JP6516579B2 - Image pickup optical system and image pickup apparatus having the same - Google Patents

Description

  The present invention relates to an imaging optical system, and is suitable for an imaging apparatus such as a silver halide film camera, a digital still camera, a digital video camera, a surveillance camera, and a TV camera.

  An imaging optical system used in an imaging apparatus is required to have a wide angle of view and to have high optical performance with little aberration fluctuation during focusing.

  Conventionally, a negative lead type imaging optical system is known as an imaging optical system having a wide angle of view (Patent Document 1). In the imaging optical system of Patent Document 1, in order from the object side to the image side, a first lens group of negative refractive power, a second lens group of positive refractive power having an aperture stop, and a third lens group of negative refractive power Discloses an imaging optical system in which is disposed.

  In Patent Document 1, off-axis aberrations such as lateral chromatic aberration, curvature of field, and distortion generated from the first lens group are corrected by the third lens group by the symmetrical refractive power arrangement, and high optical performance is obtained. Further, at the time of focusing, the first lens group is fixed, and at least the second lens group is moved among the second lens group and the third lens group.

JP, 2013-7853, A

  In the imaging optical system in which the first lens group of negative refractive power, the second lens group of positive refractive power, and the third lens group of negative refractive power are arranged in order from the object side to the image side, the imaging optical system The incident angle of the passing off-axis light flux on the imaging surface tends to be large. Then, when the incident angle of the light flux to the imaging surface becomes large, a lot of shading occurs due to the pixel structure of the imaging device.

  In the imaging optical system including the three lens groups described above, in order to reduce the incident angle of the off-axis light beam to the imaging surface, the configuration of the third lens group is sequentially changed from the object side to the image side. A lens may be arranged. According to this, it is possible to reduce the incident angle of the off-axis light flux to the imaging surface.

  In addition, in order to obtain high optical performance over the entire screen, it is necessary to cancel the aberration of the first lens group and the aberration of the third lens group. However, when the third lens unit is configured of a negative lens and a positive lens, the action of canceling out the aberration of the first lens unit and the third lens unit becomes insufficient, and it becomes difficult to obtain high optical performance. For example, when the entire movement or a part of the lens unit is moved during focusing, aberration fluctuation due to focusing tends to be large.

  In the imaging optical system of Patent Document 1, since the refractive power of the positive lens included in the third lens group is strong, the incident angle of the off-axis light beam on the imaging surface can be reduced. However, the aberration with the first lens group Can not be canceled enough. In addition, since the second lens unit is moved during focusing, the symmetry of the refractive power arrangement is broken, and the variation of the off-axis aberration becomes large. If the third lens unit is moved to correct this, the structure becomes complicated.

  An object of the present invention is to provide an imaging optical system which has a wide angle of view and high optical performance and which has less aberration fluctuation due to focusing.

The imaging optical system according to the present invention comprises a first lens group of negative refractive power, a second lens group of positive refractive power, and a third lens group of negative refractive power, which are disposed in order from the object side to the image side. The first lens group is composed of one negative lens or two negative lenses, and the second lens group has a positive lens on the most object side, and includes a plurality of lenses, The lens unit is composed of a negative lens and a positive lens, which are disposed in order from the object side to the image side,
When focusing from infinity to near distance, the positive lens included in the third lens group is immobile, and the first lens group, the second lens group, and the negative lens included in the third lens group are objects. Move to the side,
The focal length of the first lens group is f1, the focal length of the third lens group is f3, the focal length of the negative lens included in the third lens group is f3n, and the focal point of the positive lens included in the third lens group When the distance is f3p,
0.65 <f1 / f3n <1.35
−2.00 <f3p / f3 <−1.00
It is characterized by satisfying the following conditional expression.

  According to the present invention, it is possible to obtain an imaging optical system having a wide angle of view, high optical performance, and little variation in aberration due to focusing.

Lens cross section of Example 1 (A) and (B) aberration diagrams when focusing on infinity and near distance in Example 1 Lens cross section of Example 2 (A) and (B) aberration diagrams when focusing on infinity and near distance in Example 2 Lens cross section of Example 3 (A) and (B) aberration diagrams when focusing on infinity and near distance of Example 3. Lens cross section of Example 4 (A) and (B) aberration diagrams when focusing on infinity and near distance according to Example 4. Principal part schematic view of the imaging device of the present invention

  Hereinafter, the imaging optical system of the present invention and an imaging apparatus having the same will be described. The imaging optical system according to the present invention comprises a first lens group of negative refractive power, a second lens group of positive refractive power, and a third lens group of negative refractive power, which are disposed in order from the object side to the image side. Be done. The first lens group is composed of one negative lens or two negative lenses. The second lens group has a positive lens on the most object side and includes a plurality of lenses. The third lens unit includes a negative lens and a positive lens, which are disposed in order from the object side to the image side.

