Department of Optics

Abstract

To provide an optical system in which glass material of lenses constituting each group are appropriately selected and disposed, and which therefore corrects various aberrations such as a chromatic aberration and furthermore achieves shortening of an entire length and diameter and reduction in weight of the optical system, and consequently has high-performance focus.SOLUTION: An optical system is comprised of, in order from an object side,: a first lens group G1 having negative refractive power; a second lens group G2 refractive power; a third lens group G3 having positive refractive power; a fourth lens group G4 having refractive power; and a fifth lens group G5 having refractive power, wherein upon focusing, at least the second lens group moves along an optical axis, an interval between the first lens group and second lens group varies, an interval between the second lens group and third lens group varies, the fourth lens group includes a lens having the positive refractive power and a lens having the negative refractive power, the fifth lens group includes a lens having the positive refractive power, and a lens having the negative refractive power, and has the lens having the refractive power or a doublet lens including the lens having the positive refractive power arranged on the most object side, and wherein the optical system satisfies a specific conditional expression.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to an optical system suitable for lenses used in imaging devices such as still cameras and video cameras, and projection devices, and is appropriately arranged to contribute to weight reduction while effectively correcting chromatic aberration. [Background technology]

[0002] 2. Description of the Related Art In recent years, with the trend toward higher pixel counts in digital cameras and the like, strict correction of various aberrations has become a requirement for the optical systems used.

[0003] Furthermore, in order to achieve high-speed and accurate focus driving and wobbling driving for contrast detection during autofocusing, it is desirable to reduce the weight of the parts that move during focus driving.

[0004] Therefore, in optical systems that have been proposed in the past, the groups from the object side to the aperture stop have been fixed during focus drive, and the focus group has been positioned on the image side of the stop, thereby reducing the weight of the focus group. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] International Publication No. 2019 / 073744 [Patent Document 2] Japanese Patent Application Laid-Open No. 2016-009170

[0006] Patent Document 1 proposes an inner-focus optical system that suppresses various aberrations by appropriately specifying the configuration of the lens group that moves during focusing. However, the optical system described in Patent Document 1 is prone to color flare due to misalignment of the image point along the optical axis from the C-line to the F-line from the intermediate angle of view to the periphery of the image, and also has the problem that the weight of the drive parts tends to be heavy when used in an optical system with a large aperture ratio.

[0007] Patent Document 2 proposes an optical system that has a large aperture ratio but reduces the weight of the lenses that move during focusing. However, the optical system described in Patent Document 2 has problems such as insufficient correction of axial chromatic aberration and lateral chromatic aberration in addition to color flare, making it prone to sagittal coma flare. Summary of the Invention [Problem to be solved by the invention]

[0008] The object of the present invention is to provide an optical system with high-performance focusing, which achieves a reduction in overall length and diameter and weight while correcting various aberrations such as chromatic aberration, by appropriately selecting and arranging the glass materials of the lenses that make up each group. [Means for solving the problem]

[0009] A first invention, which is a means for solving the above-mentioned problem, comprises, in order from the object side, a first lens group G1 having negative refractive power, a second lens group G2 having positive or negative refractive power, a third lens group G3 having positive refractive power, a fourth lens group G4 having positive or negative refractive power, and a fifth lens group G5 having positive or negative refractive power, wherein at least the second lens group G2 moves along the optical axis during focusing, and simultaneously the distance between the first lens group G1 and the second lens group G2 changes, and simultaneously the distance between the second lens group G2 and the third lens group G3 changes, the fourth lens group G4 includes a lens having positive refractive power and a lens having negative refractive power, and the fifth lens group G5 includes a lens having positive refractive power and a lens having negative refractive power, The first lens group G1 includes a structure in which a meniscus lens having negative refractive power with a convex surface facing from the object side to the object side, a lens having negative refractive power, and a lens having positive refractive power are arranged in this order, and the fifth lens group G5 has an aspherical surface in which the positive refractive power becomes weaker or the negative refractive power becomes stronger from the center of the optical axis to the periphery. The following conditional expressions (1) to (4) are satisfied: 、(16) The optical system is characterized by satisfying the following. (1)ΔθgF_G4P > 0.000 (2)VD_GF4P > 50.00 (3)ΔθgF_G5P > 0.000 (4) VD_GF5P < 40.00 (16)nd_G5P > 1.8500 however, ΔθgF_G4P: g-line of the lens having positive refractive power that constitutes the fourth lens group G4; Average deviation of partial dispersion ratio ΔθgF for F-line The deviation ΔθgF of the partial dispersion ratio for the g-line and F-line is the partial dispersion ratio for each lens. If the dispersion ratio is θgF and the Abbe number at the d line is VD, ΔθgF=θgF-(0.648285-0.00180123×VD) is calculated as VD_GF4P: the average value of the Abbe numbers at the d-line of the lenses having positive refractive power that constitute the fourth lens group G4 ΔθgF_G5P: the average value of the deviation ΔθgF of the partial dispersion ratio for the g-line and the F-line of the lens having a positive refractive power that constitutes the fifth lens group G5 VD_GF5P: the average value of the Abbe numbers at the d-line of the lenses having positive refractive power that constitute the fifth lens group G5 nd_G5P: the average value of the refractive index at the d line of the lenses having positive refractive power that constitute the fifth lens group G5 The second invention is a lens system that is configured, in order from the object side, with a first lens group G1 having negative refractive power, a second lens group G2 having positive or negative refractive power, a third lens group G3 having positive refractive power, a fourth lens group G4 having positive or negative refractive power, and a fifth lens group G5 having positive or negative refractive power, and at the time of focusing, at least the second lens group G2 moves along the optical axis, and at the same time, the distance between the first lens group G1 and the second lens group G2 changes, and at the same time, the second lens group G2 and the third lens group G3, the fourth lens group G4 includes a lens having positive refractive power and a lens having negative refractive power, the fifth lens group G5 includes a lens having positive refractive power and a lens having negative refractive power, the fifth lens group G5 has an aspherical surface such that the positive refractive power becomes weaker or the negative refractive power becomes stronger from the center of the optical axis to the periphery, and the optical system satisfies the following conditional expressions (1) to (4), (12), and (16): (1)ΔθgF_G4P > 0.000 (2)VD_GF4P > 50.00 (3)ΔθgF_G5P > 0.000 (4) VD_GF5P < 40.00 (12)ΔθgF_G3P > ―0.005 (16)nd_G5P > 1.8500 however, ΔθgF_G4P: g-line of the lens having positive refractive power that constitutes the fourth lens group G4; Average deviation of partial dispersion ratio ΔθgF for F-line The deviation ΔθgF of the partial dispersion ratio for the g-line and F-line is the partial dispersion ratio for each lens. If the dispersion ratio is θgF and the Abbe number at the d line is VD, ΔθgF=θgF-(0.648285-0.00180123×VD) is calculated as VD_GF4P: the average value of the Abbe numbers at the d-line of the lenses having positive refractive power that constitute the fourth lens group G4 ΔθgF_G5P: the average value of the deviation ΔθgF of the partial dispersion ratio for the g-line and the F-line of the lens having a positive refractive power that constitutes the fifth lens group G5 VD_GF5P: the average value of the Abbe numbers at the d-line of the lenses having positive refractive power that constitute the fifth lens group G5 ΔθgF_G3P: the average value of the deviation ΔθgF of the partial dispersion ratio for the g-line and the F-line of the lens having a positive refractive power that constitutes the third lens group G3 nd_G5P: the average value of the refractive index at the d line of the lenses having positive refractive power that constitute the fifth lens group G5 A third invention is a lens system that includes, in order from the object side, a first lens group G1 having negative refractive power, a second lens group G2 having positive or negative refractive power, a third lens group G3 having positive refractive power, a fourth lens group G4 having positive or negative refractive power, and a fifth lens group G5 having positive or negative refractive power, and at the time of focusing, at least the second lens group G2 moves along the optical axis, and at the same time, the distance between the first lens group G1 and the second lens group G2 changes, and at the same time, the second lens group G2 and the third lens group G3, the fourth lens group G4 includes a lens having positive refractive power and a lens having negative refractive power, the fifth lens group G5 includes a lens having positive refractive power and a lens having negative refractive power, the fifth lens group G5 has an aspherical surface such that the positive refractive power becomes weaker or the negative refractive power becomes stronger from the center of the optical axis to the periphery, and the optical system satisfies the following conditional expressions (1) to (4), (13), and (16): (1)ΔθgF_G4P > 0.000 (2)VD_GF4P > 50.00 (3)ΔθgF_G5P > 0.000 (4) VD_GF5P < 40.00 (13)ΔθgF_G4N < 0.010 (16)nd_G5P > 1.8500 however, ΔθgF_G4P: g-line of the lens having positive refractive power that constitutes the fourth lens group G4; Average deviation of partial dispersion ratio ΔθgF for F-line The deviation ΔθgF of the partial dispersion ratio for the g-line and F-line is the partial dispersion ratio for each lens. If the dispersion ratio is θgF and the Abbe number at the d line is VD, ΔθgF=θgF-(0.648285-0.00180123×VD) is calculated as VD_GF4P: the average value of the Abbe numbers at the d-line of the lenses having positive refractive power that constitute the fourth lens group G4 ΔθgF_G5P: the average value of the deviation ΔθgF of the partial dispersion ratio for the g-line and the F-line of the lens having a positive refractive power that constitutes the fifth lens group G5 VD_GF5P: the average value of the Abbe numbers at the d-line of the lenses having positive refractive power that constitute the fifth lens group G5 ΔθgF_G4N: the average value of the deviation ΔθgF of the partial dispersion ratio for the g-line and the F-line of the lens having negative refractive power that constitutes the fourth lens group G4 nd_G5P: the average value of the refractive index at the d line of the lenses having positive refractive power that constitute the fifth lens group G5 A fourth invention is a lens system that is configured, in order from the object side, with a first lens group G1 having negative refractive power, a second lens group G2 having positive or negative refractive power, a third lens group G3 having positive refractive power, a fourth lens group G4 having positive or negative refractive power, and a fifth lens group G5 having positive or negative refractive power, and at the time of focusing, at least the second lens group G2 moves along the optical axis, and at the same time, the distance between the first lens group G1 and the second lens group G2 changes, and at the same time, the second lens group G2 and the third lens group G3, the fourth lens group G4 includes a lens having positive refractive power and a lens having negative refractive power, the fifth lens group G5 includes a lens having positive refractive power and a lens having negative refractive power, the fifth lens group G5 has an aspherical surface such that the positive refractive power becomes weaker or the negative refractive power becomes stronger from the center of the optical axis to the periphery, and the optical system satisfies the following conditional expressions (1) to (4), (14), and (16): (1)ΔθgF_G4P > 0.000 (2)VD_GF4P > 50.00 (3)ΔθgF_G5P > 0.000 (4) VD_GF5P < 40.00 (14)ΔθgF_G5N < 0.005 (16)nd_G5P > 1.8500 however, ΔθgF_G4P: g-line of the lens having positive refractive power that constitutes the fourth lens group G4; Average deviation of partial dispersion ratio ΔθgF for F-line The deviation ΔθgF of the partial dispersion ratio for the g-line and F-line is the partial dispersion ratio for each lens. If the dispersion ratio is θgF and the Abbe number at the d line is VD, ΔθgF=θgF-(0.648285-0.00180123×VD) is calculated as VD_GF4P: the average value of the Abbe numbers at the d-line of the lenses having positive refractive power that constitute the fourth lens group G4 ΔθgF_G5P: the average value of the deviation ΔθgF of the partial dispersion ratio for the g-line and the F-line of the lens having a positive refractive power that constitutes the fifth lens group G5 VD_GF5P: the average value of the Abbe numbers at the d-line of the lenses having positive refractive power that constitute the fifth lens group G5 ΔθgF_G5N: the average value of the deviation ΔθgF of the partial dispersion ratio for the g-line and the F-line of the lens having negative refractive power that constitutes the fifth lens group G5 nd_G5P: the average value of the refractive index at the d line of the lenses having positive refractive power that constitute the fifth lens group G5 A fifth invention is a lens system that includes, in order from the object side, a first lens group G1 having negative refractive power, a second lens group G2 having positive or negative refractive power, a third lens group G3 having positive refractive power, a fourth lens group G4 having positive or negative refractive power, and a fifth lens group G5 having positive or negative refractive power, and at the time of focusing, at least the second lens group G2 moves along the optical axis, and at the same time, the distance between the first lens group G1 and the second lens group G2 changes, and at the same time, the second lens group G2 and the third lens group G3, the fourth lens group G4 includes a lens having positive refractive power and a lens having negative refractive power, the fifth lens group G5 includes a lens having positive refractive power and a lens having negative refractive power, the fifth lens group G5 has an aspherical surface such that the positive refractive power becomes weaker or the negative refractive power becomes stronger from the center of the optical axis to the periphery, and the optical system satisfies the following conditional expressions (1) to (4), (15), and (16): (1)ΔθgF_G4P > 0.000 (2)VD_GF4P > 50.00 (3)ΔθgF_G5P > 0.000 (4) VD_GF5P < 40.00 (15)nd_G1P > 1.8500 (16)nd_G5P > 1.8500 however, ΔθgF_G4P: g-line of the lens having positive refractive power that constitutes the fourth lens group G4; Average deviation of partial dispersion ratio ΔθgF for F-line The deviation ΔθgF of the partial dispersion ratio for the g-line and F-line is the partial dispersion ratio for each lens. If the dispersion ratio is θgF and the Abbe number at the d line is VD, ΔθgF=θgF-(0.648285-0.00180123×VD) is calculated as VD_GF4P: the average value of the Abbe numbers at the d-line of the lenses having positive refractive power that constitute the fourth lens group G4 ΔθgF_G5P: the average value of the deviation ΔθgF of the partial dispersion ratio for the g-line and the F-line of the lens having a positive refractive power that constitutes the fifth lens group G5 VD_GF5P: the average value of the Abbe numbers at the d-line of the lenses having positive refractive power that constitute the fifth lens group G5 nd_G1P: the average value of the refractive index at the d line of the lenses having positive refractive power that constitute the first lens group G1 nd_G5P: the average value of the refractive index at the d line of the lenses having positive refractive power that constitute the fifth lens group G5 A sixth aspect of the present invention is a zoom lens that is configured, in order from the object side, with a first lens group G1 having negative refractive power, a second lens group G2 having positive or negative refractive power, a third lens group G3 having positive refractive power, a fourth lens group G4 having positive or negative refractive power, and a fifth lens group G5 having positive or negative refractive power, wherein at least the second lens group G2 moves along the optical axis during focusing, and at the same time, the distance between the first lens group G1 and the second lens group G2 changes, and at the same time, the distance between the second lens group G2 and the third lens group G5 changes. The optical system is characterized in that the distance between the fourth lens group G4 and the fifth lens group G5 varies, the fourth lens group G4 includes a lens having positive refractive power and a lens having negative refractive power, the fifth lens group G5 includes a lens having positive refractive power and a lens having negative refractive power, the fourth lens group G4 has one or more pairs of cemented lenses whose cemented surface faces the object side in a convex manner and whose refractive index of the medium on the object side is higher than that of the medium on the image plane side, and satisfies the following conditional expressions (1) to (4), (12), and (15): (1)ΔθgF_G4P > 0.000 (2)VD_GF4P > 50.00 (3)ΔθgF_G5P > 0.000 (4) VD_GF5P < 40.00 (12)ΔθgF_G3P > ―0.005 (15)nd_G1P > 1.8500 however, ΔθgF_G4P: g-line of the lens having positive refractive power that constitutes the fourth lens group G4; Average deviation of partial dispersion ratio ΔθgF for F-line The deviation ΔθgF of the partial dispersion ratio for the g-line and F-line is the partial dispersion ratio for each lens. If the dispersion ratio is θgF and the Abbe number at the d line is VD, ΔθgF=θgF-(0.648285-0.00180123×VD) is calculated as VD_GF4P: the average value of the Abbe numbers at the d-line of the lenses having positive refractive power that constitute the fourth lens group G4 ΔθgF_G5P: the average value of the deviation ΔθgF of the partial dispersion ratio for the g-line and the F-line of the lens having a positive refractive power that constitutes the fifth lens group G5 VD_GF5P: the average value of the Abbe numbers at the d-line of the lenses having positive refractive power that constitute the fifth lens group G5 ΔθgF_G3P: the average value of the deviation ΔθgF of the partial dispersion ratio for the g-line and the F-line of the lens having a positive refractive power that constitutes the third lens group G3 nd_G1P: the average value of the refractive index at the d line of the lenses having positive refractive power that constitute the first lens group G1

