Optical system, optical apparatus and method for manufacturing optical system

Abstract

To provide an optical system that is small-sized, light-weighted, and has excellent imaging performance, an optical apparatus, and a method for manufacturing the optical system.SOLUTION: An optical system used for an optical apparatus such as a camera 1 is composed of, in order from an object side: a first lens group having positive refractive power; a focusing group that moves along an optical axis at focusing; and a rear group. A lens group arranged on an object side with the largest air interval A in the first lens group is defined as a front A lens group, and constituted to satisfy all conditional expressions shown below: 1.00<FNo×(TL / f) 2<2.50 and 0.30<dA / dG1<0.85 . Where FNo is an F value of the optical system at infinity focusing, TL is a total track length of the optical system at infinity focusing, f is focal distance of the optical system at the infinity focusing, dA is distance of the air space A on the optical axis, and dG1 is distance of the first lens group on the optical axis.SELECTED DRAWING: Figure 1A

Description

[Technical Field]

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

[0002] BACKGROUND ART Conventionally, optical systems for use in photographic cameras, electronic still cameras, video cameras, etc. have been proposed (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2016-200685 Summary of the Invention

[0004] The optical system of the present disclosure comprises, in order from the object side, a first lens group having positive refractive power, a focusing group that moves along the optical axis during focusing, and a rear group, in which the lens group located on the object side with the largest air gap A in the first lens group is designated as the 1A lens group, and satisfies all of the following conditional expressions: 1.00 < FNo × (TL / f) 2 < 2.50 0.30 < dA / dG1 < 0.85 however, FNo: F-number of the optical system when focused at infinity TL: Total optical length of the optical system when focused at infinity f: focal length of the optical system when focused at infinity dA: Distance on the optical axis of air gap A dG1: Distance on the optical axis of the first lens group

[0005] The optical system of the present disclosure comprises, in order from the object side, a first lens group having positive refractive power, a focusing group that moves along the optical axis during focusing, and a rear group, in which the lens group located on the object side with the largest air gap A in the first lens group is designated as the 1A lens group, and satisfies all of the following conditional expressions: 0.30 < TL / f < 0.80 0.30 < dA / dG1 < 0.85 however, TL: Total optical length of the optical system when focused at infinity f: focal length of the optical system when focused at infinity dA: Distance on the optical axis of air gap A dG1: Distance on the optical axis of the first lens group

[0006] The optical system of the present disclosure is an optical system made up of a plurality of lenses, and has, in order from the object side, at least one positive lens component and a negative lens N, and satisfies all of the following conditional expressions. 1.00 < FNo × (TL / f) 2 < 2.50 0.18 < dN / TL < 0.45 however, FNo: F-number of the optical system when focused at infinity TL: Total optical length of the optical system when focused at infinity f: focal length of the optical system when focused at infinity dN: The distance on the optical axis from the surface closest to the object in the optical system to the surface of negative lens N closest to the object

[0007] The optical system of the present disclosure is an optical system consisting of a plurality of lenses, has a positive lens component closest to the object side, and has a negative lens N that is closest to the object side among negative lenses that are arranged closer to the image side than the positive lens component, and satisfies all of the following conditional expressions: 1.00 < FNo × (TL / f) 2 < 2.50 0.18 < dN / TL < 0.45 however, FNo: F-number of the optical system when focused at infinity TL: Total optical length of the optical system when focused at infinity f: focal length of the optical system when focused at infinity dN: the distance on the optical axis from the surface closest to the object side of the optical system to the surface of the negative lens N closest to the object side

[0008] The manufacturing method for an optical system disclosed herein is a manufacturing method for an optical system consisting of a plurality of lenses, and arranges, in order from the object side, a first lens group having positive refractive power, a focusing group that moves along the optical axis during focusing, and a rear group, and arranges a 1A lens group on the object side separated by the largest air gap A within the first lens group, and arranges them so as to satisfy all of the following conditional expressions: 1.00 < FNo × (TL / f) 2 < 2.50 0.30 < dA / dG1 < 0.85 however, FNo: F-number of the optical system when focused at infinity TL: Total optical length of the optical system when focused at infinity f: focal length of the optical system when focused at infinity dA: Distance on the optical axis of air gap A dG1: Distance on the optical axis of the first lens group

[0009] The method for manufacturing an optical system according to the present disclosure is a method for manufacturing an optical system consisting of multiple lenses, in which, from the object side, at least one positive lens component and a negative lens N are arranged so as to satisfy all of the following conditional expressions: 1.00 < FNo × (TL / f) 2 < 2.50 0.18 < dN / TL < 0.45 however, FNo: F-number of the optical system when focused at infinity TL: Total optical length of the optical system when focused at infinity f: focal length of the optical system when focused at infinity dN: The distance on the optical axis from the surface closest to the object in the optical system to the surface of negative lens N closest to the object [Brief explanation of the drawings]

[0010] [Figure 1A] FIG. 1A is a cross-sectional view of the optical system of the first embodiment when focused on an object at infinity. [Figure 1B] FIG. 1B is a cross-sectional view of the optical system of the first embodiment when focusing on a close-distance object. [Figure 2] FIG. 2 is a diagram showing various aberrations of the optical system of the first example when focusing on an object at infinity. [Figure 3A] FIG. 3A is a cross-sectional view of the optical system of the second embodiment when focused on an object at infinity. [Figure 3B] FIG. 3B is a cross-sectional view of the optical system of the second embodiment when focusing on a close-distance object. [Figure 4] FIG. 4 is a diagram showing various aberrations of the optical system of the second example when focused on an object at infinity. [Figure 5A] FIG. 5A is a cross-sectional view of the optical system of the third embodiment when focused on an object at infinity. [Figure 5B] FIG. 5B is a cross-sectional view of the optical system of the third example when focusing on a close-distance object. [Figure 6] FIG. 6 is a diagram showing various aberrations of the optical system of the third example when focused on an object at infinity. [Figure 7A] FIG. 7A is a cross-sectional view of the optical system of the fourth embodiment when focused on an object at infinity. [Figure 7B] FIG. 7B is a cross-sectional view of the optical system of the fourth example when focusing on a close-distance object. [Figure 8] FIG. 8 is a diagram showing various aberrations of the optical system of the fourth example when focused on an object at infinity. [Figure 9A] FIG. 9A is a cross-sectional view of the optical system of the fifth embodiment when focused on an object at infinity. [Figure 9B] FIG. 9B is a cross-sectional view of the optical system of the fifth example when focusing on a close-distance object. [Figure 10] FIG. 10 is a diagram showing various aberrations of the optical system of the fifth embodiment when focused on an object at infinity. [Figure 11A] FIG. 11A is a cross-sectional view of the optical system of Example 6 when focusing on an object at infinity. [Figure 11B] FIG. 11B is a cross-sectional view of the optical system of Example 6 when focusing on a close-distance object. [Figure 12] FIG. 12 is a diagram showing various aberrations of the optical system of Example 6 when focusing on an object at infinity. [Figure 13A]FIG. 13A is a cross-sectional view of the optical system of the seventh example when focusing on an object at infinity. [Figure 13B] FIG. 13B is a cross-sectional view of the optical system of Example 7 when focusing on a close-distance object. [Figure 14] FIG. 14 is a diagram showing various aberrations of the optical system of Example 7 when focusing on an object at infinity. [Figure 15A] FIG. 15A is a cross-sectional view of the optical system of Example 8 when focusing on an object at infinity. [Figure 15B] FIG. 15B is a cross-sectional view of the optical system of Example 8 when focusing on a close-distance object. [Figure 16] FIG. 16 is a diagram showing various aberrations of the optical system of Example 8 when focusing on an object at infinity. [Figure 17A] FIG. 17A is a cross-sectional view of the optical system of Example 9 when focusing on an object at infinity. [Figure 17B] FIG. 17B is a cross-sectional view of the optical system of Example 9 when focusing on a close-distance object. [Figure 18] FIG. 18 is a diagram showing various aberrations of the optical system of Example 9 when focusing on an object at infinity. [Figure 19A] FIG. 19A is a cross-sectional view of the optical system of the tenth example when focusing on an object at infinity. [Figure 19B] FIG. 19B is a cross-sectional view of the optical system of Example 10 when focusing on a close-distance object. [Figure 20] FIG. 20 is a diagram showing various aberrations in the optical system of Example 10 when focusing on an object at infinity. [Figure 21A] FIG. 21A is a cross-sectional view of the optical system of Example 11 when focusing on an object at infinity. [Figure 21B] FIG. 21B is a cross-sectional view of the optical system of Example 11 when focusing on a close-distance object. [Figure 22] FIG. 22 is a diagram showing various aberrations in the optical system of Example 11 when focusing on an object at infinity. [Figure 23] FIG. 23 is a schematic diagram of a camera equipped with the optical system of this embodiment. [Figure 24]FIG. 24 is a first flowchart outlining the method for manufacturing the optical system of this embodiment. [Figure 25] FIG. 25 is a second flowchart outlining the method for manufacturing the optical system of this embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0011] An optical system, an optical device, and a method for manufacturing an optical system according to embodiments of the present application will be described below.

[0012] The optical system of this embodiment comprises, in order from the object side, a first lens group having positive refractive power, a focusing group that moves along the optical axis during focusing, and a rear group, with the lens group located on the object side and separated by the largest air gap A within the first lens group being designated as the 1A lens group, and satisfies all of the following conditional expressions: (1) 1.00 < FNo × (TL / f) 2 < 2.50 (2) 0.30 < dA / dG1 < 0.85 however, FNo: F-number of the optical system when focused at infinity TL: Total optical length of the optical system when focused at infinity f: focal length of the optical system when focused at infinity dA: Distance on the optical axis of air gap A dG1: Distance on the optical axis of the first lens group

[0013] The optical system of this embodiment performs correction using a lens located closer to the image side than the 1A lens group, thereby achieving both compactness and light weight, as well as excellent optical performance. Furthermore, the optical system of this embodiment can achieve compactness by satisfying conditional expression (1). Furthermore, the optical system of this embodiment can achieve lightness by satisfying conditional expression (2). By setting the upper limit of conditional expression (1) to 2.50, the effects of this embodiment can be further ensured. Furthermore, to further ensure the effects of this embodiment, it is preferable to set the upper limit of conditional expression (1) to 2.45, 2.40, 2.35, 2.30, 2.25, 2.20, or even 2.15.

[0014] Furthermore, in the optical system of this embodiment, the effect of this embodiment can be made more certain by setting the lower limit of conditional expression (1) to 1.00. In order to make the effect of this embodiment more certain, it is preferable to set the lower limit of conditional expression (1) to 1.10, 1.20, 1.25, 1.30, or even 1.35.

[0015] In the optical system of this embodiment, the effect of this embodiment can be more reliably achieved by setting the upper limit value of conditional expression (2) to 0.85. In order to further ensure the effect of this embodiment, it is preferable to set the upper limit value of conditional expression (2) to 0.80, 0.76, 0.73, 0.70, or even 0.68.

[0016] Furthermore, in the optical system of this embodiment, the effect of this embodiment can be made more certain by setting the lower limit of conditional expression (2) to 0.30. In order to make the effect of this embodiment more certain, it is preferable to set the lower limit of conditional expression (2) to 0.31, 0.33, or even 0.35.

[0017] With the above configuration, it is possible to realize an optical system that is small, lightweight, and has good imaging performance.

[0018] The optical system of this embodiment comprises, in order from the object side, a first lens group having positive refractive power, a focusing group that moves along the optical axis during focusing, and a rear group, with the lens group located on the object side and separated by the largest air gap A within the first lens group being designated as the 1A lens group, and satisfies all of the following conditional expressions: (3) 0.30 < TL / f < 0.80 (2) 0.30 < dA / dG1 < 0.85 however, TL: Total optical length of the optical system when focused at infinity f: focal length of the optical system when focused at infinity dA: Distance on the optical axis of air gap A dG1: Distance on the optical axis of the first lens group

[0019] The optical system of this embodiment performs correction using a lens located closer to the image side than the 1A lens group, thereby achieving both a compact, lightweight optical system and good optical performance. Furthermore, the optical system of this embodiment satisfies conditional expression (3), thereby enabling the optical system to be made compact. Furthermore, the optical system of this embodiment satisfies conditional expression (2), thereby enabling the optical system to be made lightweight.

[0020] In the optical system of this embodiment, by making the ratio of the total optical length of the optical system to the focal length of the optical system smaller than the upper limit, the total length of the optical system can be prevented from becoming too long. Furthermore, by setting the upper limit of conditional expression (3) to 0.80, the effect of this embodiment can be more reliably achieved. Furthermore, to more reliably achieve the effect of this embodiment, it is preferable to set the upper limit of conditional expression (3) to 0.78, 0.76, 0.74, 0.72, or even 0.70.

[0021] The optical system of this embodiment can effectively correct field curvature by making the ratio of the total optical length of the optical system to the focal length of the optical system larger than the lower limit. Furthermore, by setting the lower limit of conditional expression (3) to 0.30, the effect of this embodiment can be further ensured. Furthermore, to further ensure the effect of this embodiment, it is preferable to set the lower limit of conditional expression (3) to 0.33, 0.36, 0.40, 0.42, or even 0.44.

[0022] In the optical system of this embodiment, the effect of this embodiment can be more reliably achieved by setting the upper limit value of conditional expression (2) to 0.85. In order to further ensure the effect of this embodiment, it is preferable to set the upper limit value of conditional expression (2) to 0.80, 0.76, 0.73, 0.70, or even 0.68.

[0023] Furthermore, in the optical system of this embodiment, the effect of this embodiment can be made more certain by setting the lower limit of conditional expression (2) to 0.30. In order to make the effect of this embodiment more certain, it is preferable to set the lower limit of conditional expression (2) to 0.31, 0.33, or even 0.35.

[0024] With the above configuration, it is possible to realize an optical system that is small, lightweight, and has good imaging performance.

[0025] The optical system of this embodiment is an optical system made up of a plurality of lenses, and has, in order from the object side, at least one positive lens component and a negative lens N, and satisfies all of the following conditional expressions. (1) 1.00 < FNo × (TL / f) 2 < 2.50 (4) 0.18 < dN / TL < 0.45 however, FNo: F-number of the optical system when focused at infinity TL: Total optical length of the optical system when focused at infinity f: focal length of the optical system when focused at infinity dN: The distance on the optical axis from the optical system's most object-side surface to the object-side surface of negative lens N

[0026] By satisfying conditional expressions (1) and (4), the optical system of this embodiment can be configured to be small and lightweight on the object side, and excellent imaging performance can be achieved by correcting various aberrations on the image side of the optical system. In this specification, the term "lens component" refers to a single lens or a cemented lens. The optical system of this embodiment can further ensure the effects of this embodiment by setting the upper limit of conditional expression (1) to 2.50. Furthermore, to further ensure the effects of this embodiment, it is preferable to set the upper limit of conditional expression (1) to 2.45, 2.40, 2.35, 2.30, 2.25, 2.20, or even 2.15.

