Optical system, optical apparatus, interchangeable lens, and method for manufacturing optical system

Abstract

An optical system having a front group, an aperture stop, and a rear group having positive refractive power in order from the object side is configured so as to simultaneously satisfy the following conditional expressions: (1) 0.10 < ff / fr < 1.50 (2) 0.13 < Tr / TL < 0.45 (3) 0.50 < f / TL < 1.20 (where ff is the focal length of the front group, fr is the focal length of the rear group, tr is the sum of the center thicknesses of the respective lenses included in the rear group, TL is the total length of the optical system, and f is the focal length of the optical system.

Description

Technical Field

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

[0002] Conventionally, an optical system for an optical device such as a photographic camera, a digital still camera, or a video camera has been proposed (for example, see Patent Document 1).

[0003] Prior Art Documents

[0004] Patent Documents

[0005] Patent Document 1: International Publication No. 2019 / 187633 Summary of the Invention

[0006] The optical system of the present disclosure includes, in order from the object side, a front group having a positive optical power, an aperture stop, and a rear group, and satisfies the following conditional expressions: 0.10 < ff / |fr| < 1.50 0.13 < tr / TL < 0.45 0.50 < f / TL < 1.20 Wherein, ff: Focal length of the front group, fr: Focal length of the rear group, tr: Sum of the center thicknesses of the respective lenses included in the rear group, TL: Overall length of the optical system, f: Focal length of the optical system.

[0007] A method for manufacturing the optical system of the present disclosure, the optical system including, in order from the object side, a front group having a positive optical power, an aperture stop, and a rear group, the method for manufacturing the optical system configuring the optical system to satisfy the following conditional expressions: 0.10 < ff / |fr| < 1.50 0.13 < tr / TL < 0.45 0.50 < f / TL < 1.20 Wherein, ff: Focal length of the front group, fr: Focal length of the rear group, tr: Sum of the center thicknesses of the respective lenses included in the rear group, TL: Overall length of the optical system, f: Focal length of the optical system. Brief Description of the Drawings

[0008] Figure 1 It is a cross-sectional view of the optical system of the first embodiment when focusing on an infinitely distant object.

[0009] Figure 2 These are aberration diagrams of the optical system of the first embodiment.

[0010] Figure 3 This is a cross-sectional view of the optical system of the second embodiment when focusing on an infinitely distant object.

[0011] Figure 4

[0012] Figure 5 These are aberration diagrams of the optical system of the second embodiment.

[0013] Figure 6

[0014] Figure 7 These are aberration diagrams of the optical system of the third embodiment.

[0015] Figure 8

[0016] Figure 9 This is a cross-sectional view of the optical system of the fourth embodiment when focusing on an infinitely distant object.

[0017] Figure 10

[0018] Figure 11 These are aberration diagrams of the optical system of the fifth embodiment.

[0019] Figure 12 This is a cross-sectional view of the optical system of the sixth embodiment when focusing on an infinitely distant object.

[0020] Figure 13 These are aberration diagrams of the optical system of the sixth embodiment.

[0021] Figure 14 This is a cross-sectional view of the optical system of the seventh embodiment when focusing on an infinitely distant object.

[0022] Figure 15 These are aberration diagrams of the optical system of the seventh embodiment.

[0022] Figure 15 This is a cross-sectional view of the optical system of the eighth embodiment when focusing on an infinitely distant object.

[0023] Figure 16 These are aberration diagrams of the optical system of the eighth embodiment.

[0024] Figure 17 This is a cross-sectional view of the optical system of the ninth embodiment when focusing on an infinitely distant object.

[0025] Figure 18These are aberration diagrams of the optical system of the 9th embodiment.

[0026] Figure 19 This is a cross-sectional view of the optical system of the 10th embodiment when focusing on an object at infinity.

[0027] Figure 20 These are aberration diagrams of the optical system of the 10th embodiment.

[0028] Figure 21 This is a schematic diagram of a camera equipped with the optical system of this embodiment.

[0029] Figure 22 This is a schematic flowchart showing the manufacturing method of the optical system of this embodiment. Detailed Embodiment

[0030] Hereinafter, the optical system, optical device, and manufacturing method of the optical system according to the embodiments of the present application will be described.

[0031] The optical system of this embodiment sequentially includes a front group having a positive optical power, an aperture stop, and a rear group from the object side, and satisfies the following conditional expressions. (1) 0.10 < ff / |fr| < 1.50 (2) 0.13 < tr / TL < 0.45 (3) 0.50 < f / TL < 1.20 Wherein, ff: Focal length of the front group fr: Focal length of the rear group tr: Sum of the center thicknesses of the lenses included in the rear group TL: Overall length of the optical system f: Focal length of the optical system

[0032] Since the front group of the optical system of this embodiment has a positive optical power, the principal point can be placed on the object side, so the overall length can be shortened relative to the focal length.

[0033] Conditional expression (1) defines the ratio of the focal length of the front group to the focal length of the rear group. By satisfying conditional expression (1), the optical system of this embodiment can appropriately correct various aberrations such as spherical aberration, coma, field curvature, and distortion while suppressing the enlargement of the optical system.

[0034] In the optical system of this embodiment, if the value of conditional expression (1) exceeds the upper limit value, the optical power of the front group becomes too strong, and high-order spherical aberration, coma, field curvature, and distortion are generated, making it difficult to appropriately correct various aberrations.

[0035] In the optical system of the present embodiment, by setting the upper limit value of conditional expression (1) to 1.50, the effects of the present embodiment can be made more reliable. Additionally, to make the effects of the present embodiment more reliable, it is preferable to set the upper limit value of conditional expression (1) to 1.40, 1.30, 1.20, 1.10, and further to 1.00.

[0036] Moreover, in the optical system of the present embodiment, if the value of conditional expression (1) is lower than the lower limit value, the optical power of the front group becomes too weak, the overall length of the optical system becomes longer, the lens diameter becomes larger, and the optical system becomes larger in size.

[0037] In the optical system of the present embodiment, by setting the lower limit value of conditional expression (1) to 0.10, the effects of the present embodiment can be made more reliable. Additionally, to make the effects of the present embodiment more reliable, it is preferable to set the lower limit value of conditional expression (1) to 0.15, 0.19, and further to 0.40.

[0038] Conditional expression (2) defines the ratio of the sum of the central thicknesses of the lenses included in the rear group to the overall length of the optical system. By satisfying conditional expression (2), the optical system of the present embodiment can suppress the increase in size and weight of the optical system.

[0039] In the optical system of the present embodiment, if the value of conditional expression (2) exceeds the upper limit value, the lens thickness increases, and thus the weight of the optical system increases.

[0040] In the optical system of the present embodiment, by setting the upper limit value of conditional expression (2) to 0.45, the effects of the present embodiment can be made more reliable. Additionally, to make the effects of the present embodiment more reliable, it is preferable to set the upper limit value of conditional expression (2) to 0.40, 0.35, and further to 0.30.

[0041] Moreover, in the optical system of the present embodiment, if the value of conditional expression (2) is lower than the lower limit value, the overall length of the optical system becomes longer, and the optical system becomes larger in size.

[0042] In the optical system of the present embodiment, by setting the lower limit value of conditional expression (2) to 0.13, the effects of the present embodiment can be made more reliable. Additionally, to make the effects of the present embodiment more reliable, it is preferable to set the lower limit value of conditional expression (2) to 0.14, 0.15, 0.16, and further to 0.17.

[0043] Conditional expression (3) defines the ratio of the focal length of the optical system to the overall length of the optical system. By satisfying conditional expression (3), the optical system of the present embodiment can suppress the increase in size of the optical system while appropriately correcting various aberrations such as spherical aberration, coma, field curvature, and distortion.

[0044] In the optical system of the present embodiment, if the value of conditional expression (3) exceeds the upper limit value, it becomes difficult to appropriately correct various aberrations such as spherical aberration, coma, field curvature, and distortion.

[0045] In the optical system of the present embodiment, by setting the upper limit value of conditional expression (3) to 1.20, the effects of the present embodiment can be made more reliable. Additionally, in order to make the effects of the present embodiment more reliable, it is preferable to set the upper limit value of conditional expression (3) to 1.15, 1.10, 1.05, and further to 1.00.

[0046] Moreover, in the optical system of the present embodiment, if the value of conditional expression (3) is lower than the lower limit value, the overall length of the optical system becomes longer and the optical system becomes larger.

[0047] In the optical system of the present embodiment, by setting the lower limit value of conditional expression (3) to 0.50, the effects of the present embodiment can be made more reliable. Additionally, in order to make the effects of the present embodiment more reliable, it is preferable to set the lower limit value of conditional expression (3) to 0.55, 0.60, 0.65, 0.70, and further to 0.80.

[0048] By simultaneously satisfying conditional expression (1), conditional expression (2), and conditional expression (3), the optical system of the present embodiment can appropriately correct various aberrations such as spherical aberration, coma, field curvature, and distortion while suppressing the increase in the size and weight of the optical system.

[0049] Moreover, in the optical system of the present embodiment, it is preferable that the rear group has a negative optical power.

[0050] In the optical system of the present embodiment, by having such a structure, the overall length of the optical system can be shortened and spherical aberration can be appropriately corrected.

[0051] Moreover, the optical system of the present embodiment preferably satisfies the following conditional expression. (4) 0.05 < fPr / |fr| < 0.70 Wherein, fPr: Focal length of the singlet Pr with the strongest optical power among the singlet lenses with a biconvex shape in the rear group

[0052] Conditional expression (4) defines the ratio of the focal length of the singlet Pr with the strongest optical power among the singlet lenses with a biconvex shape in the rear group to the focal length of the rear group. By satisfying conditional expression (4), the optical system of the present embodiment can appropriately correct various aberrations such as coma and field curvature while suppressing the increase in the size of the optical system.