[0010] Also, 7 The invention of the first Any of the above to the sixth The invention is further characterized in that the groups other than the second lens group G2 are fixed relative to the image plane during focusing.

[0012] Also, 8 The invention is the first to second 6 In any one of the above-mentioned inventions, the optical system is characterized by satisfying the following conditional expression: (10) VD_G1P < 40.00 (11)ΔθgF_G1N > ―0.010 (12)ΔθgF_G3P > ―0.005 (13)ΔθgF_G4N < 0.010 (14)ΔθgF_G5N < 0.005 (15)nd_G1P > 1.8500 (16)nd_G5P > 1.8500 however, VD_G1P: the average value of the Abbe numbers at the d-line of the lenses having positive refractive power that constitute the first lens group G1 ΔθgF_G1N: the average value of the deviation ΔθgF of the partial dispersion ratio for the g-line and the F-line of the lens having negative refractive power that constitutes the first lens group G1 ΔθgF_G3P: the average value of the deviation ΔθgF of the partial dispersion ratio for the g-line and the F-line of the lens having a positive refractive power that constitutes the third lens group G3 ΔθgF_G4N: the average value of the deviation ΔθgF of the partial dispersion ratio for the g-line and the F-line of the lens having negative refractive power that constitutes the fourth lens group G4 ΔθgF_G5N: the average value of the deviation ΔθgF of the partial dispersion ratio for the g-line and the F-line of the lens having negative refractive power that constitutes the fifth lens group G5 nd_G1P: the average value of the refractive index at the d line of the lenses having positive refractive power that constitute the first lens group G1 nd_G5P: the average value of the refractive index at the d line of the lenses having positive refractive power that constitute the fifth lens group G5

[0013] No. 9 The invention is 2 to the first 6 In any one of the above-mentioned inventions, the optical system is characterized in that the first lens group G1 includes a configuration in which a meniscus lens having negative refractive power with a convex surface facing from the object side to the object side, a lens having negative refractive power, and a lens having positive refractive power are arranged in this order.

[0014] Also, 10 The present invention is an optical system according to any one of the first to fifth inventions, further characterized in that the fourth lens group G4 includes one or more pairs of cemented lenses whose cemented surface faces the object side in a convex manner, and whose refractive index of the medium on the object side is higher than that of the medium on the image plane side.

[0015] Also, 11 The invention of Sixth The present invention is also directed to an optical system in which the fifth lens group G5 has an aspherical surface in which the positive refractive power becomes weaker or the negative refractive power becomes stronger from the center of the optical axis to the periphery.

[0016] Also, 12 The invention is the first to second 6 In any one of the above-mentioned inventions, the optical system is further characterized in that the second lens group G2 is composed of two or less lenses. [Effects of the Invention]

[0017] According to the present invention, by appropriately selecting and arranging the glass materials of the lenses that make up each group, it is possible to provide an optical system that has high-performance focusing, while achieving a reduction in overall length and diameter and a reduction in weight, and correcting various aberrations such as chromatic aberration. [Brief explanation of the drawings]

[0018] [Figure 1] Lens cross-sectional view of the optical system of Example 1 at infinity [Figure 2]Longitudinal aberration diagram at infinity for the optical system of Example 1 [Figure 3] Longitudinal aberration diagram of the optical system of Example 1 at a shooting distance of 249 mm [Figure 4] Transverse aberration diagram at infinity of the optical system of Example 1 [Figure 5] Transverse aberration diagram of the optical system of Example 1 at a shooting distance of 249 mm [Figure 6] Lens cross-sectional view of the optical system of Example 2 at infinity [Figure 7] Longitudinal aberration diagram at infinity for the optical system of Example 2 [Figure 8] Longitudinal aberration diagram of the optical system of Example 2 at a shooting distance of 250 mm [Figure 9] Transverse aberration diagram at infinity for the optical system of Example 2 [Figure 10] Transverse aberration diagram of the optical system of Example 2 at a shooting distance of 250 mm [Figure 11] Lens cross-sectional view of the optical system of Example 3 at infinity [Figure 12] Longitudinal aberration diagram at infinity for the optical system of Example 3 [Figure 13] Longitudinal aberration diagram of the optical system of Example 3 at a shooting distance of 248 mm [Figure 14] Transverse aberration diagram at infinity for the optical system of Example 3 [Figure 15] Lateral aberration diagram of the optical system of Example 3 at a shooting distance of 248 mm [Figure 16] Lens cross-sectional view of the optical system of Example 4 at infinity [Figure 17] Longitudinal aberration diagram at infinity for the optical system of Example 4 [Figure 18] Longitudinal aberration diagram of the optical system of Example 4 at a shooting distance of 245 mm [Figure 19] Transverse aberration diagram at infinity for the optical system of Example 4 [Figure 20] Transverse aberration diagram of the optical system of Example 4 at a shooting distance of 245 mm [Figure 21] 10 is a cross-sectional view of a lens at infinity at the wide-angle end of a variable magnification optical system according to a fifth embodiment. [Figure 22]Longitudinal aberration diagram at infinity at the wide-angle end of the variable magnification optical system of Example 5 [Figure 23] Longitudinal aberration diagram of the variable magnification optical system of Example 5 at infinity at an intermediate focal length [Figure 24] Longitudinal aberration diagram at infinity at the telephoto end of the variable magnification optical system of Example 5 [Figure 25] Transverse aberration diagram at infinity at the wide-angle end of the variable magnification optical system of Example 5 [Figure 26] Transverse aberration diagram of the variable magnification optical system of Example 5 at infinity at the intermediate focal length [Figure 27] Transverse aberration diagram at infinity at the telephoto end of the variable magnification optical system of Example 5 [Figure 28] Lens cross section at infinity of the optical system of Example 6 [Figure 29] Longitudinal aberration diagram at infinity for the optical system of Example 6 [Figure 30] Longitudinal aberration diagram of the optical system of Example 6 at a shooting distance of 226 mm [Figure 31] Transverse aberration diagram at infinity for the optical system of Example 6 [Figure 32] Transverse aberration diagram of the optical system of Example 6 at a shooting distance of 226 mm [Figure 33] Lens cross section at infinity of the optical system of Example 7 [Figure 34] Longitudinal aberration diagram at infinity for the optical system of Example 7 [Figure 35] Longitudinal aberration diagram of the optical system of Example 7 at a shooting distance of 227 mm [Figure 36] Transverse aberration diagram at infinity for the optical system of Example 7 [Figure 37] Lateral aberration diagram of the optical system of Example 7 at a shooting distance of 227 mm [Figure 38] Lens cross section at infinity of the optical system of Example 8 [Figure 39] Longitudinal aberration diagram at infinity for the optical system of Example 8 [Figure 40] Longitudinal aberration diagram of the optical system of Example 8 at a shooting distance of 225 mm [Figure 41] Transverse aberration diagram at infinity for the optical system of Example 8 [Figure 42] Transverse aberration diagram of the optical system of Example 8 at a shooting distance of 225 mm DETAILED DESCRIPTION OF THE INVENTION

[0019] Examples of the optical system according to the present invention will be described in detail below. Note that the following examples are merely examples of the optical system according to the present invention, and the present invention is not limited to these examples within the scope of the gist of the present invention.

[0020] When counting the number of lenses in this specification, unless otherwise specified, a single lens is counted as one lens, and in the case of a cemented lens, each of the single lenses constituting the cemented lens is counted as one lens. For example, a cemented lens consisting of a convex lens and a concave lens is counted as two lenses.

[0021] As can be seen from the lens configuration diagrams shown in Figures 1, 6, 11, 16, 21, 28, 33, and 38, the optical system of the present invention is composed of, in order from the object side, a first lens group G1 having negative refractive power, a second lens group G2 having positive or negative refractive power, a third lens group G3 having positive refractive power, a fourth lens group G4 having positive or negative refractive power, and a fifth lens group G5 having positive or negative refractive power, and at the time of focusing, at least the second lens group G2 moves along the optical axis, and at the same time, the The distance between the first lens group G1 and the second lens group G2 varies, and at the same time, the distance between the second lens group G2 and the third lens group G3 varies; the fourth lens group G4 includes a lens having positive refractive power and a lens having negative refractive power; the fifth lens group G5 includes a lens having positive refractive power and a lens having negative refractive power; and a cemented lens including a lens having positive refractive power or a lens having positive refractive power is disposed closest to the object of the fifth lens group G5.

[0022] The present invention aims to provide an optical system that achieves compactness while correcting various aberrations such as chromatic aberration, and therefore it is important to appropriately select the glass materials for the lenses that make up each lens group.

[0023] Particularly in wide-angle to standard optical systems, a known method for simultaneously correcting axial chromatic aberration and lateral chromatic aberration is to use glass materials with small wavelength dispersion of the refractive index on the image plane side of the aperture stop and large anomalous dispersion on the short wavelength side near the g-line in lenses with positive refractive power. However, since many of these glass materials have a low refractive index, they work against the control of field curvature. Furthermore, even if axial chromatic aberration and lateral chromatic aberration can be corrected, it has been difficult to correct flare caused by short-wavelength light rays on the periphery of the image.

[0024] Therefore, by dividing the lens group closer to the image plane than the aperture stop into a fourth lens group G4 on the object side and a fifth lens group G5 on the image plane side, and arranging lenses with positive refractive power and lenses with negative refractive power in each group, and by appropriately setting the dispersion characteristics of each lens with positive refractive power, it becomes possible to simultaneously correct axial chromatic aberration, chromatic aberration of magnification, and flare around the edges of the image, while also suppressing field curvature and the like.

[0025] Furthermore, by arranging the first lens group G1, the second lens group G2, and the third lens group G3 in this order from the closest to the object side of the aperture, and by designating the second lens group G2 as the group that is driven during focusing, there is no need to ensure space for focusing on the aperture image plane side, and it is possible to maximize the ability to correct the chromatic aberration described above.