[0027] Furthermore, in the optical system of this embodiment, the effect of this embodiment can be made more certain by setting the lower limit of conditional expression (1) to 1.00. In order to make the effect of this embodiment more certain, it is preferable to set the lower limit of conditional expression (1) to 1.10, 1.20, 1.25, 1.30, or even 1.35.

[0028] In the optical system of this embodiment, the effect of this embodiment can be more reliably achieved by setting the upper limit value of conditional expression (4) to 0.45. In order to further ensure the effect of this embodiment, it is preferable to set the upper limit value of conditional expression (4) to 0.42, 0.40, 0.38, or even 0.36.

[0029] Furthermore, in the optical system of this embodiment, the effect of this embodiment can be made more certain by setting the lower limit of conditional expression (4) to 0.18. To make the effect of this embodiment more certain, it is preferable to set the lower limit of conditional expression (4) to 0.19, 0.20, 0.21, or even 0.22.

[0030] With the above configuration, it is possible to realize an optical system that is small, lightweight, and has good imaging performance.

[0031] The optical system of this embodiment is an optical system made up of a plurality of lenses, has a positive lens component closest to the object, and has a negative lens N that is closest to the object among negative lenses that are arranged closer to the image than the positive lens component, and satisfies all of the following conditional expressions: (1) 1.00 < FNo × (TL / f) 2 < 2.50 (4) 0.18 < dN / TL < 0.45 however, FNo: F-number of the optical system when focused at infinity TL: Total optical length of the optical system when focused at infinity f: focal length of the optical system when focused at infinity dN: The distance on the optical axis from the surface closest to the object in the optical system to the surface of negative lens N closest to the object

[0032] By satisfying conditional expressions (1) and (4), the optical system of this embodiment can be configured to be small and lightweight on the object side, and good imaging performance can be achieved by correcting various aberrations on the image side of the optical system. The optical system of this embodiment can further ensure the effects of this embodiment by setting the upper limit of conditional expression (1) to 2.50. Furthermore, to further ensure the effects of this embodiment, it is preferable to set the upper limit of conditional expression (1) to 2.45, 2.40, 2.35, 2.30, 2.25, 2.20, or even 2.15.

[0033] Furthermore, in the optical system of this embodiment, the effect of this embodiment can be made more certain by setting the lower limit of conditional expression (1) to 1.00. In order to make the effect of this embodiment more certain, it is preferable to set the lower limit of conditional expression (1) to 1.10, 1.20, 1.25, 1.30, or even 1.35.

[0034] In the optical system of this embodiment, the effect of this embodiment can be more reliably achieved by setting the upper limit value of conditional expression (4) to 0.45. In order to further ensure the effect of this embodiment, it is preferable to set the upper limit value of conditional expression (4) to 0.42, 0.40, 0.38, or even 0.36.

[0035] Furthermore, in the optical system of this embodiment, the effect of this embodiment can be made more certain by setting the lower limit of conditional expression (4) to 0.18. To make the effect of this embodiment more certain, it is preferable to set the lower limit of conditional expression (4) to 0.19, 0.20, 0.21, or even 0.22.

[0036] With the above configuration, it is possible to realize an optical system that is small, lightweight, and has good imaging performance.

[0037] Furthermore, it is preferable that the optical system of this embodiment comprises, in order from the object side, a first lens group, a focusing group that moves along the optical axis during focusing, and a rear group, and that the first lens group has a 1A lens group that is positioned on the object side and separated by the largest air gap A within the first lens group, and that the following conditional expression be satisfied: (2) 0.30 < dA / dG1 < 0.85 however, dA: Distance on the optical axis of air gap A dG1: Distance on the optical axis of the first lens group

[0038] The optical system of this embodiment can further reduce the weight of the entire optical system by satisfying conditional expression (2). The optical system of this embodiment can further ensure the effects of this embodiment by setting the upper limit of conditional expression (2) to 0.85. Furthermore, to further ensure the effects of this embodiment, it is preferable to set the upper limit of conditional expression (2) to 0.80, 0.76, 0.73, 0.70, or even 0.68.

[0039] Furthermore, in the optical system of this embodiment, the effect of this embodiment can be made more certain by setting the lower limit of conditional expression (2) to 0.30. In order to make the effect of this embodiment more certain, it is preferable to set the lower limit of conditional expression (2) to 0.31, 0.33, or even 0.35.

[0040] It is also preferable that the optical system of this embodiment satisfies the following conditional expression: (3) 0.30 < TL / f < 0.80

[0041] By satisfying conditional expression (3), the optical system of this embodiment can achieve both compactness and excellent correction of field curvature. By making the ratio of the total optical length of the optical system to the focal length of the optical system smaller than the upper limit, the total length of the optical system can be prevented from becoming too long. Furthermore, by setting the upper limit of conditional expression (3) to 0.80, the effect of this embodiment can be further ensured. Furthermore, to further ensure the effect of this embodiment, it is preferable to set the upper limit of conditional expression (3) to 0.78, 0.76, 0.74, 0.72, or even 0.70.

[0042] The optical system of this embodiment can effectively correct field curvature by making the ratio of the total optical length of the optical system to the focal length of the optical system larger than the lower limit. Furthermore, by setting the lower limit of conditional expression (3) to 0.30, the effect of this embodiment can be further ensured. Furthermore, to further ensure the effect of this embodiment, it is preferable to set the lower limit of conditional expression (3) to 0.33, 0.36, 0.40, 0.42, or even 0.44.

[0043] In the optical system of this embodiment, it is preferable that the first lens group has a positive lens component and a negative lens N.

[0044] Furthermore, it is preferable that the optical system of this embodiment comprises, in order from the object side, a first lens group, a focusing group that moves along the optical axis during focusing, and a rear group, and that the first lens group has a 1A lens group arranged on the object side and a 1B lens group arranged on the image side, separated by the largest air gap A within the first lens group, and that the following conditional expression be satisfied: (5)-2.00 < f1A / f1B < 0.30 however, f1A: Focal length of the 1Ath lens group f1B: Focal length of the 1Bth lens group

[0045] The optical system of this embodiment satisfies conditional expression (5), thereby enabling excellent correction of various aberrations. In the optical system of this embodiment, by making the ratio of the focal length of the 1A lens group to the focal length of the 1B lens group smaller than the upper limit, the power of the 1B lens group does not become excessively positive, enabling excellent correction of spherical aberrations and the like. Furthermore, by setting the upper limit of conditional expression (5) to 0.30, the effect of this embodiment can be further ensured. Furthermore, to further ensure the effect of this embodiment, it is preferable to set the upper limit of conditional expression (5) to 0.25, 0.20, 0.15, 0.10, or even 0.07.

[0046] In the optical system of this embodiment, by making the ratio of the focal length of the 1A lens group to the focal length of the 1B lens group larger than the lower limit, the power of the 1B lens group does not become excessively negative, and coma aberration and the like can be corrected well. Furthermore, by setting the lower limit of conditional expression (5) to -2.00, the effect of this embodiment can be further ensured. Furthermore, to further ensure the effect of this embodiment, it is preferable to set the lower limit of conditional expression (5) to -1.60, -1.30, -1.00, -0.80, or even -0.60.

[0047] Furthermore, it is preferable that the optical system of this embodiment comprises, in order from the object side, a first lens group, a focusing group that moves along the optical axis during focusing, and a rear group, and that the first lens group has a 1A lens group that is positioned on the object side and separated by the largest air gap A within the first lens group, and that the following conditional expression be satisfied: (6) 0.10 < f1A / f < 0.60 however, f1A: focal length of the 1Ath lens group

[0048] By satisfying conditional expression (6), the optical system of this embodiment can achieve both lightweight and excellent correction of coma aberration. By making the ratio of the focal length of the 1A lens group to the focal length of the optical system smaller than the upper limit, the power of the 1A lens group does not weaken, and the diameter of the first lens group excluding the 1A lens group can be reduced, thereby reducing the weight of the optical system. Furthermore, by setting the upper limit of conditional expression (6) to 0.60, the effect of this embodiment can be further ensured. Furthermore, to further ensure the effect of this embodiment, it is preferable to set the upper limit of conditional expression (6) to 0.57, 0.55, 0.52, 0.48, or even 0.45.

[0049] In the optical system of this embodiment, by making the ratio of the focal length of the 1A lens group to the focal length of the optical system larger than the lower limit, the power of the 1A lens group does not become too strong, and coma aberration can be corrected well. Furthermore, by setting the lower limit of conditional expression (6) to 0.10, the effect of this embodiment can be further ensured. Furthermore, to further ensure the effect of this embodiment, it is preferable to set the lower limit of conditional expression (6) to 0.13, 0.16, 0.20, 0.22, or even 0.25.

[0050] Furthermore, it is preferable that the optical system of this embodiment comprises, in order from the object side, a first lens group, a focusing group that moves along the optical axis during focusing, and a rear group, and that the first lens group has a 1B lens group that is positioned on the image side and separated by the largest air gap A within the first lens group, and that the following conditional expression be satisfied: (7) 0.40 < dB / dG1 < 0.85 however, dB: Distance on the optical axis from the surface closest to the object in the optical system to the surface closest to the object in the 1B lens group dG1: Distance on the optical axis of the first lens group

[0051] By satisfying conditional expression (7), the optical system of this embodiment can achieve both weight reduction and excellent correction of spherical aberration. By setting the value of conditional expression (7) smaller than the upper limit, the optical system of this embodiment can effectively correct spherical aberration. Furthermore, by setting the upper limit of conditional expression (7) to 0.85, the effect of this embodiment can be further ensured. Furthermore, to further ensure the effect of this embodiment, it is preferable to set the upper limit of conditional expression (7) to 0.82, 0.80, 0.78, 0.76, or even 0.74.

[0052] In the optical system of this embodiment, by making the value of conditional expression (7) larger than the lower limit, the diameter of the 1B lens group can be made smaller, thereby reducing the weight of the optical system. Also, by setting the lower limit of conditional expression (7) to 0.40, the effect of this embodiment can be made more certain. Furthermore, to make the effect of this embodiment more certain, it is preferable to set the lower limit of conditional expression (7) to 0.44, 0.47, 0.50, 0.52, or even 0.54.

[0053] Furthermore, the optical system of this embodiment comprises, in order from the object side, a first lens group, a focusing group that moves along the optical axis during focusing, and a rear group, and the first lens group has a 1A lens group that is positioned on the object side and separated by the largest air gap A within the first lens group, and it is preferable that the 1A lens group consists of two or less positive lenses.

[0054] The optical system of this embodiment has such a configuration, which makes it possible to reduce the weight.

[0055] Furthermore, it is preferable that the optical system of this embodiment comprises, in order from the object side, a first lens group, a focusing group that moves along the optical axis during focusing, and a rear group, and that the first lens group has a 1A lens group that is positioned on the object side and separated by the largest air gap A within the first lens group, and that the following conditional expression be satisfied: (8) 0.80 < fL1 / fL2 < 3.30 however, fL1: the focal length of the first lens in the firstA lens group that is located closest to the object fL2: The focal length of the second lens element in the 1A lens group, which is the second lens element from the object side

[0056] By satisfying conditional expression (8), the optical system of this embodiment can effectively correct spherical aberration and coma. By making the ratio of the focal length of the first lens to the focal length of the second lens smaller than the upper limit, the optical system of this embodiment can effectively correct coma without the power of the first lens being too weak. Furthermore, by setting the upper limit of conditional expression (8) to 3.30, the effect of this embodiment can be further ensured. Furthermore, to further ensure the effect of this embodiment, it is preferable to set the upper limit of conditional expression (8) to 3.20, 3.10, 3.00, 2.90, or even 2.80.

[0057] In the optical system of this embodiment, by making the ratio of the focal length of the first lens to the focal length of the second lens larger than the lower limit, the power of the first lens does not become too strong, and spherical aberration can be corrected well. Furthermore, by setting the lower limit of conditional expression (8) to 0.80, the effect of this embodiment can be further ensured. Furthermore, to further ensure the effect of this embodiment, it is preferable to set the lower limit of conditional expression (8) to 0.85, 0.90, 0.95, 1.00, or even 1.05.

[0058] Furthermore, the optical system of this embodiment comprises, in order from the object side, a first lens group, a focusing group that moves along the optical axis during focusing, and a rear group, the first lens group having a 1A lens group arranged on the object side and a 1B lens group arranged on the image side, separated by the largest air gap A within the first lens group, and it is preferable that the 1B lens group have at least one positive lens Z that satisfies the following conditional expression: (9)60.00 < νd1Amax - νdLZ however, νd1Amax: the maximum value of the Abbe number of the lens included in the 1A lens group based on the d line νdLZ: Abbe number based on the d line of the positive lens Z

[0059] In the optical system of this embodiment, by making the value of conditional expression (9) larger than the lower limit, the secondary dispersion of axial chromatic aberration can be effectively corrected. Furthermore, by setting the lower limit of conditional expression (9) to 60.00, the effect of this embodiment can be further ensured. Furthermore, to further ensure the effect of this embodiment, it is preferable to set the lower limit of conditional expression (9) to 62.00, 63.00, 64.00, 65.00, or even 66.00.

[0060] Furthermore, it is preferable that the optical system of this embodiment comprises, in order from the object side, a first lens group, a focusing group that moves along the optical axis during focusing, and a rear group, and that the first lens group has a 1A lens group that is positioned on the object side and separated by the largest air gap A within the first lens group, and that the following conditional expression be satisfied: (10)55.00 < νd1Aave however, νd1Aave: average value of Abbe numbers based on the d line of the lenses included in the 1A lens group

[0061] In the optical system of this embodiment, by setting the value of conditional expression (10) greater than the lower limit, axial chromatic aberration and lateral chromatic aberration can be effectively corrected. Furthermore, by setting the lower limit of conditional expression (10) to 55.00, the effects of this embodiment can be further ensured. Furthermore, to further ensure the effects of this embodiment, it is preferable to set the lower limit of conditional expression (10) to 60.00, 65.00, 70.00, 75.00, or even 80.00.

