JP2019003074A - Converter lens and imaging apparatus having the same - Google Patents

Abstract

To provide a converter lens having a function of making a focal distance of an interchangeable lens into a short focus, the converter lens capable of calibrating each aberration excellently, and an imaging apparatus having the converter lens.SOLUTION: A converter lens is arranged on an image side of interchangeable lens, and makes a focal distance of the interchangeable lens into a short focus. An average refractive index Nd of a positive lens composing the converter lens, a curvature radius G1R1 of a lens closest to an object of the converter lens and a composite focal distance f of the converter lens are appropriately set respectively.SELECTED DRAWING: Figure 3

Description

  The present invention relates to an image pickup optical system and an image pickup apparatus that can be mounted with an interchangeable lens and have a function of displacing the focal length of the interchangeable lens.

  In recent years, imaging devices such as television cameras, movie cameras, photographic cameras, video cameras, and the like have been desired to achieve both high pixels and downsizing, and imaging devices having small-size imaging elements are required. . On the other hand, there is a demand for users to use existing interchangeable lens assets. Therefore, for example, there is a strong need to use a full-size or APS format interchangeable lens for an image pickup apparatus having a smaller image pickup device. However, when an interchangeable lens having a large format of the image sensor is attached to an image pickup apparatus having a small image sensor, the angle of view of the interchangeable lens is telephoto.

  Therefore, it is necessary to arrange an optical system for shortening the focal length of the interchangeable lens between the interchangeable lens and the image pickup device and reduce the image circle of the interchangeable lens.

  Conventionally, various methods have been proposed in which an optical system is disposed between a photographic optical system (main lens system) and an image sensor to shorten the focal length of the photographic optical system. For example, Patent Documents 1 and 2 propose a converter lens that shortens the focal length of an interchangeable lens by inserting an optical system between an interchangeable lens that is a photographing optical system and an imaging apparatus.

JP 2000-121932 A Japanese Patent Laying-Open No. 2015-40003

  In Patent Documents 1 and 2 described above, correction of various aberrations is insufficient and there is room for improvement. Accordingly, an object of the present invention is to provide a converter lens having a function of shortening the focal length of an interchangeable lens, having a large reduction magnification, and high optical performance, and an imaging device having the converter lens. .

In order to achieve the above object, the converter lens of the present invention comprises:
A converter lens that is disposed on the image side of the interchangeable lens and shortens the focal length of the interchangeable lens,
When the average refractive index of the positive lens of the converter lens is Ndp, the radius of curvature of the lens closest to the interchangeable lens of the converter lens is G1R1, and the focal length of the entire converter lens is f,
1.70 <Ndp <1.95
0.15 <G1R1 / f <0.3
It is characterized by satisfying.

  According to the present invention, a converter lens having a function of reducing the focal length of an interchangeable lens and having high optical performance, and an imaging device having the converter lens are obtained.

Cross-sectional view of interchangeable lens 1 at wide angle end, focusing on infinity Longitudinal aberration diagram of interchangeable lens 1 at the wide-angle end and focusing on infinity Sectional view of the lens with the converter lens of Example 1 attached to the interchangeable lens 1 Longitudinal aberration diagram when the interchangeable lens 1 is mounted on the interchangeable lens 1 and the interchangeable lens 1 is in the wide-angle end and focused at infinity. Sectional view of the lens when the converter lens of Example 2 is mounted on the interchangeable lens 1 Longitudinal aberration diagram when the interchangeable lens 1 is mounted on the interchangeable lens 1 and the interchangeable lens 1 is in the wide-angle end and focused at infinity. Sectional drawing of the lens with the converter lens of Example 3 attached to the interchangeable lens 1 Longitudinal aberration diagram when the interchangeable lens 1 is mounted on the interchangeable lens 1 and the interchangeable lens 1 is in the wide-angle end and focused at infinity. Sectional drawing of the lens with the converter lens of Example 4 attached to the interchangeable lens 1 Longitudinal aberration diagram when the interchangeable lens 1 is mounted on the interchangeable lens 1 and the interchangeable lens 1 is in the wide-angle end and focused at infinity. Cross-sectional view of interchangeable lens 2 at wide-angle end, focusing on infinity Longitudinal aberration diagram of interchangeable lens 2 at the wide-angle end and focusing on infinity Lens sectional view of the state in which the converter lens of Example 5 is mounted on the interchangeable lens 2 Longitudinal aberration diagram when the interchangeable lens 2 is mounted on the interchangeable lens 2 and the interchangeable lens 2 is in the wide-angle end and focused at infinity. Explanatory drawing of paraxial arrangement when a converter lens is attached to an interchangeable lens