[0053] In the optical system of the present embodiment, if the value of conditional expression (4) exceeds the upper limit value, the refractive power of the rear group becomes too weak, the overall length of the optical system becomes longer, the lens diameter becomes larger, and the optical system becomes larger in size.

[0054] In the optical system of the present embodiment, by setting the upper limit value of conditional expression (4) to 0.70, the effects of the present embodiment can be made more reliable. Additionally, to make the effects of the present embodiment more reliable, it is preferable to set the upper limit value of conditional expression (4) to 0.65, 0.60, and further to 0.40.

[0055] In the optical system of the present embodiment, if the value of conditional expression (4) is lower than the lower limit value, the refractive power of the single lens Pr becomes too strong, higher-order coma and field curvature are generated, and it becomes difficult to appropriately correct each aberration.

[0056] In the optical system of the present embodiment, by setting the lower limit value of conditional expression (4) to 0.05, the effects of the present embodiment can be made more reliable. Additionally, to make the effects of the present embodiment more reliable, it is preferable to set the lower limit value of conditional expression (4) to 0.06, 0.07, 0.08, 0.09, 0.10, and further to 0.20.

[0057] In addition, the optical system of the present embodiment preferably has at least one focusing group that moves during focusing and satisfies the following conditional expression. (5) 0.05 < fPfoi / |fr| < 0.50 Wherein, fPfoi: The focal length of the single lens Pfoi with the strongest refractive power among the double-convex-shaped single lenses arranged on the image plane side compared to the focusing group Gfo arranged on the object side in at least one focusing group

[0058] Conditional expression (5) defines the ratio of the focal length of the single lens Pfoi to the focal length of the rear group. By satisfying conditional expression (5), the optical system of the present embodiment can suppress the generation of spherical aberration, coma, and field curvature while suppressing the increase in size of the optical system.

[0059] In the optical system of the present embodiment, if the value of conditional expression (5) exceeds the upper limit value, the refractive power of the single lens fPfoi becomes too weak, and the overall length of the optical system becomes longer.

[0060] In the optical system of the present embodiment, by setting the upper limit value of conditional expression (5) to 0.70, the effects of the present embodiment can be made more reliable. Additionally, to make the effects of the present embodiment more reliable, it is preferable to set the upper limit value of conditional expression (5) to 0.65, 0.60, and further to 0.40.

[0061] In addition, in the optical system of the present embodiment, if the value of conditional expression (5) is lower than the lower limit value, the optical power of the single lens Pfoi becomes too strong, and it becomes difficult to appropriately correct various aberrations such as spherical aberration, coma, and field curvature.

[0062] In the optical system of the present embodiment, by setting the lower limit value of conditional expression (5) to 0.05, the effects of the present embodiment can be made more reliable. In addition, in order to make the effects of the present embodiment more reliable, it is preferable to set the lower limit value of conditional expression (5) to 0.06, 0.07, 0.08, 0.09, 0.10, and further to 0.20.

[0063] In addition, the optical system of the present embodiment preferably has at least one focusing group that moves during focusing and satisfies the following conditional expression. (6) 0.25 < fPfoi / f < 0.55

[0064] Conditional expression (6) defines the ratio of the focal length of the single lens Pfoi to the focal length of the optical system. By satisfying conditional expression (6), the optical system of the present embodiment can suppress the occurrence of spherical aberration, coma, and field curvature while suppressing the enlargement of the optical system.

[0065] In the optical system of the present embodiment, if the value of conditional expression (6) exceeds the upper limit value, the optical power of the single lens Pfoi becomes too weak, the overall length of the optical system becomes longer, and the lens diameter becomes larger, resulting in the enlargement of the optical system. In addition, if the value of conditional expression (6) exceeds the upper limit value, it becomes difficult to appropriately correct various aberrations such as spherical aberration, coma, and field curvature.

[0066] In the optical system of the present embodiment, by setting the upper limit value of conditional expression (6) to 0.55, the effects of the present embodiment can be made more reliable. In addition, in order to make the effects of the present embodiment more reliable, it is preferable to set the upper limit value of conditional expression (6) to 0.50, 0.48, 0.46, and further to 0.40.

[0067] In addition, in the optical system of the present embodiment, if the value of conditional expression (6) is lower than the lower limit value, the optical power of the single lens Pfoi becomes too strong, and it becomes difficult to appropriately correct various aberrations such as spherical aberration, coma, and field curvature.

[0068] In the optical system of the present embodiment, by setting the lower limit value of conditional expression (6) to 0.25, the effects of the present embodiment can be made more reliable. In addition, in order to make the effects of the present embodiment more reliable, it is preferable to set the lower limit value of conditional expression (6) to 0.28, 0.30, and further to 0.31.

[0069] In addition, the optical system of the present embodiment preferably satisfies the following conditional expressions. (7) 0.05 < Da / Bf < 1.10 Wherein, Da: The distance on the optical axis at infinity focus between the lens surface on the object side of the lens Li1 disposed closest to the image plane side and the lens surface on the image plane side of the lens Li2 disposed adjacent to the object side of the lens Li1 Bf: The back focal length in terms of air equivalent length

[0070] Conditional expression (7) defines the ratio of the distance on the optical axis at infinity focus between the lens surface on the object side of the lens Li1 and the lens surface on the image plane side of the lens Li2 to the back focal length in terms of air equivalent length of the optical system. By satisfying conditional expression (7), the optical system of the present embodiment can appropriately correct various aberrations such as field curvature, coma, and distortion.

[0071] In the optical system of the present embodiment, if the value of conditional expression (7) exceeds the upper limit value, it becomes difficult to appropriately correct field curvature and coma.

[0072] In the optical system of the present embodiment, by setting the upper limit value of conditional expression (7) to 1.10, the effects of the present embodiment can be made more reliable. In addition, in order to make the effects of the present embodiment more reliable, it is preferable to set the upper limit value of conditional expression (7) to 1.05, and further to 1.00.

[0073] In addition, in the optical system of the present embodiment, if the value of conditional expression (7) is lower than the lower limit value, it becomes difficult to appropriately correct field curvature and distortion.

[0074] In the optical system of the present embodiment, by setting the lower limit value of conditional expression (7) to 0.05, the effects of the present embodiment can be made more reliable. In addition, in order to make the effects of the present embodiment more reliable, it is preferable to set the lower limit value of conditional expression (7) to 0.06, and further to 0.07.

[0075] In addition, in the optical system of the present embodiment, it is preferable that the rear group has a plurality of lens groups, the plurality of lens groups include at least one focusing group that moves during focusing, and the intervals between the plurality of lens groups change during focusing, and satisfy the following conditional expression. (8) 0.30 < tGi / Da < 9.00 Wherein, tGi: The sum of the lengths on the optical axis of the lenses included in the lens group Gi disposed closest to the image side among the plurality of lens groups

[0076] The conditional expression (8) stipulates the ratio of the sum of the lengths of the lenses on the optical axis included in the lens group Gi to the distance on the optical axis in the case of focusing at infinity between the lens surface on the object side of the lens Li1 and the lens surface on the image side of the lens Li2. By satisfying the conditional expression (8), the optical system of the present embodiment can suppress an increase in the weight of the optical system while appropriately correcting various aberrations such as field curvature and distortion.

[0077] In the optical system of the present embodiment, if the value of the conditional expression (8) exceeds the upper limit value, the lens thickness of the lens group Gi becomes too large and the weight of the optical system increases.

[0078] In the optical system of the present embodiment, by setting the upper limit value of the conditional expression (8) to 9.00, the effects of the present embodiment can be made more reliable. Further, in order to make the effects of the present embodiment more reliable, it is preferable to set the upper limit value of the conditional expression (8) to 8.50, 8.00, 7.80, 7.60, and further to 3.00.

[0079] Further, in the optical system of the present embodiment, if the value of the conditional expression (8) is lower than the lower limit value, it becomes difficult to appropriately correct various aberrations such as field curvature and distortion.

[0080] In the optical system of the present embodiment, by setting the lower limit value of the conditional expression (8) to 0.30, the effects of the present embodiment can be made more reliable. Further, in order to make the effects of the present embodiment more reliable, it is preferable to set the lower limit value of the conditional expression (8) to 0.32, 0.34, 0.60, 1.00, and further to 1.50.

[0081] Further, the optical system of the present embodiment preferably satisfies the following conditional expression. (9) 0.40 < D1 / TL < 0.85 Wherein, D1: The distance on the optical axis in the case of focusing at infinity between the lens surface closest to the object side and the object-side surface of the singlet Pr having the strongest optical power among the singlet lenses having a biconvex shape in the rear group

[0082] The conditional expression (9) stipulates the ratio of the distance on the optical axis in the case of focusing at infinity between the lens surface closest to the object side and the object-side lens surface of the singlet Pr to the overall length of the optical system. By satisfying the conditional expression (9), the optical system of the present embodiment can suppress the enlargement of the optical system while appropriately correcting various aberrations such as spherical aberration, coma, field curvature, and distortion.

[0083] In the optical system of the present embodiment, if the value of conditional expression (9) exceeds the upper limit value, the optical power between the lens surface closest to the object side and the lens surface on the object side of the single lens Pr becomes too weak, the lens diameter increases, and the optical system becomes larger.

[0084] In the optical system of the present embodiment, by setting the upper limit value of conditional expression (9) to 0.85, the effects of the present embodiment can be made more reliable. Additionally, to make the effects of the present embodiment more reliable, it is preferable to set the upper limit value of conditional expression (9) to 0.84, 0.82, and further to 0.80.

