JP2005300902A - Anamorphic converter, lens device, and photographic device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a rear converter type anamorphic converter capable of flange-back focus length adjustment. <P>SOLUTION: The anamorphic converter has at least one anamorphic lens, arranged on an image side of an imaging optical system and comprises a fixed 1st group, a 2nd group including the anamorphic lens, and a 3rd group with positive refractive power, in this order from the imaging optical system side, with a portion or the whole of the 3rd group being made movable in the optical axis direction. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention is an anamorphic converter suitable for a film camera, a television camera, a video camera, etc., which is arranged on the image side of an image forming optical system and converts an aspect ratio and shoots an image having an aspect ratio different from that of an image sensor. The present invention relates to a lens apparatus, and a photographing apparatus such as a film camera, a television camera, and a video camera.

  Various techniques for recording / reproducing by converting the aspect ratio of an image have been proposed. Especially for movies, as a cinemascope-type video recording / playback system with an aspect ratio of 2.35: 1, an anamorphic lens is used to optically compress the horizontal direction and shoot on film. A method of optically expanding and projecting an image on a film in the horizontal direction is generally used. Many anamorphic converters have been proposed that are attached to the object side of the imaging optical system (see, for example, Patent Documents 1 to 7).

Further, a rear converter that is attached to the image side of the imaging optical system has been proposed (see, for example, Patent Document 8).
JP-A-48-24048 JP-A-2-13916 Japanese Patent Laid-Open No. 3-25407 JP-A-5-188271 JP-A-5-188272 JP-A-6-82691 Japanese Patent No. 2817074 Japanese Patent No. 3021985

  In recent years, video technology has been improved in image quality, and digital cinema systems for shooting movies with HDTV systems are becoming common. In a digital cinema system, it is common to use an image sensor with an aspect ratio of 16: 9 (1.78: 1). However, for shooting in a cinemascope format with an aspect ratio of 2.35: 1, the image sensor side There is a demand for an anamorphic converter for improving the image quality by effectively utilizing these pixels.

  As an anamorphic converter for cine, appropriate aspect ratio conversion, no vignetting, sufficient use of the effective image plane of the imaging optical system, little reduction in peripheral light intensity, and wide zoom / focus range It is necessary to have high optical performance.

  On the other hand, the current HDTV system widely adopts an interchangeable lens type, and it is essential to provide a flange back adjusting mechanism on the lens side so that the lens flange back can be adjusted according to the camera.

  The front converter type has a simple configuration as proposed in Patent Document 2, Patent Document 6, Patent Document 7 and the like, and has an advantage that vignetting does not occur by ensuring an appropriate effective diameter regardless of the conversion ratio. On the other hand, there are problems such as an increase in size and a change in astigmatism due to focusing.

  Further, Patent Literature 1, Patent Literature 3, Patent Literature 4, Patent Literature 5, and the like have been proposed as techniques for correcting astigmatism by focusing. However, correction means in the converter is interlocked with the focus of the imaging optical system. There is a problem that a complicated mechanism is required.

  The rear converter type has the advantage that there is no astigmatism change due to focus. However, there is a problem that the flange back adjustment mechanism of the imaging optical system cannot be used because the center spot is generated when the incident light beam to the converter is deviated. An object of the present invention is to provide a rear converter type anamorphic converter which is particularly suitable for a digital cinema and is adjustable in flange back.

In order to achieve the object of the present invention, the present invention provides an anamorphic converter having at least one anamorphic lens arranged on the image side of an imaging optical system,
The anamorphic converter includes a front group having the anamorphic lens in order from the imaging optical system side, and a rear group having a positive refractive power, and the rear group can be moved in the optical axis direction of the imaging optical system. The configuration is as follows.

  As described above, in the anamorphic converter arranged on the image side of the imaging optical system, by appropriately setting the movable group, the rear converter that is optimal for digital cinema and has good optical performance and adjustable flange back can be used. An anamorphic converter of the type can be achieved.

(Function)
The first invention is composed of a front group in which the anamorphic converter has the anamorphic lens in order from the imaging optical system side, a rear group having a positive refractive power,
The rear group is movable in the optical axis direction of the imaging optical system.

In the second invention, the front group is composed of a first group fixed in order from the imaging optical system side, the second group including an anamorphic lens, and the rear group is composed of a third group having a positive refractive power,
The second group as a whole is integrated with the movable third group so as to be movable in the optical axis direction.

