Optical system and image pickup apparatus including the same

Abstract

To provide a compact and lightweight optical system in which various aberrations are satisfactorily corrected, and to provide an imaging apparatus having the optical system.SOLUTION: The zoom lens includes, in order from an object side to an image side, a first lens unit L1 having a positive refractive power, a second lens unit L2 having a positive or negative refractive power that moves during focusing, and a third lens unit L3 having a negative refractive power. Where TL is a length on an optical axis from a lens surface closest to the object side to a lens surface closest to the image side in the third lens unit L3, TL3 is a length on the optical axis from the lens surface closest to the object side in the third lens unit L3 to the lens surface closest to the image side in the third lens unit L3, SD3 is a sum of thicknesses on the optical axis of lenses in the third lens unit L3, and DM3 is a thickness on the optical axis of a lens having a maximum thickness on the optical axis in the third lens unit LA. A predetermined conditional expression is satisfied.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to an optical system, and is particularly suitable for imaging devices such as video cameras, digital still cameras, broadcast cameras, and surveillance cameras. [Background technology]

[0002] Telephoto optical systems used in imaging devices are required to have a long focal length and a small F-number (large aperture). Patent documents 1 and 2 disclose optical systems that are arranged in order from the object side to the image side: a first lens group with positive refractive power, a second lens group with positive or negative refractive power, and a third lens group with positive or negative refractive power, and in which the second lens group moves during focusing. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2016-218276 [Patent Document 2] Japanese Patent Application Laid-Open No. 2012-189679 Summary of the Invention [Problem to be solved by the invention]

[0004] Here, there is also a demand for telephoto optical systems that are small and lightweight while still providing good correction for various aberrations, such as chromatic aberration and spherical aberration. However, increasing the aperture of a telephoto optical system requires a larger effective diameter, particularly of the lens positioned on the object side, making it difficult to reduce the size and weight of the entire system. Therefore, in order to achieve the above demands, it is important to appropriately set the optical arrangement of each lens group that constitutes the optical system, as well as the refractive power and arrangement of each lens that constitutes each lens group.

[0005] An object of the present invention is to provide an optical system that is small and lightweight yet has excellent correction for various aberrations, and an imaging apparatus having the same. [Means for solving the problem]

[0006] One aspect of an optical system that achieves the above-mentioned object is an optical system that includes, arranged in order from the object side to the image side, a first lens group with positive refractive power, a second lens group with positive or negative refractive power that moves during focusing, and a third lens group with negative refractive power, wherein the distance between adjacent lens groups changes during focusing, and wherein the lens in the first lens group that is positioned closest to the object is a positive meniscus lens with its convex surface facing the object side, and wherein the optical axial distance from the lens surface closest to the object side to the lens surface closest to the image side is TL, the optical axial distance from the lens surface closest to the object side in the third lens group to the lens surface closest to the image side in the third lens group is TL3, the sum of the optical axial thicknesses of the lenses in the third lens group is SD3, and the optical axial thickness of the lens in the third lens group that has the greatest thickness on the optical axis is DM3, and the following conditional expression is satisfied: 0.10 <TL3 / TL<0.40 0.70 <SD3 / TL3<0.90 0.05 <DM3 / TL3<0.14 [Effects of the Invention]

[0007] According to the present invention, it is possible to provide an optical system that is small and lightweight yet has various aberrations well corrected, and an imaging device having the same. [Brief explanation of the drawings]

[0008] [Figure 1] Cross-sectional view of the optical system of Example 1 when focused at infinity [Figure 2] Aberration diagram of the optical system of Example 1 when focused at infinity [Figure 3] Cross-sectional view of the optical system of Example 2 when focused at infinity [Figure 4] Aberration diagram of the optical system of Example 2 when focused at infinity [Figure 5] 10 is a cross-sectional view of the optical system of Example 3 when focused at infinity. [Figure 6] Aberration diagram of the optical system of Example 3 when focused at infinity [Figure 7] 10 is a cross-sectional view of the optical system of Example 4 when focused at infinity. [Figure 8] Aberration diagram of the optical system of Example 4 when focused at infinity [Figure 9] Schematic diagram of an imaging device according to an embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. Note that the drawings may be drawn at a scale different from the actual scale for convenience. In addition, the same reference numerals are used to designate the same components in the drawings, and redundant explanations will be omitted.

