Optical system, optical equipment and manufacturing method of optical system

Abstract

To provide a large diameter optical system required for imaging lenses, the optical system being satisfactorily corrected in aberration over a whole focusing region and also appropriate for manual focusing.SOLUTION: An optical system comprises, in order from an object side, a front group having positive refractive power, a diaphragm, and a rear group having a positive refractive power as a whole. The front group has a configuration in which at least 4 positive lenses are lined up consecutively, and has a negative lens Ln1 neighboring the objective side of the at least 4 positive lenses and in addition one or more lenses on the object side. At least one of the at least 4 positive lenses has a lens H that satisfies the following condition: 1.650<nH<2.100, 25.00<νH<60.00.SELECTED DRAWING: Figure 1

Description

[Technical field]

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

[0002] Conventionally, among photographic lenses primarily intended for photographing close-up objects, those suitable for autofocusing are known, as in Patent Document 1. In recent years, there has been a demand for such photographic lenses that can correct various aberrations even better and have a large aperture that is also suitable for manual focusing. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 63-147124 A Summary of the Invention

[0004] The optical system according to the first aspect comprises, in order from the object side, a front group having positive refractive power, a stop, and a rear group having positive refractive power overall, the front group having a configuration in which at least four positive lenses are arranged in succession, a negative lens Ln1 adjacent to the object side of the at least four positive lenses, and one or more lenses further on the object side, and at least one of the at least four positive lenses is a lens H that satisfies the following conditional expression: 1.650 < nH < 2.100 25.00 < νH < 60.00 however, nH: refractive index of the lens H with respect to the d line νH: Abbe number of the lens H for the d line

[0005] An optical device according to a second embodiment includes the above optical system.

[0006] Furthermore, a manufacturing method for an optical system according to a third embodiment includes, in order from the object side, a front group having positive refractive power, an aperture stop, and a rear group having positive refractive power overall, the front group having a configuration in which at least four positive lenses are arranged in succession, a negative lens Ln1 is adjacent to the object side of the at least four positive lenses, and one or more lenses are further arranged on the object side, and at least one of the at least four positive lenses is a lens H that satisfies the following conditional expression: 1.650 < nH < 2.100 25.00 < νH < 60.00 however, nH: refractive index of the lens H with respect to the d line νH: Abbe number of the lens H for the d line [Brief description of the drawings]

[0007] [Figure 1] FIG. 2 is a cross-sectional view of an optical system according to the first example. [Diagram 2] 5A to 5C are diagrams illustrating various aberrations when the optical system according to the first example is focused on an object at infinity. [Diagram 3] 5A to 5C are diagrams illustrating various aberrations when the optical system according to the first example is focused on a close-distance object. [Figure 4] FIG. 11 is a cross-sectional view of an optical system according to a second example. [Diagram 5] 11A to 11C are diagrams illustrating various aberrations when the optical system according to the second example is focused on an object at infinity. [Figure 6] 7A to 7C are diagrams showing various aberrations when the optical system according to the second example is focused on a close object. [Figure 7] FIG. 11 is a cross-sectional view of an optical system according to a third example. [Figure 8] 13A to 13C are diagrams showing various aberrations when the optical system according to the third example is focused on an object at infinity. [Figure 9] 13A to 13C are diagrams showing various aberrations when the optical system according to the third example is focused on a close object. [Figure 10] FIG. 13 is a cross-sectional view of an optical system according to a fourth example. [Figure 11] 13A to 13C are diagrams illustrating various aberrations when the optical system according to Example 4 is focused on an object at infinity. [Figure 12] 13A to 13C are diagrams showing various aberrations when the optical system according to Example 4 is focused on a close object. [Figure 13] FIG. 13 is a cross-sectional view of an optical system according to a fifth example. [Figure 14] 13A to 13C are diagrams illustrating various aberrations when the optical system according to Example 5 is focused on an object at infinity. [Figure 15] 13A to 13C are diagrams showing various aberrations in the optical system according to Example 5 when focusing on a close-distance object. [Figure 16] FIG. 13 is a cross-sectional view of an optical system according to Example 6. [Figure 17] 13A to 13C are diagrams illustrating various aberrations when the optical system according to Example 6 is focused on an object at infinity. [Figure 18] 13A to 13C are diagrams showing various aberrations when the optical system according to Example 6 is focused on a close object. [Figure 19] FIG. 13 is a cross-sectional view of an optical system according to a seventh example. [Figure 20] 13A to 13C are diagrams illustrating various aberrations when the optical system according to the seventh example is focused on an object at infinity. [Figure 21] 13A to 13C are diagrams showing various aberrations when the optical system according to the seventh example is focused on a close object. [Figure 22] FIG. 1 is a diagram showing a configuration of an optical device including an optical system. [Diagram 23] FIG. 1 is a flow chart showing an outline of a method for manufacturing an optical device. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] Hereinafter, an optical system, an optical device, and a method for manufacturing an optical system according to a first embodiment of the present application will be described. However, the present invention is not limited to the following embodiments, and any combination may be used. In addition, the reference symbols for the figures according to the embodiments may be used independently in each drawing to avoid complication of the description due to an increase in the number of reference symbols. Therefore, even if reference symbols common to other drawings are used, they do not necessarily have the same configuration as the other drawings.

[0009] First, the optical system according to the first embodiment will be described. The optical system according to the first embodiment comprises, in order from the object side, a front group having positive refractive power, an aperture stop, and a rear group having positive refractive power overall, the front group having a configuration in which at least four positive lenses are arranged in succession, a negative lens Ln1 adjacent to the object side of the at least four positive lenses, and one or more lenses further on the object side.

[0010] With this configuration, the optical system of the first embodiment can effectively correct various aberrations, particularly spherical aberration, curvature of field, chromatic aberration, i.e., axial chromatic aberration, chromatic aberration of magnification, etc. In particular, when focusing, the variation in these aberrations is small from an infinity object focusing state to a close object focusing state. Also, if the number of the at least four positive lenses is reduced to three or less, it becomes particularly difficult to correct the chromatic aberration.

[0011] With such a configuration, the optical system of the first embodiment has a lens H in which at least one of the at least four positive lenses satisfies the following conditional expressions (1) and (2). 1.650 < nH < 2.100 (1) 25.00 < νH < 60.00 (2) however, nH: refractive index of the lens H with respect to the d line νH: Abbe number of the lens H for the d line

[0012] Here, the Abbe number ν for the d-line is expressed by the following formula, where the refractive index for the C-line (wavelength 656.3 nm) is nC, the refractive index for the d-line (wavelength 587.6 nm) is nd, and the refractive index for the F-line (wavelength 486.1 nm) is nF. ν=(nd-1) / (nF-nC) The formula for the Abbe number for the d line is the same for the subsequent conditional expressions, and the explanation thereof will be omitted.

[0013] The conditional expressions (1) and (2) define the refractive index at the d-line and the Abbe number at the d-line of at least one lens H of the at least four positive lenses in the front group. When at least one lens H of the at least four positive lenses satisfies the conditional expressions (1) and (2), various aberrations, particularly spherical aberration, curvature of field, chromatic aberration, etc., can be corrected more satisfactorily. In particular, when focusing, the variation of these aberrations is reduced from an infinity-focused state to a close-distance object-focused state.

[0014] If at least one lens H of the at least four positive lenses in the first embodiment does not satisfy conditional expressions (1) and (2), it becomes difficult to more effectively correct various aberrations, particularly spherical aberration, curvature of field, chromatic aberration, etc. Furthermore, if two or less lenses H of the at least four positive lenses satisfy conditional expressions (1) and (2), chromatic aberration can be more effectively corrected, which is preferable.

[0015] In addition, by setting the lower limit of conditional formula (1) to 1.670, the effect of the first embodiment can be ensured. In order to ensure the effect of the first embodiment, it is more preferable to set the lower limit of conditional formula (1) to 1.690, 1.710, 1.730, or even 1.750.

[0016] On the other hand, by setting the upper limit value of conditional expression (1) to 2.000, the effect of the first embodiment can be ensured. In order to ensure the effect of the first embodiment, it is more preferable to set the upper limit value of conditional expression (1) to 1.980, 1.970, or even 1.960.

[0017] In addition, by setting the lower limit of conditional formula (2) to 26.00, the effect of the first embodiment can be ensured. In order to ensure the effect of the first embodiment, it is more preferable to set the lower limit of conditional formula (2) to 27.00, 28.00, 29.00, 30.00, or even 31.00.

[0018] On the other hand, by setting the upper limit value of conditional formula (2) to 58.00, the effect of the first embodiment can be ensured. In order to ensure the effect of the first embodiment, it is more preferable to set the upper limit value of conditional formula (2) to 56.00, 54.00, 52.00, or even 50.00.

[0019] With the above-described configuration, the optical system of the first embodiment can effectively correct various aberrations, and in particular, when focusing, there is little variation in these aberrations from an infinity-focused state to a close-distance object-focused state, making it possible to realize a large-aperture optical system suitable for both autofocus and manual focus.

[0020] Furthermore, with this configuration, the optical system of the first embodiment can effectively correct various aberrations, particularly spherical aberration and coma.

[0021] Furthermore, in the optical system of the first embodiment, in the negative lens Ln1 and one or more lenses further to the object side, when the radius of curvature with the smallest absolute value among the lens surfaces whose image side surface is convex toward the object side is R1 and the radius of curvature with the smallest absolute value among the lens surfaces whose object side surface is concave toward the object side is R2, it is desirable that the lens surface having R1 is closer to the object side than the lens surface having R2, and that the following conditional expression is satisfied: -0.50 < (R2+R1) / (R2-R1) < 0.50 (3)

[0022] Conditional formula (3) specifies the surface shapes of the negative lens Ln1 and one or more lenses further to the object side, where R1 is the smallest absolute radius of curvature among lens surfaces whose image side surface is convex toward the object side, and R2 is the smallest absolute radius of curvature among lens surfaces whose object side surface is concave toward the object side, and the lens surface having R1 is closer to the object side than the lens surface having R2, and these surfaces face each other. By satisfying condition (3), the Petzval sum can be made small, and the curvature of field can be corrected well, as well as the coma and spherical aberration.

[0023] It should be noted that the effect of the first embodiment can be more reliably achieved by setting the lower limit of conditional expression (3) to -0.40. In order to further ensure the effect of the first embodiment, it is more preferable to set the lower limit of conditional expression (3) to -0.35, -0.30, -0.25, -0.20, -0.15, -0.10, or even 0.00.

[0024] On the other hand, by setting the upper limit value of conditional expression (3) to 0.40, the effect of the first embodiment can be ensured. In order to ensure the effect of the first embodiment, it is more preferable to set the upper limit value of conditional expression (3) to 0.35, 0.30, 0.25, 0.20, or even 0.15.

[0025] Furthermore, in the optical system of the first embodiment, it is desirable that, in the negative lens Ln1 and one or more lenses further to the object side, the radius of curvature with the smallest absolute value among the lens surfaces whose object side surface is concave toward the object side is R2, the refractive index of the lens having R2 for the d-line is n2, and the focal length of the entire system when photographing at infinity is f, satisfy the following conditional expression: 0.40 < |R2| / (n2×f) < 1.20 (4)

[0026] Conditional formula (4) specifies an appropriate power balance between the absolute value of the focal length of a lens surface having a radius of curvature R2 with a minimum absolute value among lens surfaces whose object-side surface is concave toward the object side, in the negative lens Ln1 and one or more lenses further to the object side, and the focal length of the entire optical system when focused at infinity. By satisfying condition (4), the Petzval sum can be made small, and the curvature of field can be corrected well, as well as the coma and spherical aberration.

[0027] It should be noted that the effect of the first embodiment can be more reliably achieved by setting the lower limit of conditional expression (4) to 0.45. In order to further ensure the effect of the first embodiment, it is more preferable to set the lower limit of conditional expression (4) to 0.50, more preferably 0.55, and even more preferably 0.60.

[0028] On the other hand, by setting the upper limit value of conditional expression (4) to 1.10, the effect of the first embodiment can be ensured. In order to ensure the effect of the first embodiment, it is more preferable to set the upper limit value of conditional expression (4) to 1.00, 0.95, 0.90, or even 0.85.

[0029] Moreover, it is desirable that the optical system of the first embodiment has, in the front group, a negative lens component Pn1 adjacent to the object side of the at least four positive lenses, and has a negative lens component Pn2 adjacent to the image side of the at least four positive lenses, and that it satisfies the following conditional expression: 0.60 < fPn1 / fPn2 < 2.50 (5) however, fPn1: focal length of the negative lens component Pn1 fPn2: the focal length of the negative lens component Pn2 Incidentally, the lens component refers to a single lens or a combination of multiple lenses, and the negative lens component refers to a single negative lens or a combination of multiple negative lenses.

[0030] Conditional formula (5) specifies the ratio between the focal length of the negative lens component Pn1 arranged adjacent to the object side of the at least four positive lenses and the focal length of the negative lens component Pn2 arranged adjacent to the image side of the at least four positive lenses.

[0031] By satisfying conditional expression (5), the at least four positive lenses in the front group, the negative lens component Pn1 arranged adjacent to the object side of the at least four positive lenses, and the negative lens component Pn2 arranged adjacent to the image side of the at least four positive lenses can more effectively correct various aberrations, particularly spherical aberration, curvature of field, chromatic aberration, etc. In particular, when focusing, the fluctuation of these aberrations is reduced from an infinity object focused state to a close object focused state.