[0085] Moreover, in the optical system of the present embodiment, if the value of conditional expression (9) is lower than the lower limit value, the optical power between the lens surface closest to the object side and the lens surface on the object side of the single lens Pr becomes too strong, generating high-order spherical aberration, coma, field curvature, and distortion, making it difficult to appropriately correct each aberration.

[0086] In the optical system of the present embodiment, by setting the lower limit value of conditional expression (9) to 0.40, the effects of the present embodiment can be made more reliable. Additionally, to make the effects of the present embodiment more reliable, it is preferable to set the lower limit value of conditional expression (9) to 0.45, and further to 0.50.

[0087] Furthermore, the optical system of the present embodiment preferably satisfies the following conditional expression. (10) 0.10 < D2 / TL < 0.80 Wherein, D2: The distance on the optical axis between the aperture stop and the lens surface on the object side of the single lens Pr with the strongest optical power among the biconvex single lenses within the rear group

[0088] Conditional expression (10) stipulates the ratio of the distance on the optical axis between the aperture stop and the lens surface on the object side of the single lens Pr to the overall length of the optical system. By satisfying conditional expression (10), the optical system of the present embodiment can appropriately correct various aberrations such as spherical aberration, coma, field curvature, and distortion while suppressing the enlargement of the optical system.

[0089] In the optical system of the present embodiment, if the value of conditional expression (10) exceeds the upper limit value, the optical power between the aperture stop and the lens surface on the object side of the single lens Pr becomes too weak, the lens diameter increases, and the optical system becomes larger.

[0090] In the optical system of the present embodiment, by setting the upper limit value of conditional expression (10) to 0.80, the effects of the present embodiment can be made more reliable. Additionally, to make the effects of the present embodiment more reliable, it is preferable to set the upper limit value of conditional expression (10) to 0.70, 0.60, 0.50, 0.40, and further to 0.36.

[0091] In the optical system of the present embodiment, if the value of conditional expression (10) is lower than the lower limit value, the optical power between the aperture stop and the lens surface on the object side of the single lens Pr becomes too strong, resulting in higher-order spherical aberration, coma, field curvature, and distortion, making it difficult to appropriately correct each aberration.

[0092] In the optical system of the present embodiment, by setting the lower limit value of conditional expression (10) to 0.10, the effects of the present embodiment can be made more reliable. Additionally, to make the effects of the present embodiment more reliable, it is preferable to set the lower limit value of conditional expression (10) to 0.11, 0.12, and further to 0.13.

[0093] In addition, the optical system of the present embodiment preferably has at least one focusing group that moves during focusing and satisfies the following conditional expression. (11) 0.25 < |ffo| / f < 0.90 Wherein, ffo: The focal length of the focusing group Gfo disposed closest to the object side in at least one focusing group

[0094] Conditional expression (11) defines the ratio of the focal length of the focusing group Gfo disposed closest to the object side to the focal length of the optical system. By satisfying conditional expression (11), the optical system of the present embodiment can appropriately correct various aberrations such as spherical aberration, coma, field curvature, and distortion while suppressing an increase in the overall length of the optical system.

[0095] In the optical system of the present embodiment, if the value of conditional expression (11) exceeds the upper limit value, it becomes difficult to suppress fluctuations in various aberrations such as spherical aberration, coma, field curvature, and distortion during focusing.

[0096] In the optical system of the present embodiment, by setting the upper limit value of conditional expression (11) to 0.90, the effects of the present embodiment can be made more reliable. Additionally, to make the effects of the present embodiment more reliable, it is preferable to set the upper limit value of conditional expression (11) to 0.85, and further to 0.80.

[0097] In the optical system of the present embodiment, if the value of conditional expression (11) is lower than the lower limit value, the optical power of the focusing group disposed closest to the object side becomes too weak, and the movement amount of the focusing group during focusing increases, thus increasing the overall length of the optical system.

[0098] In the optical system of the present embodiment, by setting the lower limit value of conditional expression (11) to 0.25, the effects of the present embodiment can be made more reliable. Additionally, in order to make the effects of the present embodiment more reliable, it is preferable to set the lower limit value of conditional expression (11) to 0.26, 0.28, 0.30, 0.31, and further to 0.32.

[0099] In addition, in the optical system of the present embodiment, it is preferable that the front group has at least one positive lens Pf that simultaneously satisfies the following conditional expressions. (12) 1.60 < ndPf (13) νdPf < 31.00 (14) 0.01 < θgFPf - (0.6415 - 0.00162 × νdPf) Where, ndPf: refractive index of the positive lens Pf with respect to the d line νdPf: Abbe number of the positive lens Pf based on the d line θgFPf: relative partial dispersion of the positive lens Pf, which is defined by the following formula when the refractive index of the positive lens Pf with respect to the g line is ngPf, the refractive index of the positive lens Pf with respect to the F line is nFPf, and the refractive index of the positive lens Pf with respect to the C line is nCPf. θgFPf = (ngPf - nFPf) / (nFPf - nCPf)

[0100] The optical system of the present embodiment can appropriately correct various aberrations such as axial chromatic aberration by having at least one positive lens Pf in the front group.

[0101] The optical system of the present embodiment can suppress the generation of higher-order aberrations by making the value of conditional expression (12) regarding the positive lens Pf larger than the lower limit value.

[0102] In the optical system of the present embodiment, by setting the lower limit value of conditional expression (12) to 1.60, the effects of the present embodiment can be made more reliable. Additionally, in order to make the effects of the present embodiment more reliable, it is preferable to set the lower limit value of conditional expression (12) to 1.62, 1.64, and further to 1.66.

[0103] The optical system of the present embodiment can well correct the second-order dispersion of axial chromatic aberration by making the value of conditional expression (13) regarding the positive lens Pf smaller than the upper limit value.

[0104] In the optical system of the present embodiment, by setting the upper limit value of conditional expression (13) to 31.00, the effects of the present embodiment can be made more reliable. Additionally, in order to make the effects of the present embodiment more reliable, it is preferable to set the upper limit value of conditional expression (13) to 29.50, 28.00, and further to 27.50.

[0105] The optical system of the present embodiment can correct the second-order dispersion of axial chromatic aberration well by making the value of conditional expression (14) regarding the positive lens Pf larger than the lower limit value.

[0106] In the optical system of the present embodiment, by setting the lower limit value of conditional expression (14) to 0.01, the effects of the present embodiment can be made more reliable. Additionally, in order to make the effects of the present embodiment more reliable, it is preferable to set the lower limit value of conditional expression (14) to 0.015, 0.02, and further to 0.025.

[0107] Furthermore, in the optical system of the present embodiment, it is preferable that the front group has at least one negative lens Nf that simultaneously satisfies the following conditional expressions. (15) 1.85 < ndNf (16) νdNf < 26.00 (17) θgFNf - (0.6415 - 0.00162 × νdNf) < 0.015 Wherein, ndNf: refractive index of the negative lens Nf for the d line νdNf: Abbe number of the negative lens Nf based on the d line θgFNf: relative partial dispersion of the negative lens Nf, which is defined by the following formula when the refractive index of the negative lens Nf for the g line is ngNf, the refractive index of the negative lens Nf for the F line is nFNf, and the refractive index of the negative lens Nf for the C line is nCNf. θgFNf = (ngNf - nFNf) / (nFNf - nCNf)

[0108] The optical system of the present embodiment can appropriately correct various aberrations such as axial chromatic aberration by having at least one negative lens Nf in the front group.

[0109] The optical system of the present embodiment can suppress the generation of high-order aberrations by making the value of conditional expression (15) regarding the negative lens Nf larger than the lower limit value.

[0110] In the optical system of the present embodiment, by setting the lower limit value of conditional expression (15) to 1.85, the effects of the present embodiment can be made more reliable.

[0111] By making the value of conditional expression (16) with respect to the negative lens Nf smaller than the upper limit value, the second-order dispersion of the axial chromatic aberration can be corrected well in the optical system of the present embodiment.

[0112] In the optical system of the present embodiment, by setting the upper limit value of conditional expression (16) to 26.00, the effect of the present embodiment can be made more reliable. Additionally, in order to make the effect of the present embodiment more reliable, it is preferable to set the upper limit value of conditional expression (16) to 25.80, 25.50, and further to 25.20.

[0113] By making the value of conditional expression (17) with respect to the negative lens Nf smaller than the upper limit value, the second-order dispersion of the axial chromatic aberration can be corrected well in the optical system of the present embodiment.

[0114] In the optical system of the present embodiment, by setting the upper limit value of conditional expression (17) to 0.015, the effect of the present embodiment can be made more reliable. Additionally, in order to make the effect of the present embodiment more reliable, it is preferable to set the upper limit value of conditional expression (17) to 0.013, 0.012, and further to 0.01.

[0115] With the above structure, an optical system that is small-sized and has good optical performance can be achieved.

[0116] The optical device of the present embodiment includes an optical system having the above structure. Thus, an optical device that is small-sized and has good optical performance can be achieved.

[0117] The interchangeable lens of the present embodiment includes an optical system having the above structure. Thus, an interchangeable lens that is small-sized and has good optical performance can be achieved.

[0118] The manufacturing method of the optical system of the present embodiment includes: configuring an optical system that sequentially includes a front group with a positive optical power, an aperture stop, and a rear group from the object side to simultaneously satisfy the following conditional expressions. (1) 0.10 < ff / |fr| < 1.50 (2) 0.13 < tr / TL < 0.45 (3) 0.50 < f / TL < 1.20 Among them, ff: Focal length of the front group fr: Focal length of the rear group tr: Sum of the central thicknesses of the respective lenses included in the rear group TL: Overall length of the optical system f: Focal length of the optical system

[0119] Through such a manufacturing method of the optical system, an optical system that is small-sized and has good optical performance can be manufactured.