[0010] 1, 3, 5, and 7 are cross-sectional views including the optical axis of the optical system L0 according to Examples 1 to 4 when focused at infinity. In each cross-sectional view, the left side is the object side (front side), and the right side is the image side (rear side). The optical system L0 of each Example is an imaging optical system used in an imaging device, and the imaging surface of an imaging element is located at the position of the image plane IP. Note that the optical system L0 of each Example may also be used as a projection optical system in a projection device such as a projector, in which case the display surface of a display element such as a liquid crystal panel is located at the position of the image plane IP.

[0011] 2, 4, 6, and 8 are aberration diagrams of the optical system L0 according to Examples 1 to 4 when focused at infinity. In each aberration diagram, Fno denotes the F-number, and ω denotes the half angle of view (degrees) obtained by paraxial calculation. In the spherical aberration diagrams, d denotes spherical aberration at the d-line (wavelength 587.56 nm), g denotes spherical aberration at the g-line (wavelength 435.835 nm), C denotes spherical aberration at the C-line (wavelength 656.27 nm), and F denotes spherical aberration at the F-line (wavelength 486.13 nm). In the astigmatism diagrams, S denotes astigmatism at the d-line on the sagittal image plane, and M denotes astigmatism at the d-line on the meridional image plane. The distortion diagrams show distortion at the d-line. In the chromatic aberration diagrams, g denotes lateral chromatic aberration at the g-line, C denotes lateral chromatic aberration at the C-line, and F denotes lateral chromatic aberration at the F-line.

[0012] The optical system L0 according to Example 1 is a telephoto optical system having an F-number of 5.9 and a half angle of view of 1.51 degrees. The optical system L0 according to Example 2 is a telephoto optical system having an F-number of 8.0 and a half angle of view of 1.05 degrees. The optical system L0 according to Example 3 is a telephoto optical system having an F-number of 8.0 and a half angle of view of 1.24 degrees. The optical system L0 according to Example 4 is a telephoto optical system having an F-number of 5.9 and a half angle of view of 1.59 degrees.

[0013] The optical system L0 according to Examples 1 to 4 is composed of, arranged in order from the object side to the image side, a first lens group L1 with positive refractive power, a second lens group L2 with negative refractive power that moves during focusing, and a third lens group L3 with negative refractive power. In the optical system L0, the spacing between adjacent lens groups changes during focusing. That is, the lens group here refers to a group of lenses that move together during focusing, or a group of lenses that do not move during focusing. Note that a lens group may include one or more lenses, and may be composed of a single lens or multiple lenses. Note that the term "lens" here refers to an optical element having refractive power, and does not include optical elements such as parallel flat glass that do not have refractive power.

[0014] Next, the features of the optical system L0 according to each example will be described in detail.

[0015] Generally, the shorter the overall lens length (the distance from the lens surface closest to the object to the image plane) is in order to reduce the size of the entire optical system, the more aberrations occur, and chromatic aberration (axial chromatic aberration and lateral chromatic aberration) in particular becomes more pronounced, making it difficult to achieve high optical performance. In particular, when shortening the overall lens length in a telephoto optical system, the longer the focal length, the more chromatic aberration occurs. Furthermore, the longer the focal length of the optical system, the larger the effective diameter of the lens in the first lens group with positive refractive power tends to be.

[0016] Here, in order to achieve a compact overall optical system while effectively correcting various aberrations such as spherical aberration and axial chromatic aberration, it is effective to place many lenses in the first lens group. However, in telephoto optical systems, the effective diameter of the lens increases toward the object, and this size increases as the F-number decreases. Furthermore, as the effective diameter of the lens increases, the outer diameter of the lens also increases, and the weight of the lens increases approximately cubed. Therefore, increasing the number of lenses constituting the first lens group makes it difficult to reduce the weight of the overall system.

