conditional expression (3) is not equal to or less than the lower limit, it is advantageous for suppressing various aberrations over the entire range of variable magnification. By ensuring that the corresponding value of conditional expression (3) is not equal to or greater than the upper limit, it is advantageous for reducing the size of the entire optical system, or for obtaining a sufficient variable magnification ratio as a variable magnification optical system. 0.9<(fw×TLw) / ft 2 <3.2 (3)

[0070] In order to obtain better characteristics, the lower limit of conditional formula (3) is more preferably 1, more preferably 1.1, even more preferably 1.2, and even more preferably 1.25. In order to obtain better characteristics, the upper limit of conditional formula (3) is more preferably 3, more preferably 2.8, even more preferably 2.6, and even more preferably 2.45.

[0071] It is preferable that the variable magnification optical system satisfies the following conditional formula (4). Here, the refractive index for the d-line and the Abbe number based on the d-line of any of the lenses included in the first lens group G1 are NG1L and νG1L, respectively. Note that NG1L and νG1L in conditional formula (4) are values ​​relating to the same lens. By making the corresponding value of conditional formula (4) not equal to or less than the lower limit, it is possible to select a material other than a material with a low refractive index and a low Abbe number, which makes it easier to correct the chromatic aberration of magnification at the wide-angle end. By making the corresponding value of conditional formula (4) not equal to or more than the upper limit, it is possible to select a material other than a material with a high refractive index and a high Abbe number, which makes it easier to select a material with a low specific gravity, which makes it easier to reduce the weight. 1.6 <NG1L+0.01×νG1L<2.3 (4)

[0072] In order to obtain better characteristics, the lower limit of conditional expression (4) is more preferably 1.65, more preferably 1.7, more preferably 1.72, more preferably 1.74, more preferably 1.76, more preferably 1.78, more preferably 1.8, and more preferably 1.82. In order to obtain better characteristics, the upper limit of conditional expression (4) is more preferably 2.2, more preferably 2.16, more preferably 2.15, more preferably 2.14, more preferably 2.13, more preferably 2.12, more preferably 2.11, and more preferably 1.91. For example, it is more preferable that the variable magnification optical system satisfies the following conditional expression (4-1). 1.82 <NG1L+0.01×νG1L<1.91 (4-1)

[0073] It is preferable that the variable magnification optical system satisfies the following conditional expression (5). Here, the sum of the thicknesses on the optical axis of all the lens groups is Dsum. In other words, Dsum is the sum of the thicknesses on the optical axis of each lens group for all the lens groups in the entire system. In this specification, the "thickness on the optical axis of a lens group" refers to the distance on the optical axis from the surface of the lens group closest to the object side to the surface of the lens group closest to the image side. By making the corresponding value of conditional expression (5) not equal to or less than the lower limit, the thickness of each lens in the variable magnification optical system does not become too small, which is advantageous for ensuring good optical performance. By making the corresponding value of conditional expression (5) not equal to or more than the upper limit, it is advantageous for suppressing an increase in the weight of the entire variable magnification optical system. 0.1 <Dsum / (TLw-Bfw)<0.8 (5)

[0074] In order to obtain better characteristics, the lower limit of conditional formula (5) is more preferably 0.2, more preferably 0.25, more preferably 0.28, more preferably 0.3, and more preferably 0.32. In order to obtain better characteristics, the upper limit of conditional formula (5) is more preferably 0.75, more preferably 0.7, more preferably 0.65, more preferably 0.6, and more preferably 0.55.

[0075] It is preferable that the variable magnification optical system satisfies the following conditional expression (6). Here, the thickness on the optical axis of the first lens group G1 is dG1. The focal length of the first lens group G1 is f1. As an example, the above thickness dG1 is shown in FIG. 2. By ensuring that the corresponding value of conditional expression (6) is not equal to or less than the lower limit, it is advantageous for suppressing various aberrations over the entire range of variable magnification. By ensuring that the corresponding value of conditional expression (6) is not equal to or more than the upper limit, it is advantageous for reducing the weight of the first lens group G1. 0.4 <dG1 / |f1|<2 (6)

[0076] In order to obtain better characteristics, the lower limit of conditional expression (6) is more preferably 0.5, more preferably 0.55, more preferably 0.65, more preferably 0.7, more preferably 0.75, and more preferably 0.8. In order to obtain better characteristics, the upper limit of conditional expression (6) is more preferably 1.8, more preferably 1.65, more preferably 1.55, more preferably 1.45, more preferably 1.35, and more preferably 1.31. For example, it is more preferable for the variable magnification optical system to satisfy the following conditional expression (6-1), and it is even more preferable for the variable magnification optical system to satisfy the following conditional expression (6-2). 0.55 <dG1 / |f1|<1.65 (6-1) 0.75 <dG1 / |f1|<1.35 (6-2)

[0077] In a configuration in which the first lens group G1 includes the above L1nm lens, the above L1n lens, and the above L1p lens, the L1n lens is disposed adjacent to the image side of the L1nm lens, and the L1p lens is disposed closer to the image side than the L1n lens, it is preferable that the variable magnification optical system includes a negative lens that satisfies the following conditional expression (7). In that case, it is preferable that the negative lens that satisfies this conditional expression (7) is the L1n lens, or a negative lens disposed adjacent to the image side of the L1n lens. Here, the refractive index for the d-line and the Abbe number based on the d-line of the negative lens disposed between the L1nm lens and the L1p lens are NG1n and νG1n, respectively. By making the corresponding value of conditional expression (7) not equal to or less than the lower limit, a material other than a material with a low refractive index and a low Abbe number can be selected, which makes it easier to correct the chromatic aberration of magnification at the wide-angle end. By ensuring that the corresponding value of conditional expression (7) is not equal to or greater than the upper limit, it is possible to select a material other than a material with a high refractive index and a high Abbe number. This makes it possible to select a material with a low specific gravity, facilitating weight reduction. 1.7 <NG1n+0.01×νG1n<2.16 (7)

[0078] In order to obtain better characteristics, the lower limit of conditional expression (7) is more preferably 1.72, even more preferably 1.74, even more preferably 1.76, even more preferably 1.78, and even more preferably 1.8. In order to obtain better characteristics, the upper limit of conditional expression (7) is more preferably 2.15, even more preferably 2.14, even more preferably 2.13, even more preferably 2.12, and even more preferably 2.11. For example, it is more preferable that a negative lens satisfying conditional expression (7) also satisfies the following conditional expression (7-1). 1.74 <NG1n+0.01×νG1n<2.14 (7-1)

[0079] In a configuration in which the first lens group G1 includes the above L1nm lens, the above L1n lens, and the above L1p lens, the L1n lens is disposed adjacent to the image side of the L1nm lens, and the L1p lens is disposed on the image side of the L1n lens, it is preferable that the variable magnification optical system satisfies the following conditional expression (8). Here, the distance on the optical axis between the L1nm lens and the L1n lens is dm. As an example, the above distance dm is shown in FIG. 2. By making the corresponding value of the conditional expression (8) not equal to or less than the lower limit, it is possible to suppress the intensity of stray light that is reflected by the object side surface of the L1n lens and then reflected by the image side surface of the L1nm lens to be condensed on the image surface Sim. By making the corresponding value of the conditional expression (8) not equal to or more than the upper limit, it is possible to suppress the increase in the diameter of the L1nm lens. 0.01 <dm / dG1<0.9 (8)

[0080] In order to obtain better characteristics, the lower limit of conditional formula (8) is more preferably 0.1, more preferably 0.15, more preferably 0.17, more preferably 0.19, and even more preferably 0.2. In order to obtain better characteristics, the upper limit of conditional formula (8) is more preferably 0.8, more preferably 0.7, more preferably 0.65, more preferably 0.6, and even more preferably 0.57.

[0081] It is preferable that the variable magnification optical system satisfies the following conditional expression (9). Here, the focal length of the second lens group G2 is f2. By making the corresponding value of the conditional expression (9) not equal to or less than the lower limit, the refractive power of the first lens group G1 is not too weak and the refractive power of the second lens group G2 is not too strong, which is advantageous for correcting spherical aberration on the telephoto side. By making the corresponding value of the conditional expression (9) not equal to or more than the upper limit, the refractive power of the first lens group G1 is not too strong and the refractive power of the second lens group G2 is not too weak, which is advantageous for correcting spherical aberration on the wide-angle side. In addition, by making the corresponding value of the conditional expression (9) not equal to or more than the upper limit, it is easy to obtain a high variable magnification ratio without increasing the amount of movement of the second lens group G2 having a variable magnification function, which is advantageous for reducing the total optical length. 0.3 <f2 / |f1|<5 (9)

[0082] In order to obtain better characteristics, the lower limit of conditional expression (9) is more preferably set to 0.65, even more preferably to 0.7, even more preferably to 0.75, and even more preferably to 0.8. In order to obtain better characteristics, the upper limit of conditional expression (9) is more preferably set to 3, even more preferably to 2.8, even more preferably to 2.6, and even more preferably to 2.5. For example, it is more preferable that the variable magnification optical system satisfies the following conditional expression (9-1). 0.65 <f2 / |f1|<3 (9-1)

[0083] It is preferable that the variable magnification optical system satisfies the following conditional expression (10). By making sure that the corresponding value of conditional expression (10) is not below the lower limit, the refractive power of the first lens group G1 does not become too weak, and the amount of movement of the first lens group G1 during magnification variation can be suppressed. By making sure that the corresponding value of conditional expression (10) is not above the upper limit, the refractive power of the first lens group G1 does not become too strong, which is advantageous for suppressing aberration fluctuations during magnification variation. 0.45 <fw / |f1|<2 (10)

[0084] In order to obtain better characteristics, the lower limit of conditional formula (10) should more preferably be 0.52, more preferably 0.58, even more preferably 0.62, and even more preferably 0.65.In order to obtain better characteristics, the upper limit of conditional formula (10) should more preferably be 1.7, even more preferably 1.5, even more preferably 1.4, and even more preferably 1.3.

[0085] In a configuration in which the first lens group G1 includes the above-mentioned L1nm lens, it is preferable that the variable magnification optical system satisfies the following conditional expression (11). Here, the paraxial radius of curvature of the object-side surface of the L1nm lens is Rf. The paraxial radius of curvature of the image-side surface of the L1nm lens is Rr. Conditional expression (11) specifies the so-called shape factor of the L1nm lens. By ensuring that the corresponding value of conditional expression (11) is not equal to or less than the lower limit, it becomes easy to correct astigmatism, particularly on the telephoto side. By ensuring that the corresponding value of conditional expression (11) is not equal to or more than the upper limit, it becomes easy to properly correct spherical aberration on the telephoto side. 1<(Rf+Rr) / (Rf-Rr)<7 (11)

[0086] In order to obtain better characteristics, the lower limit of conditional formula (11) should more preferably be 1.1, even more preferably be 1.15, even more preferably be 1.2, and even more preferably be 1.25. In order to obtain better characteristics, the upper limit of conditional formula (11) should more preferably be 6, even more preferably be 5, even more preferably be 4.5, and even more preferably be 4.