[0120] (Numerical Example)

[0121] Hereinafter, embodiments of the present application will be described based on the accompanying drawings.

[0122] (First Embodiment)

[0123] Figure 1 FIG. is a cross-sectional view of the optical system according to the first embodiment when focusing on an infinitely distant object.

[0124] The optical system of this embodiment sequentially includes a first lens group G1 having a positive optical power, a second lens group G2 having a negative optical power, a third lens group G3 having a positive optical power, a fourth lens group G4 having a positive optical power, and a fifth lens group G5 having a negative optical power from the object side.

[0125] The first lens group G1 is sequentially composed of a meniscus positive lens L1 with a convex surface facing the object side, a meniscus positive lens L2 with a convex surface facing the object side, a meniscus positive lens L3 with a convex surface facing the object side, a cemented negative lens formed by a biconvex positive lens L4 and a biconcave negative lens L5, an aperture stop S, and a meniscus positive lens L6 with a convex surface facing the object side from the object side.

[0126] The second lens group G2 is composed of a meniscus negative lens L7 with a convex surface facing the object side.

[0127] The third lens group G3 is sequentially composed of a meniscus positive lens L8 with a concave surface facing the object side, a cemented negative lens formed by a biconcave negative lens L9 and a meniscus positive lens L10 with a convex surface facing the object side, a biconvex positive lens L11, and a meniscus negative lens L12 with a convex surface facing the object side from the object side.

[0128] The fourth lens group G4 is composed of a meniscus positive lens L13 with a convex surface facing the object side.

[0129] The fifth lens group G5 is sequentially composed of a biconcave negative lens L14, a meniscus positive lens L15 with a convex surface facing the object side, and a meniscus negative lens L16 with a concave surface facing the object side from the object side.

[0130] On the image plane I, an imaging element (not shown) composed of a CCD, a CMOS, or the like is disposed.

[0131] A filter FL is disposed between the optical system of this embodiment and the image plane I.

[0132] The optical system of this embodiment performs focusing by moving the second lens group G2 and the fourth lens group G4 along the optical axis. When focusing from the state of focusing on infinity to a close object, the second lens group G2 moves from the object side toward the image side, and the fourth lens group G4 moves from the image side toward the object side.

[0133] In the optical system of this embodiment, the lenses from the positive lens L1 to the negative lens L5 in the first lens group G1 are equivalent to the front group, and the positive lens L6, the second lens group G2, the third lens group G3, the fourth lens group G4, and the fifth lens group G5 in the first lens group G1 are equivalent to the rear group. The second lens group G2 and the fourth lens group G4 are equivalent to the focusing groups that move during focusing. The second lens group G2 is equivalent to the focusing group Gfo disposed closest to the object side. The fifth lens group is equivalent to the lens group Gi disposed closest to the image side.

[0134] In the optical system of this embodiment, the positive lens L11 is equivalent to the single lens Pr with the strongest optical power among the double-convex single lenses in the rear group and the single lens Pfoi with the strongest optical power among the double-convex single lenses disposed on the image side with respect to the focusing group Gfo. The negative lens L16 is equivalent to the lens Li1 disposed closest to the image side, and the positive lens L15 is equivalent to the lens Li2 disposed adjacent to the object side of the lens Li1. The positive lens L1 is equivalent to the positive lens Pf of the front group, and the negative lens L5 is equivalent to the negative lens Nf of the front group.

[0135] In Table 1 below, the parameter values of the optical system of this embodiment are listed.

[0136] In [Overall Parameters], f represents the focal length of the entire optical system, ff represents the focal length of the front group, fr represents the focal length of the rear group, TL represents the distance from the lens surface closest to the object side to the image plane, Bf represents the back focal length under the air-equivalent length of the optical system, FNO represents the F-number of the optical system, and Y represents the maximum image height.

[0137] In [Lens Parameters], m represents the order of the optical surface counted from the object side, r represents the radius of curvature, d represents the surface interval, nd represents the refractive index for the d-line (wavelength 587.6 nm), and νd represents the Abbe number for the d-line. The radius of curvature r = ∞ represents a plane. Additionally, in [Lens Parameters], the optical surface with an asterisk (*) mark indicates an aspherical surface.

[0138] In [Aspherical Data], m represents the optical surface corresponding to the aspherical data, K represents the conic constant, and A4 - A10 represent the aspherical coefficients.

[0139] When the height in the direction perpendicular to the optical axis is set as y, the distance along the optical axis (recess amount) from the tangent plane at the vertex of each aspherical surface to each aspherical surface at height y is set as S(y), the radius of curvature (paraxial radius of curvature) of the reference spherical surface is set as r, the conic constant is set as K, and the aspherical coefficient of the nth order is set as An, the aspherical surface is represented by the following formula (a). In addition, in each embodiment, the aspherical coefficient A2 of the second order is 0. Further, "E-n" represents "×10 -n ". (a) S(y)=(y 2 / r) / {1+(1-K×y 2 / r 2 ) 1 / 2}+A4×y 4 +A6×y 6 +A8×y 8 +A10×y 10

[0140] The units of the focal length f, the radius of curvature r, and other lengths described in Table 1 are all "mm". However, the optical system can obtain the same optical performance even if it is enlarged or reduced in proportion, so it is not limited thereto.

[0141] The symbols in Table 1 described above are also used in the tables of other embodiments described later.

[0142] (Table 1)

[0143] [Overall parameters]

[0144] [Lens parameters]

[0145] [Aspherical data]

[0146] [Focal length data for each group]

[0147] [Variable interval data]

[0148] Figure 2 are aberration diagrams of the optical system of the first embodiment.

[0149] In each aberration diagram, FNO represents the F-number and A represents the image height. Specifically, in the spherical aberration diagram, the value of the F-number corresponding to the maximum aperture is shown; in the astigmatism diagram and the distortion diagram, the maximum value of the image height is shown; and in the coma diagram, the values of each image height are shown. d represents the d-line (wavelength 587.6 nm), and g represents the g-line (wavelength 435.8 nm). In the astigmatism diagram, the solid line represents the sagittal image plane, and the dashed line represents the meridional image plane. In the aberration diagrams of other embodiments described later, the same symbols as those in the aberration diagrams of this embodiment are also used.

[0150] From each aberration diagram, it can be seen that the optical system of this embodiment appropriately corrects each aberration and has high optical performance.

[0151] (Second Embodiment)

[0152] Figure 3 is a cross-sectional view of the optical system of the second embodiment when focusing on an infinitely distant object.

[0153] The optical system of this embodiment sequentially includes, from the object side, a first lens group G1 having a positive focal power, an aperture stop S, a second lens group G2 having a negative focal power, a third lens group G3 having a positive focal power, a fourth lens group G4 having a positive focal power, and a fifth lens group G5 having a negative focal power.

[0154] The first lens group G1 is sequentially composed of a meniscus-shaped positive lens L1 with the convex surface facing the object side, a meniscus-shaped positive lens L2 with the convex surface facing the object side, a meniscus-shaped positive lens L3 with the convex surface facing the object side, a cemented negative lens formed by a biconvex positive lens L4 and a biconcave negative lens L5, and a biconvex positive lens L6.

[0155] The second lens group G2 is composed of a meniscus-shaped negative lens L7 with the convex surface facing the object side.

[0156] The third lens group G3 is sequentially composed of a cemented negative lens formed by a biconcave negative lens L8 and a meniscus-shaped positive lens L9 with the convex surface facing the object side, a biconvex positive lens L10, and a meniscus-shaped negative lens L11 with the convex surface facing the object side.

[0157] The fourth lens group G4 is composed of a meniscus-shaped positive lens L12 with the convex surface facing the object side.

[0158] The fifth lens group G5 is sequentially composed of a cemented positive lens formed by a meniscus-shaped negative lens L13 and a biconvex positive lens L14 with the convex surface facing the object side, and a biconcave negative lens L15.

[0159] On the image plane I, an imaging element (not shown) composed of a CCD or a CMOS, etc. is disposed.

[0160] A filter FL is disposed between the optical system and the image plane I in this embodiment.

[0161] The optical system of this embodiment performs focusing by moving the second lens group G2 and the fourth lens group G4 along the optical axis. When focusing from an infinite focus state to a close object, the second lens group G2 moves from the object side toward the image side, and the fourth lens group G4 moves from the image side toward the object side.

[0162] In the optical system of this embodiment, the first lens group G1 corresponds to the front group, and the second lens group G2, the third lens group G3, the fourth lens group G4, and the fifth lens group G5 correspond to the rear group. The second lens group G2 and the fourth lens group G4 correspond to the focusing groups that move during focusing. The second lens group G2 corresponds to the focusing group Gfo disposed closest to the object side. The fifth lens group corresponds to the lens group Gi disposed closest to the image side.

[0163] In the optical system of this embodiment, the positive lens L10 corresponds to the singlet Pr with the strongest optical power among the singlet lenses with a biconvex shape in the rear group and the singlet Pfoi with the strongest optical power among the biconvex singlet lenses disposed on the image side with respect to the focusing group Gfo. The negative lens L15 corresponds to the lens Li1 disposed closest to the image side, and the positive lens L14 corresponds to the lens Li2 disposed adjacent to the object side of the lens Li1. The positive lens L1 corresponds to the positive lens Pf of the front group, and the negative lens L5 corresponds to the negative lens Nf of the front group.

[0164] In Table 2 below, the parameter values of the optical system of this embodiment are listed.

[0165] (Table 2)

[0166] [Overall parameters]

[0167] [Lens parameters]

[0168] [Aspherical data]

[0169] [Focal length data for each group]

[0170] [Variable interval data]

[0171] Figure 4These are aberration diagrams of the optical system of the second embodiment.