[0017] Therefore, in each embodiment, the configuration of the third lens unit L3 is appropriately set to realize a telephoto optical system that is compact and lightweight yet has excellent correction for various aberrations. Specifically, the optical system L0 in each embodiment satisfies the following conditional expressions (1) to (3). Here, the distance on the optical axis from the lens surface closest to the object to the lens surface closest to the image is defined as TL, and the distance on the optical axis from the lens surface closest to the object in the third lens unit L3 to the lens surface closest to the image in the third lens unit L3 is defined as TL3. Furthermore, the sum of the thicknesses of the lenses in the third lens unit L3 on the optical axis is defined as SD3, and the thickness of the lens in the third lens unit L3 that has the greatest thickness on the optical axis is defined as DM3. 0.10 <TL3 / TL<0.40 (1) 0.70 <SD3 / TL3<0.90 (2) 0.05 <DM3 / TL3<0.14 (3) Conditional expression (1) indicates that the overall length (thickness) of the third lens group L3 is sufficiently long relative to the overall optical length of the optical system L0. As described above, if many lenses are arranged in the first lens group L1 in order to achieve both a compact overall system and correction of various aberrations, the weight of the first lens group L1 increases. Therefore, in each embodiment, a relatively large number of lenses are arranged in the third lens group L3 so as to satisfy conditional expression (1), making it possible to achieve both a compact overall system and a lightweight first lens group L1 while effectively correcting various aberrations.

[0018] If the lower limit of conditional expression (1) is exceeded, the overall length of the third lens group L3 becomes too small, making it difficult to arrange a sufficient number of lenses in the third lens group L3 to effectively correct various aberrations. Here, in order to effectively correct various aberrations with the third lens group L3, it is important to arrange many lenses on the object side, where the axial light beam passes through a relatively high position. However, if the upper limit of conditional expression (1) is exceeded, each lens on the image side in the third lens group L3 will be arranged close to the image plane, making it difficult to effectively correct various aberrations with the third lens group L3.

[0019] Conditional expression (2) indicates that the sum of the lens thicknesses in the third lens group L3 is sufficiently large relative to the overall length of the third lens group L3. If the lower limit of conditional expression (2) is not met, the image-side lenses in the third lens group L3 will be positioned close to the image plane, making it difficult for the third lens group L3 to effectively correct various aberrations. If the upper limit of conditional expression (2) is met, the spacing between the lenses in the third lens group L3 will be too narrow, preventing the lenses from sufficiently separating the light beams, making it difficult to effectively correct various aberrations.

[0020] Conditional expression (3) indicates that the thickness of the thickest lens in the third lens group L3 is sufficiently small relative to the overall length of the third lens group L3, i.e., that the thickness of each lens in the third lens group L3 is sufficiently small. If the upper limit of conditional expression (3) is exceeded, the thickness of each lens in the third lens group L3 becomes too large, reducing the number of lenses that can be provided in the third lens group L3 and making it difficult to effectively correct various aberrations. If the lower limit of conditional expression (3) is exceeded, each lens on the image side in the third lens group L3 will be positioned close to the image plane, making it difficult to effectively correct various aberrations by the third lens group L3.

[0021] As described above, the optical system L0 according to each example has a configuration including the above-described three lens groups, and by satisfying conditional expressions (1) to (3), it is possible to achieve both size and weight reduction and good correction of various aberrations.

[0022] It is preferable to set the numerical ranges of the conditional expressions (1) to (3) as follows: 0.15 <TL3 / TL<0.35 (1a) 0.71 <SD3 / TL3<0.85 (2a) 0.06 <DM3 / TL3<0.13 (3a) Furthermore, it is more preferable to set the numerical ranges of the conditional expressions (1a) to (3a) as follows: 0.20 <TL3 / TL<0.30 (1b) 0.72 <SD3 / TL3<0.80 (2b) 0.08 <DM3 / TL3<0.12 (3b) It is also desirable that the optical system L0 according to each embodiment satisfies at least one of the conditional expressions (4) to (8) described below. 0.45 <LD / f<0.80 (4) 0.15 <BF / LD<0.27 (5) -0.50 <f3 / f<-0.10 (6) 73 <vd3P<97 (7) 1.85 <nd3N<2.2 (8) Here, LD is the distance on the optical axis from the lens surface closest to the object to the image plane IP (total lens length), and BF is the distance on the optical axis from the lens surface closest to the image plane IP to the image plane IP (back focus). Note that the total lens length and back focus indicate the distances (converted into air) when a parallel plate such as a filter is ignored if it is placed in the optical path. Furthermore, f is the focal length of the optical system L0 when focused on an object at infinity (when focused at infinity), and f3 is the focal length of the third lens group L3. Furthermore, vd3P is the Abbe number of the positive lens in the third lens group L3 with the largest Abbe number based on the d-line, and nd3N is the refractive index of the negative lens in the third lens group L3 with the largest refractive index at the d-line.