[0087] In a configuration in which a vibration-reduction group that moves in a direction intersecting the optical axis Z during image blur correction is disposed closer to the image side than the first lens group G1, it is preferable that the variable magnification optical system satisfies the following conditional expression (12). Here, the focal length of the vibration-reduction group is fois. By ensuring that the corresponding value of conditional expression (12) is not equal to or less than the lower limit, the amount of movement of the vibration-reduction group during image blur correction can be suppressed, which is advantageous for reducing the size of the entire variable magnification optical system and the vibration-reduction unit. By ensuring that the corresponding value of conditional expression (12) is not equal to or more than the upper limit, the refractive power of the vibration-reduction group does not become too strong, which is advantageous for suppressing aberration fluctuations during image blur correction. 0.3 <ft / |fois|<4 (12)

[0088] In order to obtain better characteristics, the lower limit of conditional formula (12) should preferably be 0.5, more preferably 0.6, even more preferably 0.65, and even more preferably 0.7. In order to obtain better characteristics, the upper limit of conditional formula (12) should preferably be 3.5, even more preferably 3, even more preferably 2.5, and even more preferably 2.

[0089] In a configuration in which the variable magnification optical system includes a focusing lens group, it is preferable that the variable magnification optical system satisfies the following conditional expression (13). Here, the focal length of the focusing lens group is taken as ffoc. By ensuring that the corresponding value of conditional expression (13) is not below the lower limit, the refractive power of the focusing lens group does not become too weak, and the amount of movement of the focusing lens group during focusing can be suppressed. By ensuring that the corresponding value of conditional expression (13) is not above the upper limit, the refractive power of the focusing lens group does not become too strong, which is advantageous for suppressing aberration fluctuations during focusing. 0.3 <ft / |ffoc|<3 (13)

[0090] In order to obtain better characteristics, the lower limit of conditional formula (13) should more preferably be 0.4, even more preferably be 0.5, even more preferably be 0.55, and even more preferably be 0.6.In order to obtain better characteristics, the upper limit of conditional formula (13) should more preferably be 2.5, even more preferably be 2.2, even more preferably be 1.9, and even more preferably be 1.8.

[0091] In a configuration in which a variable magnification optical system includes a focusing lens group and an Lr lens arranged closer to the image side than the focusing lens group, it is preferable that the variable magnification optical system satisfies the following conditional expression (14). Here, the refractive index for the d-line and the Abbe number based on the d-line of the Lr lens are Nr and νr, respectively. By ensuring that the corresponding value of conditional expression (14) is not equal to or less than the lower limit, it is possible to select a material other than a material with a low refractive index and a low Abbe number, making it easier to correct chromatic aberration of magnification at the wide-angle end. By ensuring that the corresponding value of conditional expression (14) is not equal to or more than the upper limit, it is possible to select a material other than a material with a high refractive index and a high Abbe number, making it easier to select a material with a low specific gravity, making it easier to reduce the weight. 1.7 <Nr+0.01×νr<2.16 (14)

[0092] In order to obtain better characteristics, the lower limit of conditional formula (14) should more preferably be 1.72, more preferably 1.74, more preferably 1.76, more preferably 1.78, and even more preferably 1.8. In order to obtain better characteristics, the upper limit of conditional formula (14) should more preferably be 2.15, more preferably 2.14, more preferably 2.13, more preferably 2.12, and even more preferably 2.11.

[0093] It is preferable that the variable magnification optical system satisfies the following conditional expression (15). By making sure that the corresponding value of conditional expression (15) is not below the lower limit, the refractive power of the first lens group G1 does not become too weak, and the amount of movement of the first lens group G1 during magnification variation can be suppressed. By making sure that the corresponding value of conditional expression (15) is not above the upper limit, the refractive power of the first lens group G1 does not become too strong, which is advantageous for suppressing aberration fluctuations during magnification variation. 1 <ft / |f1|<3.5 (15)

[0094] In order to obtain better characteristics, the lower limit of condition (15) should more preferably be 1.1, even more preferably be 1.2, and even more preferably be 1.3.In order to obtain better characteristics, the upper limit of condition (15) should more preferably be 3, even more preferably be 2.8, and even more preferably be 2.5.

[0095] It is preferable that the variable magnification optical system satisfies the following conditional expression (16). By making sure that the corresponding value of conditional expression (16) is not equal to or less than the lower limit, the refractive power of the first lens group G1 does not become too strong, which is advantageous for suppressing aberration fluctuations during magnification. By making sure that the corresponding value of conditional expression (16) is not equal to or greater than the upper limit, the refractive power of the first lens group G1 does not become too weak, which can suppress the amount of movement of the first lens group G1 during magnification, and is also advantageous for suppressing distortion at the wide-angle end. 0.4<|f1| / (fw×ft) 1 / 2 <2.2 (16)

[0096] In order to obtain better characteristics, it is more preferable that the lower limit of conditional formula (16) be set to 0.5, even more preferably to 0.55, and even more preferably to 0.6.In order to obtain better characteristics, it is more preferable that the upper limit of conditional formula (16) be set to 1.8, even more preferably to 1.5, and even more preferably to 1.4.

[0097] It is preferable that the variable magnification optical system satisfies the following conditional expression (17). By making sure that the corresponding value of conditional expression (17) is not equal to or less than the lower limit, the refractive power of the second lens group G2 does not become too strong, making it possible to reduce the curvature of field that occurs in the second lens group G2 and also advantageous for correcting aberrations during magnification. By making sure that the corresponding value of conditional expression (17) is not equal to or greater than the upper limit, the refractive power of the second lens group G2 does not become too weak, making it possible to suppress the amount of movement of the second lens group G2 during magnification, making it advantageous for shortening the overall optical length. 0.4 <f2 / (fw×ft) 1 / 2 <3.5 (17)

[0098] In order to obtain better characteristics, the lower limit of conditional formula (17) should more preferably be 0.6, even more preferably be 0.7, and even more preferably be 0.8.In order to obtain better characteristics, the upper limit of conditional formula (17) should more preferably be 2.7, even more preferably be 2.2, and even more preferably be 1.8.

[0099] It is preferable that the variable magnification optical system satisfies the following conditional expression (18). By making sure that the corresponding value of conditional expression (18) is not equal to or smaller than the lower limit, it is advantageous for ensuring the strength of the first lens group G1. By making sure that the corresponding value of conditional expression (18) is not equal to or larger than the upper limit, it is advantageous for reducing the weight of the first lens group G1. 0.15 <dG1 / (TLw-Bfw)<0.5 (18)

[0100] In order to obtain better characteristics, the lower limit of condition (18) should more preferably be 0.17, even more preferably be 0.18, and even more preferably be 0.19.In order to obtain better characteristics, the upper limit of condition (18) should more preferably be 0.4, even more preferably be 0.35, and even more preferably be 0.32.

[0101] It is preferable that the variable magnification optical system satisfies the following conditional expression (19). Here, FNot is the maximum F-number when focused on an object at infinity at the telephoto end. By ensuring that the corresponding value of conditional expression (19) is not equal to or less than the lower limit, it is advantageous for improving performance. By ensuring that the corresponding value of conditional expression (19) is not equal to or greater than the upper limit, the refractive power of the first lens group G1 does not become too weak, so that the amount of movement of the first lens group G1 during magnification can be suppressed, and this is also advantageous for suppressing distortion at the wide-angle end. 1.5<|f1| / (ft / FNot)<8 (19)

[0102] In order to obtain better characteristics, it is more preferable that the lower limit of conditional formula (19) be set to 2, even more preferably to 2.3, and even more preferably to 2.5. In order to obtain better characteristics, it is more preferable that the upper limit of conditional formula (19) be set to 7, even more preferably to 6.5, and even more preferably to 6.

[0103] It is preferable that the variable magnification optical system satisfies the following conditional expression (20). By making sure that the corresponding value of conditional expression (20) is not below the lower limit, the refractive power of the focusing lens group does not become too weak, and the amount of movement of the focusing lens group during focusing can be suppressed. By making sure that the corresponding value of conditional expression (20) is not above the upper limit, the refractive power of the focusing lens group does not become too strong, which is advantageous for suppressing aberration fluctuations during focusing. 0.1 <fw / |ffoc|<2 (20)

[0104] In order to obtain better characteristics, the lower limit of conditional formula (20) should more preferably be 0.16, even more preferably be 0.18, and even more preferably be 0.2. In order to obtain better characteristics, the upper limit of conditional formula (20) should more preferably be 1.5, even more preferably be 1.2, and even more preferably be 1.

[0105] In a configuration in which the first lens group G1 includes the above-mentioned L1nm lens, it is preferable that the variable magnification optical system satisfies the following conditional expression (21). Here, the refractive index of the L1nm lens for the d-line is N1nm. By ensuring that the corresponding value of conditional expression (21) is not below the lower limit, it becomes easy for the L1nm lens to have sufficient negative refractive power, which is advantageous for satisfactory correction of distortion. By ensuring that the corresponding value of conditional expression (21) is not above the upper limit, it becomes easy to construct the L1nm lens without using a material with large dispersion, which is advantageous for satisfactory correction of lateral chromatic aberration. 1.42 <N1nm<1.8 (21)

[0106] In order to obtain better characteristics, the lower limit of conditional formula (21) should more preferably be 1.43, more preferably 1.44, more preferably 1.45, more preferably 1.46, more preferably 1.47, and more preferably 1.48. In order to obtain better characteristics, the upper limit of conditional formula (21) should more preferably be 1.75, more preferably 1.7, more preferably 1.65, more preferably 1.6, more preferably 1.55, and more preferably 1.52.

[0107] In a configuration in which the first lens group G1 includes the above L1nm lens, the above L1n lens, and the above L1p lens, the L1n lens is disposed adjacent to the image side of the L1nm lens, and the L1p lens is disposed closer to the image side than the L1n lens, it is preferable that the variable magnification optical system includes a negative lens that satisfies the following conditional expression (22). In this case, it is preferable that the negative lens that satisfies this conditional expression (22) is the L1n lens or a negative lens disposed adjacent to the image side of the L1n lens. Here, the refractive index of the negative lens disposed between the L1nm lens and the L1p lens with respect to the d-line is NG1n. By making the corresponding value of conditional expression (22) not equal to or less than the lower limit, it becomes easy for the L1n lens or the negative lens disposed adjacent to the image side of the L1n lens to have sufficient negative refractive power, which is advantageous for good correction of distortion aberration. By ensuring that the corresponding value of conditional expression (22) is not equal to or greater than the upper limit, it becomes easy to construct the L1n lens or the negative lens arranged adjacent to the image side of the L1n lens without using a material with large dispersion, which is advantageous for satisfactorily correcting lateral chromatic aberration. 1.44 <NG1n<1.8 (22)

[0108] In order to obtain better characteristics, it is more preferable that the lower limit of condition (22) be 1.48, even more preferably 1.51, and even more preferably 1.53.In order to obtain better characteristics, it is more preferable that the upper limit of condition (22) be 1.7, even more preferably 1.65, and even more preferably 1.6.