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. FIG. 1 is a cross-sectional view of a lens when the converter lens according to each embodiment of the present invention is mounted and the interchangeable lens 1 as an example is focused on an infinite object at a wide angle end (focal length: f = 17.50 mm). It is. In FIG. 1, U1 is a first lens group having a positive refractive power, U2 is a second lens group having a negative refractive power, U3 is a third lens group having a positive refractive power, and U4 has a negative refractive power. The fourth lens group U5 is a fifth lens group having a positive refractive power. During zooming from the wide-angle end to the telephoto end, the lenses U1 to U5 are moved.

  Focusing from an infinite object to a close object is performed by the second lens unit U2. SP is an aperture stop, which is disposed in the third lens unit U3. I is an imaging surface, which corresponds to the imaging surface of the solid-state imaging device.

  FIG. 2 is a longitudinal aberration diagram when the interchangeable lens 1 is focused at infinity at the wide angle end (focal length: f = 17.50 mm). The interchangeable lens 1 is a zoom lens having a zoom ratio of 3.05, an F number of 2.8, and an imaging field angle of 73.4 degrees at the wide angle end. However, the focal length is a value when numerical data of an example described later is expressed in mm. This is the same in all the following embodiments.

  FIG. 3 is a lens cross-sectional view when the interchangeable lens is in focus at infinity at the wide-angle end with the converter lens of Example 1 of the present invention attached to the interchangeable lens 1. FIG. 4 is a longitudinal aberration diagram when the converter lens of Example 1 is mounted on the interchangeable lens 1 and the interchangeable lens is focused at infinity at the wide angle end. Example 1 is a converter lens having a reduction magnification of 0.65 times that converts the focal length range of the interchangeable lens 1 to 11.38 to 34.68 and converts Fno to 1.82.

  FIG. 5 is a lens cross-sectional view when the interchangeable lens is in focus at infinity at the wide-angle end with the converter lens of Example 2 of the present invention attached to the interchangeable lens 1. FIG. 6 is a longitudinal aberration diagram when the interchangeable lens is in focus at infinity at the wide-angle end with the converter lens of Example 2 attached to the interchangeable lens 1. The second embodiment is a converter lens having a reduction ratio of 0.6, which converts the focal length range of the interchangeable lens 1 to 10.5 to 32.01 and converts Fno to 1.68.

  FIG. 7 is a lens cross-sectional view when the interchangeable lens is in focus at infinity at the wide-angle end with the converter lens of Example 3 of the present invention attached to the interchangeable lens 1. FIG. 8 is a longitudinal aberration diagram when the converter lens of Example 3 is mounted on the interchangeable lens 1 and the interchangeable lens is focused at infinity at the wide angle end. Example 3 is a converter lens with a reduction ratio of 0.7 times that converts the focal length range of the interchangeable lens 1 to 12.25 to 37.35 and converts Fno to 1.96.

  FIG. 9 is a lens cross-sectional view when the interchangeable lens is in focus at infinity at the wide-angle end with the converter lens of Example 4 of the present invention attached to the interchangeable lens 1. FIG. 10 is a longitudinal aberration diagram when the interchangeable lens is mounted on the interchangeable lens 1 and the interchangeable lens is focused at infinity at the wide angle end. Example 4 is a converter lens having a reduction magnification of 0.65 times that converts the focal length range of the interchangeable lens 1 to 11.38 to 34.68 and converts Fno to 1.82.