[0032] It should be noted that the effect of the first embodiment can be more reliably achieved by setting the lower limit of conditional expression (5) to 0.70. In order to further ensure the effect of the first embodiment, it is more preferable to set the lower limit of conditional expression (5) to 0.80, 0.90, 1.00, or even 1.10. On the other hand, by setting the upper limit of conditional expression (5) to 2.30, the effect of the first embodiment can be ensured. In order to ensure the effect of the first embodiment, it is more preferable to set the upper limit of conditional expression (5) to 2.10, 1.90, 1.70, or even 1.60.

[0033] In the optical system of the first embodiment, it is desirable that the lens H be the first or second lens from the object side among the at least four positive lenses.

[0034] This makes it possible to suppress the occurrence of aberrations in areas where the height of the marginal ray is high, and therefore makes it possible to satisfactorily correct spherical aberration, axial chromatic aberration, and curvature of field in the entire optical system. Here, the "marginal ray" refers to the ray with the highest incident light intensity among the incident light beams parallel to the optical axis. Also, the "marginal ray height" refers to the distance from the optical axis to the marginal ray (the distance in the direction perpendicular to the optical axis).

[0035] In the optical system of the first embodiment, it is desirable that the at least four positive lenses satisfy the following conditional expression: 0.100 < nHM-nLm < 0.450 (6) however, nHM: the maximum value of the refractive index for the d-line of the at least four positive lenses nLm: the minimum value of the refractive index for the d-line of the at least four positive lenses

[0036] Conditional expression (6) defines the difference between the maximum and minimum values ​​of the refractive index for the d-line of the at least four positive lenses. By satisfying conditional expression (6), spherical aberration, axial chromatic aberration, and curvature of field in the entire optical system can be well corrected.

[0037] In addition, by setting the lower limit of conditional expression (6) to 0.120, the effect of the first embodiment can be ensured. In order to ensure the effect of the first embodiment, it is more preferable to set the lower limit of conditional expression (6) to 0.140, 0.160, 0.180, 0.190, or even 0.200.

[0038] On the other hand, by setting the upper limit value of conditional expression (6) to 0.410, the effect of the first embodiment can be ensured. In order to ensure the effect of the first embodiment, it is more preferable to set the upper limit value of conditional expression (6) to 0.380, 0.360, 0.340, 0.320, or even 0.300.

[0039] Furthermore, in the optical system of the first embodiment, it is desirable that the refractive index n34 for the d-line and the Abbe number ν34 for the d-line of the third and fourth lenses from the object side among the at least four positive lenses satisfy the following conditional expressions: 1.450 < n34 < 1.700 (7) 50.00 < ν34 < 85.00 (8)

[0040] Conditional expressions (7) and (8) define the refractive index n34 for the d-line and the Abbe number ν34 for the d-line of the third and fourth lenses from the object side among the at least four positive lenses.

[0041] The optical system of the first embodiment satisfies conditional expressions (7) and (8), and thereby can satisfactorily correct various aberrations, particularly spherical aberration, curvature of field, chromatic aberration, and the like.

[0042] In addition, by setting the lower limit of conditional expression (7) to 1.470, the effect of the first embodiment can be ensured. In order to ensure the effect of the first embodiment, it is more preferable to set the lower limit of conditional expression (7) to 1.490, 1.510, 1.530, 1.550, or even 1.570. On the other hand, by setting the upper limit of conditional expression (7) to 1.680, the effect of the first embodiment can be ensured. In order to ensure the effect of the first embodiment, it is more preferable to set the upper limit of conditional expression (7) to 1.660, 1.650, 1.640, 1.630, or even 1.620.

[0043] In addition, by setting the lower limit of conditional expression (8) to 53.00, the effect of the first embodiment can be ensured. In order to ensure the effect of the first embodiment, it is more preferable to set the lower limit of conditional expression (8) to 55.00, 57.00, 59.00, 61.00, or even 63.00. On the other hand, by setting the upper limit value of conditional expression (8) to 80.00, the effect of the first embodiment can be ensured. In order to ensure the effect of the first embodiment, it is more preferable to set the upper limit value of conditional expression (8) to 73.00, 71.00, or even 69.00.

[0044] In the optical system according to the first embodiment, it is desirable that the rear group has at least four positive lenses arranged in succession.

[0045] In this way, in the optical system according to the first embodiment, the rear group is configured to have at least four positive lenses arranged in succession, and therefore various aberrations, in particular spherical aberration, curvature of field, chromatic aberration, etc., can be effectively corrected.

[0046] Moreover, it is desirable for the optical system of the first embodiment to satisfy the following conditional expression. 0.3050 < fA / fB < 3.00 (9) however, fA: focal length of the front group when shooting at infinity fB: focal length of the rear group when shooting at infinity

[0047] Conditional expression (9) defines an appropriate power balance between the front group and the rear group. By satisfying conditional expression (9), the optical system according to the first embodiment can effectively reduce the Petzval sum while effectively correcting various aberrations, particularly coma, spherical aberration, curvature of field, and the like. In order to ensure the effect of condition (9), it is preferable to set the lower limit of condition (9) to 0.40-0.60, and more preferably to 0.50, 0.60, 0.70, 0.80, 0.90, 1.00, and further preferably to 1.10. On the other hand, in order to ensure the effect of conditional expression (9), it is preferable to set the upper limit of conditional expression (9) to 2.80, and more preferably to 2.60, 2.40, 2.20, 2.00, 1.80, and further preferably to 1.60.

[0048] Moreover, it is desirable for the optical system of the first embodiment to satisfy the following conditional expression. 1.50 < fA / f < 5.00 (10) however, fA: Focal length of the front group when shooting at infinity f: focal length of the entire system when shooting at infinity

[0049] Conditional formula (10) defines an appropriate power balance between the front group and all the optical systems. By satisfying conditional formula (10), the optical system according to the first embodiment has good symmetry before and after the aperture stop, and various aberrations and curvature of field relative to the angle of view can be corrected well. In particular, when focusing, the fluctuation of these aberrations is small from the infinity object focusing state to the close object focusing state, and various aberrations in close-up photography, particularly spherical aberration and coma aberration, can be corrected well. In order to ensure the effect of condition (10), it is preferable to set the lower limit of condition (10) to 1.60, and more preferably to 1.70, 1.80, 1.90, 2.00, or 2.10. On the other hand, in order to ensure the effect of condition (10), it is preferable to set the upper limit of condition (10) to 4.80, and more preferably to 4.60, 4.20, 3.90, 3.60, 3.30, 3.00, and further preferably to 2.60.

[0050] In addition, in the optical system of this first embodiment, it is desirable that one of the lens closest to the object and the lens closest to the image, i.e., the lens closest to the object or the lens closest to the image, is a negative lens, and it is more desirable that both are negative lenses.

[0051] With this configuration, the optical system of the first embodiment can effectively correct various aberrations, particularly spherical aberration, curvature of field, chromatic aberration, i.e., axial chromatic aberration, chromatic aberration of magnification, etc. In particular, when focusing, there is little variation in these aberrations over a range from an infinity object focused state to a close object focused state.

[0052] Furthermore, in the optical system of this first embodiment, it is desirable that one of the second lens from the object side and the second lens from the image side, i.e., the second lens from the object side or the second lens from the image side, is a negative lens, and it is more desirable that both are negative lenses.

[0053] With this configuration, the optical system of the first embodiment can more effectively correct various aberrations, particularly spherical aberration, curvature of field, chromatic aberration, i.e., axial chromatic aberration, chromatic aberration of magnification, etc. In particular, when focusing, the fluctuation of these aberrations is reduced over the range from an infinity object focused state to a close object focused state.

[0054] Furthermore, in the optical system of the first embodiment, it is desirable that the rear group has at least four consecutive positive lenses, and negative lenses arranged adjacent to the object side and image side of the at least four positive lenses in the rear group.

[0055] With this configuration, the optical system of the first embodiment can effectively correct various aberrations, particularly spherical aberration, curvature of field, chromatic aberration, i.e., axial chromatic aberration, chromatic aberration of magnification, etc. In particular, when focusing, there is little variation in these aberrations over a range from an infinity object focused state to a close object focused state.

[0056] Moreover, the optical system of the first embodiment has a negative lens component located closest to the image side of the front group, and it is desirable for at least one of the negative lens components to have a negative lens Ln2 that satisfies the following conditional expression. 0.600 < θgFLn2+0.0021×νdLn2 < 0.663 (11) however, νdLn2: Abbe number of the negative lens Ln2 for the d line θgFLn2: partial dispersion ratio of the negative lens Ln2 by the g line and the F line Incidentally, the negative lens component refers to a single negative lens or a combination of a plurality of negative lenses.

[0057] Here, the partial dispersion ratio θgF is expressed by the following equation, where the refractive index for the C-line (wavelength 656.3 nm) is nC, the refractive index for the d-line (wavelength 587.6 nm) is nd, the refractive index for the F-line (wavelength 486.1 nm) is nF, and the refractive index for the g-line (wavelength 435.8 nm) is ng. θgF=(ng-nF) / (nF-nC) The expression for the partial dispersion ratio θgF is the same for the subsequent conditional expressions, and the explanation thereof will be omitted.

[0058] Conditional formula (11) defines the glass material to be used for the negative lens Ln2 of the optical system. By including the negative lens Ln2 that satisfies conditional formula (11), axial chromatic aberration can be well corrected with a small number of lenses.

[0059] When the corresponding value of conditional expression (11) of the optical system of the first embodiment falls below the lower limit, the anomalous dispersion of the negative lens Ln2 becomes small, making it difficult to correct the longitudinal chromatic aberration. By setting the lower limit of conditional expression (11) to 0.610, the effect of the first embodiment can be more assured. In order to further ensure the effect of the first embodiment, it is more preferable to set the lower limit of conditional expression (11) to 0.620, 0.630, or even 0.640.

[0060] On the other hand, if the corresponding value of conditional expression (11) of the optical system of the first embodiment exceeds the upper limit, the anomalous dispersion of the negative lens Ln2 becomes large, making it difficult to correct the longitudinal chromatic aberration. By setting the upper limit of conditional expression (11) to 0.662, the effect of the first embodiment can be more assured. In order to further ensure the effect of the first embodiment, it is more preferable to set the upper limit of conditional expression (11) to 0.661, 0.660, 0.659, 0.658, 0.657, or even 0.656.

[0061] Moreover, the optical system of the first embodiment has a negative lens component located closest to the image side of the front group, and it is desirable for at least one of the negative lenses Ln2 to satisfy the following condition: 25.00 < νdLn2 < 57.0060.00 (12) however, νdLn2: Abbe number of the negative lens Ln2 for the d line Incidentally, the negative lens component refers to a single negative lens or a combination of a plurality of negative lenses.

[0062] Conditional formula (12) defines the Abbe number for the d-line of the negative lens Ln2, which is the most image-side lens in the front group. When the negative lens Ln2 satisfies conditional formula (12), various aberrations, particularly spherical aberration, curvature of field, chromatic aberration, i.e., axial chromatic aberration, lateral chromatic aberration, etc., can be corrected more effectively. In particular, when focusing, the variation in these aberrations is reduced from the infinity object focusing state to the close object focusing state.

[0063] In addition, by setting the lower limit of conditional expression (12) to 26.00, the effect of the first embodiment can be ensured. In order to ensure the effect of the first embodiment, it is more preferable to set the lower limit of conditional expression (12) to 27.00, 28.00, 29.00, or even 30.00.

[0064] On the other hand, by setting the upper limit value of conditional formula (12) to 58.0054.00, the effect of the first embodiment can be ensured. In order to ensure the effect of the first embodiment, it is more preferable to set the upper limit value of conditional formula (12) to 56.00, 54.00, 52.00, 50.00, 48.00, 45.00, or even 42.00.

[0065] Moreover, it is preferable that the optical system of the first embodiment has a plurality of focusing lens groups, the front group being fixed and the rear group being movable on the optical axis by mutually different amounts of movement during focusing.

[0066] With this configuration, the optical system according to the first embodiment has a configuration in which the front group is fixed and the rear group has a plurality of groups that move on the optical axis by different amounts of movement relative to each other during focusing, thereby enabling even better correction of spherical aberration, coma, and field curvature.

[0067] In addition, in the optical system of the first embodiment, the front group is fixed during focusing, and the rear group has a first focusing lens group F1 and a second focusing lens group F2 that move on the optical axis by different amounts of movement, and it is desirable for the optical system to satisfy the following conditional expression (13): 0.00 < fF2 / |fF1| < 0.50 (13) however, fF1: focal length of the first focusing lens group F1 fF2: focal length of the second focusing lens group F2

[0068] Conditional expression (13) defines an appropriate power balance between the first focusing lens group F1 and the second focusing lens group F2, which move independently by different amounts. By satisfying conditional expression (13), the optical system according to the first embodiment can further suppress changes in image magnification due to focusing, and can provide an optical system with even better optical performance over the entire focusing range. By satisfying condition (13), fluctuations in various aberrations, particularly spherical aberration, coma, and the like, that occur during focusing can be suppressed. In order to ensure the effect of condition (13), it is preferable to set the lower limit of condition (13) to 0.020, and more preferably to 0.050, 0.080, 0.100, 0.120, or even 0.160. On the other hand, in order to ensure the effect of condition (13), it is preferable that the upper limit value of condition (13) be set to 0.47, and more preferably to 0.44, 0.41, 0.38, 0.35, 0.32, 0.30, 0.27, and further preferably to 0.25.