[0109] In a configuration in which a variable magnification optical system includes a focusing lens group, it is preferable that the variable magnification optical system satisfies the following conditional expression (23). Here, the thickness on the optical axis of the focusing lens group is Dfoc. Note that the "thickness on the optical axis of the focusing lens group" refers to the distance on the optical axis from the surface of the focusing lens group closest to the object to the surface of the focusing lens group closest to the image. As an example, the above thickness Dfoc is shown in FIG. 2. By making the corresponding value of conditional expression (23) not equal to or less than the lower limit, the thickness of the focusing lens group does not become too small, which is advantageous for ensuring the strength of the focusing lens group. By making the corresponding value of conditional expression (23) not equal to or more than the upper limit, the thickness of the focusing lens group does not become too large, which is advantageous for increasing the focusing speed. 0.025 <Dfoc / (ft×tanωt)<0.4 (23)

[0110] In order to obtain better characteristics, the lower limit of condition (23) should more preferably be 0.027, even more preferably be 0.029, and even more preferably be 0.03.In order to obtain better characteristics, the upper limit of condition (23) should more preferably be 0.35, even more preferably be 0.3, and even more preferably be 0.25.

[0111] When a variable magnification optical system includes a focusing lens group, and the focusing lens group is configured to consist of one lens, it is preferable that the variable magnification optical system satisfies the following conditional expression (24). Here, the Abbe number based on the d-line of the lens that constitutes the focusing lens group is νfoc. By ensuring that the corresponding value of conditional expression (24) is not equal to or less than the lower limit, it is advantageous for suppressing fluctuations in chromatic aberration during focusing. By ensuring that the corresponding value of conditional expression (24) is not equal to or greater than the upper limit, it is possible to use materials that are easily available, which is advantageous for realizing a variable magnification optical system in which spherical aberration and astigmatism are suppressed. 20<νfoc<95 (24)

[0112] In order to obtain better characteristics, it is more preferable that the lower limit of conditional formula (24) be set to 25, even more preferably to 34, even more preferably to 39, even more preferably to 43, even more preferably to 47, and even more preferably to 50. In order to obtain better characteristics, it is more preferable that the upper limit of conditional formula (24) be set to 83, even more preferably to 78, even more preferably to 73, even more preferably to 68, even more preferably to 63, and even more preferably to 58.

[0113] It is preferable that the variable magnification optical system satisfies the following conditional expression (25). Here, the maximum half angle of view when focused on an object at infinity at the wide-angle end is taken as ωw. The unit of ωw is degrees. Making sure that the corresponding value of conditional expression (25) is not equal to or smaller than the lower limit is advantageous for achieving a wider angle. Making sure that the corresponding value of conditional expression (25) is not equal to or larger than the upper limit is advantageous for achieving compactness. 40<ωw<70 (25)

[0114] In order to obtain better characteristics, it is more preferable that the lower limit of conditional formula (25) be set to 44, even more preferably to 46, and even more preferably to 48. In order to obtain better characteristics, it is more preferable that the upper limit of conditional formula (25) be set to 65, even more preferably to 60, and even more preferably to 56.

[0115] It is preferable that the variable magnification optical system satisfies the following conditional expression (26). By ensuring that the corresponding value of conditional expression (26) is not equal to or less than the lower limit, it is advantageous for realizing a high variable magnification ratio. By ensuring that the corresponding value of conditional expression (26) is not equal to or greater than the upper limit, it is advantageous for suppressing aberration fluctuations during magnification. 1.5 <ft / fw<3 (26)

[0116] In order to obtain better characteristics, it is more preferable that the lower limit of condition (26) be 1.6, even more preferably 1.65, and even more preferably 1.7.In order to obtain better characteristics, it is more preferable that the upper limit of condition (26) be 2.6, even more preferably 2.3, and even more preferably 2.1.

[0117] In a configuration in which the first lens group G1 includes the above-mentioned L1n lens, it is preferable that the variable magnification optical system satisfies the following conditional expression (27). Here, the specific gravity of the L1n lens is ρL1n. By making sure that the corresponding value of conditional expression (27) is not below the lower limit, it becomes easy to use a material that is easily available. By making sure that the corresponding value of conditional expression (27) is not above the upper limit, it is advantageous for reducing the weight of the optical system. 0.75<ρL1n<3.2 (27)

[0118] In order to obtain better characteristics, the lower limit of conditional formula (27) should more preferably be 0.8, more preferably 0.82, more preferably 0.84, more preferably 0.86, more preferably 0.88, more preferably 0.9, and more preferably 0.92. In order to obtain better characteristics, the upper limit of conditional formula (27) should more preferably be 2.9, more preferably 2.6, more preferably 2.4, more preferably 2.2, more preferably 2, more preferably 1.8, and more preferably 1.6.

[0119] In a configuration in which the first lens group G1 includes the above-mentioned L1n lens, and the L1n lens is a lens made only of resin, it is preferable that the variable magnification optical system satisfies the following conditional expression (28). Here, the central thickness of the L1n lens is dL1n. The thickness of the L1n lens in the direction parallel to the optical axis Z at the position of the maximum effective diameter of the image-side surface of the L1n lens is dL1nh. As an example, FIG. 2 shows the above-mentioned central thickness dL1n and thickness dL1nh. By making the corresponding value of the conditional expression (28) not equal to or less than the lower limit, it is advantageous for correction of distortion aberration. By making the corresponding value of the conditional expression (28) not equal to or more than the upper limit, it is possible to suppress a decrease in the moldability of the L1n lens, which is advantageous for manufacturing. In addition, by making the corresponding value of the conditional expression (28) not equal to or more than the upper limit, it is possible to suppress an increase in the volume of the L1n lens itself, which is advantageous for weight reduction. 1.1 <dL1nh / dL1n<10 (28)

[0120] In order to obtain better characteristics, it is more preferable that the lower limit of conditional formula (28) be 1.2, even more preferably 1.3, even more preferably 1.35, and even more preferably 1.4. In order to obtain better characteristics, it is more preferable that the upper limit of conditional formula (28) be 5, even more preferably 4, even more preferably 3.5, and even more preferably 3.

[0121] In a configuration in which the above-mentioned L2nm lens is disposed on the image side of the L1n lens, it is preferable that the variable magnification optical system satisfies the following conditional expression (29). Here, the specific gravity of the L2nm lens is ρL2nm. By ensuring that the corresponding value of conditional expression (29) is not below the lower limit, it becomes easy to use a material that is easily available. By ensuring that the corresponding value of conditional expression (29) is not above the upper limit, it is advantageous for reducing the weight of the optical system. 0.75<ρL2nm<3 (29)

[0122] In order to obtain better characteristics, the lower limit of conditional formula (29) should more preferably be 0.8, more preferably 0.82, more preferably 0.84, more preferably 0.86, more preferably 0.88, more preferably 0.9, and more preferably 0.92. In order to obtain better characteristics, the upper limit of conditional formula (29) should more preferably be 2.8, more preferably 2.6, more preferably 2.4, more preferably 2.2, more preferably 2, more preferably 1.8, and more preferably 1.6.

[0123] In a configuration in which the above-mentioned L2nm lens is disposed on the image side of the L1n lens and the L2nm lens is a lens made only of resin, it is preferable that the variable magnification optical system satisfies the following conditional expression (30). Here, the center thickness of the L2nm lens is dL2nm. The thickness of the L2nm lens in a direction parallel to the optical axis Z at the position of the maximum effective diameter of the image-side surface of the L2nm lens is dL2nmh. By making the corresponding value of conditional expression (30) not equal to or less than the lower limit, it is advantageous for correction of distortion aberration. By making the corresponding value of conditional expression (30) not equal to or more than the upper limit, it is possible to suppress a decrease in the moldability of the L2nm lens, which is advantageous for manufacturing. In addition, by making the corresponding value of conditional expression (30) not equal to or more than the upper limit, it is possible to suppress an increase in the volume of the L2nm lens itself, which is advantageous for weight reduction. 1.1 <dL2nmh / dL2nm<10 (30)

[0124] In order to obtain better characteristics, it is more preferable that the lower limit of conditional formula (30) be 1.13, even more preferably 1.16, even more preferably 1.18, and even more preferably 1.2. In order to obtain better characteristics, it is more preferable that the upper limit of conditional formula (30) be 5, even more preferably 4, even more preferably 3, and even more preferably 2.5.

[0125] In a configuration in which the first lens group G1 includes the above-mentioned L1nm lens, it is preferable that the variable magnification optical system satisfies the following conditional expression (31). Here, the focal length of the L1nm lens is fL1nm. By making sure that the corresponding value of conditional expression (31) is not equal to or less than the lower limit, the negative refractive power of the L1nm lens does not become too weak, so that it is possible to ensure the amount of light at the periphery of the image at the wide-angle end without increasing the diameter of the L1nm lens. This is advantageous for miniaturization. By making sure that the corresponding value of conditional expression (31) is not equal to or more than the upper limit, the negative refractive power of the L1nm lens does not become too strong, so that it is advantageous for correction of field curvature and distortion at the wide-angle end. 0.05 <fw / |fL1nm|<2 (31)

[0126] In order to obtain better characteristics, the lower limit of conditional formula (31) should more preferably be 0.1, more preferably 0.15, even more preferably 0.2, and even more preferably 0.27.In order to obtain better characteristics, the upper limit of conditional formula (31) should more preferably be 1.5, even more preferably 1.1, even more preferably 0.7, and even more preferably 0.55.

[0127] In a configuration in which a variable magnification optical system includes a focusing lens group and an Lr lens arranged closer to the image side than the focusing lens group, it is preferable that the variable magnification optical system satisfies the following conditional expression (32). Here, the specific gravity of the Lr lens is ρLr. By ensuring that the corresponding value of conditional expression (32) is not below the lower limit, it becomes easy to use a material that is easily available. By ensuring that the corresponding value of conditional expression (32) is not above the upper limit, it is advantageous for reducing the weight of the optical system. 0.75<ρLr<3 (32)

[0128] In order to obtain better characteristics, the lower limit of conditional formula (32) should more preferably be 0.8, more preferably 0.82, more preferably 0.84, more preferably 0.86, more preferably 0.88, more preferably 0.9, and more preferably 0.92. In order to obtain better characteristics, the upper limit of conditional formula (32) should more preferably be 2.8, more preferably 2.6, more preferably 2.4, more preferably 2.2, more preferably 2, more preferably 1.8, and more preferably 1.6.