  FIG. 11 is a lens cross-sectional view when the interchangeable lens 2 (focal length: f = 34.2 mm) as an example to which the converter lens of each embodiment of the present invention is attached is focused on an object at infinity. In FIG. 11, U1 is a first lens group having a negative refractive power, U2 is a second lens group having a positive refractive power, and U3 is a third lens group having a positive refractive power. Focusing from an infinite object to a close object is performed by moving the second lens unit U2 and the third lens unit U3. SP is an aperture stop, which is disposed in the third lens unit U3. I is an imaging surface, which corresponds to the imaging surface of the solid-state imaging device.

  FIG. 12 is a longitudinal aberration diagram when the interchangeable lens 2 (focal length: f = 34.2 mm) is focused at infinity. FIG. 13 is a lens cross-sectional view when the interchangeable lens is in focus at infinity with the converter lens of Example 5 of the present invention attached to the interchangeable lens 2. FIG. 14 is a longitudinal aberration diagram when the interchangeable lens is in focus at infinity with the converter lens of Example 5 attached to the interchangeable lens 2. Example 5 is a converter lens with a reduction ratio of 0.7 times that converts the focal length of the interchangeable lens 2 to 23.92 mm and converts Fno to 1.02.

  In the lens cross-sectional views of each example, the left side is the object side and the right side is the image side. In the lens cross-sectional views of Examples 1 to 5, ML is an interchangeable lens, and CL is a converter lens. SP is a stop (aperture stop), and is disposed in the interchangeable lens. F is an optical filter such as an ND filter, a low-pass filter, or an IR cut filter. I is an imaging surface, which corresponds to the imaging surface of a solid-state imaging device (photoelectric conversion device) that receives an image formed by an interchangeable lens and a converter lens and performs photoelectric conversion.

  In the converter lens of the present invention, each aberration diagram uses the e-line (wavelength 546.1 nm) as a reference wavelength.

  In the aberration diagrams, the solid line, the two-dot chain line, the one-dot chain line, and the dotted line in the spherical aberration are the e-line, g-line, C-line, and F-line, respectively. A dotted line and a solid line in astigmatism are a meridional image plane and a sagittal image plane in the e-line, respectively. The lateral chromatic aberration is represented by a g-line (two-dot chain line), a C-line (one-dot chain line), and an F-line (dotted line). ω is an imaging half angle of view (degree), and Fno is an F number. The spherical aberration is 0.5 mm, the astigmatism is 0.5 mm, the distortion is 5%, and the lateral chromatic aberration is drawn on a scale of 0.1 mm.

FIG. 15 shows a paraxial arrangement when a converter lens is attached to an interchangeable lens. In the drawing, MLR indicates the vertex position of the lens surface closest to the image side of the interchangeable lens. CL indicates a converter lens, Im indicates an image surface of the master lens, and Ic indicates an image surface after the converter lens is mounted. The paraxial relationship when the converter lens is mounted is expressed by the following equation.
β = S ′ / S (a)
1 / S ′ = 1 / S + 1 / fc (b)
Here, β is the reduction magnification of the converter lens. In order to satisfactorily correct various aberrations of the converter lens, it is effective to make β close to 1 and increase the focal length fc of the converter lens or increase S to increase the focal length fc of the converter lens. . When β of the converter lens is constant, S is increased, but in order to prevent interference with the interchangeable lens, it is necessary to position the object side principal point position of the converter lens closer to the object side.

  Therefore, the converter lens of the present invention is configured as follows, and various aberrations are favorably corrected by positioning the object side principal point position of the converter lens on the object side.

A converter lens that is disposed on the image side of the interchangeable lens and shortens the focal length of the interchangeable lens, wherein the average refractive index of the positive lens of the converter lens is Ndp, and the lens closest to the interchangeable lens of the converter lens When the curvature radius is G1R1 and the focal length of the entire converter lens is f,
1.70 <Ndp <1.95 (1)
0.1 <G1R1 / f <0.3 (2)
The following conditional expression is satisfied.