  During focusing from infinity to near distance, the positive lens included in the third lens group is immobile, and the first lens group, the second lens group, and the negative lens included in the third lens group have the same locus or Move to the object side with different trajectories.

  FIG. 1 is a lens sectional view of Example 1. FIG. FIGS. 2A and 2B are aberration diagrams when an object at infinity according to Example 1 is focused at an object distance of 3 m. Here, the object distance is the time when numerical data of an embodiment to be described later is expressed in mm. This is all the same below. FIG. 3 is a lens sectional view of Example 2. FIG. FIGS. 4A and 4B are aberration diagrams when an object at infinity according to the second embodiment and an object distance of 3 m are focused. FIG. 5 is a cross-sectional view of a lens of Example 3. FIGS. 6A and 6B are aberration diagrams when an object at infinity according to Example 3 is focused at an object distance of 3 m.

  FIG. 7 is a cross-sectional view of a lens of Example 4. FIGS. 8A and 8B are aberration diagrams when an object at infinity according to Example 4 is focused at an object distance of 3 m. FIG. 9 is a schematic view of an essential part of an image pickup apparatus having the image pickup optical system of the present invention.

  The imaging optical system of each embodiment is used in an imaging apparatus such as a digital still camera, a digital video camera, and a silver halide film camera. In the lens sectional view, the left side is the object side (front), and the right side is the image side (rear). The imaging optical system of each embodiment may be used as a projection lens of a projector or the like. At this time, the left side is the screen side, and the right side is the projected image side.

  In the lens sectional view, LO is an imaging optical system. The imaging optical system LO includes a first lens unit L1 of negative refractive power, a second lens unit L2 of positive refractive power, and a third lens unit L3 of negative refractive power. SP denotes an aperture stop, which is disposed between lenses constituting the second lens unit L2. IP is an image plane, and when used as an imaging optical system of a digital video camera or digital still camera, the imaging surface of a solid-state imaging device (photoelectric conversion device) such as a CCD sensor or a CMOS sensor is located. In the case of a camera, the film surface is positioned.

  GB represents a low pass filter, an IR cut filter, etc., and can be disposed in front of the imaging surface as needed. Also, FGB is a glass block disposed closest to the object side, and is disposed to protect lenses after the glass block FGB. The glass block FGB may be omitted if unnecessary. The glass block FGB does not constitute the imaging optical system L0. A1 and A2 are negative lenses that constitute the first lens unit L1, and satisfy conditional expression (7) described later. G3n is a negative lens included in the third lens unit L3. G3p is a positive lens included in the third lens unit L3.

  The longitudinal aberration diagrams represent, in order from the left, spherical aberration, astigmatism, distortion, and lateral chromatic aberration. In the diagrams showing spherical aberration and lateral chromatic aberration, the solid line d represents d-line (587.6 nm), and the two-dot broken line g represents g-line (435.8 nm). In the diagrams showing astigmatism, solid line ΔS represents the sagittal direction of d-line, and broken line ΔM represents the meridional direction of d-line. Also, a diagram showing distortion represents distortion at d-line. Fno is an F number, and ω is a half angle of view (degree).

  The imaging optical system LO of the present invention includes the first lens unit L1 of negative refracting power and the third lens unit L3 of negative refracting power disposed substantially symmetrically with the aperture stop SP interposed between them, so that magnification chromatic aberration and image can be obtained. Off-axis aberrations such as surface curvature and distortion are corrected well. In general, when symmetrical refractive power arrangement is performed in a wide angle imaging optical system, off-axis light beams are diverged by the third lens unit having negative refractive power, and the incident angle of off-axis light beams on the imaging surface becomes large. , Resolution will be reduced.

  Therefore, in the imaging optical system LO of the present invention, the third lens unit L3 has a configuration in which the negative lens G3n and the positive lens G3p are disposed in order from the object side to the image side, and the converging action of the positive lens G3p The incident angle of the off-axis ray to the imaging surface is prevented from increasing. At this time, if the refractive powers of the negative lens G3n and the positive lens G3p are not appropriate, cancellation of the aberration by the first lens group L1 and the third lens group L3 becomes insufficient, off-axis aberration increases, and off-axis light flux The incident angle to the imaging surface of the lens is increased, and the resolution is reduced.