[0023] Conditional expression (4) indicates that the total lens length (the sum of the total optical length and the back focus) must be sufficiently short relative to the focal length of optical system L0. If the lower limit of conditional expression (4) is not satisfied, the total lens length becomes too short, making it difficult to effectively correct axial chromatic aberration and lateral chromatic aberration. If the upper limit of conditional expression (4) is exceeded, the total lens length becomes too long, making it difficult to miniaturize the lens barrel (holding member) that holds optical system L0.

[0024] Conditional expression (5) indicates that the back focal length must be sufficiently long relative to the overall lens length. If the lower limit of conditional expression (5) is not satisfied, the back focal length becomes too short, and the third lens unit L3 is disposed close to the image plane, resulting in a lower position at which the axial light beam passes through the third lens unit L3. As a result, it becomes difficult for the third lens unit L3 to effectively correct spherical aberration and axial chromatic aberration. If the upper limit of conditional expression (5) is exceeded, the back focal length becomes too long, reducing the number of lenses that can be provided in the optical system L0 and making it difficult to effectively correct various aberrations.

[0025] Conditional expression (6) indicates that the absolute value of the focal length of the third lens group L3 is sufficiently small relative to the focal length of the entire optical system L0, i.e., the absolute value of the refractive power of the third lens group L3 is sufficiently large (strong negative refractive power). Below the lower limit of conditional expression (6), the absolute value of the focal length of the third lens group L3 becomes too large, i.e., the negative refractive power of the third lens group L3 becomes too weak, reducing the telephoto effect and making it difficult to shorten the overall lens length. Above the upper limit of conditional expression (6), the absolute value of the focal length of the third lens group L3 becomes too small, i.e., the negative refractive power of the third lens group L3 becomes too strong, making it difficult to effectively correct spherical aberration and axial chromatic aberration.

[0026] Conditional expression (7) specifies the Abbe number of the material with the largest Abbe number among the positive lenses included in the third lens group L3, and indicates a condition for better correction of longitudinal chromatic aberration in particular. If the lower limit of conditional expression (7) is not met, the Abbe number of the positive lens in the third lens group L3 becomes too small, making it difficult to effectively correct longitudinal chromatic aberration. If the upper limit of conditional expression (7) is exceeded, the Abbe number of the positive lens in the third lens group L3 becomes large, making it easy to correct longitudinal chromatic aberration. However, since the refractive index of an optical material tends to decrease as the Abbe number increases, exceeding the upper limit of conditional expression (7) may make it difficult to correct spherical aberration, coma, and other aberrations.

[0027] Conditional expression (8) specifies the refractive index at the d-line of the negative lens included in the third lens group L3 that has the largest refractive index at the d-line, and particularly specifies a condition for better correction of field curvature. Below the lower limit of conditional expression (8), the refractive index of the negative lens in the third lens group L3 becomes too small, making it difficult to effectively correct field curvature. Above the upper limit of conditional expression (8), the freedom in selecting the material for the negative lens in the third lens group L3 becomes limited. Specifically, it is difficult to select a material that can be easily processed into a lens from among materials that exceed the upper limit of conditional expression (8), making it difficult to consistently manufacture an optical system with the desired optical performance.

[0028] It is preferable to set the numerical ranges of the conditional expressions (4) to (6) as follows: 0.46 <LD / f<0.75 (4a) 0.17 <BF / LD<0.26 (5a) -0.45 <f3 / f<-0.15 (6a) Furthermore, it is more preferable to set the numerical ranges of the conditions (4a) to (6a) as follows: 0.47 <LD / f<0.60 (4b) 0.19 <BF / LD<0.25 (5b) -0.40 <f3 / f<-0.20 (6b) In the optical system L0 according to each embodiment, of the distances on the optical axis between two adjacent lenses (lens spacing), the distance between the lens located closest to the object and the lens adjacent to that lens is the longest. This allows for a reduction in the number of lenses located on the object side of the first lens group L1, which tends to have a large effective diameter, and therefore makes it possible to reduce the weight of the optical system L0. However, if necessary, other lens spacings may be maximized. Furthermore, in the optical system L0, an aperture diaphragm SP, which determines the F-number (Fno) by limiting the light beam, is located between the first lens group L1 and the second lens group L2, but the aperture diaphragm may be located at another position if necessary.