  Next, the technical meaning of each conditional expression described above will be described. Conditional expressions (1) and (2) are for correcting the various aberrations satisfactorily by positioning the principal point of the converter lens on the object side.

  Conditional expression (1) defines the range of the average refractive index of the converter lens. Thereby, when the object side principal point of the converter lens is positioned on the object side, reduction of various aberrations when the converter lens G1 has a strong refractive power is reduced. It also contributes to reducing the Petzval sum of the converter lens. If the upper limit of conditional expression (1) is exceeded, a glass material having a large refractive index is used, and a glass having a large dispersion is inevitably produced, so that it is difficult to correct axial chromatic aberration and lateral chromatic aberration.

  Conversely, when the lower limit of conditional expression (1) is exceeded, it is difficult to position the principal point on the object side, and it is difficult to reduce the reduction magnification β. Alternatively, high-order aberrations are greatly generated, and it is difficult to correct various aberrations, particularly field curvature aberration.

  Conditional expression (2) defines the relationship between the radius of curvature of the most object side lens of the converter lens and the focal length of the converter lens. Thereby, the principal point position of the converter lens is located on the object side. In addition, various aberrations are favorably corrected by strongly bending off-axis rays on the most object-side surface and lowering the ray height on subsequent surfaces.

  If the upper limit of conditional expression (2) is exceeded, the radius of curvature of the most object-side lens of the converter lens becomes too large, making it difficult to position the principal point on the object side, and making it difficult to reduce the reduction magnification β. It becomes. Alternatively, the focal length f becomes too small and it becomes difficult to correct the Petzval sum.

On the other hand, if the lower limit of conditional expression (2) is exceeded, the radius of curvature of the lens closest to the object side of the converter lens becomes too small and high-order aberrations occur greatly, making it difficult to correct various aberrations, particularly field curvature aberrations. Become. Alternatively, the focal length f becomes too large, and it becomes difficult to reduce the reduction magnification β. More preferably, the numerical ranges of the conditional expressions (1) and (2) are set as follows.
1.70 <Ndp <1.85 (1a)
0.15 <G1R1 / f <0.3 (2a)
Further, in the present invention, when the refractive index of the second positive lens from the object side of the converter lens is Ndp2 and the Abbe number is νdp2, it is preferable that the following conditional expression is satisfied.
1.43 <Ndp2 <1.8 (3)
46 <νdp (4)

Conditional expressions (3) and (4) are conditional expressions mainly for favorably correcting the lateral chromatic aberration and the axial chromatic aberration. Conditional expressions (3) and (4) define that the second positive lens from the object side of the converter lens is a low dispersion material. If the lower limit of conditional expression (4) is exceeded, the lateral chromatic aberration will become too large. Alternatively, it is difficult to correct longitudinal chromatic aberration when correcting the lateral chromatic aberration with another lens. More preferably, conditional expression (3) is preferably set as follows.
1.43 <Ndp2 <1.65 (3a)
62 <νdp <95 (4a)
Furthermore, in the present invention, when the radius of curvature of the surface of the converter lens having the strongest negative power is GnR, it is preferable that the following conditional expression is satisfied.
5 <(G1R1 + GnR) / (G1R1-GnR) <15 (5)
Conditional expression (5) is a conditional expression mainly for favorably correcting curvature of field aberration and spherical aberration. If the upper limit of conditional expression (5) is exceeded, G1R1 will be too small, or GnR will be too large, making it difficult to correct field curvature aberration. Conversely, if the lower limit of conditional expression (5) is exceeded, it will be difficult to correct spherical aberration. More preferably, conditional expression (5) is set as follows.
6 <(G1R1 + GnR) / (G1R1-GnR) <12 (5a)
Further, in the present invention, it is preferable that the converter lens has a cemented lens of a positive lens and a negative lens on the most object side, and the following conditional expression is satisfied when the average refractive index of the cemented lens is Nd1.
1.8 <Nd1 <1.95 (6)
Conditional expression (6) is a conditional expression for satisfactorily correcting spherical aberration and Petzval sum. When the upper limit of conditional expression (6) is exceeded, the refractive index difference between the positive lens and the negative lens becomes small, and it becomes difficult to reduce Petzval. Conversely, when the lower limit of conditional expression (6) is exceeded, it is difficult to correct spherical aberration. More preferably, conditional expression (6) is preferably set as follows.
1.85 <Nd1 <1.95 (6a)
Further, in the present invention, the converter lens is composed of a first lens component composed of a positive cemented lens, a second lens component composed of a negative lens, and a third lens component composed of a positive cemented lens or a single lens in order from the object side. . When the focal length of the first lens component is f1, the focal length of the second lens component is f2, and the focal length of the third lens component is f3, it is preferable that the following conditional expression is satisfied.