  The first invention and the second invention are conditions for enabling flange back adjustment in a rear converter type anamorphic converter without generating central assault.

As shown in FIG. 15, when the horizontal length of the image plane is X and the vertical length of the image plane is Y, the aspect ratio AR is
AR = X / Y (1)
It is represented by FIG. 16 is a schematic diagram of the imaging range of the imaging optical system, and FIG. 17 is a schematic diagram of the imaging range of the imaging means. From FIG. 16, the horizontal length of the effective screen size of the imaging range on the image plane of the imaging optical system is X1, the vertical length is Y1, the aspect ratio is AR1, and from FIG. When the length is X2, the vertical length is Y2, and the aspect ratio is AR2,
AR1 / AR2 = (X1 · Y2) / (X2 · Y1) (2)
It is represented by FIG. 18 shows a conceptual diagram of the imaging range after the aspect ratio conversion by the anamorphic converter. In order for an appropriate aspect ratio conversion to be performed, the conversion factor βx in the horizontal direction and the conversion factor βy in the vertical direction of the anamorphic converter are:
βx = X2 / X1 (3)
βy = Y2 / Y1 (4)
It is desirable that From the formulas (2) to (4), the ideal condition for the aspect ratio conversion is
(AR1 · βx) / (AR2 · βy) = 1 (5)
It becomes.

FIG. 19 shows a conceptual diagram of an output image during projection. When projecting, it is necessary to perform aspect ratio conversion opposite to that at the time of imaging to restore the original aspect ratio. Therefore, the horizontal length X4 and the vertical length Y4 in FIG.
X4 = βx ′ · X2 (6)
Y4 = βy ′ · Y2 (7)
It is represented by Here, the conversion magnifications βx ′ and βy ′ are set to an arbitrary constant m, and βx ′ = m / βx (8)
βy ′ = m / βy (9)
It can be expressed.

  FIG. 31 shows a conceptual diagram of an anamorphic converter without primary imaging, and FIG. 32 shows a conceptual diagram of an anamorphic converter with primary imaging. 31 and 32, the anamorphic converter AC forms an image on Im ′ using the image Im formed by the imaging optical system as an object point.

Here, when the Im position is shifted by ΔIm, the image plane position shift ΔIm ′ is determined when the horizontal conversion magnification of AC is βx, and the vertical conversion magnification is βy.
ΔIm′x = ΔIm · βx ² (10)
ΔIm′y = ΔIm · βy ² (11)
It is represented by Therefore, the central ass amount AS is
AS = △ Im'x- △ Im'y = △ Im · (βx 2 -βy 2) (12)
It is expressed. Therefore, when the flange back adjusting mechanism of the imaging optical system is used, the central ass expressed by the equation (12) is generated. This phenomenon is caused by a change in the on-axis light incident conversion inclination angle α2 to the anamorphic lens group having a function of changing the conversion magnification in the vertical direction and the horizontal direction in the converter. Therefore, even when the lens group on the imaging optical system side moves from the anamorphic lens in the converter, α2 changes, and thus a central spot is generated.

  In order to move the image point Im ′ without changing α2 and enable the flange back adjustment, the image side lens unit may be moved from the anamorphic lens unit. Further, even if the entire anamorphic lens group is moved together with the image side lens group, α2 does not change. Therefore, by satisfying the configuration of Embodiment 1 or Embodiment 2, it is possible to adjust the flange back without generating central ass.

  A third invention is an anamorphic converter characterized in that the first group has a negative refractive power.

  The third invention is the condition of the anamorphic converter for converting the aspect ratio without primary imaging by the imaging optical system.

  In order to prevent primary image formation, a negative lens group for diverging convergent light from the imaging optical system is required. Further, both the focal length conversion magnifications βx and βy must be positive.

  A fourth invention is an anamorphic converter characterized in that the first group has a positive refractive power.

  The fourth invention is a condition of an anamorphic converter for performing primary imaging by an imaging optical system and converting an aspect ratio.