[0062] Furthermore, the optical system of this embodiment comprises, in order from the object side, a first lens group, a focusing group that moves along the optical axis during focusing, and a rear group, and the first lens group has a 1B lens group that is positioned on the image side and separated by the largest air gap A within the first lens group, and it is preferable that the 1B lens group has at least one positive lens Z that satisfies all of the following conditional expressions: (11)ndLZ + (0.01425×νdLZ) < 2.12 (12)νdLZ < 35.00 (13)0.702 < θgFLZ + (0.00316×νdLZ) however, ndLZ: refractive index of positive lens Z for d line νdLZ: Abbe number based on the d line of the positive lens Z θgFLZ: partial dispersion ratio of positive lens Z, which is defined by the following formula when the refractive index of positive lens Z for the g-line is ngLZ, the refractive index of positive lens Z for the F-line is nFLZ, and the refractive index of positive lens Z for the C-line is nCLZ. θgFLZ = (ngLZ - nFLZ) / (nFLZ - nCLZ)

[0063] The optical system of this embodiment, having such a configuration, can effectively correct various aberrations. By making the value of conditional expression (11) smaller than the upper limit, the optical system of this embodiment can effectively correct field curvature without the Petzval sum becoming too small. Furthermore, by setting the upper limit of conditional expression (11) to 2.12, the effect of this embodiment can be further ensured. Furthermore, to further ensure the effect of this embodiment, it is preferable to set the upper limit of conditional expression (11) to 2.10, 2.09, 2.08, 2.07, or even 2.06.

[0064] In the optical system of this embodiment, by setting the value of conditional expression (12) smaller than the upper limit, the secondary dispersion of axial chromatic aberration can be effectively corrected. Furthermore, by setting the upper limit of conditional expression (12) to 35.00, the effect of this embodiment can be further ensured. Furthermore, to further ensure the effect of this embodiment, it is preferable to set the upper limit of conditional expression (12) to 33.00, 31.00, 30.50, 30.00, or even 29.50.

[0065] In the optical system of this embodiment, by making the value of conditional expression (13) larger than the lower limit, the secondary dispersion of axial chromatic aberration can be effectively corrected. Furthermore, by setting the upper limit of conditional expression (13) to 0.702, the effect of this embodiment can be further ensured. Furthermore, to further ensure the effect of this embodiment, it is preferable to set the upper limit of conditional expression (13) to 0.704, 0.707, 0.710, 0.712, or even 0.715.

[0066] Furthermore, it is preferable that the optical system of this embodiment comprises, in order from the object side, a first lens group, a focusing group that moves along the optical axis during focusing, and a rear group, and that the first lens group has a 1A lens group that is positioned on the object side and separated by the largest air gap A within the first lens group, and that the following conditional expression be satisfied: (14)0.00 < (L1R2+L1R1) / (L1R2-L1R1) < 3.00 however, L1R1: Radius of curvature of the object-side surface of the first lens element located closest to the object L1R2: Radius of curvature of the image-side surface of the first lens

[0067] The optical system of this embodiment can effectively correct spherical aberration and coma by satisfying conditional expression (14). The optical system of this embodiment can effectively correct spherical aberration by making the value of conditional expression (14) smaller than the upper limit. Furthermore, by setting the upper limit of conditional expression (14) to 3.00, the effect of this embodiment can be further ensured. Furthermore, to further ensure the effect of this embodiment, it is preferable to set the upper limit of conditional expression (14) to 2.70, 2.50, 2.20, 2.00, or even 1.80.

[0068] In the optical system of this embodiment, coma can be effectively corrected by setting the value of conditional expression (14) greater than the lower limit. Furthermore, by setting the lower limit of conditional expression (14) to 0.00, the effect of this embodiment can be further ensured. Furthermore, to further ensure the effect of this embodiment, it is preferable to set the lower limit of conditional expression (14) to 0.20, 0.40, 0.50, 0.60, or even 0.70.

[0069] Furthermore, it is preferable that the optical system of this embodiment comprises, in order from the object side, a first lens group, a focusing group that moves along the optical axis during focusing, and a rear group, and that the first lens group has a 1A lens group that is positioned on the object side and separated by the largest air gap A within the first lens group, and that the following conditional expression be satisfied: (15)0.00 < (L2R2+L2R1) / (L2R2-L2R1) < 3.50 however, L2R1: Radius of curvature of the object-side surface of the second lens element located second from the object side in the 1A lens group L2R2: Radius of curvature of the image side of the second lens

[0070] The optical system of this embodiment can effectively correct spherical aberration and coma by satisfying conditional expression (15). The optical system of this embodiment can effectively correct spherical aberration by making the value of conditional expression (15) smaller than the upper limit. Furthermore, by setting the upper limit of conditional expression (14) to 3.50, the effect of this embodiment can be further ensured. Furthermore, to further ensure the effect of this embodiment, it is preferable to set the upper limit of conditional expression (15) to 3.20, 3.00, 2.80, 2.60, or even 2.40.

[0071] In the optical system of this embodiment, coma can be effectively corrected by setting the value of conditional expression (15) greater than the lower limit. Furthermore, the effect of this embodiment can be further ensured by setting the lower limit of conditional expression (15) to 0.00. Furthermore, to further ensure the effect of this embodiment, it is preferable to set the lower limit of conditional expression (15) to 0.20, 0.50, 0.80, 1.00, or even 1.20.

[0072] Furthermore, the optical system of this embodiment comprises, in order from the object side, a first lens group, a focusing group that moves along the optical axis during focusing, and a rear group, and it is preferable that the following conditional expression be satisfied: (16)0.10 < f1 / f < 0.60 however, f1: focal length of the first lens group

[0073] By satisfying conditional expression (16), the optical system of this embodiment can achieve both compactness and excellent correction of spherical aberration. By making the ratio of the focal length of the first lens group to the focal length of the optical system smaller than the upper limit, the power of the first lens group does not become too weak, making it possible to compact the optical system. Furthermore, by setting the upper limit of conditional expression (16) to 0.60, the effect of this embodiment can be further ensured. Furthermore, to further ensure the effect of this embodiment, it is preferable to set the upper limit of conditional expression (16) to 0.56, 0.53, 0.50, 0.48, or even 0.45.

[0074] In the optical system of this embodiment, by making the value of conditional expression (16) larger than the lower limit, the power of the first lens group does not become too strong, and spherical aberration can be corrected well. Furthermore, by setting the lower limit of conditional expression (16) to 0.10, the effect of this embodiment can be further ensured. Furthermore, to further ensure the effect of this embodiment, it is preferable to set the lower limit of conditional expression (16) to 0.14, 0.18, 0.22, 0.25, or even 0.28.

[0075] Furthermore, the optical system of this embodiment comprises, in order from the object side, a first lens group, a focusing group that moves along the optical axis during focusing, and a rear group, and it is preferable that the following conditional expression be satisfied: (17)0.20 < (-fF) / f1 < 0.85 however, fF: focal length of focusing group f1: focal length of the first lens group

[0076] By satisfying conditional expression (17), the optical system of this embodiment can effectively correct various spherical aberrations from infinity to close distances. In the optical system of this embodiment, by making the ratio of the focal length of the focusing group to the focal length of the first lens group smaller than the upper limit, the power of the focusing group does not become too weak, thereby suppressing fluctuations in field curvature. Furthermore, by setting the upper limit of conditional expression (17) to 0.85, the effects of this embodiment can be further ensured. Furthermore, to further ensure the effects of this embodiment, it is preferable to set the upper limit of conditional expression (17) to 0.80, 0.77, 0.75, 0.72, or even 0.65.

[0077] In the optical system of this embodiment, by making the ratio of the focal length of the focusing group to the focal length of the first lens group larger than the lower limit, the power of the focusing group does not become too strong, and fluctuations in axial chromatic aberration can be suppressed. Furthermore, by setting the lower limit of conditional expression (17) to 0.20, the effect of this embodiment can be further ensured. Furthermore, to further ensure the effect of this embodiment, it is preferable to set the lower limit of conditional expression (17) to 0.24, 0.28, 0.32, 0.36, or even 0.40.

[0078] Furthermore, the optical system of this embodiment comprises, in order from the object side, a first lens group, a focusing group that moves along the optical axis during focusing, and a rear group, and it is preferable that the following conditional expression be satisfied: (18)-1.50 < (-fF) / fR < 0.60 however, fF: focal length of focusing group fR: focal length of rear group

[0079] The optical system of this embodiment can satisfactorily correct various aberrations by satisfying conditional expression (18). In the optical system of this embodiment, by making the value of conditional expression (18) smaller than the upper limit, the power of the focusing group does not become too weak, and field curvature can be satisfactorily corrected. Furthermore, by setting the upper limit of conditional expression (18) to 0.60, the effect of this embodiment can be further ensured. Furthermore, to further ensure the effect of this embodiment, it is preferable to set the upper limit of conditional expression (18) to 0.50, 0.40, 0.30, 0.20, or even 0.10.

[0080] In the optical system of this embodiment, by making the value of conditional expression (18) larger than the lower limit, the power of the focusing group does not become too strong, and lateral chromatic aberration can be corrected well. Furthermore, by setting the lower limit of conditional expression (18) to -1.50, the effect of this embodiment can be further ensured. Furthermore, to further ensure the effect of this embodiment, it is preferable to set the lower limit of conditional expression (18) to -1.40, -1.30, -1.20, -1.10, or even -1.00.

[0081] Furthermore, the optical system of this embodiment comprises, in order from the object side, a first lens group, a focusing group that moves along the optical axis during focusing, and a rear group, and it is preferable that the following conditional expression be satisfied: (19) 0.30 < dF / TL < 0.70 however, dF: The distance on the optical axis from the surface closest to the object in the optical system to the surface closest to the object in the focusing group

[0082] By satisfying conditional expression (19), the optical system of this embodiment can achieve both faster focusing by reducing the weight of the focusing group and suppressing fluctuations in field curvature. By setting the value of conditional expression (19) smaller than the upper limit, the optical system of this embodiment can prevent the focusing group from being positioned too far back, thereby suppressing fluctuations in field curvature. Furthermore, by setting the upper limit of conditional expression (19) to 0.70, the effects of this embodiment can be further ensured. Furthermore, to further ensure the effects of this embodiment, it is preferable to set the upper limit of conditional expression (19) to 0.67, 0.64, 0.61, 0.58, or even 0.56.

[0083] In the optical system of this embodiment, by making the value of conditional expression (19) larger than the lower limit, the position of the focusing group is not too forward, and the focusing group can be made lighter. Furthermore, by setting the lower limit of conditional expression (19) to 0.30, the effect of this embodiment can be further ensured. Furthermore, to further ensure the effect of this embodiment, it is preferable to set the lower limit of conditional expression (19) to 0.32, 0.34, 0.36, 0.38, or even 0.40.

[0084] Furthermore, the optical system of this embodiment comprises, in order from the object side, a first lens group, a focusing group that moves along the optical axis during focusing, and a rear group, and it is preferable that the following conditional expression be satisfied: (20)40.00 < νdFave however, νdFave: Average Abbe number based on the d-line of the lenses included in the focusing group

[0085] In the optical system of this embodiment, by making the value of conditional expression (20) larger than the lower limit, axial chromatic aberration can be effectively corrected from infinity to close distances. Furthermore, by setting the lower limit of conditional expression (20) to 40.00, the effect of this embodiment can be further ensured. Furthermore, to further ensure the effect of this embodiment, it is preferable to set the lower limit of conditional expression (20) to 50.00, 55.00, 60.00, 65.00, or even 70.00.

[0086] It is also preferable that the optical system of this embodiment satisfies the following conditional expression: (21)1.00° < 2ω < 20.00° however, 2ω: Full angle of view of the optical system

[0087] Conditional expression (21) sets an appropriate value for the total angle of view of the optical system of this embodiment. By satisfying conditional expression (21), fluctuations in various aberrations, such as coma, field curvature, and distortion, that occur during focusing can be suppressed. Furthermore, by setting the upper limit of conditional expression (21) to 20.00°, the effects of this embodiment can be further ensured. Furthermore, to further ensure the effects of this embodiment, it is preferable to set the upper limit of conditional expression (21) to 18.00°, 16.00°, 14.00°, 12.00°, or even 10.00°.

[0088] Furthermore, by setting the lower limit of conditional expression (21) to 1.00°, the effect of this embodiment can be further ensured. Furthermore, in order to further ensure the effect of this embodiment, it is preferable to set the lower limit of conditional expression (21) to 1.50°, 2.00°, 2.20°, 2.50°, or even 2.80°.

[0089] It is also preferable that the optical system of this embodiment satisfies the following conditional expression: (22)0.075 < Bf / f < 0.185 however, Bf: Back focus of the optical system

[0090] By satisfying conditional expression (22), the optical system of this embodiment can be made both compact and lightweight. By making the ratio of the back focus to the focal length of the optical system smaller than the upper limit, the back focus does not become too long, and the overall length can be shortened. Furthermore, by setting the upper limit of conditional expression (22) to 0.185, the effect of this embodiment can be made more certain. Furthermore, to make the effect of this embodiment more certain, it is preferable to set the upper limit of conditional expression (22) to 0.180, 0.175, 0.170, 0.165, or even 0.160.

[0091] In the optical system of this embodiment, by making the ratio of the back focus to the focal length of the optical system larger than the lower limit, the back focus is appropriately ensured and the optical system can be made lighter. Furthermore, by setting the lower limit of conditional expression (22) to 0.075, the effect of this embodiment can be further ensured. Furthermore, to further ensure the effect of this embodiment, it is preferable to set the lower limit of conditional expression (22) to 0.080, 0.082, 0.085, 0.088, or even 0.090.

[0092] Furthermore, the optical system of this embodiment preferably comprises, in order from the object side, a first lens group, a focusing group that moves along the optical axis during focusing, and a rear group, and the rear group preferably has an image stabilizing lens group that is movable so as to have a component in a direction perpendicular to the optical axis in order to correct image blur.

[0093] The optical system of this embodiment has such a configuration, and can effectively correct image blur.

[0094] With the above configuration, it is possible to realize an optical system that is small, lightweight, and has good imaging performance.

[0095] The optical apparatus of this embodiment has the optical system configured as described above, which makes it possible to realize an optical apparatus that is small, lightweight, and has good imaging performance.

[0096] The manufacturing method for the optical system of this embodiment is a manufacturing method for an optical system consisting of multiple lenses, and arranges, in order from the object side, a first lens group having positive refractive power, a focusing group that moves along the optical axis during focusing, and a rear group, and arranges a 1A lens group on the object side separated by the largest air gap A within the first lens group, and arranges them so as to satisfy all of the following conditional expressions: (1) 1.00 < FNo × (TL / f) 2 < 2.50 (2) 0.30 < dA / dG1 < 0.85 however, FNo: F-number of the optical system when focused at infinity TL: Total optical length of the optical system when focused at infinity f: focal length of the optical system when focused at infinity dA: Distance on the optical axis of air gap A dG1: Distance on the optical axis of the first lens group

[0097] The manufacturing method for the optical system of this embodiment is a manufacturing method for an optical system consisting of multiple lenses, and arranges, in order from the object side, at least one positive lens component and a negative lens N so as to satisfy all of the following conditional expressions: (1) 1.00 < FNo × (TL / f) 2 < 2.50 (4) 0.18 < dN / TL < 0.45 however, FNo: F-number of the optical system when focused at infinity TL: Total optical length of the optical system when focused at infinity f: focal length of the optical system when focused at infinity dN: The distance on the optical axis from the optical system's most object-side surface to the object-side surface of negative lens N

[0098] By using such a manufacturing method for an optical system, it is possible to manufacture an optical system that is small, lightweight, and has good imaging performance.