  Therefore, in each embodiment, in order to realize high optical performance over the entire screen, the refractive powers of the first lens unit L1 and the third lens unit L3 and the negative lens G3n and the positive lens G3p included in the third lens unit L3 are provided. The refractive power etc. are set appropriately. In addition, in order to reduce aberration fluctuation associated with focusing, when focusing from infinity to near distance, the positive lens G3p disposed closest to the image side and included in the third lens unit L3 is immobile. Then, each lens disposed on the object side of the positive lens G3p is moved integrally (in the same locus) to the object side.

  At this time, the negative lens G3n included in the first lens unit L1, the second lens unit L2, and the third lens unit L3 may be moved along different trajectories. Conventionally, in an imaging optical system in which refractive powers are arranged substantially symmetrically with respect to an aperture stop, an entire extension method in which all lenses are moved at the time of focusing is often used.

  On the other hand, in the imaging optical system L0 of the present invention, the positive lens G3p is disposed on the most image side of the third lens unit L3 in order to reduce the incident angle of the off-axis light beam on the imaging surface. At this time, the negative lens G3n included in the first lens unit L1 and the third lens unit L3 largely contributes to the correction of the off-axis aberration. Therefore, during focusing, the positive lens G3p disposed on the most image side of the third lens unit L3 is fixed. As a result, it is possible to reduce the incidence angle of the off-axis light beam on the imaging surface while reducing the aberration fluctuation during focusing.

The focal length of the first lens unit L1 is f1, and the focal length of the third lens unit L3 is f3. The focal length of the negative lens G3n included in the third lens unit L3 is f3n, and the focal length of the positive lens G3p included in the third lens unit L3 is f3p. At this time,
0.65 <f1 / f3n <1.35 (1)
-2.00 <f 3 p / f 3 <-1.00 (2)
Satisfy the following conditional expression.

  Next, technical meanings of the above-mentioned conditional expressions will be described. Conditional expression (1) is for reducing aberration fluctuation due to focusing while achieving high image quality. If the upper limit value or the lower limit value of conditional expression (1) is exceeded, the symmetry of the refractive power arrangement is lost, and correction of off-axis aberrations becomes difficult. In addition, aberration variation due to focusing also increases.

  Conditional expression (2) is for obtaining high optical performance while appropriately adjusting the incident angle range of the off-axis light flux to the imaging surface. When the refractive power of the positive lens G3p included in the third lens unit L3 becomes weak beyond the lower limit value of the conditional expression (2), the incident angle of the off-axis light flux on the imaging surface becomes large, and the resolving power decreases. If the refracting power of the positive lens G3p included in the third lens unit L3 becomes strong beyond the upper limit value of the conditional expression (2), the off-axis aberration generated from the first lens unit L1 is corrected by the third lens unit L3. Becomes difficult and the optical performance decreases.

In each embodiment, the above configuration provides an imaging optical system having a wide angle of view, high optical performance, and little variation in aberration due to focusing. In each embodiment, it is preferable to set the numerical range of the conditional expressions (1) and (2) as follows.
0.70 <f1 / f3n <1.30 (1a)
−1.85 <f3p / f3 <−1.05 (2a)

More preferably, the numerical range of the conditional expressions (1a) and (2a) may be set as follows.
0.74 <f1 / f3n <1.20 (1b)
−1.70 <f3p / f3 <−1.10 (2b)

  In each embodiment, it is more preferable to satisfy one or more of the following conditional expressions. The focal length of the imaging optical system L0 is f. Let L be the total lens length of the imaging optical system L0. The back focus is d3 img. The focal length of the second lens unit L2 is f2. The distance on the optical axis from the lens surface on the image side of the lens closest to the image side of the second lens unit L2 to the lens surface on the object side of the negative lens included in the third lens unit L3 is d23.

  Here, the total lens length is obtained by adding the value of back focus to the distance from the first lens surface to the final lens surface (optical total length). The back focus is a value in air conversion from the final lens surface to the image plane. The back focus d3img corresponds to an air-equivalent distance from the top of the lens surface on the image side of the positive lens G3p included in the first lens unit L3 to the image surface. At this time, it is preferable to satisfy one or more of the following conditional expressions.