  FIG. 32 shows a conceptual diagram of an anamorphic converter with primary imaging. As an optical system for re-imaging the primary image of the imaging optical system, both the focal length conversion magnifications βx and βy are required to be negative. Broadcast lenses, including digital cinema lenses, are predicated on the use of a color separation optical system, and thus have a long exit pupil and are substantially image side telecentric optical systems. Therefore, the converter needs at least a substantially bilateral telecentric optical system. As shown in FIG. 32, in the type with primary imaging, the light beam emitted from the imaging optical system is substantially afocal with a positive lens. As shown in FIG. 32, due to the bilateral telecentric condition, the anamorphic converter with primary imaging is composed of at least two positive lens groups, and the refractive power of the entire converter becomes a minute value near zero.

Here, the substantially afocal is when the axial ray conversion inclination angle (the inclination angle normalized by the axial ray emission inclination angle from the final surface) is α,
−0.1 <α <+0.1
It means that.

  The anamorphic lens used in the present invention is used in a concept including a toric lens and a cylindrical lens, and means a lens having different power in the X direction and power in the Y direction.

  Further, the anamorphic lens used in the present invention may have a diffractive function.

  Further, the conclusion optical system of the present invention may be a variable magnification system or a constant magnification system (no magnification change).

(First embodiment)
This embodiment is an anamorphic converter without primary imaging.

  FIG. 1 is a lens cross-sectional view in the Y direction and the X direction when an anamorphic converter is inserted in Numerical Example 1 of the present invention.

  FIG. 20 shows a cross-sectional view of the numerical example 1 before insertion of the anamorphic converter.

  FIGS. 21 to 23 show longitudinal aberration diagrams of Numerical Examples 1, 2, and 3 before insertion of the anamorphic converter.

  In FIG. 1, F is a front lens group having a positive refractive power as the first group. V is a variator of negative refractive power for zooming as the second group, and moves from the wide-angle end (wide) to the telephoto end (tele) by monotonically moving on the optical surface side on the optical axis. We are zooming. C is a compensator having negative refractive power as the third group, and moves in a non-linear manner with a locus convex toward the object side on the optical axis in order to correct image plane fluctuations accompanying zooming. ing. The variator V and the compensator C constitute a variable power system.

  SP is a stop, and R is a relay group fixed as a fourth group during zooming of positive refractive power. P is a color separation prism, an optical filter, or the like, and is shown as a glass block in FIG.

  The focus group F, variator V, compensator C, and relay group R constitute an imaging optical system.

Next, features of the anamorphic converter AC in Numerical Example 1 will be described. The AC includes a first group G1 having negative refractive power, a second group G2 composed of two cylindrical lenses, and a third group G3 having an imaging function and positive refractive power. Each of the G2 cylindrical lenses has a curvature only in the X direction, and has an effect of shortening the focal length in the X direction. The aspect ratio AR1 of the imaging range on the image plane of the imaging optical system, and the aspect ratio AR2 of the effective area of the imaging means are
AR1 = 2.35 (13)
AR2 = 1.78 (14)
The conversion magnification βx in the X direction and the conversion magnification βy in the Y direction are βx = 0.947 (15)
βy = 1.252 (16)
It is.

Further, the focal length fACx in the X direction and the focal length fACy in the Y direction of the AC alone are
fACx = + 32.789 (17)
fACy = + 69.848 (18)
It is.

  In this embodiment, by changing d43 for adjusting the flange back, r44 to r48 can be moved by ± 0.1 mm in the optical axis direction, and the flange back change amount at that time is ± 0.1 mm. FIG. 35 shows aberration diagrams when d43 is moved by +0.1 mm in the optical axis direction, and FIG. 36 is a graph showing aberrations when d43 is moved by −0.1 mm in the optical axis direction. As shown in FIGS. 33 and 34, the central ass does not change before and after the flange back adjustment, and high optical performance is achieved.

  Further, in this embodiment, it is possible to move r40 to r48 by ± 0.1 mm in the optical axis direction by making d39 variable for flange back adjustment, and the flange back change amount at that time is ± 0.1 mm. It is. FIG. 35 shows aberration diagrams when d39 is +0.1 mm, and FIG. 36 is d39 when −0.1 mm. As shown in FIGS. 35 and 36, the central ass does not change before and after the flange back adjustment, and high optical performance is achieved.

  In this embodiment, the entire lens group after the cylindrical lens is movable, but the same effect can be obtained even if a part of the lens group is movable.

  The material of the cylindrical lens used in this embodiment is (glass). In the following second and third embodiments, the same material is used.