[0172] From each aberration diagram, it can be seen that the optical system of this embodiment appropriately corrects each aberration and has high optical performance.

[0173] (Third Embodiment)

[0174] Figure 5 This is a cross-sectional view of the optical system of the third embodiment when focusing on an infinitely distant object.

[0175] The optical system of this embodiment sequentially includes a first lens group G1 with a positive optical power, a second lens group G2 with a negative optical power, a third lens group G3 with a positive optical power, a fourth lens group G4 with a positive optical power, and a fifth lens group G5 with a negative optical power from the object side.

[0176] The first lens group G1 is sequentially composed of a meniscus-shaped positive lens L1 with a convex surface facing the object side, a meniscus-shaped positive lens L2 with a convex surface facing the object side, a meniscus-shaped positive lens L3 with a convex surface facing the object side, a cemented negative lens formed by a biconvex positive lens L4 and a biconcave negative lens L5, an aperture stop S, and a meniscus-shaped positive lens L6 with a convex surface facing the object side from the object side.

[0177] The second lens group G2 is composed of a meniscus-shaped negative lens L7 with a convex surface facing the object side.

[0178] The third lens group G3 is sequentially composed of a cemented negative lens formed by a biconcave negative lens L8 and a meniscus-shaped positive lens L9 with a convex surface facing the object side, a biconvex positive lens L10, and a meniscus-shaped negative lens L11 with a convex surface facing the object side from the object side.

[0179] The fourth lens group G4 is composed of a meniscus-shaped positive lens L12 with a convex surface facing the object side.

[0180] The fifth lens group G5 is sequentially composed of a cemented positive lens formed by a meniscus-shaped negative lens L13 and a biconvex positive lens L14 with a convex surface facing the object side, and a biconcave negative lens L15 from the object side.

[0181] On the image plane I, an imaging element (not shown) composed of a CCD or CMOS, etc. is arranged.

[0182] A filter FL is arranged between the optical system of this embodiment and the image plane I.

[0183] The optical system of this embodiment performs focusing by moving the second lens group G2 and the fourth lens group G4 along the optical axis. When focusing from an infinite focus state to a close object, the second lens group G2 moves from the object side towards the image side, and the fourth lens group G4 moves from the image side towards the object side.

[0184] In the optical system of this embodiment, among the first lens group G1, the positive lens L1 to the negative lens L5 are equivalent to the front group, and the positive lens L6 in the first lens group G1, the second lens group G2, the third lens group G3, the fourth lens group G4, and the fifth lens group G5 are equivalent to the rear group. The second lens group G2 and the fourth lens group G4 are equivalent to the focusing groups that move during focusing. The second lens group G2 is equivalent to the focusing group Gfo disposed closest to the object side. The fifth lens group is equivalent to the lens group Gi disposed closest to the image side.

[0185] In the optical system of this embodiment, the positive lens L10 is equivalent to the single lens Pr with the strongest optical power among the double-convex single lenses in the rear group and the single lens Pfoi with the strongest optical power among the double-convex single lenses disposed on the image side compared to the focusing group Gfo. The negative lens L15 is equivalent to the lens Li1 disposed closest to the image side, and the positive lens L14 is equivalent to the lens Li2 disposed adjacent to the object side of the lens Li1. The positive lens L1 is equivalent to the positive lens Pf of the front group, and the negative lens L5 is equivalent to the negative lens Nf of the front group.

[0186] In Table 3 below, the parameter values of the optical system of this embodiment are recorded.

[0187] (Table 3)

[0188] [Overall parameters]

[0189] [Lens parameters]

[0190] [Aspherical data]

[0191] [Focal length data for each group]

[0192] [Variable interval data]

[0193] Figure 6 These are the aberration diagrams of the optical system of the third embodiment.

[0194] According to each aberration diagram, the optical system of this embodiment appropriately corrects each aberration and has high optical performance.

[0195] (Embodiment 4)

[0196] Figure 7 It is a cross-sectional view of the optical system of Embodiment 4 when focusing on an infinitely distant object.

[0197] The optical system of this embodiment sequentially includes a first lens group G1 with a positive focal power, an aperture stop S, a second lens group G2 with a negative focal power, a third lens group G3 with a positive focal power, a fourth lens group G4 with a positive focal power, and a fifth lens group G5 with a negative focal power from the object side.

[0198] The first lens group G1 is sequentially composed of a meniscus positive lens L1 with a convex surface facing the object side, a meniscus positive lens L2 with a convex surface facing the object side, a meniscus positive lens L3 with a convex surface facing the object side, a cemented negative lens formed by a biconvex positive lens L4 and a biconcave negative lens L5, and a biconvex positive lens L6 from the object side.

[0199] The second lens group G2 is composed of a meniscus negative lens L7 with a convex surface facing the object side.

[0200] The third lens group G3 is sequentially composed of a biconvex positive lens L8, a biconcave negative lens L9, a biconcave negative lens L10, and a biconvex positive lens L11 from the object side.

[0201] The fourth lens group G4 is composed of a biconvex positive lens L12.

[0202] The fifth lens group G5 is composed of a biconcave negative lens L13.

[0203] On the image plane I, an imaging element (not shown) composed of a CCD, a CMOS, etc. is arranged.

[0204] A filter FL is arranged between the optical system of this embodiment and the image plane I.

[0205] The optical system of this embodiment performs focusing by moving the second lens group G2 and the fourth lens group G4 along the optical axis. When focusing from the state of focusing on an infinitely distant object to a nearby object, the second lens group G2 moves from the object side to the image side, and the fourth lens group G4 moves from the image side to the object side.

[0206] In the optical system of this embodiment, the first lens group G1 corresponds to the front group, and the second lens group G2, the third lens group G3, the fourth lens group G4, and the fifth lens group G5 correspond to the rear group. The second lens group G2 and the fourth lens group G4 correspond to the focusing groups that move during focusing. The second lens group G2 corresponds to the focusing group Gfo disposed closest to the object side. The fifth lens group corresponds to the lens group Gi disposed closest to the image side.

[0207] In the optical system of this embodiment, the positive lens L11 corresponds to the single lens Pr with the strongest optical power among the biconvex single lenses within the rear group and the single lens Pfoi with the strongest optical power among the biconvex single lenses disposed on the image side with respect to the focusing group Gfo. The negative lens L13 corresponds to the lens Li1 disposed closest to the image plane, and the positive lens L12 corresponds to the lens Li2 disposed adjacent to the object side of the lens Li1. The positive lens L1 corresponds to the positive lens Pf of the front group, and the negative lens L5 corresponds to the negative lens Nf of the front group.

[0208] In Table 4 below, the parameter values of the optical system of this embodiment are listed.

[0209] (Table 4)

[0210] [Overall parameters]

[0211] [Lens parameters]

[0212] [Aspherical data]

[0213] [Focal length data for each group]

[0214] [Variable interval data]

[0215] Figure 8 These are the aberration diagrams of the optical system of the fourth embodiment.

[0216] From each aberration diagram, it can be seen that the optical system of this embodiment appropriately corrects various aberrations and has high optical performance.

[0217] (The fifth embodiment)

[0218] Figure 9 This is a cross-sectional view of the optical system of the fifth embodiment when focusing on an infinitely distant object.

[0219] The optical system of this embodiment sequentially includes a first lens group G1 with a positive focal power, a second lens group G2 with a negative focal power, a third lens group G3 with a positive focal power, a fourth lens group G4 with a negative focal power, and a fifth lens group G5 with a negative focal power from the object side.

[0220] The first lens group G1 is sequentially composed of a positive lens L1 with a meniscus shape having a convex surface facing the object side, a positive lens L2 with a meniscus shape having a convex surface facing the object side, a positive lens L3 with a meniscus shape having a convex surface facing the object side, a cemented negative lens formed by a positive lens L4 with a biconvex shape and a negative lens L5 with a biconcave shape, an aperture stop S, and a positive lens L6 with a meniscus shape having a convex surface facing the object side from the object side.

[0221] The second lens group G2 is composed of a negative lens L7 with a meniscus shape having a convex surface facing the object side.

[0222] The third lens group G3 is sequentially composed of a negative lens L8 with a biconcave shape, a positive lens L9 with a meniscus shape having a convex surface facing the object side, a positive lens L10 with a biconvex shape, and a positive lens L11 with a biconvex shape from the object side.

[0223] The fourth lens group G4 is composed of a negative lens L12 with a biconcave shape.

[0224] The fifth lens group G5 is sequentially composed of a positive lens L13 with a meniscus shape having a convex surface facing the object side, a negative lens L14 with a biconcave shape, and a negative lens L15 with a biconcave shape from the object side.

[0225] On the image plane I, an imaging element (not shown) composed of a CCD or CMOS, etc. is disposed.

[0226] A filter FL is disposed between the optical system of this embodiment and the image plane I.

[0227] The optical system of this embodiment performs focusing by moving the second lens group G2 and the fourth lens group G4 along the optical axis. When focusing from the state of focusing on infinity to a near-distance object, the second lens group G2 and the fourth lens group G4 move from the object side to the image side along different trajectories respectively.

[0228] In the optical system of this embodiment, the positive lens L1 to the negative lens L5 in the first lens group G1 correspond to the front group, the positive lens L6 in the first lens group G1, the second lens group G2, the third lens group G3, the fourth lens group G4, and the fifth lens group G5 correspond to the rear group. The second lens group G2 and the fourth lens group G4 correspond to the focusing groups that move during focusing. The second lens group G2 corresponds to the focusing group Gfo disposed closest to the object side. The fifth lens group corresponds to the lens group Gi disposed closest to the image side.