2.00 <L / f <7.00 (3)
0.15 <d3img / f <0.55 (4)
0.65 <f2 / f <2.05 (5)
0.25 <d23 / f <0.65 (6)

In addition, when the Abbe number of the material of the negative lens included in the first lens group L1 is dd1 n, at least one negative lens included in the first lens group L1 is
65.0 <νd1n (7)
It is good to satisfy the conditional expression

  Next, technical meanings of the above-mentioned conditional expressions will be described. Condition (3) is for obtaining high optical performance while achieving downsizing of the entire system. If the total lens length becomes short beyond the lower limit of conditional expression (3), the refractive power of each lens group must be increased, various aberrations increase, and the resolving power decreases. In particular, the positive refractive power of the second lens unit L2 having a positive refractive power becomes too strong, and spherical aberration and coma aberration increase. If the total lens length becomes too long beyond the upper limit value of the conditional expression (3), the entire system becomes large.

  Conditional expression (4) is for obtaining high optical performance while making the entire system compact and making the incident angle of the off-axis light flux on the imaging surface appropriate. When the third lens unit L3 approaches the imaging surface beyond the lower limit of the conditional expression (4), the third lens unit L3 has negative refractive power, and hence the incident angle of the off-axis light flux on the imaging surface becomes large and the resolution Will decline. When the third lens unit L3 is positioned on the object side beyond the upper limit value of the conditional expression (4), the separation of the on-axis light beam and the off-axis light beam becomes insufficient, and off-axis aberrations are reduced while reducing on-axis aberrations. It is difficult to correct the

  Conditional expression (5) is for appropriately setting the refractive power of the second lens unit L2 and achieving high image quality. If the lower limit of conditional expression (5) is exceeded and the positive refractive power of the second lens unit L2 becomes too strong, spherical aberration and coma will increase, and the resolving power will decrease. When the positive refractive power of the second lens unit L2 becomes weak beyond the upper limit of the conditional expression (5), the entire system becomes large.

  The conditional expression (6) relates to the distance between the second lens unit L2 and the third lens unit L3, and by arranging the third lens unit L3 at a position where the on-axis light beam and the off-axis light beam are separated, It is for correcting the aberration of off-axis luminous flux while reducing it. When the distance between the second lens unit L2 and the third lens unit L3 narrows beyond the lower limit value of the conditional expression (6), the separation of the on-axis light beam and the off-axis light beam becomes insufficient, and the on-axis aberration is reduced. It becomes difficult to correct external aberrations well. If the distance between the second lens unit L2 and the third lens unit L3 is increased beyond the upper limit value of the conditional expression (6), the entire system becomes large.

  Conditional expression (7) mainly relates to good correction of lateral chromatic aberration with respect to the Abbe number of the material of the negative lens included in the first lens unit L1. The material satisfying the conditional expression (7) is one having low dispersibility. If it is out of the range of the conditional expression (7), the material becomes large in dispersion, and it becomes difficult to correct the magnification chromatic aberration. In the lens cross-sectional views of the embodiments, the negative lens that satisfies the conditional expression (7) is shown as a negative lens A1 and a negative lens A2.

Preferably, the numerical ranges of the conditional expressions (3) to (7) are set as follows.
2.10 <L / f <6.50 (3a)
0.20 <d3img / f <0.50 (4a)
0.75 <f2 / f <1.95 (5a)
0.30 <d23 / f <0.55 (6a)
66.0 <d d 1 n (7a)

More preferably, the numerical ranges of the conditional expressions (3a) to (7a) are set as follows.
2.40 <L / f <5.50 (3b)
0.25 <d3img / f <0.40 (4b)
0.80 <f2 / f <1.90 (5b)
0.32 <d23 / f <0.53 (6b)
67.0 <d d 1 n (7 b)

  Next, the lens configuration of each lens unit in each embodiment will be described. Hereinafter, the lenses constituting each lens group are arranged in order from the object side to the image side. In each embodiment, the first lens unit L1 having negative refractive power, the second lens unit L2 having positive refractive power, and the third lens unit L3 having negative refractive power, which are disposed in order from the object side to the image side. ing. The aperture stop SP is disposed in the lens unit of the second lens unit L2. A glass block FGB is disposed on the most object side to protect the lens having refractive power. The glass block FGB may not be used if it is not necessary.

Example 1
Example 1 will be described. The imaging optical system of Example 1 has a focal length of 28.00 mm, an F number of 2.80, and an imaging angle of view of 64.8 degrees. The first lens unit L1 is composed of a meniscus negative lens A1 having a convex surface facing the object side and a biconcave negative lens A2. By using low dispersion glass as the material of the negative lens A1 of the first lens group L1 and the negative lens A2, lateral chromatic aberration is corrected well.