0.5 <f1 / f3 <3.0 (7)
−1.5 <f2 / f3 <−0.5 (8)
Conditional expressions (7) and (8) are conditional expressions for making the object side principal point of the converter lens closer to the object side and correcting various aberrations satisfactorily.

  Next, the converter lens configuration of each example will be described.

[Example 1]
The configuration of the converter lens of Example 1 will be specifically described with reference to FIG. In FIG. 3, ML is an interchangeable lens 1 and CL is a converter lens. SP is a stop (aperture stop), and is disposed in the interchangeable lens. F is an optical filter such as an ND filter, a low-pass filter, or an IR cut filter.
Hereinafter, the lens surfaces constituting each lens group are counted in order from the object side to the image side, and the i-th lens surface is referred to as the i-th surface.

  In numerical data described later, the converter lens corresponds to the 34th to 41st surfaces. The converter lens is composed of a cemented lens of a positive lens and a negative lens, a negative lens, and a cemented lens of a positive lens and a negative lens in order from the object side. The 38th surface has the strongest negative power in this embodiment.

  Table 1 shows values corresponding to the conditional expressions of this example. This embodiment satisfies the conditional expressions (1) to (8), and has a function of shortening the focal length of the interchangeable lens to 0.65 times while correcting various aberrations satisfactorily. .

[Example 2]
The lens configuration of the converter lens of Example 2 will be specifically described with reference to FIG. In the converter lens of Example 2, the arrangement of the interchangeable lens, the diaphragm, and the optical filter is the same as that of Example 1.

  In numerical data described later, the converter lens corresponds to the 34th to 41st surfaces. The converter lens is composed of a cemented lens of a positive lens and a negative lens, a negative lens, and a cemented lens of a positive lens and a negative lens in order from the object side. The 38th surface has the strongest negative power in this embodiment.

  Table 1 shows values corresponding to the conditional expressions of this example. This example satisfies the conditional expressions (1) to (8), and has a function of shortening the focal length of the interchangeable lens to 0.6 times while correcting various aberrations satisfactorily. .

[Example 3]
The lens configuration of the converter lens of Example 3 will be specifically described with reference to FIG. In the converter lens of Example 3, the arrangement of the interchangeable lens, the diaphragm, and the optical filter is the same as that of Example 1.

  In numerical data described later, the converter lens corresponds to the 34th to 41st surfaces. The converter lens is composed of a cemented lens of a positive lens and a negative lens, a negative lens, and a cemented lens of a positive lens and a negative lens in order from the object side. The 38th surface has the strongest negative power in this embodiment.

  Table 1 shows values corresponding to the conditional expressions of this example. This embodiment satisfies the conditional expressions (1) to (8), and has a function of shortening the focal length of the interchangeable lens by 0.7 times while correcting various aberrations satisfactorily. .

[Example 4]
The lens configuration of the converter lens of Example 4 will be specifically described with reference to FIG. In the converter lens of Example 4, the arrangement of the interchangeable lens, the diaphragm, and the optical filter is the same as that of Example 1.

  In the numerical data described later, the converter lens corresponds to the 34th to 40th surfaces. The converter lens is composed of a cemented lens of a positive lens and a negative lens, a negative lens, and a positive lens in order from the object side. The 38th surface has the strongest negative power in this embodiment.