  2 to 7 are longitudinal aberration diagrams of Numerical Example 1 in the X direction or the Y direction. fx is (focal length in X direction), fy is (focal length in Y direction), Fx is (focal length in X direction), Fy is (focal length in Y direction), and 2ω is (Angle of view).

Numerical example 1
fx = 9.74 to 142.93
fy = 12.88 to 188.96
Fx = 1.94-2.19
Fy = 2.56-2.90
2ω = 56.2 to 4.2 deg.

* R40 to r43 are cylindrical lenses. The curvature in the Y direction is zero.

(Second embodiment)
This embodiment is an anamorphic converter without primary imaging.

  FIG. 8 is a lens cross-sectional view in the Y direction and X direction when the anamorphic converter is inserted in Numerical Example 2 of the present invention. FIG. 20 shows a cross-sectional view of the numerical example 2 before insertion of the anamorphic converter.

  In FIG. 8, F is a front lens group having a positive refractive power as the first group. V is a variator of negative refractive power for zooming as the second group, and it moves from the wide-angle end (wide) to the telephoto end (tele) by monotonously moving on the optical surface side on the optical axis. We are zooming. C is a compensator having negative refractive power as the third group, and moves in a non-linear manner with a locus convex toward the object side on the optical axis in order to correct image plane fluctuations accompanying zooming. ing. The variator V and the compensator C constitute a variable power system.

  SP is a stop, and R is a relay group fixed as a fourth group during zooming of positive refractive power. P is a color separation prism, an optical filter, or the like, and is shown as a glass block in FIG.

  The focus group F, variator V, compensator C, and relay group R constitute an imaging optical system.

Next, features of the anamorphic converter AC in Numerical Example 2 will be described. The AC includes a first group G1 having negative refractive power, a second group G2 composed of two cylindrical lenses, and a third group G3 having an imaging function and positive refractive power. Each of the G2 cylindrical lenses has a curvature only in the Y direction, and has an effect of increasing the focal length in the Y direction. The aspect ratio AR1 of the imaging range on the image plane of the imaging optical system, and the aspect ratio AR2 of the effective area of the imaging means are
AR1 = 2.35 (19)
AR2 = 1.78 (20)
The conversion magnification βx in the X direction and the conversion magnification βy in the Y direction are βx = 0.947 (21)
βy = 1.252 (22)
It is.

Further, the focal length fACx in the X direction and the focal length fACy in the Y direction of the AC alone are
fACx = + 36.688 (23)
fACy = + 81.334 (24)
It is.

  In this embodiment, by changing d43 for adjusting the flange back, r44 to r48 can be moved by ± 0.5 mm in the optical axis direction, and the flange back change amount at that time is ± 0.5 mm. FIG. 37 is an aberration diagram when d43 is moved by +0.5 mm in the optical axis direction, and FIG. 38 is a graph showing aberrations when d43 is moved by −0.5 mm in the optical axis direction. As shown in FIGS. 37 and 38, the central ass does not change before and after the flange back adjustment, and high optical performance is achieved.

  Further, in this embodiment, it is possible to move r40 to r48 by ± 0.1 mm in the optical axis direction by making d39 variable for flange back adjustment, and the flange back change amount at that time is ± 0.1 mm. It is. FIG. 39 shows aberration diagrams when d39 is +0.1 mm, and FIG. 40 is d39 when −0.1 mm. As shown in FIGS. 39 and 40, the central ass does not change before and after the flange back adjustment, and high optical performance is achieved.

  In this embodiment, the entire lens group after the cylindrical lens is movable, but the same effect can be obtained even if a part of the lens group is movable.

  8 to 14 are longitudinal aberration diagrams of Numerical Example 2 in the X direction or the Y direction. fx is (focal length in X direction), fy is (focal length in Y direction), Fx is (focal length in X direction), Fy is (focal length in Y direction), and 2ω is (Angle of view).

Numerical example 2
fx = 9.74 to 142.93
fy = 12.88 to 188.96
Fx = 1.94-2.19
Fy = 2.56-2.90
2ω = 56.2 to 4.2 deg.

* R40 to r43 are cylindrical lenses. The curvature in the X direction is zero.

(Third embodiment)
This embodiment is an anamorphic converter with primary imaging.

  FIG. 24 is a lens cross-sectional view in the Y direction and the X direction when the anamorphic converter is inserted in Numerical Example 3 of the present invention. FIG. 20 shows a cross-sectional view of the numerical example 3 before insertion of the anamorphic converter.