  The second lens unit L2 includes a biconvex positive lens, a cemented lens in which a biconcave negative lens and a biconvex positive lens are cemented, an aperture stop SP, a biconvex positive lens, and a biconcave negative lens It has a cemented lens in which a positive meniscus lens with a convex surface facing the object side is cemented. Furthermore, it has a biconvex positive lens.

  The third lens unit L3 is composed of a biconcave negative lens G3n and a biconvex positive lens G3p. The lens side on the image side of the negative lens G3n is aspheric. As described above, the third lens unit L3 is disposed at a position where the incident height of the on-axis light beam and the incident height of the off-axial light beam are separated, and this aspheric surface is favorable for off-axis aberrations such as field curvature and distortion. It is corrected to.

  Focusing from infinity to near distance involves immobilizing the positive lens G3p disposed closest to the image side included in the third lens unit L3 and included in the first lens unit L1, the second lens unit L2, and the third lens unit L3. Is moved to the object side.

  That is, the positive lens G3p disposed closest to the image side is stationary, and the respective lenses disposed on the object side of the positive lens G3p are moved integrally (in the same locus) toward the object side. At the time of focusing, aberrational variation due to focusing is reduced by integrally moving the lens system on the object side with respect to the positive lens G3p that well corrects the off-axis aberration.

Example 2
The imaging optical system of Example 2 has a focal length of 35.0 mm, an F number of 2.80, and an imaging angle of view of 53.8 degrees. In the second embodiment, the lens configuration of the first lens unit L1 is the same as that of the first embodiment.

  The second lens unit L2 includes a biconvex positive lens, a cemented lens in which a biconcave negative lens and a biconvex positive lens are cemented, an aperture stop SP, a biconvex positive lens, and a biconcave negative lens And a cemented lens in which a positive biconvex lens is cemented. Furthermore, it has a biconvex positive lens. The third lens unit L3 is composed of a biconcave negative lens G3n and a meniscus positive lens G3p having a convex surface facing the object side. The lens surface of the negative lens G3n is aspheric. The focusing method is the same as in the first embodiment. By adopting the above configuration, the same effect as that of the first embodiment is obtained.

[Example 3]
The imaging optical system of Example 3 has a focal length of 33.0 mm, an F number of 2.80, and an imaging angle of view of 56.6 degrees. In the third embodiment, the lens configuration of the first lens unit L1 is the same as that of the first embodiment.

  The second lens unit L2 includes a biconvex positive lens, a cemented lens in which a biconcave negative lens and a biconvex positive lens are cemented, an aperture stop SP, a biconvex positive lens, and a biconcave negative lens And a cemented lens in which a positive biconvex lens is cemented. Furthermore, it has a biconvex positive lens. The lens configuration of the third lens unit L3 is the same as that of the first embodiment. The focusing method is the same as in the first embodiment. By adopting the above configuration, the same effect as that of the first embodiment is obtained.

Example 4
The imaging optical system of Example 4 has a focal length of 35.0 mm, an F number of 2.80, and an imaging angle of view of 53.8 degrees.

  The first lens unit L1 is composed of a biconcave negative lens A1. By using low dispersion glass as the material of the negative lens A1 of the first lens unit L1, lateral chromatic aberration is well corrected. The second lens unit L2 is a biconvex positive lens, a cemented lens in which a biconcave negative lens and a biconvex positive lens are cemented, an aperture stop SP, a biconvex positive lens, a biconcave negative lens, It has a cemented lens in which a positive biconvex lens is cemented. Furthermore, it has a biconvex positive lens. The lens configuration of the third lens unit L3 is the same as that of the first embodiment.

  The focusing method is the same as in the first embodiment. By adopting the above configuration, the same effect as that of the first embodiment is obtained.

  As mentioned above, although the preferable embodiment of this invention was described, this invention is not limited to these embodiment, A various deformation | transformation and change are possible within the range of the summary.

  Next, an embodiment using a digital still camera as an example of the image pickup apparatus of the present invention will be described with reference to FIG. In FIG. 9, reference numeral 20 denotes a camera body, and 21 denotes an imaging optical system according to the present invention. Reference numeral 22 denotes a solid-state imaging element (photoelectric conversion element) such as a CCD sensor or a CMOS sensor which is incorporated in the camera body and receives an object image formed by the imaging optical system 21.