  Table 1 shows values corresponding to the conditional expressions of this example. This embodiment satisfies the conditional expressions (1) to (8), and has a function of shortening the focal length of the interchangeable lens to 0.65 times while correcting various aberrations satisfactorily. .

[Example 5]
The lens configuration of the converter lens of Example 5 will be specifically described with reference to FIG. In FIG. 13, ML is an interchangeable lens 2 and CL is a converter lens. SP is a stop (aperture stop), and is disposed in the interchangeable lens. The arrangement of the optical filter in the converter lens of Example 5 is the same as that of Example 1.

In numerical data described later, the converter lens corresponds to the 20th to 26th surfaces. The converter lens is composed of a positive lens lens, a negative lens, and a cemented lens of a positive lens and a negative lens in order from the object side. The surface having the strongest negative power in this embodiment is the 23rd surface.
Table 1 shows values corresponding to the conditional expressions of this example. This embodiment satisfies the conditional expressions (1) to (8), and has a function of shortening the focal length of the interchangeable lens by 0.7 times while correcting various aberrations satisfactorily. .

  Numerical examples corresponding to the embodiments of the present invention will be shown below. In each numerical example, i indicates the order of the surfaces from the object side, ri is the radius of curvature of the i-th surface from the object side, di is the i-th and i + 1-th interval from the object side, ndi , Νdi are the refractive index and Abbe number of the i-th optical member. BF is an air equivalent back focus. The last two surfaces are glass blocks such as filters.

The aspherical shape is the X axis in the optical axis direction, the H axis in the direction perpendicular to the optical axis, the light traveling direction is positive, R is the paraxial radius of curvature, k is the cone constant, and A4, A6, A8, and A10 are non- The spherical coefficient is expressed by the following equation. “E-Z” means “× 10 ^−Z ”.

  As mentioned above, although 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.

<Interchangeable lens 1>
Unit mm

Surface data surface number rd nd vd θgf
1 168.682 1.40 1.84670 23.8 0.6071
2 75.740 9.48 1.62300 58.2 0.5458
3 -4024.051 0.15
4 53.196 7.39 1.71300 53.9 0.5535
5 128.361 (variable)
6 * 115.749 0.08 1.52420 51.4 0.5579
7 96.572 1.20 1.80 400 46.6 0.5665
8 12.461 5.89
9 -37.361 1.00 1.80400 46.6 0.5665
10 31.417 0.10
11 24.773 5.51 1.76180 26.5 0.6023
12 -33.521 0.17
13 -29.935 1.00 1.80 400 46.6 0.5665
14 2308.124 (variable)
15 27.412 2.15 1.48750 70.2 0.5245
16 30.874 2.85
17 (Aperture) ∞ 0.84
18 45.397 1.10 1.84670 23.8 0.6071
19 19.480 6.02 1.48750 70.2 0.5245
20 -38.720 0.15
21 * 28.790 5.70 1.58310 59.4 0.5437
22 -37.972 (variable)
23 -63.158 3.61 1.84670 23.8 0.6071
24 -18.782 0.80 1.72600 53.6 0.554
25 52.327 4.47
26 -37.992 4.70 1.51820 58.9 0.5446
27 -14.375 1.20 1.80 400 46.6 0.5665
28 -34.319 (variable)
29 -110.981 5.38 1.58310 59.4 0.5437
30 * -23.578 0.15
31 50.740 9.10 1.43880 94.9 0.4805
32 -21.931 1.50 1.84670 23.8 0.6071
33 -58.262 (variable)
Image plane ∞

Aspheric data 6th surface
K = 0.00000e + 000 A 4 = 1.22510e-005 A 6 = -8.34390e-008 A 8 = 3.99040e-010 A10 = -9.84000e-013

21st page
K = 0.00000e + 000 A 4 = -6.55760e-006 A 6 = 3.41340e-009 A 8 = 1.46780e-011 A10 = -4.58910e-014

30th page
K = 0.00000e + 000 A 4 = 2.96040e-006 A 6 = -3.52200e-009 A 8 = 3.38850e-011 A10 = -6.69840e-014