[0129] In a configuration in which the first lens group G1 includes the above L1nm lens, it is preferable that the variable magnification optical system satisfies the following conditional expression (33). Here, the central thickness of the L1nm lens is dL1nm. The thickness of the L1nm lens in the direction parallel to the optical axis Z at the position of the maximum effective diameter of the image-side surface of the L1nm lens is dL1nmh. As an example, FIG. 2 shows the central thickness dL1nm and the thickness dL1nmh. By making sure that the corresponding value of conditional expression (33) is not equal to or less than the lower limit, it is advantageous to suppress distortion at the wide-angle end. By making sure that the corresponding value of conditional expression (33) is not equal to or more than the upper limit, the central thickness of the L1nm lens does not become too thin, which is advantageous to ensure the strength of the L1nm lens. 2 <dL1nmh / dL1nm<12 (33)

[0130] In order to obtain better characteristics, it is more preferable that the lower limit of conditional formula (33) be set to 3, even more preferably to 4, even more preferably to 5, and even more preferably to 5.5. In order to obtain better characteristics, it is more preferable that the upper limit of conditional formula (33) be set to 10, even more preferably to 9, even more preferably to 8, and even more preferably to 7.5.

[0131] The above-mentioned preferred and possible configurations can be arbitrarily combined within a range not causing any contradiction, and it is preferable that they are appropriately and selectively adopted according to the required specifications.

[0132] As an example, a preferred embodiment of the variable magnification optical system of the present disclosure comprises, in order from the object side to the image side, a first lens group G1 having negative refractive power, a second lens group G2 having positive refractive power, and a subsequent group GR including one or more lens groups, wherein the first lens group G1 moves and all of the intervals between adjacent lens groups change during magnification, and one of the lens groups included in the subsequent group GR is a focusing lens group that moves along the optical axis Z during focusing, and satisfies the above conditional expressions (1), (2), (3), (4), and (5).

[0133] Next, examples of the variable magnification optical system of the present disclosure will be described with reference to the drawings. Note that the reference symbols given to each lens and each group in the cross-sectional views of each example are used independently for each example to avoid the explanation and the drawings becoming complicated due to the increase in the number of digits of the reference symbols. Therefore, even if common reference symbols are given in the drawings of different examples, they do not necessarily have the same configuration.

[0134] [Example 1] The configuration and movement locus of the variable magnification optical system of Example 1 are shown in FIG. 1, and the method of illustration is as described above, so some overlapping explanations will be omitted here. The variable magnification optical system of Example 1 is composed of, in order from the object side to the image side, a first lens group G1 having negative refractive power, a second lens group G2 having positive refractive power, and a third lens group G3 having positive refractive power. The rear group GR is composed of the third lens group G3. The first lens group G1 is composed of four lenses, lenses L11 to L14, in order from the object side to the image side. The second lens group G2 is composed of a lens L21, an aperture stop St, and lenses L22 to L23, in order from the object side to the image side. The third lens group G3 is composed of one lens, lens L31. The lens L12 is a composite aspheric lens.

[0135] When changing magnification from the wide-angle end to the telephoto end, all lens groups move along the optical axis Z while changing the spacing between adjacent lens groups. The focusing lens group consists of the third lens group G3. When focusing from an object at infinity to the closest object, the third lens group G3 moves toward the object, and the other lens groups are fixed with respect to the image plane Sim. The vibration reduction group consists of lens L21.

[0136] For the variable magnification optical system of Example 1, Table 1 shows basic lens data, Table 2 shows specifications and variable surface spacing, and Table 3 shows aspheric coefficients.

[0137] The table of basic lens data is written as follows. The "Sn" column shows the surface numbers when the surface closest to the object is designated as the first surface and the numbers increase by one toward the image side. The "R" column shows the radius of curvature of each surface. The "D" column shows the surface distance on the optical axis between each surface and its adjacent surface on the image side. The "Nd" column shows the refractive index for each lens with respect to the d-line. The "νd" column shows the Abbe number of each lens based on the d-line. The "θg,F" column shows the partial dispersion ratio between the g-line and F-line of each component. The "ED" column shows the effective diameter of each surface. The "NG1L+0.01×νG1L" column shows the corresponding value of conditional formula (4) for each lens. Note that the "ED" and "NG1L+0.01×νG1L" columns show values ​​only for related surfaces and lenses.

[0138] If the refractive indices of a lens for the g-line, F-line, and C-line are Ng, NF, and NC, respectively, and the partial dispersion ratio between the g-line and F-line of the lens is θg,F, then θg,F is defined by the following equation. θg,F=(Ng-NF) / (NF-NC)

[0139] The terms "d-line," "C-line," "F-line," and "g-line" used in this specification are emission lines, and the wavelength of the d-line is 587.56 nm (nanometers), the wavelength of the C-line is 656.27 nm (nanometers), the wavelength of the F-line is 486.13 nm (nanometers), and the wavelength of the g-line is 435.84 nm (nanometers).

[0140] In the basic lens data table, the sign of the radius of curvature of a surface with a convex shape facing the object side is positive, and the sign of the radius of curvature of a surface with a convex shape facing the image side is negative. In Table 1, the surface number and the term (St) are entered in the column for the surface number corresponding to the aperture stop St. The value in the bottom row of the D column in the table is the distance between the surface closest to the image side in the table and the image plane Sim. The symbol DD[ ] is used for the variable surface distance when varying magnification, and the surface number of this distance on the object side is entered in the [ ] in the surface distance column.

[0141] Table 2 shows the zoom ratio Zr, focal length f, back focus Bf, maximum F-number FNo., maximum full angle of view 2ω, and variable surface spacing based on the d-line. When the variable magnification optical system is a zoom lens, the zoom ratio is synonymous with the zoom magnification. [°] in the 2ω column indicates that the unit is degrees. In Table 2, the columns labeled "Wide," "Middle," and "Tele" show the values ​​for the wide-angle end state, the intermediate focal length state, and the telephoto end state, respectively.

[0142] In the basic lens data, the surface numbers of aspheric surfaces are marked with an *, and the value of the paraxial radius of curvature is given in the column for the radius of curvature of the aspheric surface. In Table 3, the Sn row shows the surface numbers of the aspheric surfaces, and the KA and Am rows show the numerical values ​​of the aspheric coefficients for each aspheric surface. Note that m in Am is an integer of 3 or more, and differs depending on the surface. For example, for the fifth surface in Example 1, m = 4, 6, 8, and 10. The numerical values ​​of the aspheric coefficients in Table 3, "E±n" (n: integer), are expressed as "×10 ±n " KA and Am are aspheric coefficients in the aspheric equation expressed below. Zd = C × h 2 / {1+(1-KA×C 2 ×h 2 ) 1 / 2}+ΣAm×h m however, Zd: Aspheric depth (the length of the perpendicular line drawn from a point on the aspheric surface at height h to a plane perpendicular to the optical axis Z where the apex of the aspheric surface is in contact) h: Height (distance from optical axis Z to lens surface) C: Reciprocal of paraxial curvature radius KA, Am: Aspheric coefficients In the aspheric surface formula, Σ means the summation with respect to m.

[0143] In the data in each table, the angle unit is degrees and the length unit is millimeters, but since the optical system can be used with proportional enlargement or reduction, other appropriate units can be used. Also, in each table shown below, values ​​are rounded to a predetermined number of decimal places.

[0144] [Table 1]

[0145] [Table 2]

[0146] [Table 3]

[0147] FIG. 4 shows each aberration diagram of the variable magnification optical system of Example 1 in a state where the optical system is focused on an object at infinity. In FIG. 4, from the left, spherical aberration, astigmatism, distortion, and lateral chromatic aberration are shown. In FIG. 4, the upper row labeled "Wide" shows the aberration in the wide-angle end state, the middle row labeled "Middle" shows the aberration in the intermediate focal length state, and the lower row labeled "Tele" shows the aberration in the telephoto end state. In the spherical aberration diagram, the aberrations at the d-line, C-line, and F-line are shown by solid lines, long dashed lines, and short dashed lines, respectively. In the astigmatism diagram, the aberration at the d-line in the sagittal direction is shown by solid lines, and the aberration at the d-line in the tangential direction is shown by short dashed lines. In the distortion diagram, the aberration at the d-line is shown by solid lines. In the lateral chromatic aberration diagram, the aberrations at the C-line and F-line are shown by long dashed lines and short dashed lines, respectively. In the spherical aberration diagram, the maximum F-number is shown after FNo. =. In the other aberration diagrams, the maximum half angle of view is shown after ω =.

[0148] The symbols, meanings, description methods, and illustration methods of each piece of data related to the above-mentioned Example 1 are basically the same in the following Examples unless otherwise specified, so duplicated explanations will be omitted below.

[0149] [Example 2] The configuration and movement locus of the variable magnification optical system of Example 2 are shown in FIG. 5. The variable magnification optical system of Example 2 is composed of, in order from the object side to the image side, a first lens group G1 having negative refractive power, a second lens group G2 having positive refractive power, and a third lens group G3 having positive refractive power. The rear group GR is composed of the third lens group G3. The first lens group G1 is composed of three lenses, lenses L11 to L13, in order from the object side to the image side. The second lens group G2 is composed of a lens L21, an aperture stop St, and lenses L22 to L24, in order from the object side to the image side. The third lens group G3 is composed of one lens, lens L31. The lens L11 is a composite aspheric lens.

[0150] When changing magnification from the wide-angle end to the telephoto end, all lens groups move along the optical axis Z while changing the spacing between adjacent lens groups. The focusing lens group consists of the third lens group G3. When focusing from an object at infinity to the closest object, the third lens group G3 moves toward the object, and the other lens groups are fixed with respect to the image plane Sim. The vibration reduction group consists of lens L21.

[0151] For the variable magnification optical system of Example 2, basic lens data is shown in Table 4, specifications and variable surface spacing in Table 5, aspheric coefficients in Table 6, and each aberration diagram in FIG.

[0152] [Table 4]

[0153] [Table 5]

[0154] [Table 6]

[0155] [Example 3] The configuration and movement locus of the variable magnification optical system of Example 3 are shown in FIG. 7. The variable magnification optical system of Example 3 is composed of, in order from the object side to the image side, a first lens group G1 having negative refractive power, a second lens group G2 having positive refractive power, and a third lens group G3 having negative refractive power. The rear group GR is composed of the third lens group G3. The first lens group G1 is composed of three lenses, lenses L11 to L13, in order from the object side to the image side. The second lens group G2 is composed of, in order from the object side to the image side, lens L21, an aperture stop St, and lenses L22 to L25. The third lens group G3 is composed of one lens, lens L31.