  In FIG. 24, F is a front lens group having a positive refractive power as the first group. V is a variator of negative refractive power for zooming as the second group, and it moves from the wide-angle end (wide) to the telephoto end (tele) by monotonously moving on the optical surface side on the optical axis. We are zooming. C is a compensator having negative refractive power as the third group, and moves in a non-linear manner with a locus convex toward the object side on the optical axis in order to correct image plane fluctuations accompanying zooming. ing. The variator V and the compensator C constitute a variable power system.

  SP is a stop, and R is a relay group fixed as a fourth group during zooming of positive refractive power. P is a color separation prism, an optical filter, or the like, and is shown as a glass block in FIG.

  The focus group F, variator V, compensator C, and relay group R constitute an imaging optical system.

Next, features of the anamorphic converter AC in Numerical Example 3 will be described. The AC includes a first group G1 having negative refractive power, a second group G2 composed of two cylindrical lenses, and a third group G3 having an imaging function and positive refractive power. Each of the G2 cylindrical lenses has a curvature only in the Y direction, and has an effect of increasing the focal length in the Y direction. The aspect ratio AR1 of the imaging range on the image plane of the imaging optical system, and the aspect ratio AR2 of the effective area of the imaging means are
AR1 = 2.35 (25)
AR2 = 1.78 (26)
The conversion magnification βx in the X direction and the conversion magnification βy in the Y direction are βx = −0.947 (27)
βy = −1.252 (28)
It is.

Further, the focal length fACx in the X direction and the focal length fACy in the Y direction of the AC alone are
fACx = −684.6 (29)
fACy = −1300.2 (30)
The absolute value is large and the refractive power is very small.

  In this embodiment, by changing d44 for flange back adjustment, r44 to r48 can be moved by ± 0.5 mm in the optical axis direction, and the flange back change amount at that time is ± 0.5 mm. FIG. 41 shows aberration diagrams when d44 is moved by +0.5 mm in the optical axis direction and FIG. 42 is moved by d44 by −0.5 mm in the optical axis direction. As shown in FIGS. 41 and 42, the central ass does not change before and after the flange back adjustment, and high optical performance is achieved.

  In this embodiment, it is also possible to move r41 to r52 by ± 0.1 mm in the optical axis direction by making d40 variable for flange back adjustment, and the flange back change amount at that time is ± 0.1 mm. It is. FIG. 43 shows aberration diagrams when d39 is +0.1 mm, and FIG. 44 is d39 when −0.1 mm. As shown in FIGS. 43 and 44, the central ass does not change before and after the flange back adjustment, and high optical performance is achieved.

  In this embodiment, the entire lens group after the cylindrical lens is movable, but the same effect can be obtained even if a part of the lens group is movable.

  25 to 30 are longitudinal aberration diagrams of Numerical Example 3 in the X direction or the Y direction. fx is (focal length in X direction), fy is (focal length in Y direction), Fx is (focal length in X direction), Fy is (focal length in Y direction), and 2ω is (Angle of view).

Numerical Example 3
fx = −9.74 to −142.93
fy = -12.88 to -188.96
Fx = -1.94 to -2.19
Fy = −2.56 to −2.90
2ω = 56.2 to 4.2 deg.

* R41 to r44 are cylindrical lenses. The curvature in the X direction is zero.