[0069] In the optical system of the first embodiment, it is desirable that the rear group has the final lens group closest to the image side. With this configuration, it is possible to effectively correct various aberrations, particularly spherical aberration, curvature of field, etc. In particular, when focusing, the fluctuation of these aberrations is reduced over the range from an infinity object focus state to a close object focus state.

[0070] In the optical system of the first embodiment, it is desirable that the rear group has at least one positive lens Lp that satisfies the following condition: 0.670 < θgFLp+0.0021×νdLp (14) 15.00 < νdLp < 35.00 (15) however, νdLp: Abbe number of the positive lens Lp for the d line θgFLp: partial dispersion ratio of the positive lens Lp by the g line and the F line Furthermore, it is more preferable that the positive lens Lp is disposed in the final lens group which is located closest to the image side of the rear group.

[0071] Conditional expressions (14) and (15) are conditional expressions that stipulate the glass material to be used for the positive lens Lp of the rear group. By using a positive lens Lp that satisfies conditional expressions (14) and (15), axial chromatic aberration, lateral chromatic aberration, etc. can be corrected well.

[0072] When the corresponding value of conditional expression (14) of the optical system of the first embodiment falls below the lower limit, the anomalous dispersion of the positive lens Lp becomes small, making it difficult to correct axial chromatic aberration, lateral chromatic aberration, etc. By setting the lower limit of conditional expression (14) to 0.675, the effect of the first embodiment can be more assured. In order to further ensure the effect of the first embodiment, it is more preferable to set the lower limit of conditional expression (14) to 0.680, 0.685, or even 0.690.

[0073] By setting the upper limit of conditional expression (14) to "<0.710", the anomalous dispersion of the positive lens Lp does not become too large, and axial chromatic aberration, lateral chromatic aberration, etc. can be corrected more satisfactorily, thereby making it possible to more reliably achieve the effects of the first embodiment. In order to more reliably achieve the effects of the first embodiment, it is more preferable to set the upper limit of conditional expression (14) to 0.705, 0.700, or even 0.695.

[0074] Furthermore, when the corresponding value of conditional formula (15) of the optical system of the first embodiment falls below the lower limit, the Abbe number of the positive lens Lp becomes small, making it difficult to correct axial chromatic aberration, lateral chromatic aberration, and the like. By setting the lower limit of conditional formula (15) to 16.00, the effect of the first embodiment can be made more certain. In order to make the effect of the first embodiment more certain, it is more preferable to set the lower limit of conditional formula (15) to 16.50, 17.00, or even 17.50.

[0075] On the other hand, if the corresponding value of conditional formula (15) of the optical system of the first embodiment exceeds the upper limit, the Abbe number of the positive lens Lp becomes large, making it difficult to correct axial chromatic aberration, lateral chromatic aberration, and the like. By setting the upper limit of conditional formula (15) to 32.00, the effect of the first embodiment can be made more certain. In order to make the effect of the first embodiment more certain, it is more preferable to set the upper limit of conditional formula (15) to 29.00, 26.00, 23.00, or even 20.00.

[0076] In the front group, when the group consisting of at least four consecutive positive lenses, from the positive lens L1 closest to the object side to the lens closest to the image side in the front group is designated as an image-side subgroup AR, and all lenses closer to the object side than the image-side subgroup AR are designated as an object-side subgroup AF, it is desirable to satisfy the following conditional expression: 0.40 < -fAF / fAR < 2.00 (16) however, fAF: focal length of the object-side AF subgroup of the front group fAR: focal length of the image-side subgroup AR of the front group

[0077] Conditional formula (16) prescribes the ratio of the focal length of the AF group to the focal length of the AR group. By satisfying conditional formula (16), the marginal ray is first raised in group A and then lowered in group B. This reduces the Petzval sum, and allows for both spherical aberration and curvature of field to be corrected, as well as coma.

[0078] It should be noted that the effect of the first embodiment can be more reliably achieved by setting the lower limit of conditional expression (16) to 0.45. In order to further ensure the effect of the first embodiment, it is more preferable to set the lower limit of conditional expression (16) to 0.50, 0.55, 0.60, or even 0.65.

[0079] On the other hand, by setting the upper limit of conditional formula (16) to 1.70, the effect of the first embodiment can be ensured. In order to ensure the effect of the first embodiment, it is more preferable to set the upper limit of conditional formula (16) to 1.50, 1.30, 1.10, or even 0.90.

[0080] In the optical system of the first embodiment, it is desirable that, of the at least four consecutive positive lenses in the front group, the positive lens closest to the image side is cemented with a negative lens.

[0081] With this configuration, the at least four positive lenses and the negative lens cemented adjacent to the image side of the at least four positive lenses in the front group can effectively correct various aberrations, particularly spherical aberration, field curvature, chromatic aberration, etc. In addition, using a cemented lens is desirable because it allows the front group to be made compact. In particular, when focusing, the variation in these aberrations is reduced from an infinity object focusing state to a close object focusing state.

[0082] In the optical system of the first embodiment, it is desirable that, of the at least four consecutive positive lenses in the front group, the second positive lens L2 from the object side satisfies the following conditional expression. -1.00 <(R22+R21) / (R22-R21) < 1.00 (17) however, R21: Radius of curvature of the object side surface of the second positive lens L2 on the object side R22: Radius of curvature of the image side of the second positive lens L2 on the object side

[0083] Condition (17) defines the surface shape of the second positive lens L2, which is the lens closest to the object, of the at least four consecutive positive lenses in the front group. By satisfying condition (17), coma, spherical aberration, curvature of field, etc. can be effectively corrected.

[0084] Note that the effect of the first embodiment can be more reliably achieved by setting the lower limit of conditional expression (17) to -0.90. In order to further ensure the effect of the first embodiment, it is more preferable to set the lower limit of conditional expression (17) to -0.80, -0.70, -0.60, -0.50, or further -0.40.

[0085] On the other hand, by setting the upper limit value of conditional formula (17) to 0.90, the effect of the first embodiment can be ensured. In order to ensure the effect of the first embodiment, it is more preferable to set the upper limit value of conditional formula (17) to 0.80, 0.70, 0.60, 0.50, 0.40, or even 0.30.

[0086] The optical device according to this embodiment has an optical system with the above-mentioned configuration, which allows various aberrations to be corrected well, and in particular reduces the variation of these aberrations during focusing from an infinity focus state to a close-distance focus state, making it possible to realize an optical device equipped with a large-aperture optical system suitable for both autofocus and manual focus.

[0087] Here, an example of a camera (optical device) equipped with the optical system OL of this embodiment will be described. Fig. 22 is a diagram showing an example of the configuration of a camera 1 having a lens OL.

[0088] As shown in FIG. 22, the camera 1 is a so-called mirrorless camera of an interchangeable lens type equipped with an optical system OL as a photographing lens 2. In the camera 1, light from an object (subject) (not shown) is collected by the photographing lens 2 and passes through an OLPF (Optical low pass filter) (not shown) to form a subject image on the imaging surface of the imaging unit 3. Then, the subject image is photoelectrically converted by a photoelectric conversion element provided in the imaging unit 3 to generate an image of the subject. This image is displayed on an EVF (Electronic view finder) 4 provided in the camera 1. This allows the photographer to observe the subject through the EVF 4. Also, when the photographer presses a release button (not shown), the image of the subject generated by the imaging unit 3 is stored in a memory (not shown). In this manner, the photographer can photograph the subject using the camera 1.

[0089] As will be understood from each of the embodiments described later, the optical system OL provided in the camera 1 as the photographing lens 2 has a characteristic lens configuration that allows various aberrations to be corrected well at a large aperture, and in particular reduces the variation of these aberrations during focusing from an infinity-focused state to a close-up-focused state. Therefore, the camera 1 can realize an optical device having an optical system that allows various aberrations to be corrected well at a large aperture, and in particular reduces the variation of these aberrations during focusing from an infinity-focused state to a close-up-focused state.

[0090] Although a mirrorless camera has been described as an example of camera 1, the optical device of this embodiment is not limited to this. For example, even if the above-mentioned optical system OL is provided in a single-lens reflex type camera that has a quick-return mirror in the camera body and observes a subject through a viewfinder optical system, the same effects as those of camera 1 can be achieved.

[0091] A manufacturing method for the optical system of this embodiment is an optical system comprising, in order from the object side, a front group having positive refractive power, an aperture stop, and a rear group having positive refractive power overall, said front group having a configuration in which at least four positive lenses are arranged in succession, said optical system being configured to have a negative lens Ln1 adjacent to the object side of said at least four positive lenses, and one or more lenses further on the object side, and at least one of said at least four positive lenses being a lens H that satisfies the following conditional expression: 1.650 < nH < 2.100 (1) 25.00 < νH < 60.00 (2) however, nH: refractive index of the lens H with respect to the d line νH: Abbe number of the lens H for the d line

[0092] This allows various aberrations to be well corrected, and in particular, when focusing, the fluctuation of these aberrations is reduced from the infinity object focus state to the close object focus state, making it possible to manufacture an optical system with a large aperture suitable for both autofocus and manual focus, in which aberrations are well corrected over the entire focusing range.

[0093] Hereinafter, an outline of a method for manufacturing an optical system OL according to this embodiment will be described with reference to Fig. 23. First, the optical system is arranged (S1) so that, in order from the object side, the optical system is composed of a front group having positive refractive power, a stop, and a rear group having positive refractive power overall, the front group having at least four positive lenses arranged in succession, a negative lens Ln1 adjacent to the object side of the at least four positive lenses, and one or more lenses further on the object side. Next, at least one of the at least four positive lenses is arranged so as to satisfy a predetermined conditional expression (S2).

[0094] According to the above-described method for manufacturing an optical system, it is possible to manufacture an optical system having a large aperture in which various aberrations are well corrected and in which the fluctuation of these aberrations is reduced particularly during focusing, from the infinity object focusing state to the close object focusing state.

[0095] It should be noted that the conditions and configurations described above each provide the effects described above, and are not limited to those that satisfy all of the conditions and configurations. The effects described above can be obtained by satisfying any one of the conditions or configurations, or any combination of the conditions or configurations.

[0096] In addition, each of the examples described below shows a specific example of the present invention, and the present invention is not limited to these. The following contents can be appropriately adopted within a range that does not impair the optical performance of the optical system of this embodiment.

[0097] For example, each of the examples described below shows a four-group configuration as a numerical example of the optical system, but the present embodiment is not limited to this, and an optical system with other group configurations (for example, five groups, six groups, etc.) can also be configured. Specifically, a lens or lens group may be added to the most object side or the most image side of the optical system in each of the examples below. Alternatively, a lens or lens group may be added between adjacent lens groups. In this specification, a lens group refers to a portion having at least one lens separated by an air gap that changes when focusing, but it may also be a lens group as long as it is composed of at least one lens separated by an air gap.

[0098] In addition, the focusing lens group can be applied to autofocusing, and is also suitable for driving a motor for autofocusing (such as an ultrasonic motor, a stepping motor, or a VCM motor).

[0099] In addition, a lens group or a partial lens group may be moved so as to have a displacement component perpendicular to the optical axis, or rotated (rocked) in a plane including the optical axis, to serve as an anti-vibration lens group that corrects image blur caused by camera shake or the like.

[0100] The lens surface may be spherical or flat, or aspheric. A spherical or flat lens surface is preferable because it facilitates lens processing and assembly adjustment, and prevents deterioration of optical performance due to processing and assembly adjustment errors. It is also preferable because there is little deterioration in depiction performance even if the image plane is shifted. When the lens surface is aspheric, the aspheric surface may be any of aspheric surfaces such as an aspheric surface formed by grinding, a glass molded aspheric surface formed by molding glass into an aspheric shape, and a composite aspheric surface formed by forming a resin into an aspheric shape on the surface of glass. The lens surface may be a diffractive surface, and the lens may be a gradient index lens (GRIN lens) or a plastic lens.

[0101] It is preferable that the aperture stop S is disposed inside or outside the lens group, but it is also possible to use the frame of the lens instead of providing a member serving as the aperture stop.

[0102] Furthermore, each lens surface may be coated with an anti-reflection coating having high transmittance over a wide wavelength range in order to reduce flare and ghosting and achieve high contrast and high optical performance.

[0103] With the above-mentioned configuration, it is possible to provide a bright optical system OL having good optical performance, and an image taking apparatus having this optical system OL.

[0104] Each example according to the present embodiment will be described below with reference to the drawings. Tables 1 to 7 are tables showing the specifications of the first to seventh examples.

[0105] The cross-sectional view of the optical system shown in FIG. 1 is a cross-sectional view of the optical system of Example 1, in which the left side of the optical system is the object side and the right side is the image side. The upper part of the page illustrates a state in which an object at infinity is focused, and the lower part of the page illustrates a state in which an object at close range is focused, and between the two, the movement trajectories of each lens group during focusing are shown. The lenses in FIG. 1 are designated L11, L12, L13, ... from the object side (left side of the page). In addition, in FIG. 1, the focusing lens group is indicated as F (F1, F2) along with its movement locus during focusing. 2 and 3 are aberration diagrams of Example 1 when focusing at infinity (FIG. 2) and when focusing at a close distance (FIG. 3), and it can be seen that aberration correction is performed well. Here, FNo is the F-number, Y is the image height, and d and g are the aberration curves of the d-line and g-line, respectively. In addition, in the astigmatism, the solid line indicates the sagittal image surface, and the dotted line indicates the meridional image surface.