[0229] In the optical system of this embodiment, the positive lens L10 is equivalent to the single lens Pr with the strongest optical power among the plano-convex single lenses in the rear group and the single lens Pfoi with the strongest optical power among the plano-convex single lenses arranged on the image plane side with respect to the focusing group Gfo. The negative lens L15 is equivalent to the lens Li1 arranged closest to the image plane side, and the positive lens L14 is equivalent to the lens Li2 arranged adjacent to the object side of the lens Li1. The positive lens L1 is equivalent to the positive lens Pf of the front group, and the negative lens L5 is equivalent to the negative lens Nf of the front group.

[0230] In Table 5 below, the parameter values of the optical system of this embodiment are listed.

[0231] (Table 5)

[0232] [Overall parameters]

[0233] [Lens parameters]

[0234] [Aspherical data]

[0235] [Focal length data of each group]

[0236] [Variable interval data]

[0237] Figure 10 They are aberration diagrams of the optical system of the fifth embodiment.

[0238] From each aberration diagram, it can be seen that the optical system of this embodiment appropriately corrects various aberrations and has high optical performance.

[0239] (Sixth embodiment)

[0240] Figure 11 It is a cross-sectional view of the optical system of the sixth embodiment when focusing on an infinitely distant object.

[0241] The optical system of this embodiment sequentially includes a first lens group G1 with positive optical power, a second lens group G2 with negative optical power, a third lens group G3 with positive optical power, a fourth lens group G4 with positive optical power, and a fifth lens group G5 with negative optical power from the object side.

[0242] The first lens group G1 is composed of, in order from the object side, a positive meniscus lens L1 with its convex surface facing the object side, a positive meniscus lens L2 with its convex surface facing the object side, a positive meniscus lens L3 with its convex surface facing the object side, a cemented negative lens formed by a biconvex positive lens L4 and a biconcave negative lens L5, an aperture stop S, and a biconvex positive lens L6.

[0243] The second lens group G2 is composed of a negative meniscus lens L7 with its convex surface facing the object side.

[0244] The third lens group G3 is composed of, in order from the object side, a cemented negative lens formed by a biconcave negative lens L8 and a positive meniscus lens L9 with its convex surface facing the object side, a biconvex positive lens L10, and a positive meniscus lens L11 with its concave surface facing the object side.

[0245] The fourth lens group G4 is composed of a plano-convex positive lens L12 with its plane surface facing the object side.

[0246] The fifth lens group G5 is composed of, in order from the object side, a cemented positive lens formed by a positive meniscus lens L13 with its concave surface facing the object side and a negative meniscus lens L14 with its concave surface facing the object side, and a plano-concave negative lens L15 with its concave surface facing the object side.

[0247] On the image plane I, an imaging element (not shown) composed of a CCD, a CMOS, etc. is arranged.

[0248] A filter FL is arranged between the optical system of this embodiment and the image plane I.

[0249] The optical system of this embodiment performs focusing by moving the second lens group G2 and the fourth lens group G4 along the optical axis. When focusing from an infinite focus state to a close object, the second lens group G2 moves from the object side toward the image side, and the fourth lens group G4 moves from the image side toward the object side.

[0250] In the optical system of this embodiment, the lenses from the positive lens L1 to the negative lens L5 in the first lens group G1 are equivalent to the front group, and the positive lens L6 in the first lens group G1, the second lens group G2, the third lens group G3, the fourth lens group G4, and the fifth lens group G5 are equivalent to the rear group. The second lens group G2 and the fourth lens group G4 are equivalent to the focusing groups that move during focusing. The second lens group G2 is equivalent to the focusing group Gfo arranged closest to the object side. The fifth lens group is equivalent to the lens group Gi arranged closest to the image side.

[0251] In the optical system of this embodiment, the positive lens L10 is equivalent to the single lens Pr with the strongest optical power among the plano-convex single lenses in the rear group and the single lens Pfoi with the strongest optical power among the plano-convex single lenses arranged on the image side with respect to the focusing group Gfo. The negative lens L15 is equivalent to the lens Li1 arranged closest to the image side, and the negative lens L14 is equivalent to the lens Li2 arranged adjacent to the object side of the lens Li1. The positive lens L1 is equivalent to the positive lens Pf in the front group, and the negative lens L5 is equivalent to the negative lens Nf in the front group.

[0252] In Table 6 below, the parameter values of the optical system of this embodiment are listed.

[0253] (Table 6)

[0254] [Overall parameters]

[0255] [Lens parameters]

[0256] [Aspherical data]

[0257] [Focal length data of each group]

[0258] [Variable interval data]

[0259] Figure 12 These are the aberration diagrams of the optical system of the sixth embodiment.

[0260] From the respective aberration diagrams, it can be seen that the optical system of this embodiment appropriately corrects various aberrations and has high optical performance.

[0261] (The seventh embodiment)

[0262] Figure 13 This is a cross-sectional view of the optical system of the seventh embodiment when focusing on an object at infinity.

[0263] The optical system of this embodiment sequentially includes a first lens group G1 with positive optical power, a second lens group G2 with negative optical power, a third lens group G3 with positive optical power, a fourth lens group G4 with positive optical power, and a fifth lens group G5 with negative optical power from the object side.

[0264] The first lens group G1 is composed of, in order from the object side, a positive lens L1 with a meniscus shape having a convex surface facing the object side, a positive lens L2 with a meniscus shape having a convex surface facing the object side, a positive lens L3 with a meniscus shape having a convex surface facing the object side, a positive lens L4 with a meniscus shape having a convex surface facing the object side, a cemented negative lens formed by a negative lens L5 with a meniscus shape having a convex surface facing the object side, an aperture stop S, and a positive lens L6 with a biconvex shape.

[0265] The second lens group G2 is composed of a negative lens L7 with a meniscus shape having a convex surface facing the object side.

[0266] The third lens group G3 is composed of, in order from the object side, a cemented negative lens formed by a negative lens L8 with a meniscus shape having a convex surface facing the object side and a positive lens L9 with a meniscus shape having a convex surface facing the object side, a positive lens L10 with a biconvex shape, and a positive lens L11 with a meniscus shape having a concave surface facing the object side.

[0267] The fourth lens group G4 is composed of a positive lens L12 with a meniscus shape having a concave surface facing the object side.

[0268] The fifth lens group G5 is composed of, in order from the object side, a cemented negative lens formed by a negative lens L13 with a meniscus shape having a convex surface facing the object side and a positive lens L14 with a meniscus shape having a convex surface facing the object side, and a negative lens L15 with a biconcave shape.

[0269] On the image plane I, an imaging element (not shown) composed of a CCD, a CMOS, etc. is disposed.

[0270] A filter FL is disposed between the optical system of the present embodiment and the image plane I.

[0271] The optical system of the present embodiment performs focusing by moving the second lens group G2 and the fourth lens group G4 along the optical axis. When focusing from an infinite focus state to a close object, the second lens group G2 moves from the object side toward the image side, and the fourth lens group G4 moves from the image side toward the object side.

[0272] In the optical system of the present embodiment, the positive lenses L1 to L5 in the first lens group G1 correspond to the front group, the positive lens L6 in the first lens group G1, the second lens group G2, the third lens group G3, the fourth lens group G4, and the fifth lens group G5 correspond to the rear group. The second lens group G2 and the fourth lens group G4 correspond to the focusing groups that move during focusing. The second lens group G2 corresponds to the focusing group Gfo disposed closest to the object side. The fifth lens group corresponds to the lens group Gi disposed closest to the image side.

[0273] In the optical system of this embodiment, the positive lens L10 is equivalent to the single lens Pr with the strongest optical power among the plano-convex single lenses in the rear group and the single lens Pfoi with the strongest optical power among the plano-convex single lenses arranged on the image plane side with respect to the focusing group Gfo. The negative lens L15 is equivalent to the lens Li1 arranged closest to the image plane side, and the positive lens L14 is equivalent to the lens Li2 arranged adjacent to the object side of the lens Li1. The positive lens L1 is equivalent to the positive lens Pf in the front group, and the negative lens L5 is equivalent to the negative lens Nf in the front group.

[0274] In Table 7 below, the parameter values of the optical system of this embodiment are listed.

[0275] (Table 7)

[0276] [Overall parameters]

[0277] [Lens parameters]

[0278] [Aspherical data]

[0279] [Focal length data of each group]

[0280] [Variable interval data]

[0281] Figure 14 These are aberration diagrams of the optical system of the 7th embodiment.

[0282] It can be seen from each aberration diagram that the optical system of this embodiment appropriately corrects various aberrations and has high optical performance.

[0283] (8th embodiment)

[0284] Figure 15 This is a cross-sectional view of the optical system of the 8th embodiment when focusing on an infinitely distant object.

[0285] The optical system of this embodiment sequentially includes a first lens group G1 with positive optical power, a second lens group G2 with negative optical power, a third lens group G3 with positive optical power, a fourth lens group G4 with positive optical power, and a fifth lens group G5 with negative optical power from the object side.

[0286] The first lens group G1 is composed of, in order from the object side, a positive meniscus lens L1 with its convex surface facing the object side, a positive meniscus lens L2 with its convex surface facing the object side, a positive meniscus lens L3 with its convex surface facing the object side, a cemented negative lens formed by a biconvex positive lens L4 and a biconcave negative lens L5, an aperture stop S, and a positive meniscus lens L6 with its convex surface facing the object side.

[0287] The second lens group G2 is composed of a negative meniscus lens L7 with its convex surface facing the object side.