[0156] When changing magnification from the wide-angle end to the telephoto end, all lens groups move along the optical axis Z while changing the spacing between adjacent lens groups. The focusing lens group consists of the third lens group G3. When focusing from an object at infinity to the closest object, the third lens group G3 moves toward the image side, and the other lens groups are fixed with respect to the image plane Sim. The vibration reduction group consists of lens L21.

[0157] For the variable magnification optical system of Example 3, basic lens data is shown in Table 7, specifications and variable surface spacing in Table 8, aspheric coefficients in Table 9, and various aberration diagrams in FIG.

[0158] [Table 7]

[0159] [Table 8]

[0160] [Table 9]

[0161] [Example 4] The configuration and movement locus of the variable magnification optical system of Example 4 are shown in FIG. 9. The variable magnification optical system of Example 4 is composed of, in order from the object side to the image side, a first lens group G1 having negative refractive power, a second lens group G2 having positive refractive power, and a third lens group G3 having negative refractive power. The rear group GR is composed of the third lens group G3. The first lens group G1 is composed of three lenses, lenses L11 to L13, in order from the object side to the image side. The second lens group G2 is composed of, in order from the object side to the image side, lens L21, an aperture stop St, and lenses L22 to L26. The third lens group G3 is composed of one lens, lens L31.

[0162] When changing magnification from the wide-angle end to the telephoto end, all lens groups move along the optical axis Z while changing the spacing between adjacent lens groups. The focusing lens group consists of the third lens group G3. When focusing from an object at infinity to the closest object, the third lens group G3 moves toward the image side, and the other lens groups are fixed with respect to the image plane Sim. The vibration reduction group consists of lens L21.

[0163] Concerning the variable magnification optical system of Example 4, basic lens data is shown in Table 10, specifications and variable surface spacing in Table 11, aspheric coefficients in Table 12, and each aberration diagram in FIG.

[0164] [Table 10]

[0165] [Table 11]

[0166] [Table 12]

[0167] [Example 5] The configuration and movement locus of the variable magnification optical system of Example 5 are shown in FIG. 11. The variable magnification optical system of Example 5 is composed of, in order from the object side to the image 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, and a fourth lens group G4 having negative refractive power. The rear group GR is composed of two lens groups, the third lens group G3 and the fourth lens group G4. The first lens group G1 is composed of three lenses, lenses L11 to L13, in order from the object side to the image side. The second lens group G2 is composed of three lenses, lenses L21 to L23, and an aperture stop St, in order from the object side to the image side. The third lens group G3 is composed of one lens, lens L31. The fourth lens group G4 is composed of one lens, lens L41.

[0168] When changing magnification from the wide-angle end to the telephoto end, all lens groups move along the optical axis Z while changing the spacing between adjacent lens groups. The focusing lens group consists of the third lens group G3. When focusing from an object at infinity to the closest object, the third lens group G3 moves toward the object, and the other lens groups are fixed with respect to the image plane Sim. The vibration reduction group consists of three lenses, lenses L21 to L23.

[0169] Concerning the variable magnification optical system of Example 5, basic lens data is shown in Table 13, specifications and variable surface spacing in Table 14, aspheric coefficients in Table 15, and each aberration diagram is shown in FIG.

[0170] [Table 13]

[0171] [Table 14]

[0172] [Table 15]

[0173] [Example 6] The configuration and movement locus of the variable magnification optical system of Example 6 are shown in FIG. 13. The variable magnification optical system of Example 6 is composed of, in order from the object side to the image 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, and a fourth lens group G4 having negative refractive power. The rear group GR is composed of two lens groups, the third lens group G3 and the fourth lens group G4. The first lens group G1 is composed of four lenses, lenses L11 to L14, in order from the object side to the image side. The second lens group G2 is composed of three lenses, lenses L21 to L23, in order from the object side to the image side, and an aperture stop St. The third lens group G3 is composed of one lens, lens L31. The fourth lens group G4 is composed of one lens, lens L41. The lens L12 is a composite aspheric lens.

[0174] When changing the magnification from the wide-angle end to the telephoto end, the fourth lens group G4 is fixed with respect to the image surface Sim, and the other lens groups move along the optical axis Z while changing the interval between the adjacent lens groups. The focusing lens group is made up of the third lens group G3. When focusing from an object at infinity to a nearest object, the third lens group G3 moves toward the object side, and the other lens groups are fixed with respect to the image surface Sim. The vibration reduction group is made up of three lenses, lenses L21 to L23. In FIG. 13, the lens groups fixed with respect to the image surface Sim during the magnification change are shown with a dotted line in the vertical direction instead of a solid arrow of the movement locus. This method of illustrating the lens groups fixed with respect to the image surface Sim during the magnification change is the same in the following embodiments.

[0175] Concerning the variable magnification optical system of Example 6, basic lens data is shown in Table 16, specifications and variable surface spacing in Table 17, aspheric coefficients in Table 18, and each aberration diagram is shown in FIG.

[0176] [Table 16]

[0177] [Table 17]

[0178] [Table 18]

[0179] [Example 7] The configuration and movement locus of the variable magnification optical system of Example 7 are shown in FIG. 15. The variable magnification optical system of Example 7 is composed of, in order from the object side to the image 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, and a fourth lens group G4 having negative refractive power. The rear group GR is composed of two lens groups, the third lens group G3 and the fourth lens group G4. The first lens group G1 is composed of four lenses, lenses L11 to L14, in order from the object side to the image side. The second lens group G2 is composed of three lenses, lenses L21 to L23, in order from the object side to the image side, and an aperture stop St. The third lens group G3 is composed of two lenses, lenses L31 to L32, in order from the object side to the image side. The fourth lens group G4 is composed of one lens, lens L41.

[0180] When changing magnification from the wide-angle end to the telephoto end, all lens groups move along the optical axis Z while changing the spacing between adjacent lens groups. The focusing lens group consists of the third lens group G3. When focusing from an object at infinity to the closest object, the third lens group G3 moves toward the object, and the other lens groups are fixed with respect to the image plane Sim. The vibration reduction group consists of three lenses, lenses L21 to L23.

[0181] Concerning the variable magnification optical system of Example 7, basic lens data is shown in Table 19, specifications and variable surface spacing in Table 20, aspheric coefficients in Table 21, and each aberration diagram is shown in FIG.

[0182] [Table 19]

[0183] [Table 20]

[0184] [Table 21]

[0185] [Example 8] The configuration and movement locus of the variable magnification optical system of Example 8 are shown in FIG. 17. The variable magnification optical system of Example 8 is composed of, in order from the object side to the image 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, and a fourth lens group G4 having negative refractive power. The rear group GR is composed of two lens groups, the third lens group G3 and the fourth lens group G4. The first lens group G1 is composed of four lenses, lenses L11 to L14, in order from the object side to the image side. The second lens group G2 is composed of three lenses, lenses L21 to L23, and an aperture stop St, in order from the object side to the image side. The third lens group G3 is composed of one lens, lens L31. The fourth lens group G4 is composed of one lens, lens L41.

[0186] When varying magnification from the wide-angle end to the telephoto end, the fourth lens group G4 is fixed with respect to the image plane Sim, and the other lens groups move along the optical axis Z while changing the spacing between adjacent lens groups. The focusing lens group consists of the third lens group G3. When focusing from an object at infinity to the closest object, the third lens group G3 moves toward the object, and the other lens groups are fixed with respect to the image plane Sim. The vibration reduction group consists of three lenses, lenses L21 to L23.

[0187] Concerning the variable magnification optical system of Example 8, basic lens data is shown in Table 22, specifications and variable surface spacing in Table 23, aspheric coefficients in Table 24, and each aberration diagram in FIG.

[0188] [Table 22]

[0189] [Table 23]

[0190] [Table 24]

[0191] [Example 9] The configuration and movement locus of the variable magnification optical system of Example 9 are shown in FIG. 19. The variable magnification optical system of Example 9 is composed of, in order from the object side to the image 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, and a fourth lens group G4 having negative refractive power. The rear group GR is composed of two lens groups, the third lens group G3 and the fourth lens group G4. The first lens group G1 is composed of three lenses, lenses L11 to L13, in order from the object side to the image side. The second lens group G2 is composed of one lens, lens L21. The third lens group G3 is composed of an aperture stop St and five lenses, lenses L31 to L35, in order from the object side to the image side. The fourth lens group G4 is composed of one lens, lens L41.

[0192] When changing magnification from the wide-angle end to the telephoto end, all lens groups move along the optical axis Z while changing the spacing between adjacent lens groups. The focusing lens group consists of the fourth lens group G4. When focusing from an object at infinity to the closest object, the fourth lens group G4 moves toward the image side, and the other lens groups are fixed with respect to the image plane Sim. The vibration reduction group consists of the second lens group G2.

[0193] Concerning the variable power optical system of Example 9, basic lens data is shown in Table 25, the specifications and variable surface spacing in Table 26, the aspheric coefficients in Table 27, and each aberration diagram in FIG.

[0194] [Table 25]

[0195] [Table 26]

[0196] [Table 27]

[0197] [Example 10] The configuration and movement locus of the variable magnification optical system of Example 10 are shown in FIG. 21. The variable magnification optical system of Example 10 is composed of, in order from the object side to the image 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 negative refractive power, and a fourth lens group G4 having positive refractive power. The rear group GR is composed of two lens groups, the third lens group G3 and the fourth lens group G4. The first lens group G1 is composed of three lenses, lenses L11 to L13, in order from the object side to the image side. The second lens group G2 is composed of a lens L21, an aperture stop St, and lenses L22 to L25, in order from the object side to the image side. The third lens group G3 is composed of one lens, lens L31. The fourth lens group G4 is composed of one lens, lens L41.

[0198] When changing magnification from the wide-angle end to the telephoto end, all lens groups move along the optical axis Z while changing the spacing between adjacent lens groups. The focusing lens group consists of the third lens group G3. When focusing from an object at infinity to the closest object, the third lens group G3 moves toward the image side, and the other lens groups are fixed with respect to the image plane Sim. The vibration reduction group consists of lens L21.

[0199] Concerning the variable power optical system of Example 10, basic lens data is shown in Table 28, the specifications and variable surface spacing in Table 29, the aspheric coefficients in Table 30, and each aberration diagram in FIG.

[0200] [Table 28]

[0201] [Table 29]

[0202] [Table 30]

[0203] [Example 11] The configuration and movement locus of the variable magnification optical system of Example 11 are shown in FIG. 23. The variable magnification optical system of Example 11 is composed of, in order from the object side to the image 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 negative refractive power, and a fourth lens group G4 having positive refractive power. The rear group GR is composed of two lens groups, the third lens group G3 and the fourth lens group G4. The first lens group G1 is composed of three lenses, lenses L11 to L13, in order from the object side to the image side. The second lens group G2 is composed of a lens L21, an aperture stop St, and lenses L22 to L26, in order from the object side to the image side. The third lens group G3 is composed of one lens, lens L31. The fourth lens group G4 is composed of one lens, lens L41.