[0106] 1 in the first embodiment are used independently for each embodiment to avoid complication of explanation due to an increase in the number of digits of the reference symbols. Therefore, even if the same reference symbols are used as those in the drawings of other embodiments, they do not necessarily have the same configuration as the other embodiments.

[0107] In each embodiment, the C-line (wavelength 656.3 nm), d-line (wavelength 587.6 nm), F-line (wavelength 486.1 nm), and g-line (wavelength 435.8 nm) are selected as the targets for calculating the aberration characteristics.

[0108] In the table (Basic specifications), f is the focal length of the entire optical system OL, FNo is the F-number, ω is the half angle of view (maximum angle of incidence unit: °), Y is the image height, BF is the back focus (the actual distance via a filter or the like from the final lens surface on the optical axis to the paraxial image plane), BFa (air-converted length) is the back focus (the distance from the final lens surface on the optical axis to the paraxial image plane converted into air), TL is the total lens length (the distance from the frontmost lens surface to the final lens surface on the optical axis plus BF), and TLa is the total lens length (the distance from the frontmost lens surface to the final lens surface on the optical axis plus BFa).

[0109] In the (surface data) in the table, the surface number indicates the order of the optical surface from the object side along the traveling direction of the light ray, r indicates the radius of curvature of each optical surface, d indicates the surface interval which is the distance on the optical axis from each optical surface to the next optical surface (or image surface), nd indicates the refractive index for the d-line of the material of the optical component, and νd indicates the Abbe number based on the d-line of the material of the optical component. In addition, (object surface) indicates the object surface, (variable) indicates the variable surface interval, the "∞" in the radius of curvature indicates a plane or an aperture, (aperture) indicates the aperture stop S, the image surface indicates the image surface I, and BF indicates the back focus (the distance from the final lens surface on the optical axis to the paraxial image surface). Even if BF is not indicated as (variable), it may be variable. The refractive index of air "1.00000" is omitted.

[0110] In the (aspheric surface data) table, the aspheric surface is expressed by the following formula (a), where y is the height in the direction perpendicular to the optical axis, S(y) is the distance (sag amount) along the optical axis from the tangent plane of the apex of each aspheric surface at height y to each aspheric surface, r is the radius of curvature (paraxial radius of curvature) of the reference sphere, κ is the conic constant, and An is the aspheric surface coefficient of order n (n=4,6,8,10,12,14,16). Note that in the following examples, "en" is "×10 -n For example, "-4.54914e-06" represents "-4.54914×10 -6 ".

[0111] S(y)=(y 2 / r) / {1+(1-κ×y 2 / r 2 ) 1 / 2} +A4×y 4 +A6×y 6 +A8×y 8 +A10×y 10 +A12×y 12 +A14×y 14 +A16×y 16 (a)

[0112] In each example, the second-order aspheric coefficient A2 is omitted because it is 0. In the table of each example, aspheric surfaces are marked with an * to the right of the surface number.

[0113] In the table (lens group focal length), the first surface indicates the surface number of each group closest to the object, the last surface indicates the surface number of each group closest to the image, and the group focal length indicates the focal length of each group.

[0114] In the table, (variable distance data) shows each variable distance di at infinity (infinity focusing state) and close distance (close distance focusing state). Here, di indicates the variable distance between the i-th surface and the (i+1)-th surface. Note that d0 indicates the distance on the optical axis from the object to the apex of the lens surface closest to the object.

[0115] In the following, for all specifications, the focal length f, radius of curvature r, surface spacing d, and other lengths are generally in "mm" unless otherwise specified, but this is not limited to this because the optical system can obtain the same optical performance even if it is proportionally enlarged or reduced. Also, the unit is not limited to "mm" and other appropriate units can be used.

[0116] The above explanation of the tables is common to all the embodiments, and will not be repeated below.

[0117] (First embodiment) FIG. 1 is a cross-sectional view of an optical system according to a first embodiment. The optical system according to this embodiment is composed of, in order from the object side, a front group A having positive refractive power, an aperture stop S, and a rear group B having positive refractive power.

[0118] The front group A is composed of, in order from the object side, an object side subgroup AF and an image side subgroup AR. Here, the object side subgroup AF is composed of a negative lens L11 having a meniscus lens shape with a convex surface facing the object side, a negative lens L12 having a meniscus lens shape with a convex surface facing the object side, a positive lens L13 having a meniscus lens shape with a convex surface facing the object side, and a negative lens L14 having a meniscus lens shape with a concave surface facing the object side, while the image side subgroup AR is composed of a cemented negative lens obtained by cementing together a plano-convex positive lens L15 having a convex surface facing the image side, a biconvex positive lens L16, a positive lens L17 having a meniscus lens shape with a convex surface facing the object side, a biconvex positive lens L18, and a biconcave negative lens L19. The rear group B is composed of, in order from the object side, a first focusing lens group F1, a second focusing lens group F2, and a final lens group R. Here, the first focusing lens group F1 is composed of a plano-concave negative lens L21 with a concave surface facing the object side, and a biconvex positive lens L22, the second focusing lens group F2 is composed of a biconvex positive lens L31, and a meniscus lens-shaped positive lens L32 with a convex surface facing the object side, and the final lens group R is composed of a meniscus lens-shaped positive lens L41 with a convex surface facing the object side, a cemented negative lens in which a plano-convex positive lens L42 with a convex surface facing the object side and a plano-concave negative lens L43 with a concave surface facing the image side are cemented together, and a biconcave negative lens L44. A filter group FL including a low-pass filter and the like is disposed between the rear group B and the image surface I. An image sensor (not shown) including a CCD, a CMOS, or the like is disposed on the image surface I.

[0119] In this optical system, in the front group A, the positive lenses L15, L16, L17, and L18 are configured as four positive lenses arranged in succession, the negative lens L14 is the negative lens Ln1 adjacent to the object side of the four positive lenses and is a negative lens component Pn1, the positive lens L15 is a lens H that satisfies conditional expressions (1) and (2) and is the positive lens L1 closest to the object side of the four positive lenses, and the positive lens L16 is the positive lens L2 that is second closest to the object side of the four positive lenses, the negative lens L19 is a negative lens Ln2 which is located closest to the image side in the front group and satisfies conditional expressions (11) and (12), and is also a negative lens component Pn2 which is adjacent to the image side of the four positive lenses; the image side surface of the negative lens L11 is a lens surface having a radius of curvature R1 with a minimum absolute value among the lenses L11, L12, and L13 whose image side surfaces are convex surfaces facing the object side and are located on the object side of the negative lens Ln1, The object side surface of the negative lens L14 is the lens surface having the smallest absolute radius of curvature R2 among the lens L14 whose object side surface is concave toward the object side among the lenses closer to the object side than the negative lens Ln1. In the rear group B, the positive lenses L22, L31, L32, L41, and L42 are configured as four or more consecutive positive lenses, and the positive lens L42 is a lens Lp that satisfies the conditional expressions (14) and (15).

[0120] In this optical system, focusing from infinity to a close object point is performed by moving the first focusing lens group F1 and the second focusing lens group F2 toward the object side by different amounts along the optical axis.

[0121] This optical system forms an image on an image plane I for photography. Figure 1 shows the optical system and its image plane I. Table 1 below shows the values ​​of each parameter in the first embodiment.

[0122] (Table 1) First Example (Basic specifications) f 34.4 FNo 1.23 ω 32.7 Y 21.7 TL 163.987 TLa (air equivalent length) 163.442 BF 12.98 BFa (air equivalent length) 12.434 (surface data) Surface number rd nd νd θgF 0 (physical surface) ∞ (variable) 1 163.28336 2.500 1.64000 60.1 2 31.10505 13.390 1.00000 3* 149.89871 3.000 1.51680 64.1 4* 47.93253 3.060 1.00000 5 73.48310 5.400 1.92119 24.0 6 357.54410 12.730 1.00000 7 -38.63142 2.100 1.73800 32.3 8 -1220.67060 0.820 1.00000 9 0.00000 7.850 1.95375 32.3 10 -62.49727 0.300 1.00000 11 91.13243 10.250 1.59349 67.0 12 -91.13243 0.200 1.00000 13 54.79591 6.750 1.59349 67.0 14 240.05962 0.200 1.00000 15 116.72066 10.250 1.59319 67.9 16 -55.03000 1.600 1.73800 32.3 0.5896 17 56.17820 5.630 1.00000 18 (aperture) ∞ d18 1.00000 19 -38.22319 1.500 1.72047 34.7 20 0.00000 0.200 1.00000 21 63.64177 6.000 1.59319 67.9 22 -130.91271 d22 1.00000 23 49.41555 8.000 1.59294 67.9 24* -821.27474 3.130 1.00000 25* 65.70231 3.750 1.77503 47.3 26 690.07952 d26 1.00000 27 60.10155 4.000 1.59319 67.9 28 231.68418 0.310 1.00000 29 90.05931 4.050 1.94594 17.98 0.6546 30 0.00000 1.400 1.78880 28.4 31 37.80163 7.530 1.00000 32* -124.60117 2.000 1.62372 58.4 33 448.63838 d33 1.00000 34 0.00000 1.600 1.51680 64.1 35 0.00000 d35 1.00000 Image plane∞ (Aspheric surface) Noodles A4 A6 A8 A10 3 1.00000e+00 -1.90130e-06 5.94470e-09 -7.37380e-12 6.82170e-15 A12 A14 A16 -2.33300e-18 0.00000e+00 0.00000e+00 Noodles A4 A6 A8 A10 4 1.00000e+00 -4.72665e-06 6.15115e-09 -1.36350e-11 1.88120e-14 A12 A14 A16 -1.56680e-17 4.21000e-21 0.00000e+00 Noodles A4 A6 A8 A10 24 1.00000e+00 -1.45539e-05 3.33136e-08 -7.38050e-11 1.27860e-13 A12 A14 A16 -1.36240e-16 8.20000e-20 -3.05140e-23 Noodles A4 A6 A8 A10 25 1.00000e+00 -1.73911e-05 2.29349e-08 -7.94700e-11 2.34280e-13 A12 A14 A16 -5.40620e-16 8.62870e-19 -6.32910e-22 Noodles A4 A6 A8 A10 32 1.00000e+00 -6.15151e-06 -3.25835e-10 1.08560e-11 -5.90780e-14 A12 A14 A16 0.00000e+00 0.00000e+00 0.00000e+00 (Lens group focal length) Lens group First surface Last surface Group focal length A 1 17 96.178 AF 1 8 -24.715 AR 9 17 31.465 B 19 33 61.454 F1 19 22 -219.406 F2 23 26 44.765 R 27 33 -130.720 (variable interval data) Infinity Close range d0∞308.07 Magnification - -0.1000 f 34.4 - d18 19.089 13.738 d22 2.019 3.693 d26 2.000 5.676 d33 10.38 10.38 d35 1.00 1.00

[0123] FIGS. 2 and 3 are diagrams showing various aberrations in the optical system of Example 1 when focused at infinity and when focused at a close distance, respectively, and show that the various aberrations are well corrected, providing excellent imaging performance.

[0124] (Second Example) FIG. 4 is a cross-sectional view of an optical system according to the second embodiment. The optical system according to this embodiment is composed of, in order from the object side, a front group A having positive refractive power, an aperture stop S, and a rear group B having positive refractive power.

[0125] The front group A is composed of, in order from the object side, an object side subgroup AF and an image side subgroup AR. Here, the object side subgroup AF is composed of a negative lens L11 having a meniscus lens shape with a convex surface facing the object side, a negative lens L12 having a meniscus lens shape with a convex surface facing the object side, a positive lens L13 having a meniscus lens shape with a convex surface facing the object side, and a biconcave negative lens L14, while the image side subgroup AR is composed of a cemented negative lens obtained by cementing together a biconvex positive lens L15, a biconvex positive lens L16, a positive lens L17 having a meniscus lens shape with a convex surface facing the object side, a biconvex positive lens L18, and a biconcave negative lens L19. The rear group B is composed of, in order from the object side, a first focusing lens group F1, a second focusing lens group F2, and a final lens group R. Here, the first focusing lens group F1 is composed of a biconcave negative lens L21 and a biconvex positive lens L22, the second focusing lens group F2 is composed of a biconvex positive lens L31 and a positive lens L32 having a meniscus lens shape with its convex surface facing the object side, and the final lens group R is composed of a positive lens L41 having a meniscus lens shape with its convex surface facing the object side, a cemented negative lens in which a biconvex positive lens L42 and a biconcave negative lens L43 are cemented together, and a negative lens L44 having a meniscus lens shape with its convex surface facing the object side. A filter group FL including a low-pass filter and the like is disposed between the rear group B and the image surface I. An image sensor (not shown) including a CCD, a CMOS, or the like is disposed on the image surface I.