Various data Zoom ratio 3.05
Wide angle Medium telephoto focal length 17.50 27.96 53.35
F number 2.80 2.80 2.80
Angle of view 36.65 24.97 13.71
Image height 13.02 13.02 13.02
Total lens length 148.81 155.98 172.70
BF 35.51 37.38 40.31

d 5 3.70 15.38 34.24
d14 12.96 6.57 1.50
d22 1.49 6.95 12.76
d28 12.06 6.61 0.80
d33 35.51 37.38 40.31

Entrance pupil position 31.63 53.12 110.83
Exit pupil position -309.87 -168.40 -101.59
Front principal point position 48.24 77.28 144.12
Rear principal point position 18.01 9.42 -13.04

Zoom lens group data group Start surface Focal length
1 1 96.90
2 6 -11.71
3 15 21.61
4 23 -32.17
5 29 39.76

<Numerical Example 1>
Unit mm

Surface data surface number rd nd v θgf
33 -58.262 3.00
34 16.612 4.03 2.00 100 29.1 0.5997
35 33.115 1.50 1.85478 24.8 0.6122
36 18.533 1.31
37 28.966 1.40 1.85478 24.8 0.6122
38 12.649 3.36
39 19.121 6.00 1.59522 67.7 0.5442
40 -23.202 1.35 1.58267 46.4 0.5671
41 -3322.928 3.00
42 ∞ 2.00 1.51680 64.1 0.5393
43 ∞ 2.00
Image plane ∞

Various data

Focal length 11.36
F number 1.82
Angle of view 36.67
Statue height 8.46
Total lens length 142.26
BF 2.00

Entrance pupil position 31.56
Exit pupil position 63.62
Front principal point position 45.02
Rear principal point position -9.37

<Numerical Example 2>
Unit mm

Surface data surface number rd nd vd θgf
33 -58.262 3.00
34 15.835 4.29 2.00 100 29.1 0.5997
35 31.580 1.50 1.85478 24.8 0.6122
36 16.393 1.36
37 24.362 1.40 1.85478 24.8 0.6122
38 11.613 2.32
39 15.716 6.53 1.59522 67.7 0.5442
40 -19.498 1.35 1.64769 33.8 0.5939
41 -213.438 2.00
42 ∞ 2.00 1.51680 64.1 0.5393
43 ∞ 2.00
Image plane ∞

Various data

Focal length 10.49
F number 1.68
Angle of view 36.67
Statue height 7.81
Total lens length 141.04
BF 2.00

Entrance pupil position 31.56
Exit pupil position 46.45
Front principal point position 44.53
Rear principal point position -8.49

<Numerical Example 3>
Unit mm

Surface data surface number rd nd vd θgf
33 -58.262 3.00
34 19.072 4.28 2.00100 29.1 0.5997
35 23.278 1.50 1.85478 24.8 0.6122
36 20.150 1.30
37 33.834 1.40 1.85478 24.8 0.6122
38 15.816 1.38
39 23.918 9.25 1.59522 67.7 0.5442
40 -19.075 1.35 1.58267 46.4 0.5671
43 ∞ 3.00
Image plane ∞

Various data

Focal length 12.24
F number 1.96
Angle of view 36.67
Statue height 9.11
Total lens length 144.75
BF 3.00

Entrance pupil position 31.56
Exit pupil position 137.94
Front principal point position 44.91
Rear principal point position -9.24

<Numerical Example 4>
Unit mm

Surface data surface number rd nd vd θgf
33 -58.262 3.00
34 16.060 4.03 1.90043 37.4 0.5774
35 29.659 1.50 1.85478 24.8 0.6122
36 17.322 1.35
37 25.974 1.40 1.64769 33.8 0.5939
38 11.955 3.54
39 16.221 8.07 1.49700 81.5 0.5374
40 556.414 2.08
41 ∞ 2.00 1.51680 64.1
42 ∞ 2.00
Image plane ∞

Focal length 11.36
F number 1.82
Angle of view 36.67
Statue height 8.46
Total lens length 142.27
BF 2.00