[0029] The optical system L0 according to each embodiment employs an inner focus system in which focusing is performed by moving the second lens group L2. As indicated by the arrows in FIGS. 1, 3, 5, and 7, in each embodiment, the second lens group L2 moves toward the image side during focusing from infinity to a close distance (closest focus). In each embodiment, the second lens group L2 is constructed from a single lens, thereby reducing weight and facilitating focusing. However, the second lens group L2 may be constructed from multiple lenses, if necessary.

[0030] In each embodiment, the second lens unit L2 has negative refractive power, but if necessary, the second lens unit L2 may have positive refractive power. In this case, the second lens unit L2 simply moves toward the object during focusing from infinity to a close distance. In each embodiment, the first lens unit L1 and the third lens unit L3 do not move during focusing, but if necessary, at least one of the first lens unit L1 and the third lens unit L3 may move during focusing.

[0031] The third lens group L3 in each embodiment includes, arranged in order from the object side to the image side, a first subgroup L3A, a second subgroup L3B that moves in a direction including a component perpendicular to the optical axis during image blur correction, and a third subgroup L3C. Note that the first subgroup L3A and the third subgroup L3C are stationary during image blur correction, and the spacing between the subgroups does not change during focusing. In this way, by using a portion of the third lens group L3, which has a relatively small effective diameter in the optical system L0, as a subgroup for image blur correction (image blur correction group), it is possible to reduce the weight of the image blur correction group and facilitate image blur correction.

[0032] In each embodiment, the first sub-group L3A has positive refractive power, the second sub-group L3B has negative refractive power, and the third sub-group L3C has negative refractive power. By providing the first sub-group L3A with positive refractive power, light incident on the second sub-group L3B can be focused, allowing the second sub-group L3B, which serves as an image stabilization group, to be made smaller and lighter. Furthermore, by providing the third sub-group L3C with negative refractive power, the telephoto effect can be enhanced and the overall lens length can be shortened. However, the signs of the refractive powers of the sub-groups are not limited to those described above. If necessary, the first sub-group L3A may have negative refractive power, the second sub-group L3B may have positive refractive power, and the third sub-group L3C may have positive refractive power.

[0033] Furthermore, if necessary, a configuration may be adopted in which at least one of the first partial group L3A and the third partial group L3C moves during image blur correction. In this case, the second partial group L3B may be stationary during image blur correction. That is, image blur correction may be performed by moving at least one of the first partial group L3A, the second partial group L3B, and the third partial group L3C. Alternatively, if necessary, a vibration reduction group may be provided in a portion of at least one of the first lens group L1 and the second lens group L2.

[0034] Numerical data corresponding to Examples 1 to 5 are shown below. In each piece of numerical data, when the number of an optical surface counted from the object side is i, r denotes the radius of curvature of the i-th surface, and d denotes the axial spacing (distance on the optical axis) between the i-th surface and the (i+1)-th surface. nd denotes the refractive index of the medium between the i-th surface and the (i+1)-th surface with respect to the d-line, and vd denotes the Abbe number of the medium with respect to the d-line. Furthermore, "focal length" denotes the focal length of the entire system when focused at infinity, "half angle of view" denotes the half angle of view (degrees), and BF denotes the air-equivalent value of the back focus. The Abbe number vd is a value defined by the following formula, where nF, nd, and nC are the refractive indices with respect to the F-line (486.13 nm), d-line (587.56 nm), and C-line (656.27 nm), respectively. νd=(nd-1) / (nF-nC)