Reference numeral 23 denotes a memory for recording information corresponding to a subject image photoelectrically converted by the imaging device 22. Reference numeral 24 denotes a finder for observing a subject image formed on a solid-state image sensor 22 and is configured by a liquid crystal display panel or the like. As described above, according to the present invention, it is possible to obtain a compact imaging device having high optical performance.

Specific numerical data of Examples 1 to 4 will be shown below. In each embodiment, i represents the order counted from the object side, ri is the radius of curvature of the i-th optical surface (i-th surface), and di is the on-axis between the i-th surface and the (i + 1) -th surface Indicates the interval. Also, ndi and νdi are the refractive index and Abbe number of the material of the i-th optical member with respect to the d-line, respectively. The aspheric surface shape is the X axis in the optical axis direction, the H axis in the direction perpendicular to the optical axis, the forward direction of light is positive, R is the paraxial radius of curvature, K is the conic constant, A4, A6, A8, A10, A12 When it is considered as an aspheric coefficient,

It is expressed by the following formula.

* Means a surface having an aspheric shape. " ^Ex " means 10-x. BF is a back focus in air conversion. The total lens length is a value obtained by adding back focus to the distance from the first lens surface to the final lens surface. Further, the relationship between the above-mentioned conditional expressions and numerical data is shown in Table 1.

Example 1
Unit mm

Surface data surface number rd nd dd effective diameter
1 2.00 1.51633 64.1 65.00
2 2.00 65.00
3 58. 393 2.50 1.43875 94.9 47. 14
4 23.741 12.01 38.44
5 -149.048 2.50 1.49700 81.5 37.74
6 32.600 18.63 34.66
7 39.474 8.12 1.85478 24.8 35.96
8-808.873 17.27 34.44
9-52.318 1.50 1.85478 24.8 20.03
10 23.464 6.63 1.59522 67.7 18.97
11-43.070 2.51 18.47
12 (F-stop) ∞ 2.00 17.81
13 25.993 6.72 1.59522 67.7 18.91
14-58.201 5.89 19.56
15 -33.053 2.00 1.65412 39.7 19.81
16 17.282 8.25 1.59522 67.7 21.84
17 109.559 0.15 23.63
18 30.375 7.24 1.80809 22.8 25.33
19 -102.258 9.31 25.13
20 -24.249 2.50 1.65412 39.7 22.92
21 * 133.021 (variable) 24.55
22 64.222 6.13 1.59522 67.7 28.93
23-144.001 7.26 30.30
24 2. 2.27 1.51633 64.1 45.00
25 1. 1.50 45.00
Image plane ∞

Aspheric surface data plane 21
K = 0.00000e + 000 A 4 = 3.04402e-005 A 6 = 2.62455e-008 A 8 = -1.08518e-010 A10 = 4.13171e-013 A12 =-1. 54603e-015

Focal length 28.00
F number 2.80
Half angle of view (degrees) 32.39
Image height 17.76
Lens total length 136.91
BF 10.25

Lens interval at focusing
Infinity object distance 3m
d21 4.01 4.41

Entrance pupil position 37.25
Exit pupil position -49.24
Front principal point position 49.80
Rear principal point position -26.50

Lens group data group Start surface Focal length Lens configuration length Front principal point position Rear side principal point position
L1 3-31.42 17.01 10.12-4.40
L2 7 43.87 68.29 59.15-49.01
L3 20 -62.19 12.64 -5.11-15.63

Single lens data lens Start surface Focal length
1 1 0.00
2 3 -93.23
3 5-53.58
4 7 44.23
5 9 -18.78
6 10 26.50
7 13 31.11
8 15-17.08
9 16 33.36
10 18 29.70
11 20 -31.16
12 22 75.45
13 24 0.00

Example 2
Unit mm

Surface data surface number rd nd dd effective diameter
1 2.00 1.51633 64.1 65.00
2 2.00 65.00
3 41.783 2.50 1.43875 94.9 38.13
4 24.486 8.99 33.40
5-72.201 2.50 1.49700 81.5 33.02
6 27.077 9.72 30.25
7 30.379 7.19 1.85478 24.8 32.17
8-330.526 11.00 31.17
9 -37.756 1.50 1.85478 24.8 21.16
10 21.718 5.79 1.59522 67.7 20.13
11-42.623 1.41 20.01
12 (F-stop) ∞ 2.00 19.01
13 29.602 5.74 1.59522 67.7 21.40
14 -47.172 8.19 21.91
15 -26.159 2.00 1.65412 39.7 22.26
16 21.598 8.22 1.59522 67.7 25.68
17 -94.704 0.85 27.12
18 38.837 7.32 1.80809 22.8 30.00
19 -120.044 13.21 29.74
20 -26.947 2.50 1.65412 39.7 25.97
21 * 314.026 Variable 27.55
22 51.818 3.85 1.59522 67.7 30.62
23 326.044 9.24 31.00
24 2. 2.27 1.51633 64.1 45.00
25 1. 1.50 45.00
Image plane ∞