[0204] When changing magnification from the wide-angle end to the telephoto end, all lens groups move along the optical axis Z while changing the spacing between adjacent lens groups. The focusing lens group consists of the third lens group G3. When focusing from an object at infinity to the closest object, the third lens group G3 moves toward the image side, and the other lens groups are fixed with respect to the image plane Sim. The vibration reduction group consists of lens L21.

[0205] Concerning the variable power optical system of Example 11, basic lens data is shown in Table 31, the specifications and variable surface spacing in Table 32, the aspheric coefficients in Table 33, and each aberration diagram in FIG.

[0206] [Table 31]

[0207] [Table 32]

[0208] [Table 33]

[0209] [Example 12] The configuration and movement locus of the variable magnification optical system of Example 12 are shown in FIG. 25. The variable magnification optical system of Example 12 is composed of, in order from the object side to the image 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 negative refractive power, and a fourth lens group G4 having positive refractive power. The rear group GR is composed of two lens groups, the third lens group G3 and the fourth lens group G4. The first lens group G1 is composed of three lenses, lenses L11 to L13, in order from the object side to the image side. The second lens group G2 is composed of a lens L21, an aperture stop St, and lenses L22 to L27, in order from the object side to the image side. The third lens group G3 is composed of one lens, lens L31. The fourth lens group G4 is composed of one lens, lens L41.

[0210] When changing magnification from the wide-angle end to the telephoto end, all lens groups move along the optical axis Z while changing the spacing between adjacent lens groups. The focusing lens group consists of the third lens group G3. When focusing from an object at infinity to the closest object, the third lens group G3 moves toward the image side, and the other lens groups are fixed with respect to the image plane Sim. The vibration reduction group consists of lens L21.

[0211] Concerning the variable power optical system of Example 12, basic lens data is shown in Table 34, the specifications and variable surface spacing in Table 35, the aspheric coefficients in Table 36, and each aberration diagram in FIG.

[0212] [Table 34]

[0213] [Table 35]

[0214] [Table 36]

[0215] [Example 13] The configuration and movement locus of the variable magnification optical system of Example 13 are shown in FIG. 27. The variable magnification optical system of Example 13 is composed of, in order from the object side to the image 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 negative refractive power, and a fourth lens group G4 having negative refractive power. The rear group GR is composed of two lens groups, the third lens group G3 and the fourth lens group G4. The first lens group G1 is composed of three lenses, lenses L11 to L13, in order from the object side to the image side. The second lens group G2 is composed of a lens L21, an aperture stop St, and lenses L22 to L25, in order from the object side to the image side. The third lens group G3 is composed of one lens, lens L31. The fourth lens group G4 is composed of one lens, lens L41.

[0216] When changing magnification from the wide-angle end to the telephoto end, all lens groups move along the optical axis Z while changing the spacing between adjacent lens groups. The focusing lens group consists of the third lens group G3. When focusing from an object at infinity to the closest object, the third lens group G3 moves toward the image side, and the other lens groups are fixed with respect to the image plane Sim. The vibration reduction group consists of lens L21.

[0217] Concerning the variable power optical system of Example 13, basic lens data is shown in Table 37, the specifications and variable surface spacing in Table 38, the aspheric coefficients in Table 39, and each aberration diagram in FIG.

[0218] [Table 37]

[0219] [Table 38]

[0220] [Table 39]

[0221] [Example 14] The configuration and movement locus of the variable magnification optical system of Example 14 are shown in FIG. 29. The variable magnification optical system of Example 14 is composed of, in order from the object side to the image 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 negative refractive power, and a fourth lens group G4 having negative refractive power. The rear group GR is composed of two lens groups, the third lens group G3 and the fourth lens group G4. The first lens group G1 is composed of three lenses, lenses L11 to L13, in order from the object side to the image side. The second lens group G2 is composed of a lens L21, an aperture stop St, and lenses L22 to L26, in order from the object side to the image side. The third lens group G3 is composed of one lens, lens L31. The fourth lens group G4 is composed of one lens, lens L41.

[0222] When changing magnification from the wide-angle end to the telephoto end, all lens groups move along the optical axis Z while changing the spacing between adjacent lens groups. The focusing lens group consists of the third lens group G3. When focusing from an object at infinity to the closest object, the third lens group G3 moves toward the image side, and the other lens groups are fixed with respect to the image plane Sim. The vibration reduction group consists of lens L21.

[0223] Concerning the variable power optical system of Example 14, basic lens data is shown in Table 40, the specifications and variable surface spacing in Table 41, the aspheric coefficients in Table 42, and each aberration diagram in FIG.

[0224] [Table 40]

[0225] [Table 41]

[0226] [Table 42]

[0227] [Example 15] The configuration and movement locus of the variable magnification optical system of Example 15 are shown in FIG. 31. The variable magnification optical system of Example 15 is composed of, in order from the object side to the image 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 negative refractive power, and a fourth lens group G4 having negative refractive power. The rear group GR is composed of two lens groups, the third lens group G3 and the fourth lens group G4. The first lens group G1 is composed of three lenses, lenses L11 to L13, in order from the object side to the image side. The second lens group G2 is composed of an aperture stop St and six lenses, lenses L21 to L26, in order from the object side to the image side. The third lens group G3 is composed of one lens, lens L31. The fourth lens group G4 is composed of two lenses, lenses L41 to L42, in order from the object side to the image side.

[0228] When changing magnification from the wide-angle end to the telephoto end, all lens groups move along the optical axis Z while changing the spacing between adjacent lens groups. The focusing lens group consists of the third lens group G3. When focusing from an object at infinity to the closest object, the third lens group G3 moves toward the image side, and the other lens groups are fixed with respect to the image plane Sim. The vibration reduction group consists of lens L21.

[0229] Concerning the variable power optical system of Example 15, basic lens data is shown in Table 43, the specifications and variable surface spacing in Table 44, the aspheric coefficients in Table 45, and each aberration diagram in FIG.

[0230] [Table 43]

[0231] [Table 44]

[0232] [Table 45]

[0233] [Example 16] The configuration and movement locus of the variable magnification optical system of Example 16 are shown in FIG. 33. The variable magnification optical system of Example 16 is composed of, in order from the object side to the image 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, and a fifth lens group G5 having positive refractive power. The rear group GR is composed of three lens groups, the third lens group G3, the fourth lens group G4, and the fifth lens group G5. The first lens group G1 is composed of three lenses, lenses L11 to L13, in order from the object side to the image side. The second lens group G2 is composed of one lens, lens L21. The third lens group G3 is composed of an aperture stop St and five lenses, lenses L31 to L35, in order from the object side to the image side. The fourth lens group G4 is composed of one lens, lens L41. The fifth lens group G5 is composed of one lens, lens L51.

[0234] When changing magnification from the wide-angle end to the telephoto end, all lens groups move along the optical axis Z while changing the spacing between adjacent lens groups. The focusing lens group consists of the fourth lens group G4. When focusing from an object at infinity to the closest object, the fourth lens group G4 moves toward the image side, and the other lens groups are fixed with respect to the image plane Sim. The vibration reduction group consists of the second lens group G2.

[0235] Concerning the variable power optical system of Example 16, basic lens data is shown in Table 46, the specifications and variable surface spacing in Table 47, the aspheric coefficients in Table 48, and each aberration diagram in FIG.

[0236] [Table 46]

[0237] [Table 47]

[0238] [Table 48]

[0239] [Example 17] The configuration and movement locus of the variable magnification optical system of Example 17 are shown in FIG. 35. The variable magnification optical system of Example 17 is composed of, in order from the object side to the image 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, and a fifth lens group G5 having positive refractive power. The rear group GR is composed of three lens groups, the third lens group G3, the fourth lens group G4, and the fifth lens group G5. The first lens group G1 is composed of three lenses, lenses L11 to L13, in order from the object side to the image side. The second lens group G2 is composed of one lens, lens L21. The third lens group G3 is composed of an aperture stop St and five lenses, lenses L31 to L35, in order from the object side to the image side. The fourth lens group G4 is composed of one lens, lens L41. The fifth lens group G5 is composed of one lens, lens L51.

[0240] When changing magnification from the wide-angle end to the telephoto end, all lens groups move along the optical axis Z while changing the spacing between adjacent lens groups. The focusing lens group consists of the fourth lens group G4. When focusing from an object at infinity to the closest object, the fourth lens group G4 moves toward the image side, and the other lens groups are fixed with respect to the image plane Sim. The vibration reduction group consists of the second lens group G2.

[0241] Concerning the variable power optical system of Example 17, basic lens data is shown in Table 49, the specifications and variable surface spacing are shown in Table 50, the aspheric coefficients are shown in Table 51, and each aberration diagram is shown in FIG.

[0242] [Table 49]

[0243] [Table 50]

[0244] [Table 51]

[0245] [Example 18] The configuration and movement locus of the variable magnification optical system of Example 18 are shown in FIG. 37. The variable magnification optical system of Example 18 is composed of, in order from the object side to the image 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, and a fifth lens group G5 having negative refractive power. The rear group GR is composed of three lens groups, the third lens group G3, the fourth lens group G4, and the fifth lens group G5. The first lens group G1 is composed of four lenses, lenses L11 to L14, in order from the object side to the image side. The second lens group G2 is composed of one lens, lens L21. The third lens group G3 is composed of an aperture stop St and five lenses, lenses L31 to L35, in order from the object side to the image side. The fourth lens group G4 is composed of one lens, lens L41. The fifth lens group G5 is composed of one lens, lens L51.

[0246] When changing magnification from the wide-angle end to the telephoto end, all lens groups move along the optical axis Z while changing the spacing between adjacent lens groups. The focusing lens group consists of the fourth lens group G4. When focusing from an object at infinity to the closest object, the fourth lens group G4 moves toward the image side, and the other lens groups are fixed with respect to the image plane Sim. The vibration reduction group consists of the second lens group G2.

[0247] Concerning the variable power optical system of Example 18, basic lens data is shown in Table 52, the specifications and variable surface spacing are shown in Table 53, the aspheric coefficients are shown in Table 54, and each aberration diagram is shown in FIG.