[0099] (Numerical example) Hereinafter, embodiments of the present invention will be described with reference to the drawings.

[0100] (First Example) FIG. 1A is a cross-sectional view of the optical system of the first embodiment when focusing on an object at infinity, and FIG. 1B is a cross-sectional view of the optical system of the first embodiment when focusing on an object at a close distance.

[0101] The optical system of this embodiment includes, in order from the object side, a first lens group G1 having positive refractive power, a focusing group GF having negative refractive power, and a rear group GR having negative refractive power. An aperture stop S is disposed between the first lens group G1 and the focusing group GF. The first lens group G1 includes, separated by the largest air gap A within the first lens group, a first-A lens group G1A having positive refractive power disposed on the object side and a first-B lens group G1B having negative refractive power disposed on the image side.

[0102] The first-A lens group G1A is composed of, in order from the object side, a positive meniscus lens L1 with a convex surface facing the object side, and a positive meniscus lens L2 with a convex surface facing the object side.

[0103] The 1Bth lens group G1B consists of, in order from the object side, a cemented negative lens consisting of a positive meniscus lens L3 with a convex surface facing the object side and a negative meniscus lens L4 with a convex surface facing the object side, a positive meniscus lens L5 with a convex surface facing the object side, and a cemented positive lens consisting of a biconvex positive lens L6 and a biconcave negative lens L7.

[0104] The focusing group GF is made up of a negative meniscus lens L8 with its convex surface facing the object side.

[0105] The rear group GR consists of, in order from the object side, a positive meniscus lens L9 with its convex surface facing the image side, a cemented negative lens consisting of a biconvex positive lens L10 and a biconcave negative lens L11, a biconcave negative lens L12, a cemented positive lens consisting of a biconvex positive lens L13 and a biconcave negative lens L14, a cemented positive lens consisting of a negative meniscus lens L15 with its convex surface facing the object side and a biconvex positive lens L16, a cemented negative lens consisting of a biconcave negative lens L17 and a positive meniscus lens L18 with its convex surface facing the object side, and a biconvex positive lens L19.

[0106] On the image plane I, an image pickup element (not shown) made up of a CCD, a CMOS, or the like is disposed.

[0107] The optical system of this embodiment focuses by moving the focusing group GF along the optical axis. When focusing on a close object from a state focused on infinity, the focusing group GF is moved from the object side to the image side.

[0108] In the optical system of this embodiment, among the lenses in the rear group GR, the cemented negative lens of a positive lens L10 and a negative lens L11, and the negative lens L12 are configured as vibration-proof lens groups that are movable so as to have a component in a direction perpendicular to the optical axis in order to correct image blur.

[0109] In the optical system of this embodiment, the positive meniscus lens L1 corresponds to the first lens, the positive meniscus lens L2 corresponds to the second lens, the negative meniscus lens L4 corresponds to the negative lens N, and the positive lens L6 corresponds to the positive lens Z.

[0110] In the optical system of this embodiment, dA is the distance on the optical axis between the image-side surface of the positive meniscus lens L2 and the object-side surface of the positive meniscus lens L3. Also, dG1 is the distance on the optical axis between the object-side surface of the positive meniscus lens L1 and the image-side surface of the negative lens L7. Also, dB is the distance on the optical axis between the object-side surface of the positive meniscus lens L1 and the object-side surface of the positive meniscus lens L3. Also, dN is the distance on the optical axis between the object-side surface of the positive meniscus lens L1 and the object-side surface of the negative meniscus lens L4. Note that dA, dG1, dB, and dN are omitted from the cross-sectional views of the optical systems of other embodiments described below.

[0111] The values ​​of the specifications of the optical system of this example are listed in Table 1 below. In Table 1, f is the focal length of the optical system when focused at infinity, Fno is the F-number of the optical system when focused at infinity, TL is the total optical length of the optical system when focused at infinity, and Bf is the back focus of the optical system.

[0112] In the [lens specifications], m is the order of the optical surface counted from the object side, r is the radius of curvature, d is the surface spacing, nd is the refractive index for the d-line (wavelength 587.6 nm), and νd is the Abbe number for the d-line. Also, in the [lens specifications], the radius of curvature r=∞ indicates a flat surface.

[0113] The units of focal length f, radius of curvature r, and other lengths listed in Table 1 are "mm." However, this is not limited to this, as the same optical performance can be obtained even when the optical system is proportionally enlarged or reduced.

[0114] The symbols in Table 1 described above will be used in the same manner in tables of other embodiments described later.

[0115] (Table 1) [Overall specifications] f 292.50 Fno 4.10 Bf 35.641 Image height 21.700 TL 190.638 2ω 8.43 [Lens specifications] mrd nd νd 1) 125.140 6.663 1.537750 74.70 2) 1851.356 0.150 3) 59.805 10.676 1.437001 95.10 4) 262.678 28.838 5) 46.054 7.325 1.437001 95.10 6) 4710.018 1.600 1.902650 35.72 7) 30.903 1.232 8) 31.124 7.235 1.437001 95.10 9) 211.923 4.436 10) 64.379 5.654 1.663820 27.35 11) -76.867 1.300 1.654115 39.68 12) 84.138 4.271 13> ∞ D13 (aperture stop) 14) 898.004 1.100 1.496997 81.61 15) 37.914 D15 16) -122.862 2.483 1.487490 70.32 17) -51.275 1.500 18) 212.753 3.300 1.620040 36.40 19) -38.078 1.100 1.593190 67.90 20) 42.404 1.650 21) -1123.057 1.100 1.593490 67.00 22) 48.084 1.500 23) 36.980 7.966 1.612660 44.46 24) -28.819 1.300 1.593190 67.90 25) 237.490 2.000 26) 60.518 1.300 1.922860 20.88 27) 21.378 7.261 1.720467 34.71 28) -1990.403 5.379 29) -44.860 1.300 1.816000 46.59 30) 36.494 4.671 1.737999 32.33 31) 197.557 0.500 32) 53.113 5.700 1.581440 40.98 33) -118.041 Bf [Focal length data for each group] Group starting plane focal length G1 1 121.914 G1A 1 103.249 G1B 5 -276.316 GF 14 -79.683 GR 16 -342.518 f1 1 -48.395 f2 6 105.403 f3 9 64.392 f4 13 -112.410 f5 19 134.882 f6 22 81.543 f7 24 -60.633 [Variable Interval Data] When focusing on infinity When focusing on a short distance object D13 4.000 19.946 D15 20.506 4.560

[0116] FIG. 2 is a diagram showing various aberrations of the optical system of the first embodiment when focused on an object at infinity.

[0117] In each aberration diagram, FNO indicates the F-number, and Y indicates the image height. More specifically, spherical aberration diagrams indicate the F-number value corresponding to the maximum aperture, astigmatism diagrams and distortion diagrams indicate the maximum image height, and coma diagrams indicate the value of each image height. d indicates the d-line, and g indicates the g-line (wavelength 435.8 nm). In astigmatism diagrams, the solid line indicates the sagittal image plane, and the dashed line indicates the meridional image plane. The same symbols as those used in the aberration diagrams of this embodiment are used in the aberration diagrams of other embodiments described below.

[0118] From each aberration diagram, it can be seen that the optical system of this embodiment effectively suppresses aberration fluctuations during focusing and has high optical performance.

[0119] (Second Example) FIG. 3A is a cross-sectional view of the optical system of the second embodiment when focusing on an object at infinity, and FIG. 3B is a cross-sectional view of the optical system of the second embodiment when focusing on an object at a close distance.

[0120] The optical system of this embodiment includes, in order from the object side, a first lens group G1 having positive refractive power, a focusing group GF having negative refractive power, and a rear group GR having positive refractive power. An aperture stop S is disposed between the first lens group G1 and the focusing group GF. The first lens group G1 includes, separated by the largest air gap A within the first lens group, a first-A lens group G1A having positive refractive power disposed on the object side, and a first-B lens group G1B having negative refractive power disposed on the image side.

[0121] The first-A lens group G1A is composed of, in order from the object side, a positive meniscus lens L1 with a convex surface facing the object side, and a positive meniscus lens L2 with a convex surface facing the object side.

[0122] The 1Bth lens group G1B consists of, in order from the object side, a cemented negative lens consisting of a biconvex positive lens L3 and a biconcave negative lens L4, a positive meniscus lens L5 with its convex surface facing the object side, and a cemented positive lens consisting of a biconvex positive lens L6 and a biconcave negative lens L7.

[0123] The focusing group GF is made up of a biconcave negative lens L8.

[0124] The rear group GR consists of, in order from the object side, a positive meniscus lens L9 with its convex surface facing the image side, a cemented negative lens consisting of a biconvex positive lens L10 and a biconcave negative lens L11, a biconcave negative lens L12, a cemented positive lens consisting of a biconvex positive lens L13 and a negative meniscus lens L14 with its convex surface facing the image side, a cemented positive lens consisting of a negative meniscus lens L15 with its convex surface facing the object side and a positive meniscus lens L16 with its convex surface facing the object side, a cemented negative lens consisting of a biconcave negative lens L17 and a positive meniscus lens L18 with its convex surface facing the object side, and a biconvex positive lens L19.

[0125] On the image plane I, an image pickup element (not shown) made up of a CCD, a CMOS, or the like is disposed.

[0126] The optical system of this embodiment focuses by moving the focusing group GF along the optical axis. When focusing on a close object from a state focused on infinity, the focusing group GF is moved from the object side to the image side.

[0127] In the optical system of this embodiment, among the lenses in the rear group GR, the cemented negative lens of a positive lens L10 and a negative lens L11, and the negative lens L12 are configured as vibration-proof lens groups that are movable so as to have a component in a direction perpendicular to the optical axis in order to correct image blur.

[0128] In the optical system of this embodiment, the positive meniscus lens L1 corresponds to the first lens, the positive meniscus lens L2 corresponds to the second lens, the negative lens L4 corresponds to the negative lens N, and the positive lens L6 corresponds to the positive lens Z.

[0129] In the optical system of this embodiment, dA is the distance on the optical axis between the image-side surface of the positive meniscus lens L2 and the object-side surface of the positive lens L3. dG1 is the distance on the optical axis between the object-side surface of the positive meniscus lens L1 and the image-side surface of the negative lens L7. dB is the distance on the optical axis between the object-side surface of the positive meniscus lens L1 and the object-side surface of the positive lens L3. dN is the distance on the optical axis between the object-side surface of the positive meniscus lens L1 and the object-side surface of the negative lens L4.

[0130] Table 2 below lists the specifications of the optical system of this example.

[0131] (Table 2) [Overall specifications] f 390.00 Fno 4.10 Bf 60.901 Image height 21.700 TL 267.445 2ω 6.30 [Lens specifications] mrd nd νd 1) 187.004 7.233 1.537750 74.70 2) 1083.302 0.200 3) 90.597 12.867 1.433837 95.16 4) 430.769 53.926 5) 60.452 9.061 1.437001 95.10 6) -2517.992 2.200 1.902650 35.72 7) 43.878 1.547 8) 43.725 8.825 1.437001 95.10 9) 492.119 11.552 10) 89.096 6.561 1.663820 27.35 11) -94.634 1.600 1.654115 39.68 12) 141.270 6.541 13> ∞ D13 (aperture stop) 14) -2070.936 1.200 1.496997 81.61 15) 46.571 D15 16) -370.106 2.907 1.487490 70.32 17) -72.395 1.500 18) 178.417 3.000 1.737999 32.33 19) -91.168 1.100 1.593190 67.90 20) 49.487 2.200 21) -130.831 1.100 1.593490 67.00 22) 65.238 2.000 23) 47.376 9.008 1.579570 53.74 24) -30.682 1.400 1.593190 67.90 25) -219.958 2.409 26) 72.361 1.400 1.922860 20.88 27) 26.665 6.906 1.720467 34.71 28) 352.438 3.947 29) -84.126 1.400 1.816000 46.59 30) 35.011 5.000 1.737999 32.33 31) 83.719 2.000 32) 67.601 5.368 1.801000 34.92 33) -179.297 Bf [Focal length data for each group] Group starting plane focal length G1 1 168.518 G1A 1 161.845 G1B 5 -1807.658 GF 14 -91.627 GR 16 1823.408 [Variable Interval Data] When focusing on infinity When focusing on a short distance object D13 6.480 23.792 D15 24.107 6.795

[0132] FIG. 4 is a diagram showing various aberrations of the optical system of the second embodiment when focused on an object at infinity.

[0133] From each aberration diagram, it can be seen that the optical system of this embodiment effectively suppresses aberration fluctuations during focusing and has high optical performance.

[0134] (Third Example) FIG. 5A is a cross-sectional view of the optical system of the third embodiment when focused on an object at infinity, and FIG. 5B is a cross-sectional view of the optical system of the third embodiment when focused on an object at a close distance.

[0135] The optical system of this embodiment includes, in order from the object side, a first lens group G1 having positive refractive power, a focusing group GF having negative refractive power, and a rear group GR having negative refractive power. An aperture stop S is disposed between the first lens group G1 and the focusing group GF. The first lens group G1 includes, separated by the largest air gap A within the first lens group, a first-A lens group G1A having positive refractive power disposed on the object side and a first-B lens group G1B having negative refractive power disposed on the image side.

[0136] The first-A lens group G1A is composed of, in order from the object side, a positive meniscus lens L1 with a convex surface facing the object side, and a positive meniscus lens L2 with a convex surface facing the object side.

[0137] The 1Bth lens group G1B consists of, in order from the object side, a cemented negative lens consisting of a biconvex positive lens L3 and a biconcave negative lens L4, a positive meniscus lens L5 with its convex surface facing the object side, and a cemented positive lens consisting of a biconvex positive lens L6 and a biconcave negative lens L7.

[0138] The focusing group GF is made up of a biconcave negative lens L8.

[0139] The rear group GR consists of, in order from the object side, a positive meniscus lens L9 with its convex surface facing the image side, a cemented negative lens consisting of a biconvex positive lens L10 and a biconcave negative lens L11, a biconcave negative lens L12, a cemented positive lens consisting of a biconvex positive lens L13 and a negative meniscus lens L14 with its convex surface facing the image side, a cemented negative lens consisting of a biconcave negative lens L15 and a biconvex positive lens L16, a cemented negative lens consisting of a biconcave negative lens L17 and a biconvex positive lens L18, and a positive meniscus lens L19 with its convex surface facing the object side.