Aspheric surface data plane 21
K = 0.00000e + 000A 4 = 2.08358e-005 A 6 = -5.14122e-009 A 8 = 3.88992e-011 A10 = -3.00860e-013 A12 = 4.77594e-016

Focal length 35.00
F number 2.80
Half angle of view (degrees) 26.90
Image height 17.76
Lens total length 120.16
BF 12.23

Lens interval at focusing
Infinity object distance 3m
d21 2.67 3.25

Entrance pupil position 33.24
Exit pupil position-50.20
Front principal point position 44.54
Rear principal point position -33.50

Lens group data group Start surface Focal length Lens configuration length Front principal point position Rear side principal point position
L1 3 -29.48 13.99 10.11-2.05
L2 7 41.03 61.22 45.87-50.61
L3 20 -63.30 9.02 -2.09 -8.88

Single lens data lens Start surface Focal length
1 1 0.00
2 3-141.03
3 5 -39.29
4 7 32.85
5 9-15.94
6 10 25.01
7 13 31.43
8 15-17.79
9 16 30.35
10 18 37.08
11 20-37.83
12 22 102.97
13 24 0.00

[Example 3]
Unit mm

Surface data surface number rd nd dd effective diameter
1 2.00 1.51633 64.1 65.00
2 2.00 65.00
3 76.302 2.50 1.43875 94.9 48.00
4 24.899 12.45 39.69
5 -94.624 2.50 1.43875 94.9 39.47
6 46.354 14.96 38.05
7 48.571 7.28 1.85478 24.8 40.46
8 -306.031 22.00 39.73
9-59.684 1.50 1.85478 24.8 23.05
10 29.465 5.43 1.59522 67.7 22.11
11-52.673 5.24 21.90
12 (F-stop) ∞ 2.00 19.83
13 36.394 5.02 1.59522 67.7 21.08
14 -58.395 8.30 21.62
15-36.082 2.00 1.6541 2 39.7 22.57
16 23.677 7.11 1.59522 67.7 25.04
17 -165.429 6.35 26.24
18 44.375 8.69 1.80809 22.8 31.65
19 -158.625 16.84 31.34
20-31.285 2.50 1.65412 39.7 27.35
21 * 112.065 variable 28.94
22 51.152 4.30 1.59522 67.7 30.52
23 -1931.351 8.38 31.00
24 2. 2.27 1.51633 64.1 45.00
25 1. 1.50 45.00
Image plane ∞

Aspheric surface data plane 21
K = 0.00000e + 000A 4 = 1.41170e-005 A 6 = 1.30405e-009 A 8 = 1.23055e-011 A10 =-2.19674e-014 A12 =-2.78134e-017

Focal length 33.00
F number 2.80
Half angle of view (degrees) 28.29
Image height 17.76
Lens total length 150.14
BF 11.37

Lens interval at focusing
Infinity object distance 3m
d21 1.02 1.57

Entrance pupil position 40.18
Exit pupil position-53.31
Front principal point position 53.31
Rear principal point position -31.50

Lens group data group Start surface Focal length Lens configuration length Front principal point position Rear side principal point position
L1 3-35.73 17.45 9.08-5.90
L2 7 60.38 80.93 86.20 -74.83
L3 20 -70.09 7.82 -1.56 -6.90

Single lens data lens Start surface Focal length
1 1 0.00
2 3 -85.51
3 5-70.53
4 7 49.51
5 9 -22.90
6 10 32.55
7 13 38.43
8 15-21.57
9 16 35.29
10 18 43.75
11 20 -37.13
12 22 83.79
13 24 0.00