[0126] In this optical system, in the front group A, the positive lenses L15, L16, L17, and L18 are configured as four positive lenses arranged in succession, the negative lens L14 is the negative lens Ln1 adjacent to the object side of the four positive lenses and is a negative lens component Pn1, the positive lens L15 is a lens H that satisfies conditional expressions (1) and (2) and is the positive lens L1 closest to the object side of the four positive lenses, and the positive lens L16 is the positive lens L2 that is second closest to the object side of the four positive lenses, the negative lens L19 is a negative lens Ln2 which is located closest to the image side in the front group and satisfies the conditional expressions (11) and (12), and is also a negative lens component Pn2 which is adjacent to the image side of the four positive lenses; the image side surface of the negative lens L11 is a lens surface having a radius of curvature R1 with a minimum absolute value among the lenses L11, L12, and L13 whose image side surfaces are convex surfaces facing the object side and are located on the object side of the negative lens Ln1, The object side surface of the negative lens L14 is the lens surface having the smallest absolute radius of curvature R2 among the lens L14 whose object side surface is concave toward the object side among the lenses closer to the object side than the negative lens Ln1. In the rear group B, the positive lenses L22, L31, L32, L41, and L42 are configured as four or more consecutive positive lenses, and the positive lens L42 is a lens Lp that satisfies the conditional expressions (14) and (15).

[0127] In this optical system, focusing from infinity to a close object point is performed by moving the first focusing lens group F1 and the second focusing lens group F2 toward the object side by different amounts along the optical axis.

[0128] This optical system forms an image on an image plane I for photography. Figure 4 shows the optical system and its image plane I. Table 2 below shows the values ​​of each parameter in the second embodiment.

[0129] (Table 2) Second Example (Basic specifications) f 35.00 FNo 1.24 ω 31.8 Y 21.70 TL 164.000 TLa (air equivalent length) 163.455 BF 12.690 BFa (air equivalent length) 12.145 (surface data) Surface number rd nd νd θgF 0 (physical surface) ∞ (variable) 1 342.75207 2.500 1.69680 55.5 2 33.23653 8.492 1.00000 3 87.52255 2.700 1.61272 58.5 4* 44.44561 2.650 1.00000 5 59.09628 5.800 1.92119 24.0 6 210.95138 15.016 1.00000 7 -37.01305 2.100 1.61266 44.5 8 686.08578 0.750 1.00000 9 367.55263 11.000 1.77250 49.6 10 -59.16636 0.200 1.00000 11 93.29233 9.300 1.60300 65.4 12 -109.48265 0.400 1.00000 13 60.02894 6.874 1.59349 67.0 14 383.03781 0.200 1.00000 15 85.72391 11.267 1.59319 67.9 16 -53.88047 1.600 1.72047 34.7 0.5834 17 51.98059 5.351 1.00000 18 (aperture) ∞ d18 1.00000 19 -35.68990 1.500 1.72047 34.7 20 235.68139 0.200 1.00000 21 80.21593 6.900 1.59319 67.9 22 -71.86613 d22 1.00000 23 46.05262 8.000 1.61800 63.3 24* -9999.90000 2.915 1.00000 25* 60.42548 3.750 1.77503 47.3 26 1000.00000 d26 1.00000 27 80.00000 3.950 1.59349 67.0 28 700.00000 0.660 1.00000 29 799.35439 5.873 1.94594 17.98 0.6546 30 -84.09652 1.400 1.73800 32.3 31 44.30349 5.612 1.00000 32* 1699.68910 2.000 1.61272 58.5 33 220.76060 d33 1.00000 34 0.00000 1.600 1.51680 64.1 35 0.00000 d35 1.00000 Image plane∞ (Aspheric surface) Noodles A4 A6 A8 A10 4 1.00000e+00 -2.43460e-06 1.22595e-10 -6.12993e-12 1.17330e-14 A12 A14 A16 -1.24240e-17 4.10530e-21 0.00000e+00 Noodles A4 A6 A8 A10 24 1.00000e+00 -1.94368e-05 3.84254e-08 -5.46736e-11 4.93843e-14 A12 A14 A16 -1.75000e-17 0.00000e+00 0.00000e+00 Noodles A4 A6 A8 A10 25 1.00000e+00 -2.09186e-05 2.36454e-08 -5.59981e-11 1.34830e-13 A12 A14 A16 -2.23140e-16 1.79940e-19 0.00000e+00 Surface κ A4 A6 A8 A10 32 1.00000e+00 -1.02868e-05 1.11715e-08 -3.23462e-11 -1.86748e-15 A12 A14 A16 0.00000e+00 0.00000e+00 0.00000e+00 (Lens group focal length) Lens group First surface Last surface Group focal length A 1 20 78.444 AF111 -25.843 AR 12 20 31.443 B 22 36 63.143 F1 22 25 -148.421 F2 26 29 41.159 R 30 36 -124.508 (variable interval data) Infinity Close range d0∞302.83 Magnification - -0.1000 f 35.00 - d18 18.350 13.228 d22 2.000 3.434 d26 2.000 5.688 d33 10.090 10.090 d35 1.000 1.000

[0130] FIGS. 5 and 6 are diagrams showing various aberrations in the optical system of Example 2 when focused at infinity and when focused at a close distance, respectively, and show that the various aberrations are well corrected, providing excellent imaging performance.

[0131] (Third Example) FIG. 7 is a cross-sectional view of an optical system according to the third embodiment. The optical system according to this embodiment is composed of, in order from the object side, a front group A having positive refractive power, an aperture stop S, and a rear group B having positive refractive power.

[0132] The front group A is composed of, in order from the object side, an object-side subgroup AF and an image-side subgroup AR. Here, the object-side subgroup AF is composed of a negative lens L11 having a meniscus lens shape with a convex surface facing the object side, a negative lens L12 having a meniscus lens shape with a convex surface facing the object side, a biconvex positive lens L13, and a negative lens L14 having a meniscus lens shape with a concave surface facing the object side, while the image-side subgroup AR is composed of a cemented negative lens obtained by cementing together a biconvex positive lens L15, a biconvex positive lens L16, a biconvex positive lens L17, a biconvex positive lens L18, and a biconcave negative lens L19. The rear group B is composed of, in order from the object side, a first focusing lens group F1, a second focusing lens group F2, and a final lens group R. Here, the first focusing lens group F1 is composed of a biconcave negative lens L21 and a biconvex positive lens L22, the second focusing lens group F2 is composed of a biconvex positive lens L31 and a biconvex positive lens L32, and the final lens group R is composed of a positive lens L41 having a meniscus lens shape with a convex surface facing the object side, a cemented negative lens formed by cementing a biconvex positive lens L42 and a biconcave negative lens L43, and a negative lens L44 having a meniscus lens shape with a convex surface facing the object side. A filter group FL including a low-pass filter and the like is disposed between the rear group B and the image surface I. An image sensor (not shown) including a CCD, a CMOS, or the like is disposed on the image surface I.

[0133] In this optical system, in the front group A, the positive lenses L15, L16, L17, and L18 are configured as four positive lenses arranged in succession, the negative lens L14 is the negative lens Ln1 adjacent to the object side of the four positive lenses and is a negative lens component Pn1, the positive lens L15 is a lens H that satisfies conditional expressions (1) and (2) and is the positive lens L1 closest to the object side of the four positive lenses, and the positive lens L16 is the positive lens L2 that is second closest to the object side of the four positive lenses, the negative lens L19 is a negative lens Ln2 which is located closest to the image side in the front group and satisfies conditional expressions (11) and (12), and is also a negative lens component Pn2 which is adjacent to the image side of the four positive lenses; the image side surface of the negative lens L11 is a lens surface having a radius of curvature R1 with a minimum absolute value among the lenses L11 and L12 whose image side surfaces are convex surfaces facing the object side and are located on the object side of the negative lens Ln1, The object side surface of the negative lens L14 is the lens surface having the smallest absolute radius of curvature R2 among the lens L14 whose object side surface is concave toward the object side among the lenses closer to the object side than the negative lens Ln1. In the rear group B, the positive lenses L22, L31, L32, L41, and L42 are configured as four or more consecutive positive lenses, and the positive lens L42 is a lens Lp that satisfies the conditional expressions (14) and (15).

[0134] In this optical system, focusing from infinity to a close object point is performed by moving the first focusing lens group F1 and the second focusing lens group F2 toward the object side by different amounts along the optical axis.

[0135] This optical system forms an image on an image plane I for photography. Figure 7 shows the optical system and its image plane I. Table 3 below shows the values ​​of each parameter in the third embodiment.

[0136] (Table 3) Third Example (Basic specifications) f 28.60 FNo 1.24 ω 37.9 Y 21.70 TL 164.000 TLa (air equivalent length) 163.455 BF 14.490 BFa (air equivalent length) 13.945 (surface data) Surface number rd nd νd θgF 0 (physical surface) ∞ (variable) 1 216.32172 2.500 1.64850 53.0 2 29.09273 16.090 1.00000 3* 589.67763 3.000 1.48749 70.3 4* 63.45311 6.985 1.00000 5 115.18633 5.400 1.85895 22.7 6 -319.72127 9.623 1.00000 7 -36.82563 2.100 1.68893 31.2 8 -1397.94320 1.437 1.00000 9 920.38688 8.300 1.95375 32.3 10 -64.63860 0.300 1.00000 11 100.75562 9.100 1.59349 67.0 12 -110.73306 0.200 1.00000 13 85.29124 6.500 1.59349 67.0 14 -1153.23950 0.200 1.00000 15 102.15971 10.250 1.59319 67.9 16 -51.16284 1.600 1.73800 32.3 0.5896 17 75.00000 5.630 1.00000 18 (aperture) ∞ d18 1.00000 19 -37.20791 1.500 1.72047 34.7 20 93.12722 0.200 1.00000 21 54.92543 7.800 1.59319 67.9 22 -56.63371 d22 1.00000 23 41.00682 8.500 1.59294 67.9 24* -263.44353 1.500 1.00000 25* 153.20964 3.400 1.77503 47.3 26 -446.79346 d26 1.00000 27 73.40773 3.700 1.59319 67.9 28 414.36052 0.600 1.00000 29 159.89589 4.050 1.94594 17.98 0.6546 30 -123.71520 1.400 1.78880 28.4 31 40.21812 4.736 1.00000 32* 163.14988 2.000 1.64000 60.2 33 88.13823 d33 1.00000 34 0.00000 1.600 1.51680 64.1 35 0.00000 d35 1.00000 Image plane∞ (Aspheric surface) Noodles A4 A6 A8 A10 3 1.00000e+00 6.31025e-07 6.01128e-09 -7.00080e-12 4.94121e-15 A12 A14 A16 5.49440e-18 0.00000e+00 0.00000e+00 Noodles A4 A6 A8 A10 4 1.00000e+00 -2.42300e-06 6.11478e-09 -1.60003e-11 1.69209e-14 A12 A14 A16 1.50070e-19 -6.58830e-21 0.00000e+00 Noodles A4 A6 A8 A10 24 1.00000e+00 -1.43351e-05 3.34550e-08 -7.62713e-11 1.35374e-13 A12 A14 A16 -1.30420e-16 1.13830e-19 -1.19990e-22 Surface κ A4 A6 A8 A10 25 1.00000e+00 -1.79382e-05 2.36564e-08 -7.97619e-11 2.49238e-13 A12 A14 A16 -5.59850e-16 9.43110e-19 -7.80130e-22 Surface κ A4 A6 A8 A10 32 1.00000e+00 -6.81826e-06 -1.47672e-08 2.49282e-11 -1.47376e-13 A12 A14 A16 0.00000e+00 0.00000e+00 0.00000e+00 (Lens group focal length) Lens group First surface Last surface Group focal length A 1 17 64.576 AF 1 8 -22.834 AR 9 17 32.322 B 19 33 62.718 F1 19 22 -215.011 F2 23 26 44.312 R 27 33 -124.887 (variable interval data) Infinity Close range d0∞250.44 Magnification - -0.1000 f 28.60 - d18 16.909 11.330 d22 2.000 4.393 d26 2.000 5.185 d33 11.890 11.890 d35 1.00 1.00

[0137] FIGS. 8 and 9 are diagrams showing various aberrations in the optical system of Example 3 when focused at infinity and when focused at a close distance, respectively, and it is clear that the various aberrations are well corrected, providing excellent imaging performance.

[0138] (Fourth Example) FIG. 10 is a cross-sectional view of an optical system according to the fourth embodiment. The optical system according to this embodiment is composed of, in order from the object side, a front group A having positive refractive power, an aperture stop S, and a rear group B having positive refractive power.

[0139] The front group A is composed of, in order from the object side, an object-side subgroup AF and an image-side subgroup AR. Here, the object-side subgroup AF is composed of a negative lens L11 having a meniscus lens shape with a convex surface facing the object side, a negative lens L12 having a meniscus lens shape with a convex surface facing the object side, a positive lens L13 having a meniscus lens shape with a convex surface facing the object side, and a biconcave negative lens L14, while the image-side subgroup AR is composed of a cemented negative lens obtained by cementing together a biconvex positive lens L15, a biconvex positive lens L16, a biconvex positive lens L17, a biconvex positive lens L18, and a biconcave negative lens L19. The rear group B is composed of, in order from the object side, a first focusing lens group F1, a second focusing lens group F2, and a final lens group R. Here, the first focusing lens group F1 is composed of a biconcave negative lens L21 and a biconvex positive lens L22, the second focusing lens group F2 is composed of a biconvex positive lens L31 and a positive lens L32 having a meniscus lens shape with a convex surface facing the object side, and the final lens group R is composed of a positive lens L41 having a meniscus lens shape with a convex surface facing the object side, a cemented negative lens in which a biconvex positive lens L42 and a biconcave negative lens L43 are cemented together, and a positive lens L44 having a meniscus lens shape with a convex surface facing the object side. A filter group FL including a low-pass filter and the like is disposed between the rear group B and the image surface I. An image sensor (not shown) including a CCD, a CMOS, or the like is disposed on the image surface I.