[0140] On the image plane I, an image pickup element (not shown) made up of a CCD, a CMOS, or the like is disposed.

[0141] The optical system of this embodiment focuses by moving the focusing group GF along the optical axis. When focusing on a close object from a state focused on infinity, the focusing group GF is moved from the object side to the image side.

[0142] In the optical system of this embodiment, among the lenses in the rear group GR, the cemented negative lens of a positive lens L10 and a negative lens L11, and the negative lens L12 are configured as vibration-proof lens groups that are movable so as to have a component in a direction perpendicular to the optical axis in order to correct image blur.

[0143] In the optical system of this embodiment, the positive meniscus lens L1 corresponds to the first lens, the positive meniscus lens L2 corresponds to the second lens, the negative lens L4 corresponds to the negative lens N, and the positive lens L6 corresponds to the positive lens Z.

[0144] In the optical system of this embodiment, dA is the distance on the optical axis between the image-side surface of the positive meniscus lens L2 and the object-side surface of the positive lens L3. dG1 is the distance on the optical axis between the object-side surface of the positive meniscus lens L1 and the image-side surface of the negative lens L7. dB is the distance on the optical axis between the object-side surface of the positive meniscus lens L1 and the object-side surface of the positive lens L3. dN is the distance on the optical axis between the object-side surface of the positive meniscus lens L1 and the object-side surface of the negative lens L4.

[0145] Table 3 below lists the specifications of the optical system of this example.

[0146] (Table 3) [Overall specifications] f 390.00 Fno 4.60 Bf 55.218 Image height 21.700 TL 243.435 2ω 6.30 [Lens specifications] mrd nd νd 1) 221.433 5.870 1.537750 74.70 2) 4228.581 0.300 3) 81.234 11.748 1.437001 95.10 4) 472.777 48.082 5) 53.231 8.876 1.437001 95.10 6) -626.318 2.000 1.900430 37.37 7) 42.149 1.500 8) 41.831 7.935 1.437001 95.10 9) 1105.379 11.821 10) 109.247 5.876 1.663820 27.35 11) -70.652 1.500 1.672999 38.26 12) 195.927 7.351 13> ∞ D13 (aperture stop) 14) -1280.351 1.200 1.496997 81.61 15) 43.128 D15 16) -115.551 2.531 1.487490 70.32 17) -51.834 2.000 18) 184.433 3.000 1.647690 33.72 19) -50.330 1.100 1.593190 67.90 20) 44.097 2.000 21) -159.759 1.100 1.593490 67.00 22) 56.912 2.000 23) 35.605 6.762 1.737999 32.33 24) -45.880 1.400 1.763850 48.49 25) -190.397 2.000 26) -742.135 1.400 1.922860 20.88 27) 23.106 7.608 1.620040 36.40 28) -75.897 3.414 29) -37.788 1.400 1.763850 48.49 30) 38.546 6.695 1.737999 32.33 31) -86.210 0.200 32) 52.571 3.600 1.581440 40.98 33) 147.363 Bf [Focal length data for each group] Group starting plane focal length G1 1 150.216 G1A 1 147.690 G1B 5 -2684.159 GF 14 -89.923 GR 16 -443.717 [Variable Interval Data] When focusing on infinity When focusing on a short distance object D13 5.381 19.508 D15 20.568 6.440

[0147] FIG. 6 is a diagram showing various aberrations of the optical system of the third embodiment when focused on an object at infinity.

[0148] From each aberration diagram, it can be seen that the optical system of this embodiment effectively suppresses aberration fluctuations during focusing and has high optical performance.

[0149] (Fourth Example) FIG. 7A is a cross-sectional view of the optical system of the fourth embodiment when focused on an object at infinity, and FIG. 7B is a cross-sectional view of the optical system of the fourth embodiment when focused on an object at a close distance.

[0150] The optical system of this embodiment includes, in order from the object side, a first lens group G1 having positive refractive power, a focusing group GF having negative refractive power, and a rear group GR having negative refractive power. An aperture stop S is disposed between the first lens group G1 and the focusing group GF. The first lens group G1 includes, separated by the largest air gap A within the first lens group, a first-A lens group G1A having positive refractive power disposed on the object side and a first-B lens group G1B having negative refractive power disposed on the image side.

[0151] The first-A lens group G1A is composed of, in order from the object side, a positive meniscus lens L1 with a convex surface facing the object side, and a positive meniscus lens L2 with a convex surface facing the object side.

[0152] The 1Bth lens group G1B consists of, in order from the object side, a cemented negative lens consisting of a positive meniscus lens L3 with a convex surface facing the object side and a negative meniscus lens L4 with a convex surface facing the object side, a positive meniscus lens L5 with a convex surface facing the object side, and a cemented positive lens consisting of a biconvex positive lens L6 and a biconcave negative lens L7.

[0153] The focusing group GF is made up of a negative meniscus lens L8 with its convex surface facing the object side.

[0154] The rear group GR consists of, in order from the object side, a positive meniscus lens L9 with its convex surface facing the image side, a cemented negative lens consisting of a biconvex positive lens L10 and a biconcave negative lens L11, a biconcave negative lens L12, a cemented positive lens consisting of a biconvex positive lens L13 and a biconcave negative lens L14, a cemented negative lens consisting of a negative meniscus lens L15 with its convex surface facing the object side and a biconvex positive lens L16, a cemented negative lens consisting of a biconcave negative lens L17 and a biconvex positive lens L18, and a positive meniscus lens L19 with its convex surface facing the object side.

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

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

[0157] In the optical system of this embodiment, among the lenses in the rear group GR, the cemented negative lens of a positive lens L10 and a negative lens L11, and the negative lens L12 are configured as vibration-proof lens groups that are movable so as to have a component in a direction perpendicular to the optical axis in order to correct image blur.

[0158] In the optical system of this embodiment, the positive meniscus lens L1 corresponds to the first lens, the positive meniscus lens L2 corresponds to the second lens, the negative meniscus lens L4 corresponds to the negative lens N, and the positive lens L6 corresponds to the positive lens Z.

[0159] In the optical system of this embodiment, dA is the distance on the optical axis between the image-side surface of the positive meniscus lens L2 and the object-side surface of the positive meniscus lens L3. Also, dG1 is the distance on the optical axis between the object-side surface of the positive meniscus lens L1 and the image-side surface of the negative lens L7. Also, dB is the distance on the optical axis between the object-side surface of the positive meniscus lens L1 and the object-side surface of the positive meniscus lens L3. Also, dN is the distance on the optical axis between the object-side surface of the positive meniscus lens L1 and the object-side surface of the negative meniscus lens L4.

[0160] Table 4 below lists the specifications of the optical system of this example.

[0161] (Table 4) [Overall specifications] f 390.00 Fno 5.77 Bf 54.579 Image height 21.700 TL 221.435 2ω 6.35 [Lens specifications] mrd nd νd 1) 129.411 6.119 1.497000 81.61 2) 4105.548 0.300 3) 61.730 9.074 1.437000 95.00 4) 230.361 35.312 5) 48.186 5.994 1.437000 95.00 6) 581.000 2.000 1.902650 35.73 7) 34.413 2.138 8) 35.952 5.925 1.437000 95.00 9) 353.395 6.718 10) 70.865 4.563 1.663820 27.35 11) -93.974 1.300 1.785900 44.17 12) 95.404 12.499 13> ∞ D13 (aperture stop) 14) 9370.670 1.200 1.497000 81.61 15) 37.965 D15 16) -85.435 2.194 1.487490 70.31 17) -44.298 1.500 18) 442.035 2.700 1.595509 39.24 19) -37.068 1.200 1.593190 67.90 20) 43.657 2.000 21) -387.508 1.200 1.593490 67.00 22) 68.415 2.000 23) 30.027 6.830 1.581440 40.98 24) -33.765 1.400 1.593190 67.90 25) 639.490 2.500 26) 97.030 1.400 1.922860 20.88 27) 20.045 6.147 1.620040 36.40 28)-13075.855 4.849 29) -31.154 1.400 1.816000 46.59 30) 42.152 7.769 1.738000 32.26 31) -42.051 0.200 32) 45.857 4.009 1.603420 38.03 33) 125,000 Bf [Focal length data for each group] Group starting plane focal length G1 1 141.309 G1A 1 111.803 G1B 5 -226.733 GF 14 -76.703 GR 16 -741.023 [Variable Interval Data] When focusing on infinity When focusing on a short distance object D13 3.000 19.346 D15 21.414 5.069

[0162] FIG. 8 is a diagram showing various aberrations of the optical system of the fourth embodiment when focused on an object at infinity.

[0163] From each aberration diagram, it can be seen that the optical system of this embodiment effectively suppresses aberration fluctuations during focusing and has high optical performance.

[0164] (Fifth Example) FIG. 9A is a cross-sectional view of the optical system of the fifth embodiment when focused on an object at infinity, and FIG. 9B is a cross-sectional view of the optical system of the fifth embodiment when focused on an object at a close distance.

[0165] The optical system of this embodiment includes, in order from the object side, a first lens group G1 having positive refractive power, a focusing group GF having negative refractive power, and a rear group GR having negative refractive power. An aperture stop S is disposed between the first lens group G1 and the focusing group GF. The first lens group G1 includes, separated by the largest air gap A within the first lens group, a first-A lens group G1A having positive refractive power disposed on the object side and a first-B lens group G1B having negative refractive power disposed on the image side.

[0166] The first-A lens group G1A is composed of, in order from the object side, a biconvex positive lens L1 and a positive meniscus lens L2 with its convex surface facing the object side.

[0167] The 1Bth lens group G1B consists of, in order from the object side, a cemented positive lens of a biconvex positive lens L3 and a biconcave negative lens L4, a cemented negative lens of a negative meniscus lens L5 with its convex surface facing the object side and a biconvex positive lens L6, and a cemented positive lens of a positive meniscus lens L7 with its convex surface facing the image side and a negative meniscus lens L8 with its convex surface facing the image side.

[0168] The focusing group GF is made up of a negative meniscus lens L9 with its convex surface facing the object side.

[0169] The rear group GR consists of, in order from the object side, a positive meniscus lens L10 with its convex surface facing the image side, a cemented negative lens formed by a biconvex positive lens L11 and a biconcave negative lens L12, a biconcave negative lens L13, a cemented positive lens formed by a biconvex positive lens L14 and a negative meniscus lens L15 with its convex surface facing the image side, a cemented positive lens formed by a negative meniscus lens L16 with its convex surface facing the object side and a biconvex positive lens L17, a cemented negative lens formed by a biconcave negative lens L18 and a positive meniscus lens L19 with its convex surface facing the object side, and a positive meniscus lens L20 with its convex surface facing the object side.

[0170] On the image plane I, an image pickup element (not shown) made up of a CCD, a CMOS, or the like is disposed.

[0171] The optical system of this embodiment focuses by moving the focusing group GF along the optical axis. When focusing on a close object from a state focused on infinity, the focusing group GF is moved from the object side to the image side.

[0172] In the optical system of this embodiment, among the lenses in the rear group GR, the cemented negative lens of a positive lens L11 and a negative lens L12, and the negative lens L13 are configured as vibration-proof lens groups that are movable so as to have a component in a direction perpendicular to the optical axis in order to correct image blur.

[0173] In the optical system of this embodiment, the positive lens L1 corresponds to the first lens, the positive meniscus lens L2 corresponds to the second lens, the negative lens L4 corresponds to the negative lens N, and the positive meniscus lens L7 corresponds to the positive lens Z.

[0174] In the optical system of this embodiment, dA is the distance on the optical axis between the image-side surface of the positive meniscus lens L2 and the object-side surface of the positive lens L3. dG1 is the distance on the optical axis between the object-side surface of the positive lens L1 and the image-side surface of the negative meniscus lens L8. dB is the distance on the optical axis between the object-side surface of the positive lens L1 and the object-side surface of the positive lens L3. dN is the distance on the optical axis between the object-side surface of the positive lens L1 and the object-side surface of the negative lens L4.

[0175] Table 5 below lists the specifications of the optical system of this example.

[0176] (Table 5) [Overall specifications] f 489.98 Fno 5.77 Bf 53.163 Image height 21.700 TL 270.475 2ω 5.05 [Lens specifications] mrd nd νd 1) 301.516 7.653 1.518600 69.89 2) -2994.078 0.248 3) 74.588 16.015 1.433837 95.16 4) 529.942 42.196 5) 60.571 11.051 1.437001 95.10 6) -204.604 2.000 1.816000 46.59 7) 358.323 0.509 8) 1130.257 2.000 1.816000 46.59 9) 40.518 10.429 1.437001 95.10 10) -366.911 18.665 11) -92.650 5.315 1.663820 27.35 12) -46.744 1.750 1.612660 44.46 13) -89.781 0.100 14> ∞ D14 (aperture stop) 15) 546.830 1.500 1.496997 81.61 16) 50.544 D16 17) -43.675 3.106 1.487490 70.32 18) -39.919 17.617 19) 196.739 4.641 1.603420 38.03 20) -46.252 1.375 1.593190 67.90 21) 44.844 2.750 22) -2713.065 1.375 1.593490 67.00 23) 63.562 2.500 24) 38.733 6.368 1.581440 40.98 25) -73.473 1.750 1.593190 67.90 26) -1339.601 0.100 27) 112.830 1.750 1.922860 20.88 28) 24.865 7.420 1.737999 32.33 29) -148.051 0.889 30) -62.799 1.750 1.816000 46.59 31) 29.752 6.237 1.737999 32.33 32) 306.380 0.100 33) 56.901 4.936 1.603420 38.03 34) 1041.086 Bf [Focal length data for each group] Group starting plane focal length G1 1 178.023 G1A 1 144.638 G1B 5 -410.279 GF 15 -112.168 GR 17 -261.402 [Variable Interval Data] When focusing on infinity When focusing on a short distance object D14 3.286 20.151 D16 38.932 22.067

[0177] FIG. 10 is a diagram showing various aberrations of the optical system of the fifth embodiment when focused on an object at infinity.

[0178] From each aberration diagram, it can be seen that the optical system of this embodiment effectively suppresses aberration fluctuations during focusing and has high optical performance.

[0179] (Sixth Example) FIG. 11A is a cross-sectional view of the optical system of the sixth embodiment when focusing on an object at infinity, and FIG. 11B is a cross-sectional view of the optical system of the sixth embodiment when focusing on an object at a close distance.