[0026] Furthermore, the optical system of the present invention is characterized in that it satisfies the following conditional expression: (1)ΔθgF_G4P > 0.000 (2)VD_GF4P > 50.00 (3)ΔθgF_G5P > 0.000 (4) VD_GF5P < 40.00 ΔθgF_G4P: the average value of the deviation ΔθgF of the partial dispersion ratio for the g-line and the F-line of the lens having a positive refractive power constituting the fourth lens group G4 The deviation ΔθgF of the partial dispersion ratio for the g-line and F-line for each lens is given by θgF, and the Abbe number for the d-line is given by VD. ΔθgF=θgF-(0.648285-0.00180123×VD) is calculated as VD_GF4P: the average value of the Abbe numbers at the d-line of the lenses having positive refractive power that constitute the fourth lens group G4 ΔθgF_G5P: the average value of the deviation ΔθgF of the partial dispersion ratio for the g-line and the F-line of the lens having a positive refractive power that constitutes the fifth lens group G5 VD_GF5P: the average value of the Abbe numbers at the d-line of the lenses having positive refractive power that constitute the fifth lens group G5 It is calculated as:

[0027] Conditional formula (1) defines a preferable range for the partial dispersion ratio for the g-line and F-line of the lens having positive refractive power that constitutes the fourth lens group G4.

[0028] If the lower limit of conditional formula (1) is exceeded and the average value of the deviation ΔθgF of the partial dispersion ratios for the g-line and F-line of the lenses having positive refractive power that make up the fourth lens group G4 becomes small, it becomes difficult to correct axial chromatic aberration within the fourth lens group G4.

[0029] Conditional expression (2) defines a preferable range for the Abbe number at the d-line of the lens having positive refractive power that constitutes the fourth lens group G4.

[0030] If the lower limit of conditional expression (2) is exceeded and the average Abbe number at the d-line of the lenses having positive refractive power that make up the fourth lens group G4 becomes small, it becomes difficult to select a glass material that exhibits large anomalous dispersion on the short wavelength side near the g-line for the lenses having positive refractive power that make up the fourth lens group G4. It also becomes difficult to correct color flare that occurs from the shift in the image point along the optical axis from the C-line to the F-line from the intermediate angle of view to the periphery of the image field.

[0031] Furthermore, by setting the lower limit of conditional expression (2) to 55.00, the effects of the present invention can be achieved more reliably.

[0032] Conditional formula (3) defines a preferable range for the partial dispersion ratio for the g-line and F-line of the lens having positive refractive power that constitutes the fifth lens group G5.

[0033] If the lower limit of conditional expression (3) is exceeded and the average value of the deviation ΔθgF of the partial dispersion ratios for the g-line and the F-line of the lenses having positive refractive power that make up the fifth lens group G5 becomes small, it becomes difficult to correct chromatic aberration of magnification for the g-line within the fifth lens group G5.

[0034] Conditional expression (4) defines a preferable range for the Abbe number at the d-line of the lens having positive refractive power that constitutes the fifth lens group G5.

[0035] If the upper limit of conditional expression (4) is exceeded and the average Abbe number at the d-line of the lenses having positive refractive power that make up the fifth lens group G5 becomes large, it becomes difficult to select a glass material with a large refractive index for the lenses having positive refractive power that make up the fifth lens group G5, making it difficult to correct curvature of field and also difficult to correct fluctuations in chromatic aberration of magnification for the C-line and F-line from the intermediate angle of view to the periphery of the image field.

[0036] Furthermore, by setting the upper limit of conditional expression (4) to 35.00, the effects of the present invention can be achieved more reliably.

[0037] In the optical system of the present invention, it is further desirable that the groups other than the second lens group G2 are fixed relative to the image plane during focusing.

[0038] By fixing the groups other than the second lens group G2 relative to the image plane during focusing, it is possible to simplify the mechanism that moves during focusing and reduce its weight.

[0039] It is also desirable that the optical system of the present invention satisfy the following conditional expression: (5)-1.50 < f / f1 < 0.00 (6) 0.05 < f / |f2| < 0.75 (7) 0.10 < f / f3 < 1.20 (8)-1.00 < f / f4 < 1.00 (9)-1.00 < f / f5 < 1.00 however, f: focal length of the entire lens system when shooting at infinity In the case of a zoom lens, the focal length at the telephoto end f1: focal length of the first lens group G1 when shooting at infinity f2: the focal length of the second lens group G2 when shooting at infinity f3: The focal length of the third lens group G3 when shooting at infinity f4: The focal length of the fourth lens group G4 when shooting at infinity f5: The focal length of the fifth lens group G5 when shooting at infinity

[0040] Condition (5) defines a preferable range for the refractive power of the first lens group G1.

[0041] If the upper limit of conditional expression (5) is exceeded and the refractive power of the first lens group G1 becomes positive, it becomes difficult to ensure a sufficiently wide angle of view.

[0042] If the lower limit of conditional expression (5) is exceeded and the negative refractive power of the first lens group G1 becomes strong, the divergence of the emitted marginal light beam becomes strong, which increases the diameter of the light beam passing through the second lens group G2 and makes it difficult to reduce the weight of the parts that move during focusing.

[0043] Furthermore, by setting the lower limit of conditional expression (5) to -1.40, the effect of the present invention can be achieved more reliably. Furthermore, by setting the upper limit of conditional expression (5) to -0.05, the effect of the present invention can be achieved more reliably.

[0044] Condition (6) defines a preferable range for the refractive power of the second lens group G2.

[0045] If the upper limit of conditional expression (6) is exceeded and the absolute value of the refractive power of the second lens group G2 becomes too strong, it becomes difficult to suppress deterioration of aberrations due to decentering of the second lens group G2. Also, even a small amount of focus movement causes a large shift in the in-focus position on the image plane side, making precise focusing difficult.

[0046] If the lower limit of conditional expression (6) is exceeded and the absolute value of the refractive power of the second lens group G2 becomes weak, the distance that the second lens group G2 moves during focusing becomes long, making it difficult to increase the focusing speed and reduce the overall length.

[0047] Furthermore, by setting the lower limit of conditional expression (6) to 0.10, the effect of the present invention can be more reliably achieved, and by setting the upper limit of conditional expression (6) to 0.60, the effect of the present invention can be more reliably achieved.

[0048] Condition (7) defines a preferable range for the refractive power of the third lens group G3.

[0049] If the upper limit of conditional expression (7) is exceeded and the refractive power of the third lens group G3 becomes too strong, it becomes difficult to suppress various aberrations, such as spherical aberration, within the group.

[0050] If the lower limit of conditional expression (7) is exceeded and the refractive power of the third lens group G3 becomes weak, the effect of converging the light beam weakens, and the diameter of the light beam passing through the second lens group G2 and the aperture stop S increases, making it difficult to reduce the weight of the parts that move during focusing and to reduce the outer diameter of the product.

[0051] Furthermore, by setting the lower limit of conditional expression (7) to 0.15, the effect of the present invention can be more reliably achieved, and by setting the upper limit of conditional expression (7) to 1.00, the effect of the present invention can be more reliably achieved.

[0052] Conditional expression (8) defines a preferable range for the refractive power of the fourth lens group G4.

[0053] If the upper limit of conditional expression (8) is exceeded and the positive refractive power of the fourth lens group G4 becomes too strong, it becomes difficult to suppress various aberrations such as coma, and in addition, the height of light rays incident on the fifth lens group G5 at the periphery of the image plane becomes lower, making it impossible for the fifth lens group G5 to fully exert its function of suppressing chromatic aberration of magnification.

[0054] If the lower limit of conditional expression (8) is exceeded and the negative refractive power of the fourth lens group G4 becomes too strong, the light beam expands, making it difficult to reduce the size in the radial direction.

[0055] Furthermore, by setting the lower limit of conditional expression (8) to −0.90, the effect of the present invention can be achieved more reliably. Furthermore, by setting the upper limit of conditional expression (8) to 0.90, the effect of the present invention can be achieved more reliably.

[0056] Condition (9) defines a preferable range for the refractive power of the fifth lens group G5.

[0057] If the upper limit of conditional expression (9) is exceeded and the positive refractive power of the fifth lens group G5 becomes too strong, it becomes difficult to suppress various aberrations such as astigmatism.

[0058] If the lower limit of conditional expression (9) is exceeded and the negative refractive power of the fifth lens group G5 becomes too strong, the outermost angle rays will be strongly diverged, making it difficult to ensure sufficient back focus and telecentricity.

[0059] Furthermore, by setting the lower limit of conditional expression (9) to −0.90, the effect of the present invention can be achieved more reliably. Furthermore, by setting the upper limit of conditional expression (9) to 0.90, the effect of the present invention can be achieved more reliably.

[0060] It is also desirable that the optical system of the present invention satisfy the following conditional expression: (10) VD_G1P < 40.00 (11)ΔθgF_G1N > ―0.010 (12)ΔθgF_G3P > ―0.005 (13)ΔθgF_G4N < 0.010 (14)ΔθgF_G5N < 0.005 (15)nd_G1P > 1.8500 (16)nd_G5P > 1.8500 VD_G1P: the average value of the Abbe numbers at the d-line of the lenses having positive refractive power that constitute the first lens group G1 ΔθgF_G1N: the average value of the deviation ΔθgF of the partial dispersion ratio for the g-line and the F-line of the lens having negative refractive power that constitutes the first lens group G1 ΔθgF_G3P: the average value of the deviation ΔθgF of the partial dispersion ratio for the g-line and the F-line of the lens having a positive refractive power that constitutes the third lens group G3 ΔθgF_G4N: the average value of the deviation ΔθgF of the partial dispersion ratio for the g-line and the F-line of the lens having negative refractive power that constitutes the fourth lens group G4 ΔθgF_G5N: the average value of the deviation ΔθgF of the partial dispersion ratio for the g-line and the F-line of the lens having negative refractive power that constitutes the fifth lens group G5 nd_G1P: the average value of the refractive index at the d line of the lenses having positive refractive power that constitute the first lens group G1 nd_G5P: the average value of the refractive index at the d line of the lenses having positive refractive power that constitute the fifth lens group G5

[0061] Conditional expression (10) defines a preferable range for the Abbe number at the d-line of the lens having positive refractive power that constitutes the first lens group G1.

[0062] If the upper limit of conditional expression (10) is exceeded and the average Abbe number at the d-line of the lenses having positive refractive power that form the first lens group G1 becomes large, it becomes difficult to correct chromatic aberration of magnification.

[0063] Conditional expression (11) defines a preferable range for the deviation of the partial dispersion ratio for the g-line and the F-line of the lens having negative refractive power that constitutes the first lens group G1.

[0064] If the lower limit of conditional expression (11) is exceeded and the average value of the deviation ΔθgF of the partial dispersion ratios for the g-line and F-line of the lenses having negative refractive power that make up the first lens group G1 becomes small, it becomes difficult to correct chromatic aberration of magnification.

[0065] Conditional expression (12) defines a preferable range for the deviation of the partial dispersion ratio for the g-line and the F-line of the lens having positive refractive power that constitutes the third lens group G3.

[0066] If the lower limit of conditional expression (12) is exceeded and the average value of the deviation ΔθgF of the partial dispersion ratios for the g-line and the F-line of the lenses having positive refractive power that make up the third lens group G3 becomes small, it becomes difficult to correct axial chromatic aberration.

[0067] Condition (13) defines a preferable range for the deviation of the partial dispersion ratio for the g-line and the F-line of the lens having negative refractive power that constitutes the fourth lens group G4.

[0068] If the upper limit of conditional expression (13) is exceeded and the average value of the deviation ΔθgF of the partial dispersion ratios for the g-line and F-line of the lenses having negative refractive power that make up the fourth lens group G4 becomes large, it becomes difficult to correct axial chromatic aberration.

[0069] Conditional expression (14) defines a preferable range for the deviation of the partial dispersion ratio for the g-line and the F-line of the lens having negative refractive power that constitutes the fifth lens group G5.

[0070] If the upper limit of conditional expression (14) is exceeded and the average value of the deviation ΔθgF of the partial dispersion ratios for the g-line and the F-line of the lenses having negative refractive power that make up the fifth lens group G5 becomes large, it becomes difficult to correct axial chromatic aberration and chromatic aberration of magnification.

[0071] Conditional expression (15) defines a preferable range for the refractive index at the d-line of the lens having positive refractive power that constitutes the first lens group G1.

[0072] If the lower limit of conditional expression (15) is exceeded and the average value of the refractive index at the d-line of the lenses having positive refractive power that make up the first lens group G1 becomes large, it becomes difficult to correct various aberrations such as field curvature.

[0073] Conditional formula (16) defines a preferable range for the refractive index at the d-line of the lens having positive refractive power that constitutes the fifth lens group G5.

[0074] If the lower limit of conditional expression (16) is exceeded and the average value of the refractive index at the d-line of the lenses having positive refractive power that make up the fifth lens group G5 becomes large, it becomes difficult to correct various aberrations such as field curvature.

[0075] Furthermore, it is desirable that the optical system of the present invention further includes a configuration in which the first lens group G1 includes, in order from the object side, a meniscus lens having negative refractive power with its convex surface facing the object side, a lens having negative refractive power, and a lens having positive refractive power.

[0076] With this configuration, it is possible to accommodate a wide angle of view while suppressing distortion and astigmatism.

[0077] In the optical system of the present invention, it is desirable that the fourth lens group G4 further includes one or more cemented lenses whose cemented surface faces the object side in a convex manner and whose refractive index of the medium on the object side is higher than that of the medium on the image plane side.

[0078] By arranging one or more pairs of cemented lenses in the fourth lens group G4, whose cemented surface faces the object side in a convex manner and whose refractive index of the medium on the object side is higher than that of the medium on the image plane side, it is possible to suppress various aberrations such as coma and spherical aberration.