[0248] [Table 52]

[0249] [Table 53]

[0250] [Table 54]

[0251] [Example 19] The configuration and movement locus of the variable magnification optical system of Example 19 are shown in FIG. 39. The variable magnification optical system of Example 19 is composed of, in order from the object side to the image 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 negative refractive power, a fourth lens group G4 having positive refractive power, and a fifth lens group G5 having positive refractive power. The rear group GR is composed of three lens groups, the third lens group G3, the fourth lens group G4, and the fifth lens group G5. The first lens group G1 is composed of three lenses, lenses L11 to L13, in order from the object side to the image side. The second lens group G2 is composed of a lens L21, an aperture stop St, and lenses L22 to L24, in order from the object side to the image side. The third lens group G3 is composed of one lens, lens L31. The fourth lens group G4 is composed of one lens, lens L41. The fifth lens group G5 is composed of one lens, lens L51.

[0252] When changing the magnification from the wide-angle end to the telephoto end, the fifth lens group G5 is fixed with respect to the image plane Sim, and the other lens groups move along the optical axis Z while changing the spacing between adjacent lens groups. The focusing lens group consists of the third lens group G3. When focusing from an object at infinity to the closest object, the third lens group G3 moves toward the image side, and the other lens groups are fixed with respect to the image plane Sim. The vibration reduction group consists of lens L21.

[0253] Concerning the variable power optical system of Example 19, basic lens data is shown in Table 55, the specifications and variable surface spacing in Table 56, the aspheric coefficients in Table 57, and each aberration diagram in FIG.

[0254] [Table 55]

[0255] [Table 56]

[0256] [Table 57]

[0257] [Example 20] The configuration and movement locus of the variable magnification optical system of Example 20 are shown in FIG. 41. The variable magnification optical system of Example 20 is composed of, in order from the object side to the image 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 negative refractive power, a fourth lens group G4 having negative refractive power, and a fifth lens group G5 having positive refractive power. The rear group GR is composed of three lens groups, the third lens group G3, the fourth lens group G4, and the fifth lens group G5. The first lens group G1 is composed of three lenses, lenses L11 to L13, in order from the object side to the image side. The second lens group G2 is composed of a lens L21, an aperture stop St, and lenses L22 to L24, in order from the object side to the image side. The third lens group G3 is composed of one lens, lens L31. The fourth lens group G4 is composed of one lens, lens L41. The fifth lens group G5 is composed of one lens, lens L51.

[0258] When changing magnification from the wide-angle end to the telephoto end, all lens groups move along the optical axis Z while changing the spacing between adjacent lens groups. The focusing lens group consists of the third lens group G3. When focusing from an object at infinity to the closest object, the third lens group G3 moves toward the image side, and the other lens groups are fixed with respect to the image plane Sim. The vibration reduction group consists of lens L21.

[0259] Concerning the variable power optical system of Example 20, basic lens data is shown in Table 58, the specifications and variable surface spacing are shown in Table 59, the aspheric coefficients are shown in Table 60, and each aberration diagram is shown in FIG.

[0260] [Table 58]

[0261] [Table 59]

[0262] [Table 60]

[0263] Tables 61 to 64 show the corresponding values ​​of conditional expressions (1) to (3) and (5) to (33) of the variable magnification optical systems of Examples 1 to 20. The corresponding values ​​of the Examples shown in Tables 61 to 64 may be used as the upper or lower limits of the conditional expressions to set preferred ranges for the conditional expressions. Note that the corresponding value of conditional expression (4) for the lens in the first lens group G1 is omitted in Tables 61 to 64 because it is shown in the column "NG1L+0.01×νG1L" of the basic lens data as described above.

[0264] [Table 61]

[0265] [Table 62]

[0266] [Table 63]

[0267] [Table 64]

[0268] The variable magnification optical systems of Examples 1 to 20 are constructed to be small and lightweight, yet maintain high optical performance with various aberrations well corrected over the entire range of magnification.

[0269] Next, an imaging device according to an embodiment of the present disclosure will be described. Fig. 43 and Fig. 44 show external views of a camera 30 which is an imaging device according to an embodiment of the present disclosure. Fig. 43 shows a perspective view of the camera 30 seen from the front side, and Fig. 44 shows a perspective view of the camera 30 seen from the rear side. The camera 30 is a so-called mirrorless type digital camera, to which an interchangeable lens 20 can be removably attached. The interchangeable lens 20 is configured to include a variable magnification optical system 1 according to an embodiment of the present disclosure housed in a lens barrel.

[0270] The camera 30 includes a camera body 31. A shutter button 32 and a power button 33 are provided on the top surface of the camera body 31. An operation unit 34, an operation unit 35, and a display unit 36 ​​are provided on the back surface of the camera body 31. The display unit 36 ​​is capable of displaying a captured image and an image within the angle of view before the image was captured.

[0271] A photographic opening through which light from a subject is incident is provided in the center of the front surface of the camera body 31. A mount 37 is provided at a position corresponding to the photographic opening, and the interchangeable lens 20 is attached to the camera body 31 via the mount 37.

[0272] An imaging element 38 is provided in the camera body 31. The imaging element 38 outputs an imaging signal corresponding to a subject image formed by the interchangeable lens 20. For example, a charge coupled device (CCD) or a complementary metal oxide semiconductor (CMOS) is used as the imaging element 38. A signal processing circuit (not shown) and a recording medium (not shown) are provided in the camera body 31. The signal processing circuit processes the imaging signal output from the imaging element 38 to generate an image. The recording medium is for recording the generated image. With the camera 30, it is possible to shoot a still image or a video by pressing the shutter button 32, and image data obtained by this shooting is recorded on the recording medium.

[0273] Although the technology of the present disclosure has been described above with reference to the embodiments and examples, the technology of the present disclosure is not limited to the above embodiments and examples, and various modifications are possible. For example, the radius of curvature, surface spacing, refractive index, Abbe number, aspheric coefficient, etc. of each lens are not limited to the values ​​shown in the above examples, and may take other values.

[0274] Furthermore, the imaging device according to the embodiment of the present disclosure is not limited to the above example, and can take various forms, such as a camera other than a mirrorless type, a film camera, a video camera, and a security camera.

[0275] Regarding the above-mentioned embodiments and examples, the following supplementary notes are further disclosed. [Appendix 1] the first lens group having a negative refractive power, the second lens group having a positive refractive power, and a subsequent group including one or more lens groups, During magnification change, the first lens group moves and all intervals between adjacent lens groups change; one of the lens groups included in the subsequent group is a focusing lens group that moves along the optical axis during focusing; TLw is the sum of the distance on the optical axis from the lens surface of the first lens group closest to the object side to the lens surface of the subsequent lens group closest to the image side when focused on an object at infinity at the wide-angle end, and the back focus in terms of the air equivalent distance of the entire system; The focal length of the entire system when focused on an object at infinity at the telephoto end is ft. The maximum half angle of view when focused on an object at infinity at the telephoto end is ωt. The back focus in the air equivalent distance of the entire system when focused on an object at infinity at the wide-angle end is Bfw, The focal length of the entire system when focused on an object at infinity at the wide-angle end is fw. The refractive index for the d-line and the Abbe number based on the d-line of any one of the lenses included in the first lens group are NG1L and νG1L, respectively. If the sum of the thicknesses of all lens groups on the optical axis is Dsum, 4.5 <TLw / (ft×tanωt)<8 (1) 0.4 <Bfw / (ft×tanωt)<3 (2) 0.9<(fw×TLw) / ft 2 <3.2 (3) 1.6 <NG1L+0.01×νG1L<2.3 (4) 0.1 <Dsum / (TLw-Bfw)<0.8 (5) A variable magnification optical system that satisfies conditional expressions (1), (2), (3), (4), and (5) expressed by the following formula: [Appendix 2] 5.4 <TLw / (ft×tanωt)<7 (1-1) 2. The variable magnification optical system according to claim 1, which satisfies the conditional expression (1-1) shown below. [Appendix 3] 0.55 <Bfw / (ft×tanωt)<2 (2-1) 3. The variable magnification optical system according to claim 1, which satisfies conditional expression (2-1) shown below. [Appendix 4] 1.82 <NG1L+0.01×νG1L<1.91 (4-1) 4. A variable magnification optical system according to claim 1, which satisfies conditional expression (4-1) shown below. [Appendix 5] The thickness of the first lens group on the optical axis is dG1. If the focal length of the first lens group is f1, then 0.4 <dG1 / |f1|<2 (6) 5. A variable magnification optical system according to claim 1, which satisfies conditional expression (6) shown below. [Appendix 6] 0.55 <dG1 / |f1|<1.65 (6-1) The variable magnification optical system according to claim 5, which satisfies the conditional expression (6-1) shown below. [Appendix 7] 0.75 <dG1 / |f1|<1.35 (6-2) The variable magnification optical system according to claim 5, which satisfies the conditional expression (6-2) shown below. [Appendix 8] the first lens group includes an L1nm lens which is a non-cemented negative meniscus lens having a convex surface facing the object side, an L1n lens which is a non-cemented negative lens having a concave surface facing the image side, and an L1p lens which is a positive lens, The L1n lens is disposed adjacent to the image side of the L1nm lens, 8. The variable magnification optical system according to claim 1, wherein the L1p lens is disposed on the image side of the L1n lens. [Appendix 9] When the refractive index for the d-line and the Abbe number based on the d-line of the negative lens disposed between the L1nm lens and the L1p lens are NG1n and νG1n, respectively, 1.7 <NG1n+0.01×νG1n<2.16 (7) and a negative lens satisfying condition (7) expressed by: 9. The variable magnification optical system according to claim 8, wherein the negative lens satisfying the conditional expression (7) is the L1n lens or a negative lens disposed adjacent to the image side of the L1n lens. [Appendix 10] The negative lens satisfying the conditional expression (7) is 1.74 <NG1n+0.01×νG1n<2.14 (7-1) 10. The variable magnification optical system according to claim 9, which satisfies the condition (7-1) shown below. [Appendix 11] The distance on the optical axis between the L1nm lens and the L1n lens is dm. If the thickness of the first lens group on the optical axis is dG1, 0.01 <dm / dG1<0.9 (8) 11. A variable magnification optical system according to claim 8, which satisfies conditional expression (8) represented by: [Appendix 12] 12. A variable magnification optical system according to claim 8, wherein the object-side surface of the L1n lens is an aspheric surface in which the refractive power at the position of the maximum effective diameter is shifted in the positive direction compared to the refractive power in the paraxial region. [Appendix 13] 13. The variable magnification optical system according to claim 12, wherein the object-side surface of the L1n lens has a concave shape in the paraxial region and a convex shape in a peripheral portion including the position of the maximum effective diameter. [Appendix 14] The focal length of the second lens group is f2. If the focal length of the first lens group is f1, then 0.3 <f2 / |f1|<5 (9) 14. A variable magnification optical system according to claim 1, which satisfies conditional expression (9) shown below. [Appendix 13] 0.65 <f2 / |f1|<3 (9-1) 13. The variable magnification optical system according to claim 12, which satisfies the condition (9-1) shown below. [Appendix 14] 14. The variable magnification optical system according to claim 1, wherein the first lens group includes a positive lens, the most object-side lens being convex toward the object side. [Appendix 15] 15. The variable magnification optical system according to claim 1, wherein the first lens group is composed of four or less lenses. [Appendix 16] If the focal length of the first lens group is f1, then 0.45 <fw / |f1|<2 (10) 16. A variable magnification optical system according to claim 1, which satisfies conditional expression (10) represented by: [Appendix 17] the first lens group includes an L1 nm lens which is a non-cemented negative meniscus lens having a convex surface facing an object side; The paraxial radius of curvature of the object side surface of the L1nm lens is Rf. If the paraxial radius of curvature of the image side surface of the L1nm lens is Rr, 1<(Rf+Rr) / (Rf-Rr)<7 (11) 17. A variable magnification optical system according to claim 1, which satisfies conditional expression (11) represented by: [Appendix 18] a vibration reduction group that moves in a direction intersecting with the optical axis during image blur correction is disposed on the image side of the first lens group, If the focal length of the image stabilization group is fois, 0.3 <ft / |fois|<4 (12) 18. A variable magnification optical system according to claim 1, which satisfies conditional expression (12) represented by: [Appendix 19] If the focal length of the focusing lens group is ffoc, 0.3 <ft / |ffoc|<3 (13) 19. A variable magnification optical system according to claim 1, which satisfies conditional expression (13) represented by: [Appendix 20] an Lr lens is disposed on the image side of the focusing lens group; When the refractive index of the Lr lens with respect to the d-line and the Abbe number based on the d-line are Nr and νr, respectively, 1.7 <Nr+0.01×νr<2.16 (14) 20. A variable magnification optical system according to claim 1, which satisfies conditional expression (14) represented by: [Appendix 21] An imaging device comprising the variable magnification optical system according to any one of claims 1 to 20. [Explanation of symbols]