[0180] The optical system of this embodiment includes, in order from the object side, a first lens group G1 having positive refractive power, a focusing group GF having negative refractive power, and a rear group GR having negative refractive power. An aperture stop S is disposed between the first lens group G1 and the focusing group GF. The first lens group G1 includes, separated by the largest air gap A within the first lens group, a first-A lens group G1A having positive refractive power disposed on the object side and a first-B lens group G1B having negative refractive power disposed on the image side.

[0181] The first-A lens group G1A is composed of, in order from the object side, a positive meniscus lens L1 with a convex surface facing the object side, and a positive meniscus lens L2 with a convex surface facing the object side.

[0182] The 1Bth lens group G1B consists of, in order from the object side, a cemented negative lens consisting of a positive meniscus lens L3 with a convex surface facing the object side and a negative meniscus lens L4 with a convex surface facing the object side, a positive meniscus lens L5 with a convex surface facing the object side, and a cemented positive lens consisting of a biconvex positive lens L6 and a biconcave negative lens L7.

[0183] The focusing group GF is made up of a biconcave negative lens L8.

[0184] The rear group GR consists of, in order from the object side, a positive meniscus lens L9 with a convex surface facing the image side, a cemented negative lens formed by a positive meniscus lens L10 with a convex surface facing the image side and a biconcave negative lens L11, a biconcave negative lens L12, a cemented positive lens formed by a biconvex positive lens L13 and a biconcave negative lens L14, a cemented negative lens formed by a biconcave negative lens L15 and a biconvex positive lens L16, a cemented positive lens formed by a biconvex positive lens L17 and a negative meniscus lens L18 with a convex surface facing the image side, and a cemented negative lens formed by a biconcave negative lens L19, a biconvex positive lens L20 and a negative meniscus lens L21 with a convex surface facing the image side.

[0185] On the image plane I, an image pickup element (not shown) made up of a CCD, a CMOS, or the like is disposed.

[0186] The optical system of this embodiment focuses by moving the focusing group GF along the optical axis. When focusing on a close object from a state focused on infinity, the focusing group GF is moved from the object side to the image side.

[0187] In the optical system of this embodiment, among the lenses in the rear group GR, the cemented negative lens of a positive meniscus lens L10 and a negative lens L11, and the negative lens L12 are configured as an image-stabilizing lens group that is movable so as to have a component in a direction perpendicular to the optical axis in order to correct image blur.

[0188] In the optical system of this embodiment, the positive meniscus lens L1 corresponds to the first lens, the positive meniscus lens L2 corresponds to the second lens, the negative meniscus lens L4 corresponds to the negative lens N, and the positive lens L6 corresponds to the positive lens Z.

[0189] In the optical system of this embodiment, dA is the distance on the optical axis between the image-side surface of the positive meniscus lens L2 and the object-side surface of the positive meniscus lens L3. Also, dG1 is the distance on the optical axis between the object-side surface of the positive meniscus lens L1 and the image-side surface of the negative lens L7. Also, dB is the distance on the optical axis between the object-side surface of the positive meniscus lens L1 and the object-side surface of the positive meniscus lens L3. Also, dN is the distance on the optical axis between the object-side surface of the positive meniscus lens L1 and the object-side surface of the negative meniscus lens L4.

[0190] Table 6 below lists the specifications of the optical system of this example.

[0191] (Table 6) [Overall specifications] f 582.00 Fno 5.80 Bf 57.650 Image height 21.700 TL 305.483 2ω 4.20 [Lens specifications] mrd nd νd 1) 209.874 7.062 1.537750 74.70 2) 952.422 0.400 3) 91.788 13.513 1.433837 95.16 4) 361.924 60.210 5) 66.958 8.900 1.437001 95.10 6) 1878.152 2.300 1.902650 35.72 7) 52.955 1.200 8) 54.318 8.485 1.437001 95.10 9) 954.336 15.349 10) 115.853 6.613 1.663820 27.35 11) -90.371 1.600 1.834810 42.73 12) 221.211 15.183 13> ∞ D13 (aperture stop) 14)-19374.039 1.200 1.496997 81.61 15) 46.568 D15 16) -106.679 2.037 1.487490 70.32 17) -61.741 1.500 18) -2608.847 3.600 1.612660 44.46 19) -47.129 1.200 1.593190 67.90 20) 69.720 2.300 21) -1020.983 1.200 1.593490 67.00 22) 91.287 2.000 23) 33.441 7.067 1.581440 40.98 24) -48.899 1.400 1.593190 67.90 25) 173.712 3.445 26) -751.444 1.400 1.922860 20.88 27) 25.644 6.052 1.620040 36.40 28) -1371.263 5.043 29) 65.099 9.464 1.737999 32.33 30) -26.310 1.600 1.638540 55.34 31) -90.430 5.913 32) -46.530 1.600 1.883000 40.66 33) 59.262 8.391 1.737999 32.33 34) -30.461 1.600 1.883000 40.66 35) -104.675 Bf [Focal length data for each group] Group starting plane focal length G1 1 206.631 G1A 1 179.755 G1B 5 -499.661 GF 14 -93.471 GR 16 -277.391 [Variable Interval Data] When focusing on infinity When focusing on a short distance object D13 11.493 28.469 D15 27.470 10.494

[0192] FIG. 12 is a diagram showing various aberrations of the optical system of the sixth embodiment when focused on an object at infinity.

[0193] From each aberration diagram, it can be seen that the optical system of this embodiment effectively suppresses aberration fluctuations during focusing and has high optical performance.

[0194] (Seventh Example) FIG. 13A is a cross-sectional view of the optical system of the seventh embodiment when focusing on an object at infinity, and FIG. 13B is a cross-sectional view of the optical system of the seventh embodiment when focusing on an object at a close distance.

[0195] The optical system of this embodiment includes, in order from the object side, a first lens group G1 having positive refractive power, a focusing group GF having negative refractive power, and a rear group GR having negative refractive power. An aperture stop S is disposed between the first lens group G1 and the focusing group GF. The first lens group G1 includes, separated by the largest air gap A within the first lens group, a first-A lens group G1A having positive refractive power disposed on the object side and a first-B lens group G1B having negative refractive power disposed on the image side.

[0196] The first-A lens group G1A is composed of, in order from the object side, a biconvex positive lens L1 and a positive meniscus lens L2 with its convex surface facing the object side.

[0197] The 1Bth lens group G1B consists of, in order from the object side, a cemented negative lens consisting of a biconvex positive lens L3 and a biconcave negative lens L4, a positive meniscus lens L5 with its convex surface facing the object side, and a cemented negative lens consisting of a biconvex positive lens L6 and a biconcave negative lens L7.

[0198] The focusing group GF is made up of a biconcave negative lens L8.

[0199] The rear group GR consists of, in order from the object side, a positive meniscus lens L9 with its convex surface facing the image side, a cemented negative lens of a biconvex positive lens L10 and a biconcave negative lens L11, a biconcave negative lens L12, a cemented positive lens of a biconvex positive lens L13 and a biconcave negative lens L14, a cemented negative lens of a biconcave negative lens L15 and a biconvex positive lens L16, a cemented positive lens of a biconvex positive lens L17 and a negative meniscus lens L18 with its convex surface facing the image side, and a cemented negative lens of a biconcave negative lens L19, a biconvex positive lens L20 and a negative meniscus lens L21 with its convex surface facing the image side.

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

[0201] The optical system of this embodiment focuses by moving the focusing group GF along the optical axis. When focusing on a close object from a state focused on infinity, the focusing group GF is moved from the object side to the image side.

[0202] In the optical system of this embodiment, among the lenses in the rear group GR, the cemented negative lens of a positive lens L10 and a negative lens L11, and the negative lens L12 are configured as vibration-proof lens groups that are movable so as to have a component in a direction perpendicular to the optical axis in order to correct image blur.

[0203] In the optical system of this embodiment, the positive lens L1 corresponds to the first lens, the positive meniscus lens L2 corresponds to the second lens, the negative lens L4 corresponds to the negative lens N, and the positive lens L6 corresponds to the positive lens Z.

[0204] In the optical system of this embodiment, dA is the axial distance between the image-side surface of the positive meniscus lens L2 and the object-side surface of the positive lens L3. dG1 is the axial distance between the object-side surface of the positive lens L1 and the image-side surface of the negative lens L7. dB is the axial distance between the object-side surface of the positive lens L1 and the object-side surface of the positive lens L3. dN is the axial distance between the object-side surface of the positive lens L1 and the object-side surface of the negative lens L4.

[0205] Table 7 below lists the specifications of the optical system of this example.

[0206] (Table 7) [Overall specifications] f 780.00 Fno 5.80 Bf 72.401 Image height 21.700 TL 395.435 2ω 3.14 [Lens specifications] mrd nd νd 1) 278.114 11.437 1.433837 95.16 2) -9931.397 0.536 3) 118.790 17.646 1.433837 95.16 4) 411.233 88.454 5) 80.169 11.750 1.437001 95.10 6) -7177.582 2.800 1.902650 35.72 7) 70.344 1.582 8) 75.393 9.074 1.437001 95.10 9) 609.803 23.491 10) 149.143 7.987 1.663820 27.35 11) -111.061 1.800 1.834810 42.73 12) 276.625 15.689 13> ∞ D13 (aperture stop) 14) -2132.794 1.400 1.487490 70.32 15) 59.025 D15 16) -100.905 3.000 1.552981 55.07 17) -67.183 1.500 18) 913.713 3.800 1.581440 40.98 19) -64.402 1.200 1.593190 67.90 20) 77.939 2.700 21) -251.245 1.200 1.593490 67.00 22) 144.773 2.000 23) 48.967 7.712 1.581440 40.98 24) -36.112 1.600 1.593190 67.90 25) 2585.012 8.971 26) -64.468 1.600 1.922860 20.88 27) 41.597 7.601 1.620040 36.40 28) -60.377 5.315 29) 118.399 9.843 1.737999 32.33 30) -31.787 1.600 1.593490 67.00 31) -65.797 5.539 32) -61.040 1.600 1.883000 40.66 33) 62.377 9.440 1.737999 32.33 34) -36.957 1.600 1.883000 40.66 35) -146.016 Bf [Focal length data for each group] Group starting plane focal length G1 1 279.705 G1A 1 236.223 G1B 5 -511.433 GF 14 -117.794 GR 16 -437.474 [Variable Interval Data] When focusing on infinity When focusing on a short distance object D13 16.594 41.036 D15 34.974 10.531

[0207] FIG. 14 is a diagram showing various aberrations of the optical system of the seventh embodiment when focused on an object at infinity.

[0208] From each aberration diagram, it can be seen that the optical system of this embodiment effectively suppresses aberration fluctuations during focusing and has high optical performance.

[0209] (Eighth Example) FIG. 15A is a cross-sectional view of the optical system of the eighth embodiment when focusing on an object at infinity, and FIG. 15B is a cross-sectional view of the optical system of the eighth embodiment when focusing on an object at a close distance.

[0210] The optical system of this embodiment includes, in order from the object side, a first lens group G1 having positive refractive power, a focusing group GF having negative refractive power, and a rear group GR having negative refractive power. An aperture stop S is disposed between the first lens group G1 and the focusing group GF. The first lens group G1 includes, separated by the largest air gap A within the first lens group, a first-A lens group G1A having positive refractive power disposed on the object side and a first-B lens group G1B having negative refractive power disposed on the image side.

[0211] The first-A lens group G1A is composed of, in order from the object side, a biconvex positive lens L1 and a positive meniscus lens L2 with its convex surface facing the object side.

[0212] The 1Bth lens group G1B consists of, in order from the object side, a cemented negative lens consisting of a negative meniscus lens L3 with a convex surface facing the object side and a positive meniscus lens L4 with a convex surface facing the object side, a cemented positive lens consisting of a biconvex positive lens L5 and a biconcave negative lens L6, and a cemented negative lens consisting of a positive meniscus lens L7 with a convex surface facing the object side and a negative meniscus lens L8 with a convex surface facing the object side.

[0213] The focusing group GF is made up of a negative meniscus lens L9 with its convex surface facing the object side.

[0214] The rear group GR consists of, in order from the object side, a positive meniscus lens L10 with its convex surface facing the image side, a cemented negative lens formed by a positive meniscus lens L11 with its convex surface facing the image side and a biconcave negative lens L12, a biconcave negative lens L13, a cemented positive lens formed by a biconvex positive lens L14 and a biconcave negative lens L15, a cemented negative lens formed by a biconcave negative lens L16 and a biconvex positive lens L17, a cemented positive lens formed by a biconvex positive lens L18 and a negative meniscus lens L19 with its convex surface facing the image side, and a cemented negative lens formed by a biconcave negative lens L20, a biconvex positive lens L21 and a negative meniscus lens L22 with its convex surface facing the image side.

[0215] On the image plane I, an image pickup element (not shown) made up of a CCD, a CMOS, or the like is disposed.

[0216] The optical system of this embodiment focuses by moving the focusing group GF along the optical axis. When focusing on a close object from a state focused on infinity, the focusing group GF is moved from the object side to the image side.

[0217] In the optical system of this embodiment, among the lenses in the rear group GR, the cemented negative lens formed by a positive lens meniscus L11 and a negative lens L12, and the negative lens L13 are configured as vibration-proof lens groups that are movable so as to have a component in a direction perpendicular to the optical axis in order to correct image blur.

[0218] In the optical system of this embodiment, the positive lens L1 corresponds to the first lens, the positive meniscus lens L2 corresponds to the second lens, the negative meniscus lens L3 corresponds to the negative lens N, and the positive meniscus lens L7 corresponds to the positive lens Z.

[0219] In the optical system of this embodiment, dA is the distance on the optical axis between the image-side surface of the positive meniscus lens L2 and the object-side surface of the negative meniscus lens L3. dG1 is the distance on the optical axis between the object-side surface of the positive lens L1 and the image-side surface of the negative meniscus lens L8. dB is the distance on the optical axis between the object-side surface of the positive lens L1 and the object-side surface of the negative meniscus lens L3. dN is the distance on the optical axis between the object-side surface of the positive lens L1 and the object-side surface of the negative meniscus lens L3.

[0220] Table 8 below lists the specifications of the optical system of this example.