[0079] In the optical system of the present invention, it is further preferable that the fifth lens group G5 has an aspherical surface whose positive refractive power becomes weaker or whose negative refractive power becomes stronger from the center of the optical axis toward the periphery.

[0080] By having the aspherical surface of the above-mentioned shape in the fifth lens group G5, it is possible to suppress curvature of field and distortion.

[0081] Furthermore, in the optical system of the present invention, it is desirable that the second lens group G2 is composed of two or less lenses.

[0082] By adopting such a configuration, it is possible to reduce the weight of the parts that move during focusing.

[0083] Numerical examples of the optical system of the present invention and corresponding values ​​of the conditional expressions will be described below.

[0084] Next, the lens configurations of examples of the optical system of the present invention will be described. In the following description, the lens configurations will be described in order from the object side to the image plane side. Furthermore, the notation Ln in the examples indicates the nth lens from the object side.

[0085] In the [Surface Data] section, the surface number is the lens surface or aperture stop number counted from the object side, r is the radius of curvature of each lens surface, d is the spacing between each lens surface, nd is the refractive index for the d-line (wavelength 587.56 nm), vd is the Abbe number for the d-line, and θgF is the partial dispersion ratio between the g-line (wavelength 435.84 nm) and the F-line (wavelength 486.13 nm).

[0086] An asterisk (*) next to a surface number indicates that the lens surface is aspherical.

[0087] The (diaphragm) next to the surface number indicates that an aperture diaphragm is located at that position. The radius of curvature for the plane or aperture diaphragm is marked as ∞ (infinity).

[0088] [Aspherical Surface Data] shows the values ​​of each coefficient that determines the aspherical shape of lens surfaces marked with an * in [Surface Data]. The shape of an aspherical surface is expressed by the following formula. In the formula below, y represents the displacement from the optical axis in a direction perpendicular to the optical axis, z represents the displacement (sag) from the intersection of the aspherical surface and the optical axis toward the optical axis, r represents the radius of curvature of the reference sphere, and K represents the Conic coefficient. Additionally, A3, A4, A5, A6, A7, A8, A9, A10, A11, A12, A13, A14, A15, and A16 represent the aspherical coefficients of the 3rd, 4th, 5th, 6th, 7th, 8th, 9th, 10th, 11th, 12th, 13th, 14th, 15th, and 16th orders, respectively. TIFF0007747325000001.tif17122

[0089] [Various Data] shows values ​​such as focal length at each shooting distance and in focus state.

[0090] [Variable Distance Data] shows the variable distance and BF values ​​for each focusing distance.

[0091] [Lens Group Data] shows the surface number of each lens group closest to the object and the composite focal length of the entire group.

[0092] In the aberration diagrams corresponding to the respective examples, d, g, and C represent the d-line, g-line, and C-line, respectively, and ΔS and ΔM represent the sagittal image surface and meridional image surface, respectively.

[0093] In the following specification values, the focal length f, radius of curvature r, lens surface spacing d, and other length units are all in millimeters (mm) unless otherwise specified; however, this is not a limitation, as optical systems can achieve equivalent optical performance with proportional magnification and proportional reduction. [Example]

[0094] FIG. 1 is a diagram showing the lens configuration of an optical system according to a first embodiment of the present invention.

[0095] The first embodiment is composed of, in order from the object side, a first lens group G1 with negative refractive power, a second lens group G2 with positive refractive power, a third lens group G3 with positive refractive power, a fourth lens group G4 with negative refractive power, and a fifth lens group G5 with positive refractive power. An aperture stop S is disposed between the third lens group G3 and the fourth lens group G4.

[0096] The first lens group G1 is composed of, in order from the object side, a negative meniscus lens L1 with a convex surface facing the object side, a negative meniscus lens L2 with a convex surface facing the object side, a biconvex lens L3, a biconcave lens L4, and a positive meniscus lens L5 with a convex surface facing the object side, and the lens surfaces on both sides of the negative meniscus lens L1 and the positive meniscus lens L5 have a predetermined aspherical shape.

[0097] The second lens group G2 is composed only of a biconvex lens L6, and moves toward the image plane during focusing from an infinity object distance to a close distance.

[0098] The third lens group G3 is composed of, in order from the object side, a negative meniscus lens L7 with its convex surface facing the image side, a biconvex lens L8, and a cemented lens consisting of a biconvex lens L9 and a biconcave lens L10, and the lens surfaces on both sides of the biconvex lens L8 have a predetermined aspherical shape.

[0099] The fourth lens group G4 is composed of, in order from the object side, a cemented lens consisting of a biconvex lens L11 and a biconcave lens L12, and a cemented lens consisting of a negative meniscus lens L13 with its convex surface facing the object side and a positive meniscus lens L14 with its convex surface facing the object side.

[0100] The fifth lens group G5 is composed of, in order from the object side, a biconvex lens L15, a negative meniscus lens L16 with its convex surface facing the object side, and a biconcave lens L17, and the lens surfaces on both sides of the biconcave lens L17 have a predetermined aspherical shape.

[0101] The specifications of the optical system according to the first embodiment are shown below. Numerical Example 1 Unit: mm [Face Data] Surface number rd nd vd θgF Object surface ∞ (d0) 1* 161.4805 2.8015 1.58313 59.38 0.000922 2* 26.5270 2.7786 3 31.5334 1.5000 1.43700 95.10 0.056526 4 19.7048 9.4216 5 102.0441 3.2383 2.00069 25.46 0.011062 6 -444.8551 6.9281 7 -28.8940 1.0500 1.61340 44.27 -0.005289 8 74.0668 0.4500 9* 32.7524 3.0446 1.73077 40.50 -0.003978 10* 60.9305 (d10) 11 173.5602 5.9483 1.59349 67.00 0.008940 12 -34.1836 (d12) 13 -36.8596 0.9500 1.77047 29.74 0.000271 14 -173.8209 0.1500 15* 44.3951 6.8110 1.77250 49.50 -0.007316 16* -80.7953 0.1500 17 67.0933 3.8187 2.00100 29.13 0.003566 18 -237.0573 0.9500 1.61340 44.27 -0.005289 19 71.4524 3.3044 20 (Aperture) ∞ 1.4000 21 225.1592 7.2264 1.55032 75.50 0.027580 22 -22.5226 0.9000 1.85451 25.15 0.007183 23 93.2011 0.1500 24 40.7178 0.9000 1.77047 29.74 0.000271 25 23.0838 4.7828 1.43700 95.10 0.056526 26 99.7497 0.5000 27 47.5495 6.1520 2.00100 29.13 0.003566 28 -47.5495 0.1500 29 65.5334 0.9000 1.61340 44.27 -0.005289 30 35.4713 3.9899 31* -160.0000 1.5000 1.80610 40.73 -0.005657 32* 240.0000 (BF) Image plane ∞ [Aspherical data] 1st page 2nd page 9th page K 0.00000 0.00000 0.00000 A4 9.70576E-06 2.95756E-06 -2.42866E-05 A6 -1.86433E-08 -1.66290E-08 5.00209E-08 A8 2.75229E-11 2.98210E-11 6.27171E-11 A10 -2.96311E-14 -1.49159E-13 -3.63242E-13 A12 2.10699E-17 2.74816E-16 3.31214E-16 A14 -6.75390E-21 -1.93740E-19 0.00000E+00 A16 0.00000E+00 0.00000E+00 0.00000E+00 10th page 15th page 16th page K 0.00000 0.00000 0.00000 A4 -2.30319E-05 -5.38648E-06 1.60401E-06 A6 5.54940E-08 7.55003E-09 7.34939E-10 A8 4.43002E-11 7.81632E-12 6.17228E-12 A10 -2.63258E-13 -1.85817E-14 2.52853E-14 A12 2.18796E-16 -1.74128E-17 -8.42590E-17 A14 0.00000E+00 0.00000E+00 0.00000E+00 A16 0.00000E+00 0.00000E+00 0.00000E+00 Page 31 Page 32 K 0.00000 0.00000 A4 -2.74145E-05 -1.43072E-06 A6 1.40603E-07 1.49542E-07 A8 -8.91781E-10 -7.26583E-10 A10 2.43875E-12 1.86133E-12 A12 -2.31913E-15 -2.03497E-15 A14 0.00000E+00 0.00000E+00 A16 0.00000E+00 0.00000E+00 [Various data] INF Focal length 23.86 F-number 1.46 Full angle of view 2ω 84.43 Image height Y 21.63 Lens length 113.95 [Variable Interval Data] INF 249mm d0 ∞ 136.5000 d10 3.7171 9.2968 d12 8.1632 2.5835 BF 23.0355 23.0355 [Lens group data] Group starting plane focal length G1 1 -26.10 G2 11 48.64 G3 13 51.61 G4 21 -49.60 G5 27 36.37 [Example]

[0102] FIG. 6 is a lens configuration diagram of an optical system according to a second embodiment of the present invention.

[0103] The second embodiment is composed of, in order from the object side, a first lens group G1 with negative refractive power, a second lens group G2 with positive refractive power, a third lens group G3 with positive refractive power, a fourth lens group G4 with negative refractive power, and a fifth lens group G5 with positive refractive power. An aperture stop S is disposed between the third lens group G3 and the fourth lens group G4.

[0104] The first lens group G1 is composed of, in order from the object side, a negative meniscus lens L1 with a convex surface facing the object side, a negative meniscus lens L2 with a convex surface facing the object side, a positive meniscus lens L3 with a convex surface facing the object side, a biconcave lens L4, and a positive meniscus lens L5 with a convex surface facing the object side, and the lens surfaces on both sides of the negative meniscus lens L1 and the positive meniscus lens L5 have a predetermined aspherical shape.

[0105] The second lens group G2 is composed only of a biconvex lens L6, and moves toward the image plane during focusing from an infinity object distance to a close distance.

[0106] The third lens group G3 is composed of, in order from the object side, a biconcave lens L7, a biconvex lens L8, and a cemented lens consisting of a biconvex lens L9 and a negative meniscus lens L10 with its convex surface facing the image side, and the lens surfaces on both sides of the biconvex lens L8 have a predetermined aspherical shape.

[0107] The fourth lens group G4 is composed solely of a triplet cemented lens consisting of a positive meniscus lens L11 with a convex surface facing the image side, a biconcave lens L12, and a positive meniscus lens L13 with a convex surface facing the object side.

[0108] The fifth lens group G5 is composed of, in order from the object side, a biconvex lens L14, a negative meniscus lens L15 with its convex surface facing the object side, and a biconcave lens L16, and the lens surfaces on both sides of the biconcave lens L16 have a predetermined aspherical shape.

[0109] The specifications of the optical system according to the second embodiment are shown below. Numerical Example 2 Unit: mm [Face Data] Surface number rd nd vd θgF Object surface ∞ (d0) 1* 98.0747 2.6500 1.51633 64.06 0.000431 2* 26.2988 2.7431 3 31.5978 1.5000 1.43700 95.10 0.056526 4 20.1096 7.4774 5 45.4016 3.6278 2.05090 26.94 0.005288 6 98.4178 7.8734 7 -30.9119 1.0500 1.65412 39.68 -0.003165 8 67.5752 0.5000 9* 35.5334 3.0364 1.80610 40.73 -0.005657 10* 71.3864 (d10) 11 138.6537 5.9557 1.59349 67.00 0.008940 12 -35.6502 (d12) 13 -34.4139 0.9500 1.77047 29.74 0.000271 14 556.2391 0.1500 15* 57.8783 5.7412 1.77250 49.50 -0.007316 16* -86.5801 0.2727 17 48.6890 5.8879 2.00100 29.13 0.003566 18 -97.5610 1.0000 1.85451 25.15 0.007183 19 -384.0925 1.6796 20 (Aperture) ∞ 2.2686 21 -359.1621 6.6225 1.55032 75.50 0.027580 22 -23.3708 1.0000 1.85451 25.15 0.007183 23 39.3014 3.2766 1.49700 81.61 0.037456 24 91.4740 0.8176 25 54.0211 5.8590 2.00100 29.13 0.003566 26 -46.1958 0.2364 27 47.6671 0.9345 1.73037 32.23 -0.000407 28 36.7621 4.0737 29* -150.0000 1.4000 1.80610 40.73 -0.005657 30* 270.0000 (BF) Image plane ∞ [Aspherical data] 1st page 2nd page 9th page K 0.00000 0.00000 0.00000 A4 3.84265E-06 -3.67055E-06 -2.51028E-05 A6 3.23398E-09 1.86413E-09 6.78972E-08 A8 -1.38777E-11 1.31003E-11 -1.63358E-11 A10 1.66457E-14 -1.41804E-13 -2.04320E-13 A12 -8.39283E-18 2.48960E-16 2.11272E-16 A14 1.49973E-21 -1.85862E-19 0.00000E+00 A16 0.00000E+00 0.00000E+00 0.00哪000E+00 10 faces, 15 faces, 16 faces K 0.00000 0.00000 0.00000 A4 -2.39734E-05 -6.00813E-06 4.62100E-07 A6 7.24070E-08 8.77634E-09 -1.07297E-09 A8 -5.50282E-11 3.57499E-11 3.36217E-11 A10 -2.61072E-14 -1.19064E-13 -4.26202E-14 A12 1.66709E-仃 9.19244E-17 -3.12046E-17 A14 0.00000E+00 0.00000E+00 0.00000E+00 A16 0.00000E+00 0.00000E+00 0.00000E+00 29 faces, 30 faces K 0.00000 0.00000 A4 -4.90052E-05 -2.69920E-05 A6 2.78055E-07 2.95567E-07 A8 -1.05923E-09 -1.06047E-09 It should be noted that there seems to be a typo in the translation of line where "哪00000E+00" should probably be "0.00000E+00".A10 1.55034E-12 2.01880E-12 A12 -2.78235E-16 -1.69976E-15 A14 0.00000E+00 0.00000E+00 A16 0.00000E+00 0.00000E+00 [Various data] INF Focal length 27.50 F-number 1.46 Full angle of view 2ω 76.53 Image height Y 21.63 Lens length 113.50 [Variable Interval Data] INF 250mm d0 ∞ 134.7000 d10 3.9697 7.9748 d12 6.3557 2.3506 BF 21.7787 21.7787 [Lens group data] Group starting plane focal length G1 1 -31.72 G2 11 48.40 G3 13 41.08 G4 21 -33.72 G5 25 34.45 [Example]

[0110] FIG. 11 is a diagram showing the lens arrangement of an optical system according to a third embodiment of the present invention.