[0035] [Numeric data 1] Unit: mm Surface Data Surface number rd nd vd 1 154.563 14.23 1.59522 67.7 2 679.967 120.54 3 94.854 14.30 1.43700 95.1 4 -304.998 0.17 5 -287.507 1.50 1.80610 33.3 6 74.518 2.79 7 74.498 11.84 1.43700 95.1 8∞17.88 9 67.130 5.78 1.89286 20.4 10 126.373 1.51 11 70.327 2.00 1.83400 37.2 12 40.256 10.32 1.43700 95.1 13 136.385 6.96 14 (Aperture) ∞ 5.00 15 -565.591 1.60 1.61800 63.4 16 60.054 36.49 17 100.609 1.40 1.89286 20.4 18 65.895 7.56 1.51742 52.4 19 -93.947 1.00 20 93.499 5.02 1.80610 33.3 21 -121.235 1.20 1.53775 74.7 22 36.546 5.43 23 -82.443 1.20 1.72916 54.7 24 68.591 3.01 25 137.981 4.68 1.65412 39.7 26 -1079.970 6.25 27 71.027 10.18 1.72047 34.7 28 -58.536 1.50 1.80810 22.8 29 -358.382 2.00 30 137.275 1.40 1.92286 20.9 31 66.149 6.02 1.49700 81.5 32 -67.277 4.78 33 -90.283 1.20 1.77250 49.6 34 21.745 10.05 1.71736 29.5 35 -33.233 0.55 36 -25.355 1.47 1.72916 54.7 37 33.912 9.48 1.54072 47.2 38 -22.646 0.10 39 -36.033 1.20 1.65160 58.5 40 45.606 0.10 41 39.716 8.07 1.73800 32.3 42 -26.727 1.20 1.92286 20.9 43 -1863.408 88.12 Image plane ∞ Various data Focal length 820.00 F-number 5.90 Half angle of view 1.51 Image height 21.64 Lens total length 437.08 BF 88.12 Lens group data Group starting plane focal length 1 1 187.58 2 15 -87.76 3 17 -178.50

[0036] [Numeric data 2] Unit: mm Surface Data Surface number rd nd vd 1 202.979 13.85 1.59349 67.0 2 1146.213 159.36 3 112.201 13.48 1.43387 95.1 4 -294.589 0.08 5 -285.813 2.03 1.80610 33.3 6 95.724 0.64 7 85.744 9.70 1.43387 95.1 8 383.200 41.51 9 80.052 5.75 1.80810 22.8 10 167.608 0.15 11 91.557 2.26 1.77250 49.6 12 45.827 10.97 1.43875 94.7 13 202.203 20.88 14 (Aperture) ∞ 5.00 15 2486.000 2.00 1.59349 67.0 16 68.618 36.49 17 155.135 1.80 1.89286 20.4 18 60.697 5.22 1.70154 41.2 19 -150.303 8.04 20 64.876 3.66 1.85478 24.8 21 -242.070 1.45 1.61800 63.4 22 33.397 4.39 23 -100.746 1.10 1.81600 46.6 24 149.076 5.00 25 48.596 3.17 1.74077 27.8 26 -404.782 1.18 27 138.695 2.77 1.71736 29.5 28 -130.959 0.86 1.92286 20.9 29 419.022 1.92 30 -162.632 1.40 1.91082 35.2 31 79.849 6.02 1.53775 74.7 32 -65.599 3.25 33 -75.659 1.20 1.81600 46.6 34 55.017 10.05 1.65412 39.7 35 -32.781 0.87 36 -28.199 1.50 1.59522 67.7 37 33.147 9.51 1.51823 58.9 38 -27.446 0.38 39 -33.252 1.20 1.70300 52.4 40 82.476 0.30 41 69.620 8.05 1.71736 29.5 42 -28.138 1.20 1.92286 20.9 43 -103.166 140.36 Image plane ∞ Various data Focal length 1180.10 F-number 8.00 Half angle of view 1.05 Image height 21.64 Lens total length 550.00 BF 140.36 Lens group data Group starting plane focal length 1 1 262.69 2 15 -118.94 3 17 -201.50