[0221] (Table 8) [Overall specifications] f 779.95 Fno 5.80 Bf 76.376 Image height 21.700 TL 383.444 2ω 3.14 [Lens specifications] mrd nd νd 1) 267.172 12.157 1.433837 95.16 2) -3942.417 0.536 3) 129.878 14.435 1.433837 95.16 4) 334.092 69.154 5) 130.441 3.000 1.883000 40.66 6) 71.048 15.415 1.437001 95.10 7) 408.661 1.000 8) 90.710 16.409 1.437001 95.10 9) -185.763 2.800 1.487490 70.32 10) 138.066 19.365 11) 88.996 5.626 1.663820 27.35 12) 214.056 2.100 1.883000 40.66 13) 78.689 29.715 14> ∞ D14 (aperture stop) 15) 16674.224 1.400 1.487490 70.32 16) 64.208 D16 17) -116.010 3.000 1.552981 55.07 18) -69.086 1.500 19) -644.448 4.500 1.612660 44.46 20) -48.050 1.200 1.593190 67.90 21) 72.757 2.700 22) -880.699 1.200 1.593490 67.00 23) 104.682 2.000 24) 40.326 7.576 1.581440 40.98 25) -39.781 1.600 1.593190 67.90 26) 960.480 2.513 27) -280.010 1.600 1.922860 20.88 28) 34.990 5.733 1.620040 36.40 29) -146.116 9.399 30) 73.204 7.919 1.620040 36.40 31) -32.773 1.600 1.593190 67.90 32) -531.178 2.818 33) -112.016 1.600 1.883000 40.66 34) 37.168 9.936 1.737999 32.33 35) -32.206 1.600 1.883000 40.66 36) -153.819 Bf [Focal length data for each group] Group starting plane focal length G1 1 271.114 G1A 1 262.482 G1B 5 -704.528 GF 15 -132.223 GR 17 -196.255 [Variable Interval Data] When focusing on infinity When focusing on a short distance object D14 14.482 39.187 D16 29.480 4.775

[0222] FIG. 16 is a diagram showing various aberrations of the optical system of Example 8 when focusing on an object at infinity.

[0223] From each aberration diagram, it can be seen that the optical system of this embodiment effectively suppresses aberration fluctuations during focusing and has high optical performance.

[0224] (Ninth Example) FIG. 17A is a cross-sectional view of the optical system of the ninth embodiment when focusing on an object at infinity, and FIG. 17B is a cross-sectional view of the optical system of the ninth embodiment when focusing on an object at a close distance.

[0225] The optical system of this embodiment includes, in order from the object side, a first lens group G1 having positive refractive power, a focusing group GF having negative refractive power, and a rear group GR having negative refractive power. An aperture stop S is disposed between the focusing group GF and the rear group GR. The first lens group G1 includes, separated by the largest air gap A within the first lens group, a first-A lens group G1A having positive refractive power and a first-B lens group G1B having negative refractive power and disposed on the image side.

[0226] The first-A lens group G1A is composed of, in order from the object side, a positive meniscus lens L1 with a convex surface facing the object side, and a positive meniscus lens L2 with a convex surface facing the object side.

[0227] The 1Bth lens group G1B consists of, in order from the object side, a cemented negative lens consisting of a negative meniscus lens L3 with a convex surface facing the object side and a positive meniscus lens L4 with a convex surface facing the object side, a cemented positive lens consisting of a biconvex positive lens L5 and a biconcave negative lens L6, and a cemented negative lens consisting of a positive meniscus lens L7 with a convex surface facing the object side and a negative meniscus lens L8 with a convex surface facing the object side.

[0228] The focusing group GF is made up of a biconcave negative lens L9.

[0229] The rear group GR consists of, in order from the object side, a positive meniscus lens L10 with its convex surface facing the image side, a cemented negative lens consisting of a biconvex positive lens L11 and a biconcave negative lens L12, a biconcave negative lens L13, a cemented positive lens consisting of a biconvex positive lens L14 and a biconcave negative lens L15, a cemented negative lens consisting of a negative meniscus lens L16 with its convex surface facing the object side and a biconvex positive lens L17, a cemented positive lens consisting of a biconvex positive lens L18 and a biconcave negative lens L19, and a cemented negative lens consisting of a biconcave negative lens L20, a biconvex positive lens L21, and a negative meniscus lens L22 with its convex surface facing the image side.

[0230] On the image plane I, an image pickup element (not shown) made up of a CCD, a CMOS, or the like is disposed.

[0231] The optical system of this embodiment focuses by moving the focusing group GF along the optical axis. When focusing on a close object from a state focused on infinity, the focusing group GF is moved from the object side to the image side.

[0232] In the optical system of this embodiment, among the lenses in the rear group GR, the cemented negative lens of a positive lens L11 and a negative lens L12, and the negative lens L13 are configured as vibration-proof lens groups that are movable so as to have a component in a direction perpendicular to the optical axis in order to correct image blur.

[0233] In the optical system of this embodiment, the positive meniscus lens L1 corresponds to the first lens, the positive meniscus lens L2 corresponds to the second lens, the negative meniscus lens L3 corresponds to the negative lens N, and the positive meniscus lens L7 corresponds to the positive lens Z.

[0234] In the optical system of this embodiment, dA is the distance on the optical axis between the image-side surface of the positive meniscus lens L2 and the object-side surface of the negative meniscus lens L3. Also, dG1 is the distance on the optical axis between the object-side surface of the positive meniscus lens L1 and the image-side surface of the negative meniscus lens L8. Also, dB is the distance on the optical axis between the object-side surface of the positive meniscus lens L1 and the object-side surface of the negative meniscus lens L3. Also, dN is the distance on the optical axis between the object-side surface of the positive meniscus lens L1 and the object-side surface of the negative meniscus lens L3.

[0235] Table 9 below lists the specifications of the optical system of this example.

[0236] (Table 9) [Overall specifications] f 779.97 Fno 6.40 Bf 79,800 Image height 21.700 TL 399.450 2ω 3.15 [Lens specifications] mrd nd νd 1) 255.258 9.091 1.537750 74.70 2) 1685.759 0.500 3) 138.346 12.666 1.433837 95.16 4) 418.938 72.302 5) 177.080 3.000 1.883000 40.66 6) 76.888 13.971 1.437001 95.10 7) 2084.544 1.000 8) 95.651 14.302 1.437001 95.10 9) -201.556 2.800 1.487490 70.32 10) 121.665 9.654 11) 151.928 5.707 1.663820 27.35 12) 1406.765 2.100 1.902650 35.72 13) 183.823 D13 14) -1678.708 1.300 1.487490 70.32 15) 76.764 D15 16> ∞ 19.548 (aperture stop) 17) -279.837 3.000 1.487490 70.32 18) -80.022 1.500 19) 412.066 3.500 1.612660 44.46 20) -55.502 1.200 1.593190 67.90 21) 63.474 2.700 22) -284.371 1.200 1.593490 67.00 23) 84.284 2.000 24) 38.563 7.200 1.581440 40.98 25) -69.150 1.400 1.593190 67.90 26) 285.565 2.553 27) 348.792 1.400 1.922860 20.88 28) 31.874 6.500 1.620040 36.40 29) -610.498 9.220 30) 59.656 9.000 1.620040 36.40 31) -34.040 1.400 1.593190 67.90 32) 549.515 4.295 33) -54.352 1.400 1.883000 40.66 34) 60.916 9.500 1.737999 32.33 35) -29.296 1.400 1.883000 40.66 36) -73.592 Bf [Focal length data for each group] Group starting plane focal length G1 1 266.946 G1A 1 255.843 G1B 5 -1307.740 GF 14 -150.545 GR 17 -208.953 [Variable Interval Data] When focusing on infinity When focusing on a short distance object D13 51.181 73.947 D15 30.161 7.394

[0237] FIG. 18 is a diagram showing various aberrations of the optical system of the ninth embodiment when focused on an object at infinity.

[0238] From each aberration diagram, it can be seen that the optical system of this embodiment effectively suppresses aberration fluctuations during focusing and has high optical performance.

[0239] (Tenth Example) FIG. 19A is a cross-sectional view of the optical system of the tenth embodiment when focusing on an object at infinity, and FIG. 19B is a cross-sectional view of the optical system of the tenth embodiment when focusing on an object at a close distance.

[0240] The optical system of this embodiment includes, in order from the object side, a first lens group G1 having positive refractive power, a focusing group GF having negative refractive power, and a rear group GR having negative refractive power. An aperture stop S is disposed between the first lens group G1 and the focusing group GF. The first lens group G1 includes, separated by the largest air gap A within the first lens group, a first-A lens group G1A having positive refractive power disposed on the object side and a first-B lens group G1B having negative refractive power disposed on the image side.

[0241] The first-A lens group G1A is composed of, in order from the object side, a biconvex positive lens L1 and a positive meniscus lens L2 with its convex surface facing the object side.

[0242] The 1Bth lens group G1B consists of, in order from the object side, a cemented negative lens consisting of a negative meniscus lens L3 with a convex surface facing the object side and a positive meniscus lens L4 with a convex surface facing the object side, a cemented positive lens consisting of a biconvex positive lens L5 and a biconcave negative lens L6, and a cemented negative lens consisting of a negative meniscus lens L7 with a convex surface facing the object side and a positive meniscus lens L8 with a convex surface facing the object side.

[0243] The focusing group GF is made up of a biconcave negative lens L9.

[0244] The rear group GR consists of, in order from the object side, a positive meniscus lens L10 with its convex surface facing the image side, a cemented negative lens formed by a positive meniscus lens L11 with its convex surface facing the image side and a biconcave negative lens L12, a biconcave negative lens L13, a cemented positive lens formed by a biconvex positive lens L14 and a biconcave negative lens L15, a cemented negative lens formed by a biconcave negative lens L16 and a biconvex positive lens L17, a cemented positive lens formed by a biconvex positive lens L18 and a negative meniscus lens L19 with its convex surface facing the image side, and a cemented negative lens formed by a biconcave negative lens L20, a biconvex positive lens L21 and a negative meniscus lens L22 with its convex surface facing the image side.

[0245] On the image plane I, an image pickup element (not shown) made up of a CCD, a CMOS, or the like is disposed.

[0246] The optical system of this embodiment focuses by moving the focusing group GF along the optical axis. When focusing on a close object from a state focused on infinity, the focusing group GF is moved from the object side to the image side.

[0247] In the optical system of this embodiment, among the lenses in the rear group GR, the cemented negative lens of a positive meniscus lens L11 and a negative lens L12, and the negative lens L13 are configured as vibration-proof lens groups that are movable so as to have a component in a direction perpendicular to the optical axis in order to correct image blur.

[0248] In the optical system of this embodiment, the positive lens L1 corresponds to the first lens, the positive meniscus lens L2 corresponds to the second lens, the negative meniscus lens L3 corresponds to the negative lens N, and the positive meniscus lens L8 corresponds to the positive lens Z.

[0249] In the optical system of this embodiment, dA is the distance on the optical axis between the image-side surface of the positive meniscus lens L2 and the object-side surface of the negative meniscus lens L3. dG1 is the distance on the optical axis between the object-side surface of the positive lens L1 and the image-side surface of the positive meniscus lens L8. dB is the distance on the optical axis between the object-side surface of the positive lens L1 and the object-side surface of the negative meniscus lens L3. dN is the distance on the optical axis between the object-side surface of the positive lens L1 and the object-side surface of the negative meniscus lens L3.

[0250] Table 10 below lists the specifications of the optical system of this example.

[0251] (Table 10) [Overall specifications] f 780.00 Fno 8.00 Bf 92.159 Image height 21.700 TL 351.452 2ω 3.13 [Lens specifications] mrd nd νd 1) 195.329 8.988 1.433837 95.16 2)-26364.519 0.500 3) 109.812 9.691 1.433837 95.16 4) 284.676 60.820 5) 114.988 2.700 1.883000 40.66 6) 58.226 9.887 1.437001 95.10 7) 257.690 1.000 8) 82.822 10.837 1.437001 95.10 9) -150.828 2.500 1.487490 70.32 10) 114.026 9.268 11) 69.040 1.800 1.883000 40.66 12) 52.239 4.278 1.663820 27.35 13) 68.880 36.122 14> ∞ D14 (aperture stop) 15) -6404.001 1.400 1.487490 70.32 16) 60.905 D16 17) -62.158 3.000 1.487490 70.32 18) -50.943 1.500 19) -348.240 3.500 1.612660 44.46 20) -40.905 1.200 1.593190 67.90 21) 107.146 2.700 22) -282.696 1.200 1.593490 67.00 23) 118.438 2.000 24) 34.139 6.300 1.581440 40.98 25) -31.938 1.400 1.593190 67.90 26) 86.990 3.741 27) -81.495 1.400 1.922860 20.88 28) 36.499 6.000 1.620040 36.40 29) -51.643 4.422 30) 70.463 7.000 1.664460 35.87 31) -28.039 1.400 1.593190 67.90 32) -52.198 2.000 33) -52.381 1.400 1.883000 40.66 34) 27.748 9.000 1.737999 32.33 35) -26.889 1.400 1.883000 40.66 36) -195.546 Bf [Focal length data for each group] Group starting plane focal length G1 1 232.062 G1A 1 213.189 G1B 5 -700.761 GF 15 -123.749 GR 17 -139.187 [Variable Interval Data] When focusing on infinity When focusing on a short distance object D14 14.926 33.005 D16 24.011 5.933

[0252] FIG. 20 is a diagram showing various aberrations of the optical system of the tenth embodiment when focused on an object at infinity.

[0253] From each aberration diagram, it can be seen that the optical system of this embodiment effectively suppresses aberration fluctuations during focusing and has high optical performance.

[0254] (Eleventh Example) FIG. 21A is a cross-sectional view of the optical system of the 11th embodiment when focusing on an object at infinity, and FIG. 21B is a cross-sectional view of the optical system of the 11th embodiment when focusing on an object at a close distance.

[0255] The optical system of this embodiment includes, in order from the object side, a first lens group G1 having positive refractive power, a focusing group GF having negative refractive power, and a rear group GR having negative refractive power. An aperture stop S is disposed between the first lens group G1 and the focusing group GF. The first lens group G1 includes a first-A lens group G1A having positive refractive power disposed on the object side and a first-B lens group G1B having positive refractive power disposed on the image side, separated by the largest air gap A within the first lens group.

[0256] The first-A lens group G1A is made up of a positive meniscus lens L1 with its convex surface facing the object side.

[0257] The 1Bth lens group G1B consists of, in order from the object side, a cemented positive lens consisting of a negative meniscus lens L2 with a convex surface facing the object side and a positive meniscus lens L3 with a convex surface facing the object side, a cemented negative lens consisting of a biconvex positive lens L4 and a biconcave negative lens L5, and a positive meniscus lens L6 with a convex surface facing the object side.

[0258] The focusing group GF is made up of a biconcave negative lens L7.

[0259] The rear group GR consists of, in order from the object side, a positive meniscus lens L8 with a convex surface facing the image side, a cemented negative lens formed by a positive meniscus lens L9 with a convex surface facing the image side and a biconcave negative lens L10, a plano-concave negative lens L11 with a concave surface facing the image side, a cemented positive lens formed by a biconvex positive lens L12 and a biconcave negative lens L13, a cemented negative lens formed by a negative meniscus lens L14 with a convex surface facing the object side and a biconvex positive lens L15, a cemented positive lens formed by a biconvex positive lens L16 and a biconcave negative lens L17, and a cemented negative lens formed by a biconcave negative lens L18, a biconvex positive lens L19, and a negative meniscus lens L20 with a convex surface facing the image side.