[0111] The third embodiment is composed of, in order from the object side, a first lens group G1 with negative refractive power, a second lens group G2 with negative refractive power, a third lens group G3 with positive refractive power, a fourth lens group G4 with negative refractive power, and a fifth lens group G5 with positive refractive power. An aperture stop S is disposed between the third lens group G3 and the fourth lens group G4.

[0112] The first lens group G1 is composed of, in order from the object side, a negative meniscus lens L1 with a convex surface facing the object side, a negative meniscus lens L2 with a convex surface facing the object side, a positive meniscus lens L3 with a convex surface facing the object side, a biconcave lens L4, and a biconvex lens L5, and the lens surfaces on both sides of the negative meniscus lens L1 have a predetermined aspherical shape.

[0113] The second lens group G2 is composed solely of a biconcave lens L6, and moves toward the object side during focusing from an infinity object distance to a close distance.

[0114] The third lens group G3 is composed of, in order from the object side, a biconvex lens L7 and a cemented lens consisting of a biconvex lens L8 and a negative meniscus lens L9 with its convex surface facing the image side, and the lens surfaces on both sides of the biconvex lens L7 have a predetermined aspherical shape.

[0115] The fourth lens group G4 is composed of, in order from the object side, a cemented lens consisting of a positive meniscus lens L10 with its convex surface facing the image side and a negative meniscus lens L11 with its convex surface facing the image side, and a cemented lens consisting of a negative meniscus lens L12 with its convex surface facing the object side and a positive meniscus lens L13 with its convex surface facing the object side.

[0116] The fifth lens group G5 is composed of, in order from the object side, a biconvex lens L14, a negative meniscus lens L15 with its convex surface facing the object side, and a biconcave lens L16, and the lens surfaces on both sides of the biconcave lens L16 have a predetermined aspherical shape.

[0117] The specifications of the optical system according to the third embodiment are shown below. Numerical Example 3 Unit: mm [Face Data] Surface number rd nd vd θgF Object surface ∞ (d0) 1* 158.9756 2.7000 1.69350 53.20 -0.005975 2* 25.3935 3.3481 3 35.3539 1.5000 1.43700 95.10 0.056526 4 21.6410 7.7549 5 55.0435 3.8563 2.00069 25.46 0.011062 6 237.1280 9.1250 7 -32.8486 1.1000 1.67300 38.26 -0.003721 8 82.0510 0.1500 9 47.1154 6.6041 1.80420 46.50 -0.007389 10 -48.9500 (d10) 11 -29.7477 0.9000 1.61340 44.27 -0.005289 12 193.4370 (d12) 13* 39.2782 8.3421 1.85135 40.10 -0.006643 14* -46.0226 0.1500 15 380.5234 6.0701 1.55032 75.50 0.027580 16 -29.8395 0.9000 1.77047 29.74 0.000271 17 -101.5703 1.0000 18 (Aperture) ∞ 2.8078 19 -90.2024 5.6214 1.59282 68.62 0.019331 20 -23.3653 0.8500 1.85451 25.15 0.007183 21 -3013.4949 0.1500 22 36.5386 0.8500 1.73037 32.23 -0.000407 23 22.0999 4.7992 1.43700 95.10 0.056526 24 64.2496 0.3000 25 42.6594 6.1923 2.00100 29.13 0.003566 26 -60.5255 0.1500 27 54.8315 0.8500 1.51742 52.15 0.004478 28 30.3227 4.3240 29* -160.0000 1.3800 1.80610 40.73 -0.005657 30* 240.0000 (BF) Image plane ∞ [Aspherical data] Page 1 Page 2 Page 13 K 0.00000 0.00000 0.00000 A4 5.68260E-06 -1.42009E-06 -5.67998E-06 A6 -1.83236E-08 -2.84502E-08 4.49108E-09 A8 3.70160E-11 3.10653E-11 -7.86437E-12 A10 -4.32178E-14 -8.42275E-14 -1.89103E-14 A12 2.88252E-17 1.87072E-16 6.22723E-17 A14 -8.52313E-21 -2.07684E-19 0.00000E+00 A16 0.00000E+00 0.00000E+00 0.00000E+00 14 pages 29 pages 30 pages K 0.00000 0.00000 0.00000 A4 2.73221E-06 -1.98555E-05 6.54967E-06 A6 3.75041E-09 8.21791E-08 9.04896E-08 A8 -2.06476E-11 -7.82409E-10 -6.10494E-10 A10 3.54685E-14 2.69898E-12 2.11233E-12 A12 -6.53308E-18 -3.10410E-15 -2.83245E-15 A14 0.00000E+00 0.00000E+00 0.00000E+00 A16 0.00000E+00 0.00000E+00 0.00000E+00 [Various data] INF Focal length 23.75 F-number 1.46 Full angle of view 2ω 84.84 Image height Y 21.63 Lens length 114.15 [Variable Interval Data] INF 248mm d0 ∞ 134.0000 d10 7.5572 4.1234 d12 2.5000 5.9338 BF 22.3176 22.3176 [Lens group data] Group starting plane focal length G1 1 -313.82 G2 11 -41.97 G3 13 25.20 G4 19 -55.42 G5 25 38.53 [Example]

[0118] FIG. 16 is a lens configuration diagram of an optical system according to a fourth embodiment of the present invention.

[0119] The fourth embodiment is composed of, in order from the object side, a first lens group G1 with negative refractive power, a second lens group G2 with positive refractive power, a third lens group G3 with positive refractive power, a fourth lens group G4 with positive refractive power, and a fifth lens group G5 with negative refractive power. An aperture stop S is disposed between the third lens group G3 and the fourth lens group G4.

[0120] The first lens group G1 is composed of, in order from the object side, a negative meniscus lens L1 with a convex surface facing the object side, a negative meniscus lens L2 with a convex surface facing the object side, a negative meniscus lens L3 with a convex surface facing the object side, and a cemented lens made up of a positive meniscus lens L4 with a convex surface facing the object side and a negative meniscus lens L5 with a convex surface facing the object side, and the object side lens surface of the negative meniscus lens L1 and both lens surfaces of the negative meniscus lens L3 have a predetermined aspherical shape.

[0121] The second lens group G2 is composed solely of a cemented lens consisting of a negative meniscus lens L6 with its convex surface facing the object side and a positive meniscus lens L7 with its convex surface facing the object side. The second lens group G2 moves toward the image plane during focusing from an infinity object distance to a close distance.

[0122] The third lens group G3 is composed of, in order from the object side, a cemented lens consisting of a biconvex lens L8 and a negative meniscus lens L9 with its convex surface facing the image side, and a cemented lens consisting of a biconcave lens L10 and a positive meniscus lens L11 with its convex surface facing the object side.

[0123] The fourth lens group G4 is composed of, in order from the object side, a biconvex lens L12, and a cemented lens made up of a negative meniscus lens L13 with its convex surface facing the object side and a biconvex lens L14.

[0124] The fifth lens group G5 is composed of, in order from the object side, a cemented lens consisting of a biconcave lens L15 and a biconvex lens L16, a negative meniscus lens L17 with its convex surface facing the object side, and a negative meniscus lens L18 with its convex surface facing the image side, and the lens surfaces on both sides of the negative meniscus lens L18 have a predetermined aspherical shape.

[0125] The specifications of the optical system according to the fourth embodiment are shown below. Numerical Example 4 Unit: mm [Face Data] Surface number rd nd vd θgF Object surface ∞ (d0) 1* 471.8640 3.2000 1.69350 53.18 -0.004302 2 23.3252 7.8659 3 37.2224 1.7000 1.59282 68.62 0.019331 4 20.3339 8.7321 5* 44.2713 1.8800 1.59201 67.02 0.008202 6* 19.3637 1.8808 7 25.5810 9.2425 1.85451 25.15 0.007183 8 2127.1283 1.4371 1.49700 81.61 0.037456 9 20.4660 (d9) 10 42.8355 0.7000 2.00069 25.46 0.011062 11 18.8523 4.5870 1.75211 25.05 0.015918 12 270.7821 (d12) 13 32.1984 6.5850 1.90043 37.37 -0.004428 14 -23.5539 0.8000 2.00100 29.13 0.003566 15 -51.9319 0.1500 16 -191.0397 0.8000 2.00100 29.13 0.003566 17 16.2949 5.0356 1.59349 67.00 0.008940 18 225.0938 2.7131 19 (Aperture) ∞ 2.6613 20 25.6241 5.0798 1.55032 75.50 0.027580 21 -63.4156 0.1500 22 38.7245 0.8000 1.90043 37.37 -0.004428 23 13.8480 7.5881 1.55032 75.50 0.027580 24 -64.2856 1.2046 25 -30.2250 0.8000 1.77047 29.74 0.000271 26 22.7584 7.5549 1.92286 20.88 0.028164 27 -37.8376 0.1500 28 36.8692 0.8000 1.85451 25.15 0.007183 29 26.5120 4.5946 30* -58.8156 1.3000 1.77250 49.50 -0.007316 31* -124.9641 (BF) Image plane ∞ [Aspherical data] Page 1 Page 30 Page 31 K 0.00000 0.00000 0.00000 A4 1.29054E-05 -1.60215E-05 1.09092E-05 A6 -1.87125E-08 -6.24124E-08 -6.84574E-08 A8 2.25220E-11 7.16066E-10 1.60827E-09 A10 -1.73138E-14 -2.39500E-11 -3.07684E-11 A12 7.79393E-18 2.90938E-13 2.92894E-13 A14 -1.73492E-21 -1.40856E-15 -1.25091E-15 A16 1.20930E-25 2.43801E-18 1.96470E-18 5th and 6th K 0.00000 0.00000 A3 1.49399E-04 1.47841E-04 A4 -1.24864E-05 -1.66448E-05 A5 -1.65207E-05 -1.60637E-05 A6 2.20111E-06 2.03129E-06 A7 -7.50285E-08 -4.31628E-08 A8 -2.00492E-09 -5.27553E-09 A9 8.71437E-11 2.20676E-10 A10 5.16192E-12 7.70884E-12 A11 -5.66066E-14 -4.72437E-13 A12 -1.40295E-14 -1.93075E-14 A13 2.96473E-16 9.32046E-16 A14 4.93754E-18 1.12593E-16 A15 8.72088E-20 -7.91729E-18 A16 -7.73546E-21 1.31152E-19 [Various data] INF Focal length 14.48 F-number 2.07 Full angle of view 2ω 114.27 Image height Y 21.63 Lens total length 128.00 [Variable Interval Data] INF 245mm d0∞117.0000 d9 10.1953 14.0048 d12 7.8122 4.0028 BF 20.0000 20.0000 [Lens group data] Group starting plane focal length G1 1 -16.87 G2 10 131.52 G3 13 78.85 G4 20 28.77 G5 25 -110.77 [Example]

[0126] FIG. 21 is a lens configuration diagram of a variable magnification optical system according to a fifth embodiment of the present invention.

[0127] Example 5 is composed of, from the object side, a first lens group G1 with negative refractive power, a second lens group G2 with positive refractive power, a third lens group G3 with positive refractive power, a fourth lens group G4 with positive refractive power, and a fifth lens group G5 with negative refractive power. When zooming from the wide-angle end to the telephoto end, the distance between the first lens group G1 and the second lens group G2 decreases, the distance between the second lens group G2 and the third lens group G3 increases, and the distance between the third lens group G3 and the fourth lens group G4 decreases. The distance between the fourth lens group G4 and the fifth lens group G5 does not change during zooming. An aperture stop S is disposed between the third lens group G3 and the fourth lens group G4.

[0128] The first lens group G1 is composed of, in order from the object side, a negative meniscus lens L1 with a convex surface facing the object side, a negative meniscus lens L2 with a convex surface facing the object side, a negative meniscus lens L3 with a convex surface facing the object side, a biconcave lens L4, and a positive meniscus lens L5 with a convex surface facing the object side, and the object side lens surface of the negative meniscus lens L1 and both lens surfaces of the negative meniscus lens L3 have a predetermined aspherical shape.

[0129] The second lens group G2 is composed solely of a biconvex lens L6, and both lens surfaces of the biconvex lens L6 have a predetermined aspherical shape. The second lens group G2 moves toward the image plane during focusing from an infinity object distance to a close distance.

[0130] The third lens group G3 is composed of, in order from the object side, a biconcave lens L7, and a cemented lens made up of a negative meniscus lens L8 with its convex surface facing the object side and a biconvex lens L9.