[0276] 1 Variable magnification optical system 20 Interchangeable Lenses 30 Camera 31 Camera body 32 Shutter button 33 Power button 34 Control section 35 Control section 36 Display section 37 Mount 38 Image sensor Bfw back focus dG1 Thickness dL1n center thickness dL1nh Thickness dL1nm center thickness dL1nmh Thickness dm distance Dfoc thickness ED Effective Diameter G1 First lens group G2 2nd lens group G3 3rd lens group G4 4th lens group G5 5th lens group GR Successor Group L11~L51 Lens Lx Lens Px position Sim image plane St aperture stop TLw optical total length Xa On-axis luminous flux Xb Off-axis luminous flux Xb1 ray Z optical axis ωt Maximum half angle of view ωw Maximum half angle of view

Claims

1. the first lens group having a negative refractive power, the second lens group having a positive refractive power, and a subsequent group including one or more lens groups, During magnification change, the first lens group moves and all the intervals between the adjacent lens groups change. one of the lens groups included in the subsequent group is a focusing lens group that moves along the optical axis during focusing; TLw is the sum of the distance on the optical axis from the lens surface of the first lens group closest to the object side to the lens surface of the subsequent lens group closest to the image side when focused on an object at infinity at the wide-angle end, and the back focus in terms of the air equivalent distance of the entire system; The focal length of the entire system when focused on an object at infinity at the telephoto end is ft. The maximum half angle of view when focused on an object at infinity at the telephoto end is ωt. The back focus of the entire system in the air equivalent distance when focused on an object at infinity at the wide-angle end is Bfw, The focal length of the entire system when focused on an object at infinity at the wide-angle end is fw. The refractive index for the d-line and the Abbe number based on the d-line of any one of the lenses included in the first lens group are NG1L and νG1L, respectively; If the sum of the thicknesses of all the lens groups on the optical axis is Dsum, 4.5<TLw / (ft×tanωt)<8 (1) 0.4<Bfw / (ft×tanωt)<3 (2) 0.9<(fw×TLw) / ft ２ <3.2 (3) 1.6<NG1L+0.01×νG1L<2.3 (4) 0.1<Dsum / (TLw-Bfw)<0.8 (5) A variable magnification optical system that satisfies the conditional expressions (1), (2), (3), (4), and (5) expressed by the following formula:

2. 5.4<TLw / (ft×tanωt)<7 (1-1) 2. The variable magnification optical system according to claim 1, which satisfies the conditional expression (1-1) represented by:

3. 0.55<Bfw / (ft×tanωt)<2 (2-1) 2. The variable magnification optical system according to claim 1, which satisfies the conditional expression (2-1) expressed by:

4. The thickness of the first lens group on the optical axis is dG1. If the focal length of the first lens group is f1, 0.4<dG1 / |f1|<2 (6) 2. The variable magnification optical system according to claim 1, which satisfies conditional expression (6) expressed as follows:

5. 0.55<dG1 / |f1|<1.65 (6-1) 5. The variable magnification optical system according to claim 4, which satisfies the conditional expression (6-1) expressed by:

6. the first lens group includes an L1nm lens which is a non-cemented negative meniscus lens having a convex surface facing the object side, an L1n lens which is a non-cemented negative lens having a concave surface facing the image side, and an L1p lens which is a positive lens, The L1n lens is disposed adjacent to the image side of the L1nm lens, 2. The variable magnification optical system according to claim 1, wherein the L1p lens is disposed closer to the image side than the L1n lens.

7. When the refractive index for the d-line and the Abbe number based on the d-line of the negative lens disposed between the L1nm lens and the L1p lens are NG1n and νG1n, respectively, 1.7<NG1n+0.01×νG1n<2.16 (7) The negative lens satisfies condition (7) expressed by:

7. The variable magnification optical system according to claim 6, wherein the negative lens satisfying the conditional expression (7) is the L1n lens or a negative lens disposed adjacent to the image side of the L1n lens.

8. The negative lens satisfying the conditional expression (7) is 1.74<NG1n+0.01×νG1n<2.14 (7-1) 8. The variable magnification optical system according to claim 7, which satisfies the conditional expression (7-1) represented by:

9. The distance on the optical axis between the L1nm lens and the L1n lens is dm. If the thickness of the first lens group on the optical axis is dG1, 0.01<dm / dG1<0.9 (8) 7. The variable magnification optical system according to claim 6, which satisfies conditional expression (8) expressed as follows:

10. 7. The variable magnification optical system according to claim 6, wherein the object side surface of said L1n lens is an aspheric surface whose refractive power at the position of the maximum effective diameter is shifted in a positive direction compared with the refractive power in the paraxial region.

11. 11. The variable magnification optical system according to claim 10, wherein the object side surface of the L1n lens has a concave shape in the paraxial region and a convex shape in the peripheral portion including the position of the maximum effective diameter.

12. The focal length of the second lens group is f2. If the focal length of the first lens group is f1, 0.3<f2 / |f1|<5 (9) 2. The variable magnification optical system according to claim 1, which satisfies conditional expression (9) expressed as follows:

13. 0.65<f2 / |f1|<3 (9-1) 13. The variable magnification optical system according to claim 12, which satisfies the conditional expression (9-1) expressed by:

14. 5.4<TLw / (ft×tanωt)<7 (1-1) 14. The variable magnification optical system according to claim 13, which satisfies the conditional expression (1-1) represented by:

15. the first lens group includes an L1nm lens which is a non-cemented negative meniscus lens having a convex surface facing the object side, an L1n lens which is a non-cemented negative lens having a concave surface facing the image side, and an L1p lens which is a positive lens, The L1n lens is disposed adjacent to the image side of the L1nm lens, 15. The variable magnification optical system according to claim 14, wherein the L1p lens is disposed closer to the image side than the L1n lens.

16. When the refractive index for the d-line and the Abbe number based on the d-line of the negative lens disposed between the L1nm lens and the L1p lens are NG1n and νG1n, respectively, 1.74<NG1n+0.01×νG1n<2.14 (7-1) The negative lens satisfies the condition (7-1) expressed by 16. The variable magnification optical system according to claim 15, wherein the negative lens satisfying the conditional expression (7-1) is the L1n lens, or a negative lens disposed adjacent to the image side of the L1n lens.

17. 17. The variable magnification optical system according to claim 16, wherein the first lens group includes a positive lens, the most object-side lens being convex toward the object side.

18. 1.82<NG1L+0.01×νG1L<1.91 (4-1) 17. The variable magnification optical system according to claim 16, which satisfies the conditional expression (4-1) represented by:

19. If the thickness of the first lens group on the optical axis is dG1, 0.55<dG1 / |f1|<1.65 (6-1) 17. The variable magnification optical system according to claim 16, which satisfies conditional expression (6-1) expressed by:

20. 0.75<dG1 / |f1|<1.35 (6-2) 20. The variable magnification optical system according to claim 19, which satisfies conditional expression (6-2) expressed by:

21. When the distance on the optical axis between the L1nm lens and the L1n lens is dm, 0.01<dm / dG1<0.9 (8) 20. The variable magnification optical system according to claim 19, which satisfies conditional expression (8) expressed by:

22. 20. The variable magnification optical system according to claim 19, wherein the first lens group is made up of four or less lenses.

23. 20. The variable magnification optical system according to claim 19, wherein the object side surface of the L1n lens is an aspheric surface whose refractive power at the position of the maximum effective diameter is shifted in a positive direction compared to its refractive power in the paraxial region.

24. If the focal length of the first lens group is f1, 0.45<fw / |f1|<2 (10) 2. The variable magnification optical system according to claim 1, which satisfies conditional expression (10) expressed as follows:

25. the first lens group includes an L1 nm lens which is a non-cemented negative meniscus lens having a convex surface facing an object side, The paraxial radius of curvature of the object side surface of the L1 nm lens is Rf. If the paraxial radius of curvature of the image side surface of the L1 nm lens is Rr, 1<(Rf+Rr) / (Rf-Rr)<7 (11) 2. The variable magnification optical system according to claim 1, which satisfies the conditional expression (11) expressed as follows:

26. a vibration reduction group that moves in a direction intersecting with the optical axis during image blur correction is disposed on the image side of the first lens group, If the focal length of the image stabilization group is fois, 0.3<ft / |fois|<4 (12) 2. The variable magnification optical system according to claim 1, which satisfies conditional expression (12) expressed as follows:

27. If the focal length of the focusing lens group is ffoc, 0.3<ft / |ffoc|<3 (13) 2. The variable magnification optical system according to claim 1, which satisfies conditional expression (13) expressed as follows:

28. an Lr lens is disposed on the image side of the focusing lens group; When the refractive index of the Lr lens with respect to the d-line and the Abbe number based on the d-line are Nr and νr, respectively, 1.7<Nr+0.01×νr<2.16 (14) 2. The variable magnification optical system according to claim 1, which satisfies conditional expression (14) expressed as follows:

29. 29. An imaging apparatus comprising the variable magnification optical system according to claim 1.

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