[0260] On the image plane I, an image pickup element (not shown) made up of a CCD, a CMOS, or the like is disposed.

[0261] The optical system of this embodiment focuses by moving the focusing group GF along the optical axis. When focusing on a close object from a state focused on infinity, the focusing group GF is moved from the object side to the image side.

[0262] In the optical system of this embodiment, among the lenses in the rear group GR, the cemented negative lens formed by a positive meniscus lens L9 and a negative lens L10, and the negative lens L11 are configured as vibration-proof lens groups that are movable so as to have a component in a direction perpendicular to the optical axis in order to correct image blur.

[0263] In the optical system of this embodiment, the positive meniscus lens L1 corresponds to the first lens, the negative meniscus lens L2 corresponds to the negative lens N, and the positive meniscus lens L6 corresponds to the positive lens Z.

[0264] In the optical system of this embodiment, dA is the distance on the optical axis between the image-side surface of the positive meniscus lens L1 and the object-side surface of the negative meniscus lens L2. Also, dG1 is the distance on the optical axis between the object-side surface of the positive meniscus lens L1 and the image-side surface of the positive meniscus lens L6. Also, dB is the distance on the optical axis between the object-side surface of the positive meniscus lens L1 and the object-side surface of the negative meniscus lens L2. Also, dN is the distance on the optical axis between the object-side surface of the positive meniscus lens L1 and the object-side surface of the negative meniscus lens L2.

[0265] Table 11 below lists the specifications of the optical system of this example.

[0266] (Table 11) [Overall specifications] f 779.95 Fno 8.00 Bf 87.483 Image height 21.700 TL 399.482 2ω 3.14 [Lens specifications] mrd nd νd 1) 136.085 11.698 1.433837 95.16 2) 2886.820 93.585 3) 84.536 3.000 1.900430 37.37 4) 57.130 11.614 1.437001 95.10 5) 342.893 1.000 6) 77.480 12.561 1.496997 81.61 7) -125.841 2.800 1.589130 61.22 8) 56.630 2.000 9) 49.759 4.345 1.663820 27.35 10) 60.512 51.451 11> ∞ D11 (aperture stop) 12) -1013.842 1.400 1.487490 70.32 13) 88.130 D13 14) -77.126 3.000 1.487490 70.32 15) -53.565 2.000 16) -3867.417 4.000 1.617720 49.81 17) -42.148 1.200 1.593190 67.90 18) 116.314 1.200 19) ∞ 1.200 1.593490 67.00 20) 81.561 3.000 21) 40.019 6.700 1.531720 48.78 22) -37.697 1.500 1.593190 67.90 23) 238.406 3.118 24) 345.221 1.500 1.922860 20.88 25) 38.137 5.300 1.603420 38.03 26) -123.170 14.480 27) 62.684 6.500 1.620040 36.40 28) -35.175 1.500 1.593190 67.90 29) 189.726 4.455 30) -79.833 1.500 1.883000 40.66 31) 36.649 8.000 1.737999 32.33 32) -30.820 1.500 1.883000 40.66 33) -167.720 Bf [Focal length data for each group] Group starting plane focal length G1 1 277.319 G1A 1 328.772 G1B 3 7228.305 GF 12 -166.256 GR 14 -168.016 [Variable Interval Data] When focusing on infinity When focusing on a short distance object D11 13.975 40.029 D13 30.918 4.865

[0267] FIG. 22 is a diagram showing various aberrations of the optical system of Example 11 when focusing on an object at infinity.

[0268] From each aberration diagram, it can be seen that the optical system of this embodiment effectively suppresses aberration fluctuations during focusing and has high optical performance.

[0269] According to each of the above embodiments, it is possible to realize an optical system that is small, lightweight, and has good imaging performance.

[0270] Below is a list of conditional expressions and corresponding values ​​for each embodiment.

[0271] FNo is the F-number of the optical system when focused at infinity, TL is the total optical length of the optical system when focused at infinity, and f is the focal length of the optical system when focused at infinity. dA is the axial distance of air gap A, and dG1 is the axial distance of the first lens group. dN is the axial distance from the surface closest to the object of the optical system to the object side of negative lens N. f1A is the focal length of lens group 1A, and f1B is the focal length of lens group 1B. dB is the axial distance from the surface closest to the object of the optical system to the surface closest to the object of lens group 1B. fL1 is the focal length of the first lens located closest to the object, and fL2 is the focal length of the second lens located second from the object. νd1Amax is the maximum Abbe number of the lenses in lens group 1A based on the d-line, and νdLZ is the Abbe number of positive lens Z based on the d-line. νd1Aave is the average value of the Abbe numbers of the lenses included in the 1A lens group with the d line as the reference.

[0272] ndLZ is the refractive index of the positive lens Z for the d-line, θgFLZ is the partial dispersion ratio of the positive lens Z, and is defined by the following equation, where ngLZ is the refractive index of the positive lens Z for the g-line, nFLZ is the refractive index of the positive lens Z for the F-line, and nCLZ is the refractive index of the positive lens Z for the C-line. θgFLZ = (ngLZ - nFLZ) / (nFLZ - nCLZ)

[0273] L1R1 is the radius of curvature of the object-side surface of the first lens element located closest to the object, and L1R2 is the radius of curvature of the image-side surface of the first lens element. L2R1 is the radius of curvature of the object-side surface of the second lens element located second from the object side, and L2R2 is the radius of curvature of the image-side surface of the second lens element. f1 is the focal length of the first lens group. fF is the focal length of the focusing group. fR is the focal length of the rear group. dF is the distance on the optical axis from the surface closest to the object in the optical system to the surface closest to the object in the focusing group. νdFave is the average Abbe number based on the d-line of the lenses included in the focusing group. 2ω is the total angle of view of the optical system. BF is the back focus of the optical system.

[0274] [Conditional Expression List] (1) Fno * (TL / f) 2 (2) dA / dG1 (3) TL / f (4) dN / TL (5) f1A / f1B (6) f1A / f (7) dB / dG1 (8) fL1 / fL2 (9) νd1Amax - νdLZ (10) νd1Aave (11) ndLZ + (0.01425 * νdLZ) (12) νdLZ (13) θgFLZ + (0.00316 * νdLZ) (14) (L1R2 + L1R1) / (L1R2 - L1R1) (15) (L2R2 + L2R1) / (L2R2 - L2R1) (16) f1 / f (17) (-fF) / f1 (18) (-fF) / fR (19) dF / TL (20) νdFave (21) 2ω (22) Bf / f

[0275] [Conditional expression corresponding value] Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 (1) 1.742 1.928 1.792 1.860 1.877 1.597 (2) 0.384 0.467 0.456 0.444 0.358 0.479 (3) 0.652 0.686 0.624 0.568 0.570 0.525 (4) 0.281 0.311 0.308 0.257 0.276 0.295 (5) -0.374 -0.090 -0.055 -0.493 -0.353 -0.360 (6) 0.353 0.415 0.379 0.287 0.295 0.309 (7) 0.617 0.642 0.626 0.640 0.561 0.646 (8) 1.429 1.603 1.953 1.415 2.670 1.785 (9) 67.75 67.81 67.75 67.75 67.81 67.81 (10) 84.90 84.93 84.90 88.36 82.53 84.93 (11) 2.054 2.054 2.054 2.054 2.054 2.054 (12) 27.35 27.35 27.35 27.35 27.35 27.35 (13) 0.120 0.120 0.120 0.120 0.120 0.120 (14) 1.145 1.417 1.111 1.065 0.817 1.565 (15) 1.590 1.533 1.415 1.732 1.328 1.680 (16) 0.417 0.432 0.385 0.362 0.363 0.355 (17) 0.654 0.544 0.599 0.543 0.630 0.452 (18) -0.233 0.050 -0.203 -0.104 -0.429 -0.337 (19) 0.437 0.481 0.486 0.429 0.434 0.499 (20) 81.61 81.61 81.61 81.61 81.61 81.61 (21) 8.43 6.30 6.30 6.35 5.05 4.20 (22) 0.122 0.156 0.142 0.140 0.108 0.099

[0276] Example 7 Example 8 Example 9 Example 10 Example 11 (1) 1.490 1.402 1.679 1.624 2.099 (2) 0.501 0.427 0.492 0.497 0.656 (3) 0.507 0.492 0.512 0.451 0.512 (4) 0.328 0.251 0.237 0.228 0.264 (5) -0.462 -0.373 -0.196 -0.304 0.045 (6) 0.303 0.337 0.328 0.273 0.422 (7) 0.669 0.594 0.643 0.654 0.738 (8) 1.650 1.204 1.188 1.103 (N / A) (9) 67.81 67.81 67.81 67.81 67.81 (10) 95.16 95.16 84.93 95.16 95.16 (11) 2.054 2.054 2.054 2.054 2.054 (12) 27.35 27.35 27.35 27.35 27.35 (13) 0.120 0.120 0.120 0.120 0.120 (14) 0.946 0.873 1.357 0.985 1.099 (15) 1.812 2.272 1.986 2.256 (N / A) (16) 0.359 0.348 0.342 0.298 0.356 (17) 0.421 0.488 0.564 0.533 0.600 (18) -0.269 -0.674 -0.720 -0.889 -0.990 (19) 0.528 0.538 0.496 0.493 0.521 (20) 70.32 70.32 70.32 70.32 70.32 (21) 3.14 3.14 3.15 3.13 3.14 (22) 0.093 0.098 0.102 0.118 0.112

[0277] The above examples are merely illustrative of the present invention, and the present invention is not limited thereto. The following content can be appropriately adopted within the scope that does not impair the optical performance of the optical system of the embodiment of the present application.

[0278] In addition, the lens surfaces of the lenses constituting the optical systems of the above examples may be coated with an anti-reflection coating that has high transmittance over a wide wavelength range, thereby reducing flare and ghosting and achieving high-contrast optical performance.

[0279] Next, a camera equipped with the optical system of this embodiment will be described with reference to FIG. FIG. 23 is a schematic diagram of a camera equipped with the optical system of this embodiment.

[0280] The camera 1 is an interchangeable lens camera equipped with the optical system according to the first embodiment as the photographic lens 2.

[0281] In camera 1, light from an object (subject) (not shown) is collected by photographic lens 2 and formed into an image on focusing screen 4 via quick-return mirror 3. The light formed into an image on focusing screen 4 is reflected multiple times within pentaprism 5 and directed to eyepiece 6. This allows a photographer with their eye positioned at eyepoint EP to observe the subject image as an erect image.

[0282] Furthermore, when the photographer presses a release button (not shown), the quick-return mirror 3 moves out of the optical path, allowing light from a subject (not shown) to reach the image sensor 7. As a result, the light from the subject is captured by the image sensor 7 and stored in a memory (not shown) as a subject image. In this way, the photographer can capture a subject using the camera 1.

[0283] Here, the optical system of the first embodiment mounted on the camera 1 as the photographic lens 2 is a small, lightweight optical system with good imaging performance. Therefore, the camera 1 can be made small and achieve good optical performance. Note that even if a camera is constructed with the optical systems of the second to eleventh embodiments mounted on the photographic lens 2, the same effects as those of the camera 1 can be achieved.

[0284] Finally, a method for manufacturing the optical system of this embodiment will be outlined with reference to FIGS. FIG. 24 is a first flowchart outlining the method for manufacturing the optical system of this embodiment.

[0285] The method for manufacturing an optical system according to this embodiment shown in FIG. 24 is a method for manufacturing an optical system made up of a plurality of lenses, and includes the following steps S11, S12, and S13.

[0286] Step S11: Arranged in order from the object side are a first lens group having positive refractive power, a focusing group that moves along the optical axis during focusing, and a rear group.

[0287] Step S12: The 1Ath lens group is disposed on the object side, with the largest air gap A in the first lens group.

[0288] Step S13: The optical system is made to satisfy all predetermined conditional expressions. (1) 1.00 < FNo × (TL / f) 2 < 2.50 (2) 0.30 < dA / dG1 < 0.85 however, FNo: F-number of the optical system when focused at infinity TL: Total optical length of the optical system when focused at infinity f: focal length of the optical system when focused at infinity dA: Distance on the optical axis of air gap A dG1: Distance on the optical axis of the first lens group

[0289] According to the manufacturing method of the optical system of this embodiment, it is possible to manufacture an optical system that is small, lightweight, and has good imaging performance.

[0290] FIG. 25 is a second flowchart outlining the method for manufacturing the optical system of this embodiment.

[0291] The method for manufacturing an optical system according to this embodiment shown in FIG. 25 is a method for manufacturing an optical system made up of a plurality of lenses, and includes the following steps S21, S22, and S23.

[0292] Step S21: Prepare a plurality of lenses.

[0293] Step S22: At least one positive lens component and a negative lens N are arranged in order from the object side.

[0294] Step S23: The optical system is made to satisfy all predetermined conditional expressions. (1) 1.00 < FNo × (TL / f) 2 < 2.50 (4) 0.18 < dN / TL < 0.45 however, FNo: F-number of the optical system when focused at infinity TL: Total optical length of the optical system when focused at infinity f: focal length of the optical system when focused at infinity dN: The distance on the optical axis from the optical system's most object-side surface to the object-side surface of negative lens N

[0295] According to the manufacturing method of the optical system of this embodiment, it is possible to manufacture an optical system that is small, lightweight, and has good imaging performance.

[0296] It should be understood that those skilled in the art can make various changes, substitutions and alterations thereto without departing from the spirit and scope of the present invention. [Explanation of symbols]

[0297] S aperture stop I image plane 1 camera 2. Shooting lens 7. Image sensor

Claims

[Claim 1] In order from the object side, a first lens group having positive refractive power; It consists of a focusing group that moves along the optical axis during focusing, and a rear group, a lens group disposed on the object side with the largest air gap A in the first lens group is designated as a first-A lens group; An optical system that satisfies all of the following conditions: 1.00 < FNo × (TL / f) ２ < 2.50 0.30 < dA / dG1 < 0.85 0.00 < (L1R2+L1R1) / (L1R2-L1R1) < 3.00 however, FNo: F-number of the optical system when focused at infinity TL: total optical length of the optical system when focused at infinity f: focal length of the optical system when focused at infinity dA: distance on the optical axis of the air gap A dG1: the distance on the optical axis of the first lens group L1R1: radius of curvature of the object-side surface of the first lens arranged closest to the object side in the first A lens group L1R2: Radius of curvature of the image-side surface of the first lens

Images