Sectional view in the X and Y directions at the wide-angle end of Numerical Example 1 Longitudinal aberration diagram in the X direction in numerical example 1 at fx = 9.7 mm, fy = 12.9 mm, and object distance 2.5 m Longitudinal aberration diagram in the Y direction at numerical value example 1 at fx = 9.7 mm, fy = 12.9 mm, and object distance 2.5 m Longitudinal aberration diagram in the X direction at fx = 37.3 mm, fy = 49.3 mm, and object distance 2.5 m in Numerical Example 1 Longitudinal aberration diagram in the Y direction at fx = 37.3 mm, fy = 49.3 mm, and object distance 2.5 m in Numerical Example 1 Longitudinal aberration diagram in the X direction in numerical value example 1 at fx = 142.9 mm, fy = 189.0 mm, and object distance 2.5 m Longitudinal aberration diagram in the Y direction at numerical value example 1 at fx = 142.9 mm, fy = 189.0 mm, and object distance 2.5 m Sectional drawing in X and Y direction of the wide angle end of Numerical Example 2 Longitudinal aberration diagram in the X direction in numerical example 2 at fx = 9.7 mm, fy = 12.9 mm, and object distance 2.5 m Longitudinal aberration diagram in the Y direction at numerical value example 2 at fx = 9.7 mm, fy = 12.9 mm, and object distance 2.5 m Longitudinal aberration diagram in the X direction at numerical value example 2 at fx = 37.3 mm, fy = 49.3 mm, and object distance 2.5 m Longitudinal aberration diagram in the Y direction at numerical value example 2 at fx = 37.3 mm, fy = 49.3 mm, and object distance 2.5 m Longitudinal aberration diagram in the X direction in numerical example 2 when fx = 142.9 mm, fy = 189.0 mm, and object distance is 2.5 m Longitudinal aberration diagram in the Y direction at numerical value example 2 at fx = 142.9 mm, fy = 189.0 mm, and object distance 2.5 m Conceptual diagram of aspect ratio Conceptual diagram of image circle and imaging range on image plane of imaging optical system Conceptual diagram of image circle and imaging range after conversion by the converter of the present invention Conceptual diagram of effective area of imaging means Conceptual diagram of the output image display area during projection Sectional view at the wide-angle end before inserting the anamorphic converter of Numerical Examples 1, 2, and 3 Longitudinal aberration diagrams at f = 10.3 mm and object distance 2.5 m before insertion of anamorphic converters of Numerical Examples 1, 2, and 3. Longitudinal aberration diagrams at f = 39.5 mm and object distance 2.5 m before insertion of the anamorphic converters of Numerical Examples 1, 2, and 3. Longitudinal aberration diagrams at f = 151.1 mm and object distance 2.5 m before insertion of anamorphic converters of Numerical Examples 1, 2, and 3 Sectional drawing in X and Y direction of wide angle end of Numerical Example 3 Longitudinal aberration diagram in the X direction at numerical value example 3 at fx = −9.7 mm, fy = 1−12.9 mm, and object distance 2.5 m Longitudinal aberration diagram in the Y direction at numerical value example 3 at fx = −9.7 mm, fy = 1−12.9 mm, and object distance 2.5 m Longitudinal aberration diagram in the X direction in the numerical value example 3 at fx = −37.3 mm, fy = −49.3 mm, and object distance 2.5 m Longitudinal aberration diagram in the Y direction at numerical value example 3 at fx = −37.3 mm, fy = −49.3 mm, and object distance 2.5 m Longitudinal aberration diagram in the X direction in the numerical value example 3 when fx = −142.9 mm, fy = −189.0 mm, and the object distance is 2.5 m Longitudinal aberration diagram in the Y direction at numerical value example 3 at fx = −142.9 mm, fy = −189.0 mm, and object distance 2.5 m Conceptual diagram of anamorphic converter without primary imaging Conceptual diagram of anamorphic converter with primary imaging Longitudinal aberration diagram in the X direction when fx = 9.7 mm, fy = 12.9 mm, and object distance 2.5 m when d43 is changed by +0.1 mm in Numerical Example 1 Longitudinal aberration diagram in the X direction at fx = 9.7 mm, fy = 12.9 mm, and object distance 2.5 m when d43 is changed by −0.1 mm in Numerical Example 1 Longitudinal aberration diagram in the X direction at fx = 9.7 mm, fy = 12.9 mm, and object distance 2.5 m when d39 is changed by +0.2 mm in Numerical Example 1 Longitudinal aberration diagram in the X direction when fx = 9.7 mm, fy = 12.9 mm, and object distance 2.5 m when d39 is changed by −0.2 mm in Numerical Example 1 Longitudinal aberration diagram in the X direction when fx = 9.7 mm, fy = 12.9 mm, and object distance 2.5 m when d43 is changed by +0.5 mm in Numerical Example 2 Longitudinal aberration diagram in the X direction when fx = 9.7 mm, fy = 12.9 mm, and object distance 2.5 m when d43 is changed by −0.5 mm in Numerical Example 2 Longitudinal aberration diagram in the X direction at fx = 9.7 mm, fy = 12.9 mm, and object distance 2.5 m when d39 is changed by +0.1 mm in Numerical Example 2 Longitudinal aberration diagram in the X direction at fx = 9.7 mm, fy = 12.9 mm, object distance 2.5 m when d39 is changed by −0.1 mm in Numerical Example 2 Longitudinal aberration diagram in the X direction at fx = −9.7 mm, fy = −12.9 mm, object distance 2.5 m when d44 is changed by +0.5 mm in Numerical Example 3 Longitudinal aberration diagram in the X direction at fx = −9.7 mm, fy = −12.9 mm, and object distance 2.5 m when d44 is changed by −0.5 mm in Numerical Example 3 Longitudinal aberration diagram in the X direction at fx = −9.7 mm, fy = −12.9 mm, object distance 2.5 m when d40 is changed by +0.1 mm in Numerical Example 3 Longitudinal aberration diagram in the X direction at fx = −9.7 mm, fy = −12.9 mm, object distance 2.5 m when d40 is changed by −0.1 mm in Numerical Example 3