Example 4
Unit mm

Surface data surface number rd nd dd effective diameter
1 2.00 1.51633 64.1 50.00
2 4.00 50.00
3-75.225 2.50 1.59522 67.7 32.93
4 26.866 12.10 29.47
5 37.808 5.58 1.85478 24.8 30.80
6 -1400.510 10.60 30.04
7 -137.910 1.50 1.85478 24.8 23.18
8 23.897 5.27 1.59522 67.7 21.94
9 -124.205 1.00 21.63
10 (aperture) 2.00 2.00 21.12
11 25.094 6.94 1.59522 67.7 23.51
12 -45.589 4.65 23.67
13 -26.960 2.00 1.65412 39.7 22.89
14 29.362 6.76 1.59522 67.7 24.63
15 -78.187 0.10 25.49
16 28.789 4.74 1.80809 22.8 26.64
17 107.387 13.65 25.91
18-19.467 2.50 1.65412 39.7 22.35
19 * 419.858 Variable 24.66
20 49.175 4.76 1.59522 67.7 30.39
21-272.953 6.67 31.00
22 2. 2.27 1.51633 64.1 45.00
23 1. 1.50 45.00
Image plane ∞

Aspheric surface data plane 19
K = 0.00000e + 000A 4 = 3.89624e-005 A 6 =-3.0.902e-008 A 8 = 2.78619e-010 A10 = -2.30065e-012 A12 = 5.33380e-015

Focal length 35.00
F number 2.80
Half angle of view (degrees) 26.90
Image height 17.76
Lens total length 100.93
BF 9.67

Lens interval at focusing
Infinity object distance 3m
d19 3.85 4.48

Entrance pupil position 25.38
Exit pupil position -43.37
Front principal point position 33.07
Rear principal point position -33.50

Zoom lens group data group Start surface Focal length Lens configuration length Front principal point position Rear side principal point position
L1 3 -32.96 2.50 1.14 -0.41
L2 5 31.47 51.14 28.22 -29.30
L2 18-55.09 11.11-4.43-13.70

Single lens data lens Start surface Focal length
1 1 0.00
2 3 -32.96
3 5 43.15
4 7-23.73
5 8 34.12
6 11 28.23
7 13 -21.19
8 14 36.72
9 16 47.40
10 18 -28.38
11 20 70.39
12 22 0.00

L0 Imaging optical system L1 First lens unit L2 Second lens unit L3 Third lens unit G3p Positive lens G3n Negative lens

Claims (8)

The first lens group having a negative refractive power, the second lens group having a positive refractive power, and the third lens group having a negative refractive power, which are disposed in order from the object side to the image side The second lens group has a positive lens on the most object side and includes a plurality of lenses, and the third lens group has an image from the object side It consists of a negative lens and a positive lens, arranged in order to the side,
When focusing from infinity to near distance, the positive lens included in the third lens group is immobile, and the first lens group, the second lens group, and the negative lens included in the third lens group are objects. Move to the side,
The focal length of the first lens group is f1, the focal length of the third lens group is f3, the focal length of the negative lens included in the third lens group is f3n, and the focal point of the positive lens included in the third lens group When the distance is f3p,
0.65 <f1 / f3n <1.35
−2.00 <f3p / f3 <−1.00
An imaging optical system satisfying the following conditional expression. When the focal length of the imaging optical system is f and the total lens length of the imaging optical system is L,
2.00 <L / f <7.00
The imaging optical system according to claim 1, which satisfies the following conditional expression. Assuming that the focal length of the imaging optical system is f and the back focus is d3 img,
0.15 <d3img / f <0.55
The imaging optical system according to claim 1 or 2, wherein the following conditional expression is satisfied. Assuming that the focal length of the imaging optical system is f and the focal length of the second lens group is f2,
0.65 <f2 / f <2.05
The imaging optical system according to any one of claims 1 to 3, wherein the following conditional expression is satisfied. The focal length of the imaging optical system is f, and the optical axis from the lens surface on the image side of the lens closest to the image in the second lens group to the lens surface on the object side of the negative lens included in the third lens group When the distance is d23,
0.25 <d23 / f <0.65
The imaging optical system according to any one of claims 1 to 4, wherein the following conditional expression is satisfied. Assuming that the Abbe number of the material of the negative lens included in the first lens group is d d1 n, at least one negative lens included in the first lens group is
65.0 <νd1n
The imaging optical system according to any one of claims 1 to 5, wherein the following conditional expression is satisfied.   The second lens group is composed of, in order from the object side to the image side, a positive lens, a cemented lens in which a negative lens and a positive lens are cemented, a positive lens, a cemented lens in which a negative lens and a positive lens are cemented, and a positive lens. The imaging optical system according to any one of claims 1 to 6, characterized in that   An image pickup apparatus comprising: the image pickup optical system according to any one of claims 1 to 7; and a solid-state image pickup device for receiving an image formed by the image pickup optical system.