[0288] The third lens group G3 is composed of, in order from the object side, a cemented positive lens formed by a negative meniscus lens L8 with its concave surface facing the object side and a positive meniscus lens L9 with its concave surface facing the object side, a biconvex positive lens L10, and a biconcave negative lens L11.

[0289] The fourth lens group G4 is composed of a plano-convex positive lens L12 with its convex surface facing the object side.

[0290] The fifth lens group G5 is composed of, in order from the object side, a cemented negative lens formed by a plano-concave negative lens L13 with its concave surface facing the object side and a plano-convex positive lens L14 with its plane surface facing the object side, and a biconcave negative lens L15.

[0291] On the image plane I, an imaging element (not shown) composed of a CCD, a CMOS, etc. is arranged.

[0292] A filter FL is arranged between the optical system of this embodiment and the image plane I.

[0293] The optical system of this embodiment performs focusing by moving the second lens group G2 and the fourth lens group G4 along the optical axis. When focusing from an infinite focus state to a close object, the second lens group G2 moves from the object side toward the image side, and the fourth lens group G4 moves from the image side toward the object side.

[0294] In the optical system of this embodiment, the lenses from the positive lens L1 to the negative lens L5 in the first lens group G1 correspond to the front group, the positive lens L6 in the first lens group G1, the second lens group G2, the third lens group G3, the fourth lens group G4, and the fifth lens group G5 correspond to the rear group. The second lens group G2 and the fourth lens group G4 correspond to the focusing groups that move during focusing. The second lens group G2 corresponds to the focusing group Gfo arranged closest to the object side. The fifth lens group corresponds to the lens group Gi arranged closest to the image side.

[0295] In the optical system of this embodiment, the positive lens L10 is equivalent to the single lens Pr with the strongest optical power among the plano-convex single lenses in the rear group and the single lens Pfoi with the strongest optical power among the plano-convex single lenses arranged on the image plane side with respect to the focusing group Gfo. The negative lens L15 is equivalent to the lens Li1 arranged closest to the image plane side, and the positive lens L14 is equivalent to the lens Li2 arranged adjacent to the object side of the lens Li1. The positive lens L1 is equivalent to the positive lens Pf of the front group, and the negative lens L5 is equivalent to the negative lens Nf of the front group.

[0296] In Table 8 below, the parameter values of the optical system of this embodiment are listed.

[0297] (Table 8)

[0298] [Overall parameters]

[0299] [Lens parameters]

[0300] [Aspherical data]

[0301] [Focal length data of each group]

[0302] [Variable interval data]

[0303] Figure 16 These are the aberration diagrams of the optical system of the eighth embodiment.

[0304] From the aberration diagrams, it can be seen that the optical system of this embodiment appropriately corrects various aberrations and has high optical performance.

[0305] (Ninth embodiment)

[0306] Figure 17 This is a cross-sectional view of the optical system of the ninth embodiment when focusing on an object at infinity.

[0307] The optical system of this embodiment sequentially includes a first lens group G1 with positive optical power, an aperture stop S, a second lens group G2 with negative optical power, and a third lens group G3 with positive optical power from the object side.

[0308] The first lens group G1 is composed of, in order from the object side, a positive lens L1 with a biconvex shape, a positive lens L2 with a biconvex shape, a cemented negative lens formed by a negative lens L3 with a biconcave shape, and a positive lens L4 with a biconvex shape.

[0309] The second lens group G2 is composed of a cemented negative lens formed by a positive lens L5 with a biconvex shape and a negative lens L6 with a biconcave shape.

[0310] The third lens group G3 is composed of, in order from the object side, a positive lens L7 with a biconvex shape, a cemented negative lens formed by a negative lens L8 with a biconcave shape and a positive lens L9 with a biconvex shape, a cemented negative lens formed by a negative lens L10 with a plano-convex shape having the plane facing the object side and a positive lens L11 with a meniscus shape having the convex surface facing the object side, a positive lens L12 with a meniscus shape having the convex surface facing the object side, and a negative lens L13 with a meniscus shape having the concave surface facing the object side.

[0311] On the image plane I, an imaging element (not shown) composed of a CCD, a CMOS, or the like is disposed.

[0312] Between the optical system of the present embodiment and the image plane I, a filter FL is disposed.

[0313] The optical system of the present embodiment performs focusing by moving the second lens group G2 along the optical axis. When focusing from an infinite focus state to a close object, the second lens group G2 moves from the object side toward the image side.

[0314] In the optical system of the present embodiment, the first lens group G1 corresponds to the front group, and the second lens group G2 and the third lens group G3 correspond to the rear group. The second lens group G2 corresponds to the focusing group that moves during focusing. The second lens group G2 corresponds to the focusing group Gfo disposed closest to the object side. The third lens group corresponds to the lens group Gi disposed closest to the image side.

[0315] In the optical system of the present embodiment, the positive lens L7 corresponds to the single lens Pr with the strongest optical power among the biconvex single lenses in the rear group and the single lens Pfoi with the strongest optical power among the biconvex single lenses disposed on the image side with respect to the focusing group Gfo. The negative lens L13 corresponds to the lens Li1 disposed closest to the image side, and the positive lens L12 corresponds to the lens Li2 disposed adjacent to the object side of the lens Li1.

[0316] In Table 9 below, the parameter values of the optical system of the present embodiment are described.

[0317] (Table 9)

[0318] [Overall parameters]

[0319] [Lens parameters]

[0320] [Focal length data for each group]

[0321] [Variable interval data]

[0322] Figure 18 These are aberration diagrams of the optical system of the 9th embodiment.

[0323] From the aberration diagrams, it can be seen that the optical system of this embodiment appropriately corrects various aberrations and has high optical performance.

[0324] (10th embodiment)

[0325] Figure 19 This is a cross-sectional view of the optical system of the 10th embodiment when focusing on an object at infinity.

[0326] The optical system of this embodiment sequentially includes a first lens group G1 with positive optical power, an aperture stop S, a second lens group G2 with positive optical power, and a third lens group G3 with negative optical power from the object side.

[0327] The first lens group G1 is sequentially composed of a meniscus positive lens L1 with the convex surface facing the object side, a cemented negative lens of a biconvex positive lens L2 and a biconcave negative lens L3, and a cemented negative lens of a biconvex positive lens L4 and a biconcave negative lens L5 from the object side.

[0328] The second lens group G2 is sequentially composed of a biconcave negative lens L6, a biconvex positive lens L7, a meniscus negative lens L8 with the convex surface facing the object side, and a cemented positive lens of a biconcave negative lens L9 and a biconvex positive lens L10 from the object side.

[0329] The third lens group G3 is sequentially composed of a meniscus positive lens L11 with the concave surface facing the object side and a meniscus negative lens L12 with the concave surface facing the object side from the object side.

[0330] On the image plane I, an imaging element (not shown) composed of a CCD or CMOS, etc. is arranged.

[0331] A filter FL is arranged between the optical system of this embodiment and the image plane I.

[0332] The optical system of this embodiment performs focusing by moving the second lens group G2 along the optical axis. When focusing from an infinite focus state to a close object, the second lens group G2 moves from the image plane side toward the object side.

[0333] In the optical system of this embodiment, the first lens group G1 corresponds to the front group, and the second lens group G2 and the third lens group G3 correspond to the rear group. The second lens group G2 corresponds to the focusing group that moves during focusing. The second lens group G2 corresponds to the focusing group Gfo disposed closest to the object side. The third lens group corresponds to the lens group Gi disposed closest to the image side.

[0334] In the optical system of this embodiment, the positive lens L7 corresponds to the single lens Pr with the strongest optical power among the double-convex single lenses within the rear group. The negative lens L12 corresponds to the lens Li1 disposed closest to the image plane side, and the positive lens L11 corresponds to the lens Li2 disposed adjacent to the object side of the lens Li1.

[0335] In Table 10 below, the parameter values of the optical system of this embodiment are listed.

[0336] (Table 10)

[0337] [Overall parameters]

[0338] [Lens parameters]

[0339] [Aspherical data]

[0340] [Focal length data for each group]

[0341] [Variable interval data]

[0342] Figure 20 These are the aberration diagrams of the optical system of the tenth embodiment.

[0343] From each aberration diagram, it can be seen that the optical system of this embodiment appropriately corrects various aberrations and has high optical performance.

[0344] According to the above-described embodiments, an optical system that is small and has good optical performance can be realized.

[0345] Below, the conditional corresponding values of each embodiment are shown.

[0346] TL is the overall length of the optical system, f is the focal length of the optical system, Bf is the back focal length under the air equivalent length. ff is the focal length of the front group, fr is the focal length of the rear group. fPr is the focal length of the single lens Pr, fPfo1 is the focal length of the single lens Pfo1, and ffo is the focal length of the focusing group Gfo.

[0347] tr is the sum of the central thicknesses of the respective lenses included in the rear group, and tGi is the sum of the lengths on the optical axis of the respective lenses included in the lens group Gi. Da is the distance on the optical axis at infinity focusing between the lens surface on the object side of Li1 and the lens surface on the image side of the lens Li2. D1 is the distance on the optical axis at infinity focusing between the lens surface closest to the object side and the object-side surface of the single lens Pr, and D2 is the distance on the optical axis between the aperture stop and the object-side lens surface of the single lens Pr.

[0348] ndPf is the refractive index of the positive lens Pf with respect to the d line, νdPf is the Abbe number of the positive lens Pf based on the d line, and θFPf is the relative partial dispersion of the positive lens Pf. ndNf is the refractive index of the negative lens Nf with respect to the d line, νdNf is the Abbe number of the negative lens Nf based on the d line, and θFNf is the relative partial dispersion of the negative lens Nf.