[0140] In this optical system, in the front group A, the positive lenses L15, L16, L17, and L18 are configured as four positive lenses arranged in succession, the negative lens L14 is the negative lens Ln1 adjacent to the object side of the four positive lenses and is a negative lens component Pn1, the positive lens L15 is a lens H that satisfies conditional expressions (1) and (2) and is the positive lens L1 closest to the object side of the four positive lenses, and the positive lens L16 is the positive lens L2 that is second closest to the object side of the four positive lenses, the negative lens L19 is a negative lens Ln2 which is located closest to the image side in the front group and satisfies the conditional expressions (11) and (12), and is also a negative lens component Pn2 which is adjacent to the image side of the four positive lenses; the image side surface of the negative lens L11 is a lens surface having a radius of curvature R1 with a minimum absolute value among the lenses L11, L12, and L13 whose image side surfaces are convex surfaces facing the object side and are located on the object side of the negative lens Ln1, The object side surface of the negative lens L14 is the lens surface having the smallest absolute radius of curvature R2 among the lens L14 whose object side surface is concave toward the object side among the lenses closer to the object side than the negative lens Ln1. In the rear group B, the positive lenses L22, L31, L32, L41, and L42 are configured as four or more consecutive positive lenses, and the positive lens L42 is a lens Lp that satisfies the conditional expressions (14) and (15).

[0141] In this optical system, focusing from infinity to a close object point is performed by moving the first focusing lens group F1 and the second focusing lens group F2 toward the object side by different amounts along the optical axis.

[0142] This optical system forms an image on an image plane I for photography. Figure 10 shows the optical system and its image plane I. Table 4 below shows the values ​​of each parameter in the fourth embodiment.

[0143] (Table 4) Fourth Example (Basic specifications) f 28.50 FNo 1.22 ω 38.8 Y 21.70 TL 164.499 TLa (air equivalent length) 163.954 BF 12.690 BFa (air equivalent length) 12.145 (surface data) Surface number rd nd νd θgF 0 (physical surface) ∞ (variable) 1 170.49804 2.500 1.69680 55.5 2 29.27481 10.959 1.00000 3* 110.71148 3.000 1.61272 58.5 4* 39.51925 2.678 1.00000 5 53.82829 5.800 1.92119 24.0 6 287.12309 12.222 1.00000 7 -36.39661 2.100 1.61266 44.5 8 599.79898 4.541 1.00000 9 489.55803 8.300 1.81600 46.6 10 -73.33850 0.200 1.00000 11 135.06512 9.300 1.60300 65.4 12 -80.46070 0.400 1.00000 13 63.80553 6.900 1.59349 67.0 14 -8151.39820 0.200 1.00000 15 104.41165 10.600 1.59319 67.9 16 -46.35547 1.600 1.72047 34.7 0.5834 17 61.63025 5.400 1.00000 18 (aperture) ∞ d18 1.00000 19 -37.87171 1.500 1.72047 34.7 20 276.38209 0.200 1.00000 21 72.45345 6.900 1.59319 67.9 22 -79.49410 d22 1.00000 23 44.19973 8.000 1.59324 67.9 24* -9999.90000 2.612 1.00000 25* 63.99327 3.750 1.77503 47.3 26 1000.00000 d26 1.00000 27 80.00000 3.950 1.59349 67.0 28 700.00000 0.660 1.00000 29 635.46960 8.876 1.94594 17.98 0.6546 30 -88.72079 1.400 1.73800 32.3 31 39.40012 4.301 1.00000 32* 92.86676 2.000 1.61272 58.5 33 120.00000 d33 1.00000 34 0.00000 1.600 1.51680 64.1 35 0.00000 d35 1.00000 Image plane∞ (Aspheric surface) Noodles A4 A6 A8 A10 3 1.00000e+00 -2.04731e-06 4.80777e-09 -7.21986e-12 9.58260e-15 A12 A14 A16 -5.17530e-18 0.00000e+00 0.00000e+00 Noodles A4 A6 A8 A10 4 1.00000e+00 -5.23690e-06 3.69844e-09 -1.14861e-11 1.68089e-14 A12 A14 A16 -1.36780e-17 -1.71140e-23 0.00000e+00 Noodles A4 A6 A8 A10 24 1.00000e+00 -1.87921e-05 4.00680e-08 -6.80576e-11 7.85544e-14 A12 A14 A16 -4.00850e-17 0.00000e+00 0.00000e+00 Noodles A4 A6 A8 A10 25 1.00000e+00 -2.02511e-05 2.40591e-08 -6.02929e-11 1.32924e-13 A12 A14 A16 -1.89800e-16 1.37580e-19 0.00000e+00 Noodles A4 A6 A8 A10 32 1.00000e+00 -8.48123e-06 -4.64343e-10 -4.03053e-12 -6.82114e-14 A12 A14 A16 0.00000e+00 0.00000e+00 0.00000e+00 (レンズ group focus distance) Focus distance of the starting and ending surfaces of the レンズ group A 1 17 77.591 AF 1 8 -24.479 AR 9 17 33.939 B 19 33 54.867 F1 19 22 -189.866 F2 23 26 42.212 R 27 33 -172.832 (Can change the interval) Infinitely far to short distances d0∞250.46 Magnification - -0.1000 f 28.50 - d18 16.960 11.517 d22 2.000 4.248 d26 2.000 5.195 d33 10.090 10.090 d35 1.00 1.00

[0144] FIGS. 11 and 12 are diagrams showing various aberrations in the optical system of Example 4 when focused on infinity and when focused on a close distance, respectively, and it is clear that the various aberrations are well corrected, providing excellent imaging performance.

[0145] (Fifth Example) FIG. 13 is a cross-sectional view of an optical system according to the fifth embodiment. The optical system according to this embodiment is composed of, in order from the object side, a front group A having positive refractive power, an aperture stop S, and a rear group B having positive refractive power.

[0146] The front group A is composed of, in order from the object side, an object side subgroup AF and an image side subgroup AR. Here, the object side subgroup AF is composed of a negative lens L11 having a meniscus lens shape with a convex surface facing the object side, a negative lens L12 having a meniscus lens shape with a convex surface facing the object side, a negative lens L13 having a meniscus lens shape with a concave surface facing the object side, a biconvex positive lens L14, and a biconcave negative lens L15, while the image side subgroup AR is composed of a cemented negative lens obtained by cementing together a biconvex positive lens L16, a biconvex positive lens L17, a biconvex positive lens L18, a biconvex positive lens L19, and a biconcave negative lens L110. The rear group B is composed of, in order from the object side, a first focusing lens group F1, a second focusing lens group F2, and a final lens group R. Here, the first focusing lens group F1 is composed of a biconcave negative lens L21 and a biconvex positive lens L22, the second focusing lens group F2 is composed of a positive lens L31 having a meniscus lens shape with a convex surface facing the object side and a biconvex positive lens L32, and the final lens group R is composed of a biconvex positive lens L41, a cemented negative lens in which a positive lens L42 having a meniscus lens shape with a concave surface facing the object side and a biconcave negative lens L43 are cemented together, and a negative lens L44 having a meniscus lens shape with a convex surface facing the object side. A filter group FL including a low-pass filter and the like is disposed between the rear group B and the image surface I. An image sensor (not shown) including a CCD, a CMOS, or the like is disposed on the image surface I.

[0147] In this optical system, in the front group A, the positive lenses L16, L17, L18, and L19 are configured as four positive lenses arranged in succession, the negative lens L15 is the negative lens Ln1 adjacent to the object side of the four positive lenses and is a negative lens component Pn1, the positive lens L16 is a lens H that satisfies conditional expressions (1) and (2) and is the positive lens L1 closest to the object side of the four positive lenses, and the positive lens L17 is the positive lens L2 that is second closest to the object side of the four positive lenses, the negative lens L110 is a negative lens Ln2 which is located closest to the image side in the front group and satisfies the conditional expressions (11) and (12), and is also a negative lens component Pn2 which is adjacent to the image side of the four positive lenses; the image side surface of the negative lens L11 is a lens surface having a radius of curvature R1 with a minimum absolute value among the lenses L11 and L12 whose image side surfaces are convex surfaces facing the object side and are located on the object side of the negative lens Ln1, The object side surface of the negative lens L15 is the lens surface having the smallest absolute radius of curvature R2 among the lenses L13 and L15 whose object side surfaces are concave toward the object side and are located closer to the object side than the negative lens Ln1. In the rear group B, the positive lenses L22, L31, L32, L41, and L42 are configured as four or more consecutive positive lenses, and the positive lens L42 is a lens Lp that satisfies the conditional expressions (14) and (15).

[0148] In this optical system, focusing from infinity to a close object point is performed by moving the first focusing lens group F1 and the second focusing lens group F2 toward the object side by different amounts along the optical axis.

[0149] This optical system forms an image on an image plane I for photography. Figure 13 shows the optical system and its image plane I. Table 5 below shows the values ​​of each parameter in the fifth embodiment.

[0150] (Table 5) Fifth Example (Basic specifications) f 24.39 FNo 1.23 ω 42.1 Y 21.70 TL 163.825 TLa (air equivalent length) 163.280 BF 15.490 BFa (air equivalent length) 14.945 (surface data) Surface number rd nd νd θgF 0 (physical surface) ∞ (variable) 1 144.55417 2.400 1.72000 43.6 2* 31.70862 5.846 1.00000 3* 60.86790 2.500 1.55880 62.6 4* 33.44110 17.783 1.00000 5 -86.15073 2.500 1.56873 63.1 6 -303.66747 0.200 1.00000 7 166.41315 5.000 2.00069 25.5 8 -217.57038 16.031 1.00000 9 -36.82698 2.100 1.73800 32.3 10 1368.87490 0.200 1.00000 11 290.40404 7.700 1.95375 32.3 12 -65.53286 0.300 1.00000 13 111.98900 7.800 1.62230 53.2 14 -103.10538 0.200 1.00000 15 73.98183 6.500 1.59349 67.0 16 -409.27743 0.200 1.00000 17 452.73626 9.591 1.59319 67.9 18 -41.83981 1.600 1.68376 37.6 0.5782 19 197.76229 5.641 1.00000 20 (aperture) ∞ d20 1.00000 21 -38.28154 1.500 1.77047 29.7 22 80.80380 0.200 1.00000 23 47.67016 8.400 1.59319 67.9 24 -54.41613 d24 1.00000 25 36.30814 7.600 1.59294 67.9 26* 172.75198 1.500 1.00000 27* 83.94122 3.750 1.77503 47.3 28 -432.42745 d28 1.00000 29 270.66041 3.250 1.59319 67.9 30 -154.33103 0.750 1.00000 31 -380.35780 4.050 1.94594 17.98 0.6546 32 -55.20065 1.400 1.78880 28.4 33 56.72273 2.973 1.00000 34* 100.13558 2.000 1.72000 46.0 35* 76.97941 d35 1.00000 36 0.00000 1.600 1.51680 64.1 37 0.00000 d37 1.00000 Image plane∞ (Aspheric surface) Noodles A4 A6 A8 A10 2 1.00000e+00 -1.38342e-06 3.22917e-09 -2.68150e-13 1.78669e-15 A12 A14 A16 2.27710e-18 -5.44780e-21 0.00000e+00 Noodles A4 A6 A8 A10 3 1.00000e+00 4.24991e-06 2.01111e-09 -1.68348e-12 4.61501e-15 A12 A14 A16 0.00000e+00 0.00000e+00 0.00000e+00 Noodles A4 A6 A8 A10 4 1.00000e+00 2.96606e-06 -3.38508e-09 -8.02733e-12 1.00700e-14 A12 A14 A16 0.00000e+00 0.00000e+00 0.00000e+00 Noodles A4 A6 A8 A10 26 1.00000e+00 -1.81031e-05 2.01610e-08 -7.80479e-11 2.35954e-13 A12 A14 A16 -2.61450e-16 1.99340e-19 -2.48530e-22 Noodles A4 A6 A8 A10 27 1.00000e+00 -2.15278e-05 9.52732e-09 -1.00835e-10 3.88493e-13 A12 A14 A16 -6.09930e-16 7.11230e-19 -6.21660e-22 Noodles A4 A6 A8 A10 34 1.00000e+00 -1.30542e-05 -9.04198e-09 2.72141e-11 -1.15956e-13 A12 A14 A16 0.00000e+00 0.00000e+00 0.00000e+00 Noodles A4 A6 A8 A10 35 1.00000e+00 -1.03940e-06 -1.15972e-08 3.12115e-11 0.00000e+00 A12 A14 A16 0.00000e+00 0.00000e+00 0.00000e+00 (レンズ group focus distance) Focus distance of the starting and ending surfaces of the レンズ group A 1 19 45.212 AF 1 10 -17.9237 AR 11 19 28.8618 B 21 35 70.846 F1 21 24 -201.632 F2 25 28 43.416 R 29 35 -106.160 (Can change the interval) Infinitely far to short distances d0 ∞ 211.22 Magnification - -0.1000 f 24.39 - d20 12.870 9.426 d24 2.000 2.944 d28 2.000 4.500 d35 12.890 12.890 d37 1.00 1.00

[0151] 14 and 15 are diagrams showing various aberrations in the optical system of Example 5 when focused on infinity and when focused on a close distance, respectively, and it is clear that the various aberrations are well corrected, providing excellent imaging performance.