[0131] The fourth lens group G4 is composed of, in order from the object side, a biconvex lens L10, a cemented lens consisting of a negative meniscus lens L11 with its convex surface facing the object side and a positive meniscus lens L12 with its convex surface facing the object side, and a cemented lens consisting of a negative meniscus lens L13 with its convex surface facing the object side and a biconvex lens L14.

[0132] The fifth lens group G5 is composed of, in order from the object side, a cemented lens consisting of a biconcave lens L15 and a positive meniscus lens L16 with its convex surface facing the object side, and a biconvex lens L17, and the lens surfaces on both sides of the biconvex lens L17 have a predetermined aspherical shape.

[0133] The specifications of the variable magnification optical system according to the fifth embodiment are shown below. Numerical Example 5 Unit: mm [Face Data] Surface number rd nd vd θgF Object surface ∞ (d0) 1* 70.4056 3.2000 1.69350 53.18 -0.004302 2 26.3386 9.8191 3 47.0173 1.8000 1.59282 68.62 0.019331 4 19.2586 8.4461 5* 50.7510 1.7500 1.59201 67.02 0.008202 6* 30.2021 8.4415 7 -58.3804 1.4000 1.59282 68.62 0.019331 8 60.3888 0.1500 9 40.5975 4.1753 1.86966 20.02 0.031106 10 150.6826 (d10) 11* 87.6942 2.3385 1.83441 37.28 -0.003944 12* -443.8662 (d12) 13 -228.6959 2.9412 1.90110 27.06 0.007486 14 128.5843 0.1500 15 23.9776 1.0000 2.00100 29.13 0.003566 16 18.0559 5.9169 1.51742 52.15 0.004478 17 -164.8550 (d17) 18 (Aperture) ∞ 1.1000 19 36.3694 3.8106 1.49700 81.61 0.037456 20 -228.9718 0.1500 21 23.8338 1.0000 1.77250 49.62 -0.008651 22 13.5457 6.9990 1.55032 75.50 0.027580 23 704.5748 2.7133 24 32.5040 0.8000 1.85451 25.15 0.007183 25 13.8138 4.5867 1.49700 81.61 0.037456 26 -177.6588 1.2521 27 -49.7382 1.0000 1.90043 37.37 -0.004428 28 15.9790 3.7832 1.94595 17.98 0.038540 29 45.9074 1.3235 30* 115.5755 2.3746 1.85135 40.10 -0.006643 31* -120.5601 (BF) Image plane ∞ [Aspherical data] 1st page 5th page 6th page K 0.00000 0.00000 0.00000 A4 6.76142E-06 -4.34833E-05 -3.67663E-05 A6 -5.65111E-09 5.14860E-07 5.77736E-07 A8 6.38647E-12 -2.29384E-09 -2.77453E-09 A10 -3.90433E-15 6.60944E-12 9.65781E-12 A12 1.33264E-18 -1.15011E-14 -2.15232E-14 A14 0.00000E+00 9.07791E-18 2.06192E-17 A16 0.00000E+00 0.00000E+00 0.00000E+00 11 face 12 face K 0.00000 0.00000 A4 -2.76654E-06 2.58838E-06 A6 9.97585E-08 9.36424E-08 A8 -5.39819E-10 -5.25720E-10 A10 2.58396E-12 2.74232E-12 A12 0.00000E+00 0.00000E+00 A14 0.00000E+00 0.00000E+00 A16 0.00000E+00 0.00000E+00 30 face 31 face K 0.00000 0.00000 A4 -8.79011E-06 1.19492E-05 A6 -6.32573E-08 -4.14136E-08 A8 -3.08927E-10 -4.07840E-10 A10 6.81396E-12 5.41523E-12 A12 0.00000E+00 0.00000E+00 A14 0.00000E+00 0.00000E+00 A16 0.00000E+00 0.00000E+00 [Various data] Zoom ratio 1.60 Wide-angle Mid-range Telephoto Focal length 14.50 17.90 23.15 F-number 2.93 2.93 2.93 Full angle of view 2ω 114.20 100.78 84.98 Image height Y 21.63 21.63 21.63 Lens total length 133.00 130.36 130.13 [Variable Interval Data] Wide-angle Mid-range Telephoto d0 ∞ ∞ ∞ d10 15.8366 8.2249 1.7698 d12 4.3397 8.2201 10.0568 d17 10.4021 5.7620 2.0809 BF 20.0000 25.7267 33.8026 [Lens group data] Group starting plane focal length G1 1 -17.59 G2 11 87.93 G3 13 132.19 G4 19 29.86 G5 27 -48.34 [Example]

[0134] FIG. 28 is a lens configuration diagram of an optical system according to a sixth embodiment of the present invention.

[0135] The sixth embodiment is composed of, in order from the object side, a first lens group G1 with negative refractive power, a second lens group G2 with negative refractive power, a third lens group G3 with positive refractive power, a fourth lens group G4 with positive refractive power, and a fifth lens group G5 with positive refractive power. An aperture stop S is disposed between the third lens group G3 and the fourth lens group G4.

[0136] The first lens group G1 is composed of, in order from the object side, a negative meniscus lens L1 with a convex surface facing the object side, a negative meniscus lens L2 with a convex surface facing the object side, a positive meniscus lens L3 with a convex surface facing the image side, a biconcave lens L4, and a biconvex lens L5, and the lens surfaces on both sides of the negative meniscus lens L1 have a predetermined aspherical shape.

[0137] The second lens group G2 is composed solely of a negative meniscus lens L6 with its convex surface facing the image side. The second lens group G2 moves toward the object side during focusing from an infinity object distance to a close distance.

[0138] The third lens group G3 is composed of, in order from the object side, a positive meniscus lens L7 with its convex surface facing the object side, a biconvex lens L8, a negative meniscus lens L9 with its convex surface facing the object side, and a positive meniscus lens L10 with its convex surface facing the image side, and the lens surfaces on both sides of the biconvex lens L8 have a predetermined aspherical shape.

[0139] The fourth lens group G4 is composed of, in order from the object side, a cemented lens consisting of a positive meniscus lens L11 with a convex surface facing the image side and a negative meniscus lens L12 with a convex surface facing the image side, and a cemented lens consisting of a negative meniscus lens L13 with a convex surface facing the object side and a biconvex lens L14.

[0140] The fifth lens group G5 is composed of, in order from the object side, a biconvex lens L15, a negative meniscus lens L16 with its convex surface facing the object side, and a biconcave lens L17, and the lens surfaces on both sides of the biconcave lens L17 have a predetermined aspherical shape.

[0141] The specifications of the optical system according to Example 6 are shown below. Numerical Example 6 Unit: mm [Face Data] Surface number rd nd vd θgF Object surface ∞ (d0) 1* 161.7900 2.8000 1.69350 53.18 -0.004302 2* 32.1600 5.3700 3 55.0200 1.1000 1.77250 49.62 -0.008651 4 27.5400 14.0300 5 -64.1800 3.3100 2.00100 29.13 0.003566 6 -42.3300 1.7200 7 -39.6800 1.0000 1.71700 47.98 -0.006244 8 154.7400 0.1500 9 65.0800 6.2100 2.00100 29.13 0.003566 10 -146.5000 (d10) 11 -42.4900 1.0000 1.51680 64.20 0.001526 12 -244.6900 (d12) 13 38.7200 4.8000 1.95375 32.32 -0.000070 14 500.2700 0.1200 15* 56.1000 4.0000 1.69350 53.20 -0.005975 16* -200.0000 0.9600 17 753.2600 1.0000 1.86966 20.02 0.031106 18 44.1300 4.5500 19 -133.1200 2.8300 1.55032 75.50 0.027580 20 -52.8000 2.3100 21 (Aperture) ∞ 3.5600 22 -228.8400 8.3500 1.59282 68.62 0.019331 23 -18.3400 1.0000 1.85451 25.15 0.007183 24 -322.3600 0.1500 25 61.6500 1.0000 1.85451 25.15 0.007183 26 20.6300 8.1400 1.75500 52.32 -0.006799 27 -144.0200 1.4800 28 44.4500 6.2600 1.92286 20.88 0.028164 29 -62.0800 0.6000 30 69.2200 1.0000 1.54814 45.82 0.004146 31 28.7400 4.8500 32* -143.1800 1.6200 1.80610 40.73 -0.005657 33* 207.3800 (BF) Image plane ∞ [Aspherical data] 1st page 2nd page 15th page K 0.00000 -1.00000 0.00000 A4 3.42610E-06 3.57650E-06 -6.40520E-06 A6 -1.83420E-09 2.20430E-09 6.10890E-09 A8 1.62440E-12 -2.63630E-12 -2.75570E-11 A10 -1.14130E-15 1.15770E-14 2.25740E-13 A12 2.61090E-19 -1.41510E-17 -6.85160E-16 A14 0.00000E+00 0.00000E+00 6.57300E-19 A16 0.00000E+00 0.00000E+00 0.00000E+00 16 pages 32 pages 33 pages K 0.00000 0.00000 0.00000 A4 1.97340E-06 -1.86250E-05 5.56010E-06 A6 1.13490E-08 -2.85340E-09 2.29820E-08 A8 -5.37460E-11 -7.29380E-11 -2.99780E-11 A10 2.24120E-13 1.66680E-13 -1.45880E-14 A12 -4.61220E-16 0.00000E+00 0.00000E+00 A14 2.19690E-19 0.00000E+00 0.00000E+00 A16 0.00000E+00 0.00000E+00 0.00000E+00 [Various data] INF Focal length 20.33 F-number 1.46 Full angle of view 2ω 96.47 Image height Y 21.63 Lens length 129.04 [Variable Interval Data] INF 226mm d0 ∞ 97.4379 d10 11.3900 3.7932 d12 2.0000 9.5968 BF 20.3784 20.3784 [Lens group data] Group starting plane focal length G1 1 -57.92 G2 11 -99.66 G3 13 37.61 G4 22 2394.83 G5 28 56.26 [Example]

[0142] FIG. 33 is a diagram showing the lens configuration of an optical system according to a seventh embodiment of the present invention.

[0143] The seventh embodiment is composed of, from the object side, a first lens group G1 with negative refractive power, a second lens group G2 with negative refractive power, a third lens group G3 with positive refractive power, a fourth lens group G4 with positive refractive power, and a fifth lens group G5 with positive refractive power. An aperture stop S is disposed between the third lens group G3 and the fourth lens group G4.

[0144] The first lens group G1 is composed of, in order from the object side, a negative meniscus lens L1 with a convex surface facing the object side, a negative meniscus lens L2 with a convex surface facing the object side, a positive meniscus lens L3 with a convex surface facing the image side, a biconcave lens L4, and a biconvex lens L5, and the object side lens surface of the negative meniscus lens L1 has a predetermined aspherical shape.

[0145] The second lens group G2 is composed solely of a negative meniscus lens L6 with its convex surface facing the image side. The second lens group G2 moves toward the object side during focusing from an infinity object distance to a close distance.

[0146] The third lens group G3 is composed of, in order from the object side, a positive meniscus lens L7 with its convex surface facing the object side, a biconvex lens L8, a negative meniscus lens L9 with its convex surface facing the object side, and a positive meniscus lens L10 with its convex surface facing the image side, and the lens surfaces on both sides of the biconvex lens L8 have a predetermined aspherical shape.

[0147] The fourth lens group G4 is composed of, in order from the object side, a cemented lens consisting of a positive meniscus lens L11 with a convex surface facing the image side and a negative meniscus lens L12 with a convex surface facing the image side, and a cemented lens consisting of a negative meniscus lens L13 with a convex surface facing the object side and a biconvex lens L14.

[0148] The fifth lens group G5 is composed of, in order from the object side, a biconvex lens L15, a negative meniscus lens L16 with its convex surface facing the object side, and a biconcave lens L17, and the lens surfaces on both sides of the biconcave lens L17 have a predetermined aspherical shape.