[0349] [Condition formula corresponding value]

[0350] Each of the above embodiments shows a specific example of the present invention, but the present invention is not limited thereto. The following contents can be appropriately adopted within the range that does not impair the optical performance of the optical system of the embodiment of the present application.

[0351] The optical system of the present embodiment may not have an optical member such as a filter between the lens surface closest to the image side and the image surface.

[0352] The optical system of the present embodiment may have an anti-shake lens group that corrects image blur caused by hand shake by moving in a direction having a component perpendicular to the optical axis. The anti-shake lens group may be a lens group or a partial lens group composed of one or more lens components included in the lens group. "Lens component" refers to a single lens or a cemented lens formed by cementing two or more single lenses.

[0353] In the optical system of the present embodiment, the lens surface may be formed as a spherical surface or a plane surface, or may be formed as an aspherical surface. When the lens surface is a spherical surface or a plane surface, lens processing and assembly adjustment are relatively easy, and deterioration of optical performance due to errors in processing and assembly adjustment can be prevented, so it is preferred. In addition, when the lens surface is a spherical surface or a plane surface, deterioration of the description performance during image plane shift is less, so it is preferred.

[0354] When the lens surface is an aspherical surface, the aspherical surface can be formed by grinding the glass or by glass molding using a mold having an aspherical shape, or can be formed on the resin surface bonded to the glass surface. In addition, in the optical system of the present embodiment, the lens surface can also be a diffractive surface, and the lens can also be a refractive index distribution type lens (GRIN lens) or a plastic lens.

[0355] Next, based on Figure 21 A camera including the optical system of the present embodiment will be described.

[0356] Figure 21 FIG. is a schematic diagram of a camera including the optical system of the present embodiment.

[0357] The camera 1 is an example of an optical device, and is a so-called mirrorless camera having an interchangeable lens as a photographic lens 2, and the interchangeable lens includes the optical system of the first embodiment described above.

[0358] In the camera 1, light from an object (subject) (not shown) is condensed by the photographic lens 2 and reaches the imaging element 3. The imaging element 3 converts the light from the subject into image data. The image data is displayed on the electronic viewfinder 4. Thus, a photographer placing their eye at the eye point EP can observe the subject.

[0359] In addition, when a photographer presses a release button (not shown), the image data is stored in a memory (not shown). In this way, the photographer can perform photography of the subject using the camera 1.

[0360] Here, the optical system of the first embodiment mounted as the photographic lens 2 in the camera 1 is a small-sized optical system having good optical performance. Therefore, the camera 1 can be miniaturized and has good optical performance. In addition, even when a camera is configured to mount the optical systems of the second to tenth embodiments as the photographic lens 2, the same effects as those of the camera 1 can be obtained.

[0361] Finally, based on Figure 22 An outline of a manufacturing method of the optical system of the present embodiment will be described.

[0362] Figure 22 FIG. is a flowchart showing an outline of the manufacturing method of the optical system of the present embodiment. Figure 22 The manufacturing method of the optical system of the present embodiment shown includes the following steps S11 - S12.

[0363] Step S11: Prepare the front group, the aperture stop S, and the rear group.

[0364] Step S12: Make the optical system simultaneously satisfy the following conditional expressions. (1) 0.10 < ff / |fr| < 1.50 (2) 0.13 < tr / TL < 0.45 (3) 0.50 < f / TL < 1.20 Wherein, ff: Focal length of the front group fr: Focal length of the rear group tr: Sum of the central thicknesses of the lenses included in the rear group TL: Overall length of the optical system f: Focal length of the optical system

[0365] According to the manufacturing method of the optical system of the present embodiment, an optical system that is small and has good imaging performance can be manufactured.

[0366] Those skilled in the art should understand that various changes, substitutions, and modifications can be made to the present invention without departing from the spirit and scope of the present disclosure.

[0367] Reference numeral description

[0368] S Aperture stop

[0369] I Image plane

[0370] 1 Camera

[0371] 2 Photographic lens

[0372] 3 Imaging element

Claims

1. An optical system sequentially includes, from the object side, a front group having a positive optical power, an aperture stop, and a rear group. The optical system simultaneously satisfies the following conditional expressions: 0.10 < ff / |fr| < 1.50 0.13 < tr / TL < 0.45 0.50 < f / TL < 1.20 Wherein, ff: The focal length of the front group. fr: The focal length of the rear group. tr: The sum of the central thicknesses of the respective lenses included in the rear group. TL: The overall length of the optical system. f: The focal length of the optical system.

2. The optical system according to claim 1, wherein, The rear group has a negative optical power.

3. The optical system according to claim 1 or claim 2, wherein, The optical system satisfies the following conditional expression: 0.05 < fPr / |fr| < 0.70 Wherein, fPr: The focal length of the single lens Pr having the strongest optical power among the biconvex single lenses within the rear group.

4. The optical system according to any one of claims 1 to 3, wherein, The optical system has at least one focusing group that moves during focusing. The optical system satisfies the following conditional expression: 0.05 < fPfoi / |fr| < 0.70 Wherein, fPfoi: The focal length of the single lens Pfoi having the strongest optical power among the biconvex single lenses disposed on the image plane side with respect to the focusing group Gfo disposed closest to the object side among the at least one focusing group.

5. The optical system according to any one of claims 1 to 4, wherein, The optical system has at least one focusing group that moves during focusing. The optical system satisfies the following conditional expression: 0.25 < fPfoi / f < 0.55 Wherein, fPfoi: The focal length of the single lens Pfoi having the strongest optical power among the biconvex single lenses disposed on the image plane side with respect to the focusing group Gfo disposed closest to the object side among the at least one focusing group.

6. The optical system according to any one of claims 1 to 5, wherein, The optical system satisfies the following conditional expression: 0.05 < Da / Bf < 1.10 Wherein, Da: The distance on the optical axis in the case of infinity focusing between the lens surface on the object side of the lens Li1 disposed closest to the image plane and the lens surface on the image plane side of the lens Li2 disposed adjacent to the object side of the lens Li1. Bf: The back focal length in terms of air equivalent length.

7. The optical system according to any one of claims 1 to 6, wherein, The rear group has a plurality of lens groups, and the plurality of lens groups include at least one focusing group that moves during focusing. The intervals between the plurality of lens groups change during focusing. The optical system satisfies the following conditional expression: 0.30 < tGi / Da < 9.00 Wherein, tGi: The sum of the lengths on the optical axis of the respective lenses included in the lens group Gi disposed closest to the image side among the plurality of lens groups. Da: The distance on the optical axis in the case of infinity focusing between the lens surface on the object side of the lens Li1 disposed closest to the image plane and the lens surface on the image plane side of the lens Li2 disposed adjacent to the object side of the lens Li1.

8. The optical system according to any one of claims 1 to 7, wherein the optical system satisfies the following conditional expression: 0.40 < D1 / TL < 0.85 wherein D1: The distance on the optical axis at infinity focus between the lens surface closest to the object side and the object side surface of the single lens Pr with the strongest optical power among the plano-convex single lenses within the rear group.

9. The optical system according to any one of claims 1 to 8, wherein the optical system satisfies the following conditional expression: 0.10 < D2 / TL < 0.80 wherein D2: The distance on the optical axis between the aperture stop and the object side lens surface of the single lens Pr with the strongest optical power among the plano-convex single lenses within the rear group.

10. The optical system according to any one of claims 1 to 9, wherein the optical system has at least one focusing group that moves during focusing, the optical system satisfies the following conditional expression: 0.25 < |ffo| / f < 0.90 wherein ffo: The focal length of the focusing group Gfo disposed closest to the object side among the at least one focusing group.

11. The optical system according to any one of claims 1 to 10, wherein the front group has at least one positive lens Pf that simultaneously satisfies the following conditional expressions: 1.60 < ndPf νdPf < 31.00 0.01 < θgFPf - (0.6415 - 0.00162 × νdPf) wherein ndPf: The refractive index of the positive lens Pf for the d line, νdPf: The Abbe number of the positive lens Pf based on the d line, θgFPf: The relative partial dispersion of the positive lens Pf, which is defined by the following formula when the refractive index of the positive lens Pf for the g line is ngPf, the refractive index of the positive lens Pf for the F line is nFPf, and the refractive index of the positive lens Pf for the C line is nCPf, that is, θgFPf = (ngPf - nFPf) / (nFPf - nCPf).

12. The optical system according to any one of claims 1 to 11, wherein the front group has at least one negative lens Nf that simultaneously satisfies the following conditional expressions: 1.85 < ndNf νdNf < 26.00 θgFNf - (0.6415 - 0.00162 × νdNf) < 0.015 wherein ndNf: The refractive index of the negative lens Nf for the d line, νdNf: The Abbe number of the negative lens Nf based on the d line, θgFNf: The relative partial dispersion of the negative lens Nf, which is defined by the following formula when the refractive index of the negative lens Nf for the g line is ngNf, the refractive index of the negative lens Nf for the F line is nFNf, and the refractive index of the negative lens Nf for the C line is nCNf, that is, θgFNf = (ngNf - nFNf) / (nFNf - nCNf).

13. An optical device comprising the optical system according to any one of claims 1 to 12.

14. An interchangeable lens comprising the optical system according to any one of claims 1 to 12.

15. A manufacturing method of an optical system, the optical system sequentially including, from the object side, a front group having a positive optical power, an aperture stop, and a rear group. The manufacturing method of the optical system configures the optical system to simultaneously satisfy the following conditional expressions: 0.10 < ff / |fr| < 1.50 0.13 < tr / TL < 0.45 0.50 < f / TL < 1.20 wherein, ff: the focal length of the front group, fr: the focal length of the rear group, tr: the sum of the center thicknesses of the respective lenses included in the rear group, TL: the overall length of the optical system, f: the focal length of the optical system.

Images