[0152] (Sixth Example) FIG. 16 is a cross-sectional view of an optical system according to the sixth example. The optical system according to this embodiment is composed of, in order from the object side, a front group A having positive refractive power, an aperture stop S, and a rear group B having positive refractive power.

[0153] The front group A is composed of, in order from the object side, an object side subgroup AF and an image side subgroup AR. Here, the object side subgroup AF is composed of a negative lens L11 having a meniscus lens shape with a convex surface facing the object side, a negative lens L12 having a meniscus lens shape with a convex surface facing the object side, a positive lens L13 having a meniscus lens shape with a convex surface facing the object side, and a biconcave negative lens L14, while the image side subgroup AR is composed of a cemented negative lens obtained by cementing together a biconvex positive lens L15, a biconvex positive lens L16, a positive lens L17 having a meniscus lens shape with a convex surface facing the object side, a biconvex positive lens L18, and a biconcave negative lens L19. The rear group B is composed of, in order from the object side, a first focusing lens group F1, a second focusing lens group F2, and a final lens group R. Here, the first focusing lens group F1 is composed of a biconcave negative lens L21 and a biconvex positive lens L22, the second focusing lens group F2 is composed of a biconvex positive lens L31 and a positive lens L32 having a meniscus lens shape with a convex surface facing the object side, and the final lens group R is composed of a cemented negative lens obtained by cementing together a positive lens L41 having a meniscus lens shape with a convex surface facing the object side and a negative lens L42 having a meniscus lens shape with a convex surface facing the object side, and a negative lens L43 having a meniscus lens shape with a convex surface facing the object side. A filter group FL including a low-pass filter and the like is disposed between the rear group B and the image surface I. An image sensor (not shown) including a CCD, a CMOS, or the like is disposed on the image surface I.

[0154] In this optical system, in the front group A, the positive lenses L15, L16, L17, and L18 are configured as four positive lenses arranged in succession, the negative lens L14 is the negative lens Ln1 adjacent to the object side of the four positive lenses and is a negative lens component Pn1, the positive lens L15 is a lens H that satisfies conditional expressions (1) and (2) and is the positive lens L1 closest to the object side of the four positive lenses, and the positive lens L16 is the positive lens L2 that is second closest to the object side of the four positive lenses, the negative lens L19 is a negative lens Ln2 which is located closest to the image side in the front group and satisfies conditional expressions (11) and (12), and is also a negative lens component Pn2 which is adjacent to the image side of the four positive lenses; the image side surface of the negative lens L11 is a lens surface having a radius of curvature R1 with a minimum absolute value among the lenses L11, L12, and L13 whose image side surfaces are convex surfaces facing the object side and are located on the object side of the negative lens Ln1, The object side surface of the negative lens L14 is the lens surface having the smallest absolute radius of curvature R2 among the lens L14 whose object side surface is concave toward the object side among the lenses closer to the object side than the negative lens Ln1. In the rear group B, the positive lenses L22, L31, L32, and L41 are configured as four or more positive lenses arranged in succession, and the positive lens L41 is a lens Lp that satisfies the conditional expressions (14) and (15).

[0155] In this optical system, focusing from infinity to a close object point is performed by moving the first focusing lens group F1 and the second focusing lens group F2 toward the object side by different amounts along the optical axis.

[0156] This optical system forms an image on an image plane I for photography. Figure 16 shows the optical system and its image plane I. Table 6 below shows the values ​​of each parameter in the sixth embodiment.

[0157] (Table 6) Sixth Example (Basic specifications) f 33.48 FNo 1.22 ω 33.9 Y 21.70 TL 164.000 TLa (air equivalent length) 163.455 BF 12.690 BFa (air equivalent length) 12.145 (surface data) Surface number rd nd νd θgF 0 (physical surface) ∞ (variable) 1 210.82772 2.500 1.69680 55.5 2 33.18005 9.190 1.00000 3* 83.08187 3.000 1.61272 58.5 4* 41.01510 2.650 1.00000 5 53.57468 5.800 1.92119 24.0 6 132.63622 17.503 1.00000 7 -35.50068 2.100 1.61266 44.5 8 227.36543 0.200 1.00000 9 209.42166 11.000 1.81600 46.6 10 -58.38005 0.200 1.00000 11 87.52767 9.300 1.60300 65.4 12 -118.73652 0.400 1.00000 13 55.14739 6.900 1.59349 67.0 14 271.82097 0.200 1.00000 15 89.61503 10.600 1.59319 67.9 16 -57.30063 1.600 1.72047 34.7 0.5834 17 50.71691 5.400 1.00000 18 (aperture) d18 1.00000 19 -37.78291 1.500 1.72047 34.7 20 1862.86170 0.200 1.00000 21 63.57223 6.900 1.59319 67.9 22 -94.02816 d22 1.00000 23 44.19973 8.000 1.59324 67.9 24* -9999.90000 2.487 1.00000 25* 63.75757 3.750 1.77503 47.3 26 1000.00000 d26 1.00000 27 99.60630 9.592 1.94594 17.98 0.6546 28 322.06906 1.400 1.73800 32.3 29 38.45669 5.439 1.00000 30* 404.64424 2.000 1.61272 58.5 31 220.76060 d31 1.00000 32 0.00000 1.600 1.51680 64.1 33 0.00000 d33 1.00000 Image plane ∞ (aspheric data) Surface κ A4 A6 A8 A10 3 1.00000e+00 -2.47861e-06 4.69808e-09 -6.51605e-12 8.01734e-15 A12 A14 A16 -3.92250e-18 0.00000e+00 0.00000e+00 Noodles A4 A6 A8 A10 4 1.00000e+00 -4.67804e-06 4.42676e-09 -1.07067e-11 1.69121e-14 A12 A14 A16 -1.50450e-17 4.23300e-21 0.00000e+00 Noodles A4 A6 A8 A10 24 1.00000e+00 -1.62031e-05 3.39042e-08 -5.24473e-11 4.92187e-14 A12 A14 A16 -1.61020e-17 0.00000e+00 0.00000e+00 Noodles A4 A6 A8 A10 25 1.00000e+00 -1.94884e-05 2.13646e-08 -6.51585e-11 1.83670e-13 A12 A14 A16 -3.28680e-16 2.74500e-19 0.00000e+00 Noodles A4 A6 A8 A10 30 1.00000e+00 -6.83615e-06 7.14674e-09 -1.17773e-11 -3.39255e-14 A12 A14 A16 0.00000e+00 0.00000e+00 0.00000e+00 (レンズ group focus distance) Focus distance of the starting and ending surfaces of the レンズ group A 1 17 82.003 AF 1 8 -22.675 AR 9 17 29.084 B 19 31 62.515 F1 19 22 -309.624 F2 23 26 42.106 R 27 31 -94.725 (variable interval data) Infinity Close range d0∞296.70 Magnification - -0.1000 f 33.48 - d18 17.499 12.196 d22 2.000 4.230 d26 2.000 5.073 d31 10.090 10.099 d33 1.000 1.000

[0158] 17 and 18 are diagrams showing various aberrations in the optical system of Example 6 when focused on infinity and when focused on a close distance, respectively, and it is clear that the various aberrations are well corrected, providing excellent imaging performance.

[0159] (Seventh Example) FIG. 19 is a cross-sectional view of an optical system according to the seventh example. The optical system according to this embodiment is composed of, in order from the object side, a front group A having positive refractive power, an aperture stop S, and a rear group B having positive refractive power.

[0160] The front group A is composed of, in order from the object side, an object side subgroup AF and an image side subgroup AR. Here, the object side subgroup AF is composed of a negative lens L11 having a meniscus lens shape with a convex surface facing the object side, a negative lens L12 having a meniscus lens shape with a convex surface facing the object side, a positive lens L13 having a meniscus lens shape with a convex surface facing the object side, and a biconcave negative lens L14, while the image side subgroup AR is composed of a positive lens L15 having a meniscus lens shape with a convex surface facing the object side, a biconvex positive lens L16, a biconvex positive lens L17, a biconvex positive lens L18, a biconvex positive lens L19, a cemented negative lens formed by cementing together a biconcave negative lens L110, and a negative lens L111 having a meniscus lens shape with a convex surface facing the object side. The rear group B is composed of, in order from the object side, a first focusing lens group F1, a second focusing lens group F2, and a final lens group R. Here, the first focusing lens group F1 is composed of a biconcave negative lens L21 and a biconvex positive lens L22, the second focusing lens group F2 is composed of a biconvex positive lens L31 and a positive lens L32 having a meniscus lens shape with a convex surface facing the object side, and the final lens group R is composed of a positive lens L41 having a meniscus lens shape with a convex surface facing the object side, a cemented negative lens in which a positive lens L42 having a meniscus lens shape with a concave surface facing the object side and a biconcave negative lens L43 are cemented together, and a positive lens L44 having a meniscus lens shape with a convex surface facing the object side. A filter group FL including a low-pass filter and the like is disposed between the rear group B and the image surface I. An image sensor (not shown) including a CCD, a CMOS, or the like is disposed on the image surface I.

[0161] In this optical system, in the front group A, the positive lenses L15, L16, L17, L18, and L19 are configured as five positive lenses arranged in succession, the negative lens L14 is the negative lens Ln1 adjacent to the object side of the five positive lenses and is a negative lens component Pn1, the positive lens L15 is the positive lens L1 closest to the object side of the five positive lenses, and the positive lens L16 is a lens H that satisfies conditional expressions (1) and (2) and is the second positive lens L2 closest to the object side of the five positive lenses, each of the negative lens L110 and the negative lens L111 is a negative lens Ln2 located closest to the image side of the front group and satisfying conditional expressions (11) and (12); the negative lens L110 and the negative lens L111 are a negative lens component Pn2 adjacent to the image side of the five positive lenses; the image side surface of the negative lens L11 is a lens surface having a radius of curvature R1 with a minimum absolute value among the lenses L11, L12, and L13 whose image side surfaces are convex surfaces facing the object side and are located on the object side of the negative lens Ln1, The object side surface of the negative lens L14 is the lens surface having the smallest absolute radius of curvature R2 among the lens L14 whose object side surface is concave toward the object side among the lenses closer to the object side than the negative lens Ln1. In the rear group B, the positive lenses L22, L31, L32, L41, and L42 are configured as four or more consecutive positive lenses, and the positive lens L42 is a lens Lp that satisfies the conditional expressions (14) and (15).

[0162] In this optical system, focusing from infinity to a close object point is performed by moving the first focusing lens group F1 and the second focusing lens group F2 toward the object side by different amounts along the optical axis.

[0163] This optical system forms an image on an image plane I for photography. Figure 19 shows the optical system and its image plane I. Table 7 below shows the values ​​of each parameter in the seventh embodiment.

[0164] (Table 7) Seventh Example (Basic specifications) f 28.46 FNo 1.24 ω 38.8 Y 21.70 TL 165.500 TLa (air equivalent length) 164.955 BF 12.690 BFa (air equivalent length) 12.145 (surface data) Surface number rd nd νd θgF 0 (physical surface) ∞ (variable) 1 134.90429 2.000 1.69680 55.5 2 29.72126 11.500 1.00000 3* 122.15694 2.000 1.61272 58.5 4* 37.87462 2.816 1.00000 5 50.63575 7.316 1.92119 24.0 6 205.39946 14.096 1.00000 7 -37.40676 2.100 1.61266 44.5 8 173.45353 2.605 1.00000 9 176.04972 3.700 1.51680 63.9 10 6658.57150 0.100 1.00000 11 543.27396 7.000 1.81600 46.6 12 -75.95006 0.100 1.00000 13 141.76902 8.500 1.60300 65.4 14 -82.89415 0.100 1.00000 15 68.78476 6.800 1.59349 67.0 16 -618.83899 0.100 1.00000 17 113.63572 10.600 1.59319 67.9 18 -45.18884 1.400 1.72047 34.7 0.5834 19 100.43894 0.679 1.00000 20 108.39657 1.000 1.55298 55.1 0.5447 21 69.25382 4.118 1.00000 22 (aperture) d22 1.00000 23 -37.14717 1.500 1.72047 34.7 24 266.15734 0.200 1.00000 25 81.24190 6.900 1.59319 67.9 26 -71.06552 d26 1.00000 27 44.19973 8.000 1.59324 67.9 28* -9999.90000 2.715 1.00000 29* 62.11703 3.750 1.77503 47.3 30 1000.00000 d30 1.00000 31 80.00000 3.950 1.59349 67.0 32 700.00000 0.660 1.00000 33 -617.22219 8.498 1.94594 17.98 0.6546 34 -64.36163 1.400 1.73800 32.3 35 44.03335 3.985 1.00000 36* 103.59912 2.000 1.61272 58.5 37 120.00000 d37 1.00000 38 0.00000 1.600 1.51680 64.1 39 0.00000 d39 1.00000 Image plane∞ (Aspheric surface) Noodles A4 A6 A8 A10 3 1.00000e+00 -2.19012e-06 4.73369e-09 -6.66155e-12 7.96263e-15 A12 A14 A16 -4.00810e-18 0.00000e+00 0.00000e+00 Noodles A4 A6 A8 A10 4 1.00000e+00 -4.92249e-06 3.84270e-09 -1.17279e-11 1.92546e-14 A12 A14 A16 -1.91120e-17 5.17280e-21 0.00000e+00 Noodles A4 A6 A8 A10 28 1.00000e+00 -2.08093e-05 4.46361e-08 -7.32040e-11 8.20207e-14 A12 A14 A16 -4.14720e-17 0.00000e+00 0.00000e+00 Noodles A4 A6 A8 A10 29 1.00000e+00 -2.14644e-05 2.53592e-08 -5.79901e-11 1.27212e-13 A12 A14 A16 -1.87380e-16 1.41430e-19 0.00000e+00 Surface κ A4 A6 A8 A10 36 1.00000e+00 -8.14733e-06 3.79286e-09 -1.71338e-11 -3.89973e-14 A12 A14 A16 0.00000e+00 0.00000e+00 0.00000e+00 (Lens group focal length) Lens group First surface Last surface Group focal length A12168.987 AF 1 8 -22.337 AR 9 21 31.527 B 23 37 58.193 F1 23 26 -177.493 F2 27 30 41.662 R 31 37 -144.039 (variable interval data) Infinity Close range d0∞248.47 Magnification - -0.1000 f 28.46 - d22 16.622 11.263 d26 2.000 4.224 d30 2.000 5.135 d37 10.090 10.090 d39 1.000 1.000

[0165] 20 and 21 are diagrams showing various aberrations in the optical system of Example 7 when focused on infinity and when focused on a close distance, respectively, and it is clear that the various aberrations are well corrected, providing excellent imaging performance.