Entrance pupil position 31.56
Exit pupil position 61.26
Front principal point position 45.11
Rear principal point position -9.36

<Interchangeable lens 2>
Unit mm

Surface data surface number rd nd vd θgf
1 320.116 2.80 1.51633 64.1 0.5352
2 41.977 5.78
3 174.176 2.30 1.51823 58.9 0.5456
4 39.095 14.53
5 83.274 4.44 1.77250 49.6 0.5521
6 -395.333 6.26
7 57.067 5.14 1.77250 49.6 0.5521
8 -200.681 8.71
9 607.365 6.47 1.77250 49.6 0.5521
10 -28.883 1.50 1.65412 39.7 0.5737
11 57.419 4.23
12 (Aperture) ∞ 7.82
13 -19.812 1.60 1.80518 25.4 0.6161
14 162.417 4.90 1.83481 42.7 0.5642
15 * -75.797 0.20
16 -470.465 6.60 1.77250 49.6 0.5521
17 -32.806 0.20
18 -154.187 6.32 1.77250 49.6 0.5521
19 -34.950 39.35
Image plane ∞

Aspheric data 15th surface
K = 4.82454e + 000 A 4 = 1.27386e-005 A 6 = 2.46580e-009 A 8 = -1.63965e-011 A10 = 1.16481e-014

Focal length 34.20
F number 1.45
Angle of View 32.32
Statue height 21.64
Total lens length 129.16
BF 39.35

Entrance pupil position 35.84
Exit pupil position -47.92
Front principal point position 56.64
Rear principal point position 5.15

<Numerical example 5>
Unit mm

Surface data surface number rd nd vd θgf
19 -34.950 3.00
20 25.719 7.16 1.95375 32.3 0.5898
21 52.039 1.29
22 63.455 1.40 1.85478 24.8 0.6122
23 19.255 4.57
24 40.973 10.88 1.59522 67.7 0.5442
25 -36.355 1.35 1.54814 45.8 0.5685
26 -231.460 2.13
27 ∞ 2.00 1.51680 64.1 0.5393
28 ∞ 2.00
Image plane ∞

Focal length 23.92
F number 1.02
Angle of View 32.33
Statue height 15.14
Total lens length 125.59
BF 2.00


Entrance pupil position 35.80
Exit pupil position -136.11
Front principal point position 55.58
Rear principal point position -21.92

101 Imaging Device 102 Optical System 103 Imaging Device 104 Mount 105 Optical Filter

Claims (6)

A converter lens that is disposed on the image side of the interchangeable lens and shortens the focal length of the interchangeable lens, wherein the average refractive index of the positive lens of the converter lens is Ndp, and the curvature of the lens closest to the object side of the converter lens When the radius is G1R1 and the combined focal length of the converter lens is f,
1.70 <Ndp <1.95
0.15 <G1R1 / f <0.3
A converter lens characterized by satisfying the following conditional expression: When the converter lens has at least two positive lenses, the refractive index of the second positive lens from the object side of the converter lens is Ndp2, and the Abbe number is νdp2,
1.43 <Ndp2 <1.8
46 <νdp <95
The converter lens according to claim 1, wherein: When the curvature radius of the surface having the strongest negative power of the converter lens is GnR,
5 <(G1R1 + GnR) / (G1R1-GnR) <15
The converter lens according to claim 1 or 2, wherein: The converter lens has a cemented lens of a positive lens and a negative lens on the most object side, and when the average refractive index of the cemented lens is Nd1,
1.8 <Nd1 <1.95
The converter lens according to any one of claims 1 to 3, wherein: The converter lens includes, in order from the object side, a first lens component including a positive cemented lens, a second lens component including a negative lens, and a third lens component including a positive cemented lens or a single lens. When the focal length of the component is f1, the focal length of the second lens component is f2, and the focal length of the third lens component is f3,
0.5 <f1 / f3 <3.0
−1.5 <f2 / f3 <−0.5
5. The converter lens according to claim 1, wherein:   An imaging apparatus comprising: the converter lens according to claim 1; and a solid-state imaging device that receives an image formed by the converter lens.