[0149] The specifications of the optical system according to Example 7 are shown below. Numerical Example 7 Unit: mm [Face Data] Surface number rd nd vd θgF Object surface ∞ (d0) 1* 200.0000 2.8000 1.51633 64.06 0.000431 2 32.5800 5.3200 3 55.3700 1.0000 1.83481 42.72 -0.006698 4 24.6000 14.1700 5 -59.5900 3.2200 1.92286 20.88 0.028164 6 -39.5600 1.4500 7 -36.5700 1.0000 1.72342 37.99 0.002034 8 134.5600 0.1500 9 63.6800 6.5900 2.00100 29.13 0.003566 10 -105.2700 (d10) 11 -42.1700 1.0000 1.56883 56.04 0.001063 12 -245.8300 (d12) 13 36.2300 5.4100 1.90043 37.37 -0.004428 14 1000.0000 0.7000 15* 97.0800 4.0000 1.77250 49.46 -0.005328 16* -200.0000 0.6600 17 295.9200 1.0000 1.86966 20.02 0.031106 18 51.2600 4.1400 19 -182.8700 2.8400 1.59282 68.62 0.019331 20 -60.0400 2.4700 21 (Aperture) ∞ 3.6800 22 -176.3800 9.0700 1.61997 63.88 0.009171 23 -17.5800 1.0000 1.85451 25.15 0.007183 24 -275.0200 0.1500 25 59.2900 1.0000 1.85451 25.15 0.007183 26 20.3900 8.2900 1.75500 52.32 -0.006799 27 -143.1000 1.3300 28 43.2300 6.4800 1.86966 20.02 0.031106 29 -58.6500 0.6000 30 91.1500 1.0000 1.60342 38.01 0.002866 31 31.8400 4.5400 32* -144.9600 1.6200 1.80610 40.73 -0.005657 33* 205.6000 (BF) Image plane ∞ [Aspherical data] 1st page 15th page 16th page K 0.00000 0.00000 0.00000 A4 5.08610E-06 -9.10480E-06 -1.12080E-06 A6 -3.34790E-09 1.15870E-08 1.76880E-08 A8 3.40150E-12 -5.40470E-11 -8.80040E-11 A10 -2.06800E-15 6.08490E-13 7.42160E-13 A12 6.37810E-19 -1.94800E-15 -2.33440E-15 A14 0.00000E+00 1.87910E-18 2.22670E-18 A16 0.00000E+00 0.00000E+00 0.00000E+00 32nd page 33rd page K 0.00000 0.00000 A4 -1.91220E-05 5.09400E-06 A6 -5.64530E-09 2.07170E-08 A8 -6.18430E-11 -3.68810E-11 A10 1.57780E-13 0.00000E+00 A12 0.00000E+00 0.00000E+00 A14 0.00000E+00 0.00000E+00 A16 0.00000E+00 0.00000E+00 [Various data] INF Focal length 20.36 F-number 1.46 Full angle of view 2ω 96.42 Image height Y 21.63 Lens length 129.06 [Variable Interval Data] INF 227mm d0 ∞ 97.7171 d10 10.0200 3.3892 d12 2.0000 8.6308 BF 20.3590 20.3590 [Lens group data] Group starting plane focal length G1 1 -58.98 G2 11 -89.64 G3 13 36.15 G4 22 690.99 G5 28 63.15 [Example]

[0150] FIG. 38 is a lens configuration diagram of an optical system according to an eighth embodiment of the present invention.

[0151] The eighth embodiment is composed of, in order from the object side, a first lens group G1 with negative refractive power, a second lens group G2 with negative refractive power, a third lens group G3 with positive refractive power, a fourth lens group G4 with positive refractive power, and a fifth lens group G5 with positive refractive power. An aperture stop S is disposed between the third lens group G3 and the fourth lens group G4.

[0152] The first lens group G1 is composed of, in order from the object side, a negative meniscus lens L1 with a convex surface facing the object side, a negative meniscus lens L2 with a convex surface facing the object side, a positive meniscus lens L3 with a convex surface facing the object side, a biconcave lens L4, and a biconvex lens L5, and the lens surfaces on both sides of the negative meniscus lens L1 have a predetermined aspherical shape.

[0153] The second lens group G2 is composed solely of a biconcave lens L6, and moves toward the object side during focusing from an infinity object distance to a close distance.

[0154] The third lens group G3 is composed of, in order from the object side, a biconvex lens L7, a biconvex lens L8, a biconcave lens L9, and a positive meniscus lens L10 with its convex surface facing the object side, and the lens surfaces on both sides of the biconvex lens L8 have a predetermined aspherical shape.

[0155] The fourth lens group G4 is composed of, in order from the object side, a cemented lens consisting of a positive meniscus lens L11 with a convex surface facing the image side and a negative meniscus lens L12 with a convex surface facing the image side, and a cemented lens consisting of a negative meniscus lens L13 with a convex surface facing the object side and a biconvex lens L14.

[0156] The fifth lens group G5 is composed of, in order from the object side, a biconvex lens L15, a negative meniscus lens L16 with its convex surface facing the object side, and a biconcave lens L17, and the lens surfaces on both sides of the biconcave lens L17 have a predetermined aspherical shape.

[0157] The specifications of the optical system according to Example 8 are shown below. Numerical Example 8 Unit: mm [Face Data] Surface number rd nd vd θgF Object surface ∞ (d0) 1* 89.3100 2.8000 1.77250 49.50 -0.007316 2* 25.5200 5.0000 3 45.8200 1.0000 1.91082 35.25 -0.002688 4 26.1800 8.8900 5 84.3500 3.5300 1.90366 31.31 0.002786 6 265.7400 6.7600 7 -50.1600 1.0000 1.55032 75.50 0.027580 8 115.0800 0.1500 9 62.6300 6.5700 2.00100 29.13 0.003566 10 -134.5400 (d10) 11 -41.6600 1.0000 1.48749 70.44 0.009085 12 1116.3700 (d12) 13 50.2600 5.0500 1.87070 40.73 -0.006808 14 -114.6900 0.1200 15* 145.0900 4.0000 1.85135 40.10 -0.006643 16* -200.0000 1.7200 17 -172.8600 1.0000 1.86966 20.02 0.031106 18 82.6400 1.4400 19 77.9100 2.7600 1.55032 75.50 0.027580 20 833.4400 4.3100 21 (Aperture) ∞ 3.7400 22 -145.7400 8.1300 1.49700 81.61 0.037456 23 -17.7700 1.0000 1.85451 25.15 0.007183 24 -48.1300 0.1500 25 588.0900 1.0000 1.85451 25.15 0.007183 26 20.8800 8.7100 1.80420 46.50 -0.007389 27 -85.0100 1.6600 28 47.2200 6.6500 1.92286 20.88 0.028164 29 -59.2100 0.6000 30 65.8300 1.0000 1.78472 25.72 0.013736 31 32.7300 4.9900 32* -156.4300 1.6200 1.85135 40.10 -0.006643 33* 203.5200 (BF) Image plane ∞ [Aspherical data] 1st page 2nd page 15th page K 0.00000 -1.00000 0.00000 A4 1.09530E-06 1.96920E-06 -5.89030E-07 A6 -1.31490E-09 -1.42520E-09 -1.84690E-09 A8 7.23620E-13 -2.78970E-12 6.65580E-11 A10 -2.14310E-16 -2.66360E-15 -3.41850E-13 A12 2.53790E-20 3.68990E-18 6.95290E-16 A14 0.00000E+00 0.00000E+00 -5.05920E-19 A16 0.00000E+00 0.00000E+00 0.00000E+00 16 pages 32 pages 33 pages K 0.00000 0.00000 0.00000 A4 3.78710E-06 -2.34740E-05 -3.94420E-06 A6 -5.67530E-09 -5.47810E-08 -2.70810E-08 A8 9.47370E-11 3.60940E-10 3.19840E-10 A10 -5.16290E-13 -9.95610E-13 -8.54480E-13 A12 1.09790E-15 1.04770E-15 7.35040E-16 A14 -8.30860E-19 0.00000E+00 0.00000E+00 A16 0.00000E+00 0.00000E+00 0.00000E+00 [Various data] INF Focal length 20.29 F-number 1.46 Full angle of view 2ω 94.46 Image height Y 21.63 Lens total length 129.05 [Variable Interval Data] INF 225mm d0 ∞ 96.2352 d10 10.6800 3.5577 d12 2.0000 9.1223 BF 20.0244 20.0245 [Lens group data] Group starting plane focal length G1 1 -75.93 G2 11 -82.36 G3 13 38.11 G4 22 285.35 G5 28 61.12

[0158] The values ​​corresponding to the conditional expressions for each of the above embodiments are shown below. [Conditional expression corresponding value] Conditional Expression Example 1 Example 2 Example 3 (1) ΔθgF_G4P > 0.000 0.042 0.033 0.038 (2) VD_GF4P > 50.00 85.30 78.55 81.86 (3) ΔθgF_G5L1 > 0.000 0.004 0.004 0.004 (4) VD_GF5L1 < 40.00 29.13 29.13 29.13 (5) -1.50 < f / f1 < 0.00 -0.91 -0.87 -0.08 (6) 0.05 < f / |f2| < 0.75 0.49 0.57 0.57 (7) 0.10 < f / f3 < 1.20 0.46 0.67 0.94 (8) -1.00 < f / f4 < 1.00 -0.48 -0.82 -0.43 (9) -1.00 < f / f5 < 1.00 0.66 0.80 0.62 (10) VD_G1P < 40.00 32.98 33.84 35.98 (11) ΔθgF_G1N > -0.010 0.017 0.018 0.016 (12) ΔθgF_G3P > -0.005 -0.002 -0.002 0.010 (13) ΔθgF_G4N < 0.010 0.004 0.007 0.003 (14) ΔθgF_G5N < 0.005 -0.005 -0.003 -0.001 (15) nd_G1P > 1.8500 1.8657 1.9285 1.9024 (16) nd_G5P > 1.8500 2.0010 2.0010 2.0010 Conditional Expression Example 4 Example 5T (1) ΔθgF_G4P > 0.000 0.028 0.034 (2) VD_GF4P > 50.00 75.50 79.57 (3) ΔθgF_G5L1 > 0.000 0.028 0.016 (4) VD_GF5L1 < 40.00 20.88 29.04 (5) -1.50 < f / f1 < 0.00 -0.86 -1.32 (6) 0.05 < f / |f2| < 0.75 0.11 0.26 (7) 0.10 < f / f3 < 1.20 0.18 0.18 (8) -1.00 < f / f4 < 1.00 0.50 0.78 (9) -1.00 < f / f5 < 1.00 -0.13 -0.48 (10) VD_G1P < 40.00 25.15 20.02 (11) ΔθgF_G1N > -0.010 0.015 0.011 (12) ΔθgF_G3P > -0.005 0.002 0.004 (13) ΔθgF_G4N < 0.010 -0.004 -0.001 (14) ΔθgF_G5N < 0.005 0.000 -0.004 (15) nd_G1P > 1.8500 1.8545 1.8697 (16) nd_G5P > 1.8500 1.9229 1.8986 Conditional Expression Example 6 Example 7 Example 8 (1) ΔθgF_G4P > 0.000 0.006 0.001 0.015 (2) VD_GF4P > 50.00 60.47 58.10 64.05 (3) ΔθgF_G5L1 > 0.000 0.028 0.016 0.028 (4) VD_GF5L1 < 40.00 20.88 25.01 20.88 (5) -1.50 < f / f1 < 0.00 -0.35 -0.35 -0.27 (6) 0.05 < f / |f2| < 0.75 0.20 0.23 0.25 (7) 0.10 < f / f3 < 1.20 0.54 0.56 0.53 (8) -1.00 < f / f4 < 1.00 0.01 0.03 0.07 (9) -1.00 < f / f5 < 1.00 0.36 0.32 0.33 (10) VD_G1P < 40.00 29.13 25.01 30.22 (11) ΔθgF_G1N > -0.010 -0.006 -0.001 0.006 (12) ΔθgF_G3P > -0.005 0.007 0.003 0.005 (13) ΔθgF_G4N < 0.010 0.007 0.007 0.007 (14) ΔθgF_G5N < 0.005 -0.001 -0.001 0.004 (15) nd_G1P > 1.8500 2.0010 1.9619 1.9523 (16) nd_G5P > 1.8500 1.9229 1.8697 1.9229 *Example 5 shows the value of Tele. [Explanation of symbols]

[0159] G1: First lens group G2: Second lens group G3: Third lens group G4: Fourth lens group G5: Fifth lens group S: Aperture stop I: image plane CC line (wavelength λ=656.3nm) dd line (wavelength λ=587.6nm) gg line (wavelength λ=435.8nm) Y image height ΔS sagittal image plane ΔM medional image plane

Claims

1. The optical system is composed of, in order from the object side, a first lens group G1 having negative refractive power, a second lens group G2 having positive or negative refractive power, a third lens group G3 having positive refractive power, a fourth lens group G4 having positive or negative refractive power, and a fifth lens group G5 having positive or negative refractive power. During focusing, at least the second lens group G2 moves along the optical axis, and at the same time, the distance between the first lens group G1 and the second lens group G2 changes, and at the same time, the distance between the second lens group G2 and the third lens group G3 changes. The fourth lens group G4 is a lens having positive refractive power. the fifth lens group G5 includes a lens having positive refractive power and a lens having negative refractive power, the first lens group G1 includes a configuration in which a meniscus lens having negative refractive power with a convex surface facing the object side, a lens having negative refractive power, and a lens having positive refractive power are arranged in this order from the object side, the fifth lens group G5 has an aspheric surface in which the positive refractive power becomes weaker or the negative refractive power becomes stronger from the center of the optical axis to the periphery, and satisfies the following conditional expressions (1) to (4) and (16): (1) ΔθgF_G4P > 0.000 (2) VD_GF4P > 50.00 (3) ΔθgF_G5P > 0.000 (4) VD_GF5P < 40.00 (16)nd_G5P > 1.8500 however, ΔθgF_G4P: g-line of the lens having positive refractive power constituting the fourth lens group G4; Average value of deviation ΔθgF of partial dispersion ratio for F line The deviation ΔθgF of the partial dispersion ratio for the g-line and F-line is the partial dispersion ratio for each lens. If the dispersion ratio is θgF and the Abbe number at the d line is VD, ΔθgF=θgF-(0.648285-0.00180123×VD) is calculated as VD_GF4P: average value of Abbe numbers at d-line of lenses having positive refractive power constituting the fourth lens group G4 ΔθgF_G5P: the average value of the deviation ΔθgF of the partial dispersion ratio for the g-line and the F-line of the lens having positive refractive power that constitutes the fifth lens group G5 VD_GF5P: average value of Abbe numbers at d-line of lenses having positive refractive power that constitute the fifth lens group G5 nd_G5P: the average value of the refractive index at the d line of the lenses having positive refractive power that constitute the fifth lens group G5