[0166] According to each of the above embodiments, various aberrations can be effectively corrected from an infinity-object-focused state to a close-object-focused state, and in particular, when focusing, the fluctuation of these aberrations is reduced from an infinity-object-focused state to a close-object-focused state, making it possible to realize a large-aperture optical system suitable for both autofocus and manual focus.

[0167] Next, a table of [Values ​​Corresponding to Conditional Expressions] is shown below. In this table, values ​​corresponding to each of the conditional expressions (1) to (17) are shown for all the examples (Examples 1 to 7). Condition (1) 1.650 <nH<2.100 Condition (2) 25.00<νH<60.00 Conditional expression (3) -0.50<(R2+R1) / (R2-R1)<0.50 Conditional expression (4) 0.40<|R2| / (n2×f)<1.20 Condition (5) 0.60 <fPn1 / fPn2<2.50 Condition (6) 0.100 <nHM-nLm<0.450 Condition (7) 1.450 <n34<1.700 Conditional expression (8) 50.00<ν34<85.00 Condition (9) 0.30 <fA / fB<3.00 Condition (10) 1.50 <fA / f<5.00 Conditional expression (11) 0.600<θgFLn2+0.0021×νdLn2<0.663 Conditional expression (12) 25.00<νdLn2<60.00 Condition (13): 0.00 <fF2 / |fF1|<0.50 Conditional expression (14) 0.670<θgFLp+0.0021×νdLp Conditional expression (15) 15.00<νdLp<35.00 Condition (16) 0.40<-fAF / fAR<2.00 Conditional expression (17) -1.00<(R22+R21) / (R22-R21)<1.00

[0168] [Conditional expression corresponding value] Conditional Expression 1st Example 2nd Example 3rd Example 4th Example (1) 1.95375(L15) 1.77250(L15) 1.95375(L15) 1.81600(L15) (2) 32.3(L15) 49.6(L15) 32.3(L15) 46.6(L15) (3) 0.108(L11,14) 0.054(L11,14) 0.117(L11,14) 0.108(L11,14) (4) 0.646(L14) 0.656(L14) 0.762(L14) 0.792(L14) (5) 1.445(L14,19) 1.569(L14,19) 1.340(L14,19) 1.533(L14,19) (6) 0.36056(L15,18) 0.17931(L15,18) 0.36056(L15,18) 0.22281(L15,18) (7) 1.59349(L17) 1.59349(L17) 1.59349(L17) 1.59349(L17) 1.59319(L18) 1.59319(L18) 1.59319(L18) 1.59319(L18) (8) 67.0(L17) 67.0(L17) 67.0(L17) 67.0(L17) 67.9(L18) 67.9(L18) 67.9(L18) 67.9(L18) (9) 1.566 1.242 1.030 1.414 (10) 2.796 2.241 2.258 2.723 (11) 0.657(L19) 0.656(L19) 0.657(L19) 0.656(L19) (12) 32.3(L19) 47.3((L19) 32.3((L19) 34.7((L19) (13) 0.204 0.277 0.206 0.222 (14) 0.692(L42) 0.692(L42) 0.692(L42) 0.692(L42) (15) 17.98(L42) 17.98(L42) 17.98(L42) 17.98(L42) (16) 0.786 0.822 0.706 0.721 (17) 0.000(L16) 0.080(L16) 0.047(L16) -0.253(L16) Conditional Expression 5th Example 6th Example 7th Example (1) 1.95375(L16) 1.81600(L15) 1.81600(L16) (2) 32.3(L16) 46.6(L15) 46.6(L16) (3) 0.075(L11,15) 0.034(L11,14) 0.115(L11,14) (4) 0.869(L15) 0.658(L14) 0.815(L14) (5) 0.964(L15,110) 1.346(L14,19) 1.314(L14,110,111) (6) 0.36056(L16,19) 0.223(L15,18) 0.223(L16,19) (7) 1.59349(L18) 1.59349(L17) 1.60300(L17) 1.59319(L19) 1.59319(L18) 1.59349(L18) (8) 67.0(L18) 67.0(L17) 65.4(L17) 67.9(L19) 67.9(L18) 67.0(L18) (9) 0.638 1.312 1.185 (10) 1.853 2.449 2.424 (11) 0.657(L110) 0.656(L19) 0.656(L110),0.6604(L111) (12) 37.6(L110) 34.7((L19) 34.7((L110),55.1(L111) (13) 0.215 0.136 0.235 (14) 0.692(L42) 0.692(L41) 0.692(L42) (15) 17.98(L42) 17.98(L41) 17.98(L42) (16) 0.621 0.780 0.708 (17) -0.041(L17) 0.151(L16) -0.755(L16) However, in the above conditional expressions, (L15) etc. following the numerical values ​​are the lens numbers corresponding to those numerical values. [Explanation of symbols]

[0169] OL optical equipment A front group B rear group S aperture stop I image plane FL Filter Group F1 First focusing lens group F2 2nd focusing lens group R The last lens group in the rear group

Claims

1. the lens comprises, in order from the object side, a front group having positive refractive power, a stop, and a rear group having positive refractive power as a whole, the front group having at least four positive lenses arranged in succession, A negative lens Ln1 is disposed adjacent to the object side of the at least four positive lenses, and one or more lenses are disposed further toward the object side, An optical system having a lens H, at least one of the at least four positive lenses satisfying the following conditional expression: 1.650 < nH < 2.100 25.00 < νH < 60.00 however, nH: refractive index of the lens H with respect to the d line νH: Abbe number of the lens H with respect to the d line

2. 2. The optical system according to claim 1 , wherein, in the negative lens Ln1 and one or more lenses further to the object side, when a radius of curvature having a smallest absolute value among lens surfaces whose image side surface is convex toward the object side is R1 and a radius of curvature having a smallest absolute value among lens surfaces whose object side surface is concave toward the object side is R2, the lens surface having R1 is closer to the object side than the lens surface having R2, and the following conditional expression is satisfied: -0.50 < (R2+R1) / (R2-R1) < 0.50

3. 3. The optical system according to claim 1, wherein in the negative lens Ln1 and one or more lenses further to the object side, the radius of curvature with the smallest absolute value among lens surfaces whose object-side surface is concave toward the object side is R2, the refractive index of the lens having R2 with respect to the d-line is n2, and the focal length of the entire system when photographing at infinity is f, the following conditional expression is satisfied: 0.40 < |R2| / (n2×f) < 1.20

4. The optical system according to any one of claims 1 to 3, wherein the front group has a negative lens component Pn1 adjacent to the object side of the at least four positive lenses, and a negative lens component Pn2 adjacent to the image side of the at least four positive lenses, and the optical system satisfies the following conditional expression: 0.60 < fPn1 / fPn2 < 2.50 however, fPn1: focal length of the negative lens component Pn1 fPn2: focal length of the negative lens component Pn2 Incidentally, the negative lens component refers to a single negative lens or a combination of a plurality of negative lenses.

5. 5. The optical system according to claim 1, wherein the lens H is the first or second lens closest to the object side among the at least four positive lenses.

6. 6. The optical system according to claim 1, wherein the at least four positive lenses satisfy the following formula: 0.100<nHM-nLm<0.450 however, nHM: the maximum value of the refractive index for the d-line of the at least four positive lenses nLm: the minimum value of the refractive index for the d-line of the at least four positive lenses

7. The optical system according to any one of claims 1 to 6, wherein the refractive index n34 for the d-line and the Abbe number ν34 for the d-line of the third and fourth lenses from the object side among the at least four positive lenses each satisfy the following conditional expressions: 1.450 < n34 < 1.700 50.00 < ν34 < 85.00

8. 8. The optical system according to claim 1, wherein the rear group has a configuration in which at least four positive lenses are arranged in succession.

9. 9. The optical system according to claim 1, which satisfies the following condition: 0.5030 < fA / fB < 3.000 however, fA: focal length of the front group when shooting at infinity fB: focal length of the rear group when shooting at infinity

10. 10. The optical system according to claim 1, which satisfies the following condition: 1.500 < fA / f < 5.000 however, fA: focal length of the front group when shooting at infinity f: focal length of the entire system when shooting at infinity

11. 11. The optical system according to claim 1, wherein one or both of the lens closest to the object side and the lens closest to the image side are negative lenses.

12. 12. The optical system according to claim 11, wherein one or both of the second lens closest to the object side and the second lens closest to the image side are negative lenses.

13. The optical system according to any one of claims 1 to 12, wherein the rear group includes at least four consecutive positive lenses, and negative lenses arranged adjacent to the object side and image side of the at least four positive lenses of the rear group.

14. 14. The optical system according to claim 1, further comprising a negative lens component located closest to the image side of the front group, at least one of the negative lens components being a negative lens Ln2 that satisfies the following condition: 0.600 < θgFLn2+0.0021×νdLn2 < 0.663 however, νdLn2: Abbe number of the negative lens Ln2 with respect to the d line θgFLn2: partial dispersion ratio of the negative lens Ln2 by the g-line and the F-line Incidentally, the negative lens component refers to a single negative lens or a combination of a plurality of negative lenses.

15. 15. The optical system according to claim 1, further comprising a negative lens component located closest to the image side of the front group, at least one of the negative lens components being a negative lens Ln2 that satisfies the following condition: 25.00 < νdLn2 < 57.0060.00 however, νdLn2: Abbe number of the negative lens Ln2 with respect to the d line Incidentally, the negative lens component refers to a single negative lens or a combination of a plurality of negative lenses.

16. 16. The optical system according to claim 1, wherein, during focusing, the front group is fixed, and the rear group comprises a plurality of focusing lens groups which move on the optical axis by mutually different amounts of movement.

17. The optical system according to any one of claims 1 to 16, comprising a first focusing lens group F1 and a second focusing lens group F2, the front group being fixed and the rear group being moved on the optical axis by mutually different amounts of movement during focusing, and satisfying the following conditional expression: 0.00 < fF2 / |fF1| < 0.50 however, fF1: focal length of the first focusing lens group F1 fF2: focal length of the second focusing lens group F2

18. 18. The optical system according to claim 1, wherein the rear group has a final lens group closest to the image side.

19. 19. The optical system according to claim 1, wherein the rear group has at least one positive lens Lp that satisfies the following condition: 0.670 < θgFLp+0.0021×νdLp 15.00 < νdLp < 35.00 however, νdLp: Abbe number of the positive lens Lp with respect to the d line θgFLp: partial dispersion ratio of the positive lens Lp by the g-line and the F-line

20. The optical system according to any one of claims 1 to 19, wherein, in the front group, of at least four consecutive positive lenses, a positive lens L1 closest to the object side to a lens closest to the image side in the front group is defined as an image side subgroup AR, and all lenses on the object side of the image side subgroup AR are defined as an object side subgroup AF, the following conditional expression is satisfied: 0.40 < -fAF / fAR < 2.00 however, fAF: focal length of the object-side subgroup AF of the front group fAR: focal length of the image-side subgroup AR of the front group

21. 21. The optical system according to claim 1, wherein, of the at least four consecutive positive lenses in the front group, the positive lens closest to the image side is cemented with a negative lens.

22. 22. The optical system according to claim 1, wherein, of the at least four consecutive positive lenses in the front group, a second positive lens L2 from the object side satisfies the following conditional expression: 1 / 2 n<L2 / 2 n<L2 / 2. -1.00 <(R22+R21) / (R22-R21) < 1.00 however, R21: the radius of curvature of the object side surface of the second positive lens L2 on the object side R22: the radius of curvature of the image side surface of the second positive lens L2 on the object side

23. An optical instrument comprising the optical system according to any one of claims 1 to 22.

24. the lens comprises, in order from the object side, a front group having positive refractive power, a stop, and a rear group having positive refractive power as a whole, the front group having at least four positive lenses arranged in succession, A negative lens Ln1 is disposed adjacent to the object side of the at least four positive lenses, and one or more lenses are disposed further toward the object side, A method for manufacturing an optical system, comprising: configuring the optical system such that at least one of the at least four positive lenses includes a lens H that satisfies the following conditional expression: 1.650 < nH < 2.100 25.00 < νH < 60.00 however, nH: refractive index of the lens H with respect to the d line νH: Abbe number of the lens H with respect to the d line

Images