Explanation of symbols

F focus group V variator group C compensator group R relay group AC anamorphic converter P color separation prism

Claims (14)

An anamorphic converter having at least one anamorphic lens arranged on the image side of the imaging optical system,
The anamorphic converter is composed of a front group having the anamorphic lens in order from the imaging optical system side, a rear group having a positive refractive power,
An anamorphic converter characterized in that the rear group is movable in the optical axis direction of the imaging optical system.   The front group includes a first group fixed in order from the imaging optical system side and a second group including an anamorphic lens, and the rear group includes a third group having a positive refractive power. Item 1. An anamorphic converter according to item 1.   The anamorphic converter according to claim 2, wherein the entire second group is movable in the optical axis direction integrally with the movable third group.   The anamorphic converter according to any one of claims 1 to 3, wherein the anamorphic converter is an optical system in which parallel light enters the second group.   The anamorphic converter according to any one of claims 1 to 4, wherein the first group has a negative refractive power.   The anamorphic converter according to any one of claims 1 to 4, wherein the first group has a positive refractive power.   The second group includes an anamorphic lens having at least one positive refractive power in an arbitrary cross section perpendicular to the optical axis, and an anamorphic lens having at least one negative refractive power in the cross section. The anamorphic converter according to any one of -6. The third group includes a plurality of positive lenses and at least one negative lens. When the average Abbe number of positive lenses is νp3 and the average Abbe number of negative lenses is νn3,
νp3-νn3> 30
The anamorphic converter according to any one of claims 1 to 6, wherein the anamorphic converter is any one of the above. The first group has at least one positive lens and a plurality of negative lenses. When the average Abbe number of positive lenses is νp1, and the average value of Abbe numbers of negative lenses is νn1,
νn1-νp1> 10
The anamorphic converter according to claim 5, wherein The first group includes a plurality of positive lenses and at least one negative lens. When the average Abbe number of positive lenses is νp1 and the average Abbe number of negative lenses is νn1,
νp1-νn1> 10
The anamorphic converter according to claim 6.   11. A lens apparatus comprising: the anamorphic converter according to claim 1; and the imaging optical system disposed on the object side of the anamorphic converter.   An imaging apparatus comprising: the anamorphic converter according to any one of claims 1 to 11, an imaging optical system disposed on an object side of the anamorphic converter, and an imaging unit disposed on an image side of the anamorphic converter. A method for adjusting the flange back of a lens apparatus, comprising: an anamorphic converter having at least one anamorphic lens arranged on the image side of the imaging optical system; and an imaging optical system arranged on the object side from the anamorphic converter,
The anamorphic converter is composed of a front group having the anamorphic lens in order from the imaging optical system side, a rear group having a positive refractive power,
A method of adjusting a flange back of a lens device, wherein when the lens device is mounted on a camera device, flange back adjustment is performed by moving the rear group in the optical axis direction of the imaging optical system. A lens device including an anamorphic converter having at least one anamorphic lens disposed on the image side of the imaging optical system, and an imaging optical system disposed on the object side from the anamorphic converter, and attached to the lens device A method for adjusting a flange back of a photographing apparatus including a camera device,
The anamorphic converter is composed of a front group having the anamorphic lens in order from the imaging optical system side, a rear group having a positive refractive power,
A method for adjusting a flange back of an imaging apparatus, which performs flange back adjustment by moving the rear group in the optical axis direction of the imaging optical system when the lens device is mounted on a camera device.

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