2. The optical system is configured to include, in order from the object side, a first lens group G1 having negative refractive power, a second lens group G2 having positive or negative refractive power, a third lens group G3 having positive refractive power, a fourth lens group G4 having positive or negative refractive power, and a fifth lens group G5 having positive or negative refractive power, wherein at least the second lens group G2 moves along the optical axis during focusing, and simultaneously a distance between the first lens group G1 and the second lens group G2 changes, and simultaneously a distance between the second lens group G2 and the third lens group G3 changes, the fourth lens group G4 includes a lens having positive refractive power and a lens having negative refractive power, the fifth lens group G5 includes a lens having positive refractive power and a lens having negative refractive power, the fifth lens group G5 has an aspheric surface whose positive refractive power becomes weaker or whose negative refractive power becomes stronger from the center of the optical axis toward the periphery, and wherein the optical system satisfies the following conditional expressions (1) to (4), (12), and (16): (1) ΔθgF_G4P > 0.000 (2) VD_GF4P > 50.00 (3) ΔθgF_G5P > 0.000 (4) VD_GF5P < 40.00 (12) ΔθgF_G3P > -0.005 (16)nd_G5P > 1.8500 however, ΔθgF_G4P: g-line of the lens having positive refractive power constituting the fourth lens group G4; Average value of deviation ΔθgF of partial dispersion ratio for F line The deviation ΔθgF of the partial dispersion ratio for the g-line and F-line is the partial dispersion ratio for each lens. If the dispersion ratio is θgF and the Abbe number at the d line is VD, ΔθgF=θgF-(0.648285-0.00180123×VD) is calculated as VD_GF4P: average value of Abbe numbers at d-line of lenses having positive refractive power constituting the fourth lens group G4 ΔθgF_G5P: the average value of the deviation ΔθgF of the partial dispersion ratio for the g-line and the F-line of the lens having positive refractive power that constitutes the fifth lens group G5 VD_GF5P: average value of Abbe numbers at d-line of lenses having positive refractive power that constitute the fifth lens group G5 ΔθgF_G3P: the average value of the deviation ΔθgF of the partial dispersion ratio for the g-line and the F-line of the lens having positive refractive power that constitutes the third lens group G3 nd_G5P: the average value of the refractive index at the d line of the lenses having positive refractive power that constitute the fifth lens group G5

3. The optical system is configured to include, in order from the object side, a first lens group G1 having negative refractive power, a second lens group G2 having positive or negative refractive power, a third lens group G3 having positive refractive power, a fourth lens group G4 having positive or negative refractive power, and a fifth lens group G5 having positive or negative refractive power, wherein at least the second lens group G2 moves along the optical axis during focusing, and simultaneously a distance between the first lens group G1 and the second lens group G2 changes, and simultaneously a distance between the second lens group G2 and the third lens group G3 changes, the fourth lens group G4 includes a lens having positive refractive power and a lens having negative refractive power, the fifth lens group G5 includes a lens having positive refractive power and a lens having negative refractive power, the fifth lens group G5 has an aspheric surface whose positive refractive power becomes weaker or whose negative refractive power becomes stronger from the center of the optical axis toward the periphery, and wherein the optical system satisfies the following conditional expressions (1) to (4), (13), and (16): (1) ΔθgF_G4P > 0.000 (2) VD_GF4P > 50.00 (3) ΔθgF_G5P > 0.000 (4) VD_GF5P < 40.00 (13) ΔθgF_G4N < 0.010 (16)nd_G5P > 1.8500 however, ΔθgF_G4P: g-line of the lens having positive refractive power constituting the fourth lens group G4; Average value of deviation ΔθgF of partial dispersion ratio for F line The deviation ΔθgF of the partial dispersion ratio for the g-line and F-line is the partial dispersion ratio for each lens. If the dispersion ratio is θgF and the Abbe number at the d line is VD, ΔθgF=θgF-(0.648285-0.00180123×VD) is calculated as VD_GF4P: average value of Abbe numbers at d-line of lenses having positive refractive power constituting the fourth lens group G4 ΔθgF_G5P: the average value of the deviation ΔθgF of the partial dispersion ratio for the g-line and the F-line of the lens having positive refractive power that constitutes the fifth lens group G5 VD_GF5P: average value of Abbe numbers at d-line of lenses having positive refractive power that constitute the fifth lens group G5 ΔθgF_G4N: the average value of the deviation ΔθgF of the partial dispersion ratio for the g-line and the F-line of the lens having negative refractive power that constitutes the fourth lens group G4 nd_G5P: the average value of the refractive index at the d line of the lenses having positive refractive power that constitute the fifth lens group G5

4. The optical system is configured to include, in order from the object side, a first lens group G1 having negative refractive power, a second lens group G2 having positive or negative refractive power, a third lens group G3 having positive refractive power, a fourth lens group G4 having positive or negative refractive power, and a fifth lens group G5 having positive or negative refractive power, wherein at least the second lens group G2 moves along the optical axis during focusing, and simultaneously a distance between the first lens group G1 and the second lens group G2 changes, and simultaneously a distance between the second lens group G2 and the third lens group G3 changes, the fourth lens group G4 includes a lens having positive refractive power and a lens having negative refractive power, the fifth lens group G5 includes a lens having positive refractive power and a lens having negative refractive power, the fifth lens group G5 has an aspheric surface whose positive refractive power becomes weaker or whose negative refractive power becomes stronger from the center of the optical axis toward the periphery, and wherein the optical system satisfies the following conditional expressions (1) to (4), (14), and (16): (1) ΔθgF_G4P > 0.000 (2) VD_GF4P > 50.00 (3) ΔθgF_G5P > 0.000 (4) VD_GF5P < 40.00 (14) ΔθgF_G5N < 0.005 (16)nd_G5P > 1.8500 however, ΔθgF_G4P: g-line of the lens having positive refractive power constituting the fourth lens group G4; Average value of deviation ΔθgF of partial dispersion ratio for F line The deviation ΔθgF of the partial dispersion ratio for the g-line and F-line is the partial dispersion ratio for each lens. If the dispersion ratio is θgF and the Abbe number at the d line is VD, ΔθgF=θgF-(0.648285-0.00180123×VD) is calculated as VD_GF4P: average value of Abbe numbers at d-line of lenses having positive refractive power constituting the fourth lens group G4 ΔθgF_G5P: the average value of the deviation ΔθgF of the partial dispersion ratio for the g-line and the F-line of the lens having positive refractive power that constitutes the fifth lens group G5 VD_GF5P: average value of Abbe numbers at d-line of lenses having positive refractive power that constitute the fifth lens group G5 ΔθgF_G5N: the average value of the deviation ΔθgF of the partial dispersion ratio for the g-line and the F-line of the lens having negative refractive power that constitutes the fifth lens group G5 nd_G5P: the average value of the refractive index at the d line of the lenses having positive refractive power that constitute the fifth lens group G5

5. The optical system is configured to include, in order from the object side, a first lens group G1 having negative refractive power, a second lens group G2 having positive or negative refractive power, a third lens group G3 having positive refractive power, a fourth lens group G4 having positive or negative refractive power, and a fifth lens group G5 having positive or negative refractive power, wherein at least the second lens group G2 moves along the optical axis during focusing, and simultaneously a distance between the first lens group G1 and the second lens group G2 changes, and simultaneously a distance between the second lens group G2 and the third lens group G3 changes, the fourth lens group G4 includes a lens having positive refractive power and a lens having negative refractive power, the fifth lens group G5 includes a lens having positive refractive power and a lens having negative refractive power, the fifth lens group G5 has an aspheric surface whose positive refractive power becomes weaker or whose negative refractive power becomes stronger from the center of the optical axis toward the periphery, and wherein the optical system satisfies the following conditional expressions (1) to (4), (15), and (16): (1) ΔθgF_G4P > 0.000 (2) VD_GF4P > 50.00 (3) ΔθgF_G5P > 0.000 (4) VD_GF5P < 40.00 (15)nd_G1P > 1.8500 (16)nd_G5P > 1.8500 however, ΔθgF_G4P: g-line of the lens having positive refractive power constituting the fourth lens group G4; Average value of deviation ΔθgF of partial dispersion ratio for F line The deviation ΔθgF of the partial dispersion ratio for the g-line and F-line is the partial dispersion ratio for each lens. If the dispersion ratio is θgF and the Abbe number at the d line is VD, ΔθgF=θgF-(0.648285-0.00180123×VD) is calculated as VD_GF4P: average value of Abbe numbers at d-line of lenses having positive refractive power constituting the fourth lens group G4 ΔθgF_G5P: the average value of the deviation ΔθgF of the partial dispersion ratio for the g-line and the F-line of the lens having positive refractive power that constitutes the fifth lens group G5 VD_GF5P: average value of Abbe numbers at d-line of lenses having positive refractive power that constitute the fifth lens group G5 nd_G1P: the average value of the refractive index at the d line of the lenses having positive refractive power that constitute the first lens group G1 nd_G5P: the average value of the refractive index at the d line of the lenses having positive refractive power that constitute the fifth lens group G5

6. The optical system is configured to include, in order from the object side, a first lens group G1 having negative refractive power, a second lens group G2 having positive or negative refractive power, a third lens group G3 having positive refractive power, a fourth lens group G4 having positive or negative refractive power, and a fifth lens group G5 having positive or negative refractive power, wherein at least the second lens group G2 moves along the optical axis during focusing, and at the same time, the distance between the first lens group G1 and the second lens group G2 changes, and at the same time, the distance between the second lens group G2 and the third lens group G the fourth lens group G4 includes a lens having positive refractive power and a lens having negative refractive power, the fifth lens group G5 includes a lens having positive refractive power and a lens having negative refractive power, the fourth lens group G4 has one or more pairs of cemented lenses whose cemented surface faces the object side in a convex manner and whose refractive index of the medium on the object side is higher than that of the medium on the image plane side, and the optical system satisfies the following conditional expressions (1) to (4), (12), and (15): (1) ΔθgF_G4P > 0.000 (2) VD_GF4P > 50.00 (3) ΔθgF_G5P > 0.000 (4) VD_GF5P < 40.00 (12) ΔθgF_G3P > -0.005 (15)nd_G1P > 1.8500 however, ΔθgF_G4P: g-line of the lens having positive refractive power constituting the fourth lens group G4; Average value of deviation ΔθgF of partial dispersion ratio for F line The deviation ΔθgF of the partial dispersion ratio for the g-line and F-line is the partial dispersion ratio for each lens. If the dispersion ratio is θgF and the Abbe number at the d line is VD, ΔθgF=θgF-(0.648285-0.00180123×VD) is calculated as VD_GF4P: average value of Abbe numbers at d-line of lenses having positive refractive power constituting the fourth lens group G4 ΔθgF_G5P: the average value of the deviation ΔθgF of the partial dispersion ratio for the g-line and the F-line of the lens having positive refractive power that constitutes the fifth lens group G5 VD_GF5P: average value of Abbe numbers at d-line of lenses having positive refractive power that constitute the fifth lens group G5 ΔθgF_G3P: the average value of the deviation ΔθgF of the partial dispersion ratio for the g-line and the F-line of the lens having positive refractive power that constitutes the third lens group G3 nd_G1P: the average value of the refractive index at the d line of the lenses having positive refractive power that constitute the first lens group G1

7. 7. The optical system according to claim 1, wherein all groups other than the second lens group G2 are fixed relative to the image plane during focusing.

8. 7. The optical system according to claim 1, wherein the following condition is satisfied: (10) VD_G1P < 40.00 (11) ΔθgF_G1N > -0.010 (12) ΔθgF_G3P > -0.005 (13) ΔθgF_G4N < 0.010 (14) ΔθgF_G5N < 0.005 (15)nd_G1P > 1.8500 (16)nd_G5P > 1.8500 however, VD_G1P: average value of Abbe numbers at d-line of lenses having positive refractive power that constitute the first lens group G1 ΔθgF_G1N: the average value of the deviation ΔθgF of the partial dispersion ratio for the g-line and the F-line of the lens having negative refractive power that constitutes the first lens group G1 ΔθgF_G3P: the average value of the deviation ΔθgF of the partial dispersion ratio for the g-line and the F-line of the lens having positive refractive power constituting the third lens group G3 ΔθgF_G4N: the average value of the deviation ΔθgF of the partial dispersion ratio for the g-line and the F-line of the lens having negative refractive power constituting the fourth lens group G4 ΔθgF_G5N: the average value of the deviation ΔθgF of the partial dispersion ratio for the g-line and the F-line of the lens having negative refractive power that constitutes the fifth lens group G5 nd_G1P: the average value of the refractive index at the d line of the lenses having positive refractive power that constitute the first lens group G1 nd_G5P: the average value of the refractive index at the d line of the lenses having positive refractive power that constitute the fifth lens group G5

9. 7. The optical system according to claim 2, wherein the first lens group G1 includes a configuration in which a meniscus lens having negative refractive power with a convex surface facing from the object side to the object side, a lens having negative refractive power, and a lens having positive refractive power are arranged in this order.

10. 6. The optical system according to claim 1, wherein the fourth lens group G4 includes one or more cemented lenses whose cemented surface faces a convex surface toward the object side, and whose refractive index of a medium on the object side is higher than that of a medium on the image plane side.

11. 7. The optical system according to claim 6, wherein the fifth lens group G5 has an aspherical surface whose positive refractive power becomes weaker or whose negative refractive power becomes stronger from the center of the optical axis toward the periphery.

12. 7. The optical system according to claim 1, wherein the second lens group G2 is composed of two or less lenses.

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