[0037] [Numerical data 3] Unit: mm Surface Data Surface number rd nd vd 1 239.922 10.06 1.59349 67.0 2 7630.475 143.66 3 92.483 11.58 1.43387 95.1 4 -609.787 0.07 5 -571.874 1.85 1.80610 33.3 6 110.755 0.15 7 80.471 8.00 1.43387 95.1 8 268.516 29.41 9 74.041 3.77 1.92286 18.9 10 114.095 0.15 11 81.951 2.10 1.83481 42.7 12 40.678 10.10 1.43700 95.1 13 212.122 13.05 14 (Aperture) ∞ 5.00 15 453.386 1.60 1.59522 67.7 16 67.582 36.49 17 250.519 1.30 1.89286 20.4 18 41.617 4.42 1.80610 33.3 19 -260.662 8.04 20 69.888 4.44 1.66680 33.0 21 -53.319 1.30 1.59522 67.7 22 42.907 3.59 23 -112.551 1.10 1.77250 49.6 24 63.547 3.00 25 71.157 2.95 1.76182 26.5 26 -3456.991 2.76 27 67.168 2.77 1.68893 31.1 28 -162.677 3.76 1.90043 37.4 29 110.060 1.06 30 146.490 1.40 1.90043 37.4 31 58.451 6.02 1.49700 81.5 32 -64.196 3.25 33 -101.733 1.20 1.75500 52.3 34 22.804 10.05 1.72047 34.7 35 -33.199 0.87 36 -26.967 1.50 1.69930 51.1 37 48.467 9.51 1.51742 52.4 38 -24.871 0.38 39 -35.800 1.20 1.61772 49.8 40 50.064 0.30 41 44.202 8.05 1.71736 29.5 42 -27.006 1.20 1.92286 20.9 43 -294.520 115.01 Image plane ∞ Various data Focal length 1000.00 F-number 8.00 Half angle of view: 1.24 Image height 21.64 Lens total length 477.48 BF 115.01 Lens group data Group starting plane focal length 1 1 215.09 2 15 -133.64 3 17 -103.47

[0038] [Numeric data 4] Unit: mm Surface Data Surface number rd nd vd 1 148.873 15.64 1.59349 67.0 2 588.063 117.90 3 89.476 14.55 1.43700 95.1 4 -297.675 0.20 5 -288.374 2.10 1.80610 33.3 6 66.359 2.06 7 66.691 12.93 1.43700 95.1 8 14668.598 17.05 9 64.298 6.21 1.89286 20.4 10 132.593 0.32 11 69.442 2.72 1.83400 37.2 12 38.710 9.67 1.43875 94.7 13 95.465 9.65 14 (Aperture) ∞ 4.50 15 -477.364 1.90 1.61800 63.4 16 61.827 32.21 17 115.625 2.10 1.89286 20.4 18 72.037 7.20 1.53172 48.8 19 -92.175 2.10 20 110.462 5.13 1.80610 33.3 21 -136.740 1.60 1.53775 74.7 22 39.052 4.91 23 -91.721 1.60 1.72916 54.7 24 73.953 6.75 25 87.265 6.00 1.65412 39.7 26 -746.562 2.75 27 92.618 10.23 1.72047 34.7 28 -56.836 2.10 1.80810 22.8 29 -669.731 1.64 30 145.532 1.40 1.92286 20.9 31 64.398 6.12 1.49700 81.5 32 -62.120 3.30 33 -93.129 1.30 1.77250 49.6 34 21.107 10.15 1.71736 29.5 35 -32.887 0.90 36 -24.583 1.50 1.72916 54.7 37 38.446 9.51 1.54072 47.2 38 -22.396 0.38 39 -35.368 1.30 1.65160 58.5 40 45.856 0.30 41 38.488 8.05 1.73800 32.3 42 -25.087 1.30 1.92286 20.9 43 -714.778 87.88 Image plane ∞ Various data Focal length 780.00 F-number 5.90 Half angle of view 1.59 Image height 21.64 Lens total length 437.12 BF 87.88 Lens group data Group starting plane focal length 1 1 196.48 2 15 -88.45 3 17 -251.98 The following table shows the values ​​for the above-mentioned conditional expressions in each example.

[0039] [Table 1]

[0040] 9 is a schematic diagram (schematic diagram) of an imaging device (digital still camera) as an optical apparatus according to an embodiment of the present invention. The imaging device of this embodiment includes a camera body 10, an optical system 11, and an imaging element (photoelectric conversion element) 12 that photoelectrically converts an image formed by the optical system 11. The optical system 11 is an optical system L0 according to any of the above-described embodiments, and is held by a holding member (lens barrel). The imaging element 12 is an element that receives light from the optical system 11 to capture an image of an object, and may be a photoelectric conversion element such as a CCD sensor or a CMOS sensor.

[0041] The imaging device according to this embodiment is assumed to be an integrated lens camera in which the camera body 10 and the optical system 11 are integrated, but it may also be an interchangeable lens camera. For example, an optical device (lens device) in which a holding member for holding the optical system 11 is detachable from the camera body 10 serving as the imaging device may be used. The optical systems of the respective embodiments are not limited to the imaging devices described above, but can also be applied to various optical devices such as silver halide film cameras, digital video cameras, telescopes, binoculars, and projectors (projection devices).

[0042] Although the preferred embodiments and examples of the present invention have been described above, the present invention is not limited to these embodiments and examples, and various combinations, modifications, and changes are possible within the scope of the gist of the present invention. [Explanation of symbols]

[0043] L0 optical system L1 First lens group L2 Second lens group L3: Third lens group

Claims

1. An optical system comprising a first lens group having positive refractive power, a second lens group having positive or negative refractive power that moves during focusing, and a third lens group having negative refractive power, which are arranged in this order from the object side to the image side, and in which the spacing between adjacent lens groups changes during focusing, the lens arranged closest to the object side in the first lens group is a positive meniscus lens with a convex surface facing the object side, Let TL be the distance on the optical axis from the lens surface closest to the object to the lens surface closest to the image, TL3 be the distance on the optical axis from the lens surface closest to the object in the third lens group to the lens surface closest to the image in the third lens group, SD3 be the sum of thicknesses on the optical axis of the lenses in the third lens group, and DM3 be the thickness on the optical axis of the lens in the third lens group that has the largest thickness on the optical axis. 0.10<TL3 / TL<0.40 0.70<SD3 / TL3<0.90 0.05<DM3 / TL3<0.14 An optical system characterized by satisfying the following conditional expression:

2. When the distance on the optical axis from the lens surface closest to the object side to the image plane is LD and the focal length of the optical system when focused at infinity is f, 0.45<LD / f<0.80 2. The optical system according to claim 1, wherein the following condition is satisfied:

3. When the distance on the optical axis from the lens surface closest to the image side to the image plane is BF, and the distance on the optical axis from the lens surface closest to the object side to the image plane is LD, 0.15<BF / LD<0.27 3. The optical system according to claim 1, wherein the following condition is satisfied:

4. When the focal length of the third lens group is f3 and the focal length of the optical system when focused at infinity is f, -0.50<f3 / f<-0.10 4. The optical system according to claim 1, wherein the following condition is satisfied:

5. When the Abbe number of the lens with the largest Abbe number based on the d line among the positive lenses included in the third lens group is vd3P, 73<vd3P<97 5. The optical system according to claim 1, wherein the following condition is satisfied:

6. When the refractive index of the lens with the largest refractive index for the d-line among the negative lenses included in the third lens group is nd3N, 1.85<nd3N<2.2 6. The optical system according to claim 1, wherein the following condition is satisfied:

7. 7. The optical system according to claim 1, wherein the third lens group has a first subgroup, a second subgroup, and a third subgroup arranged in this order from the object side to the image side, the first subgroup and the third subgroup being stationary during image blur compensation, and the second subgroup being movable in a direction including a component perpendicular to the optical axis during image blur compensation.

8. 8. The optical system according to claim 7, wherein the first subgroup has a positive refractive power.

9. 9. The optical system according to claim 7, wherein the second subgroup has negative refractive power.

10. 10. The optical system according to claim 7, wherein the third subgroup has a negative refractive power.

11. 11. The optical system according to claim 1, wherein the second lens group has a negative refractive power.

12. 12. The optical system according to claim 11, wherein the second lens group moves toward the image side during focusing from infinity to a close distance.

13. 13. The optical system according to claim 1, wherein the second lens group is composed of one lens.

14. 14. The optical system according to claim 1, wherein, of the distances on the optical axis between two adjacent lenses, the distance between the lens located closest to the object and the lens adjacent to said lens is the longest.

15. 15. The optical system according to claim 1, wherein the first lens group and the third lens group are stationary during focusing.

16. 16. The optical system according to claim 1, wherein an aperture stop is disposed between the first lens group and the second lens group.

17. An imaging device comprising: the optical system according to claim 1; and an imaging element for capturing an image of an object via the optical system.

18. An optical device comprising: the optical system according to claim 1; and a holding member for holding the optical system.

Images