JPH04158323A - Image forming lens device with unequal vertical/ horizontal magnification - Google Patents

Abstract

PURPOSE:To form the image of a photographed object with a high vertical/ horizontal magnification ratio on an image forming screen with no shading by arranging a cylindrical lens constituting a lens group on the photographed object side so that the equidistant face from the surface and back face is formed into a curved face and the protruded side of the curved face is faced to the photographed object side. CONSTITUTION:The light flux 8X from an object space forms an image via the effect of only a camera lens 2 in the vertical plane and forms the image 9X on an image forming face. The visual field is expanded via the lens effect of two lens groups 4, 5 in the horizontal plane more than via only the lens 2. The light flux 8Y from the expanded object space forms an image 9Y. A photographed image with the horizontal size length shrunk is obtained. Even when the image of a photographed object with a changed horizontal image formation magnification at a high vertical/horizontal magnification ratio is obtained, a shade-less image removed with aberration on the periphery of the visual field can be formed according to this lens constitution.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is attached as an attachment in front of the camera lens of a photo camera or a television camera, and is used to determine the shape and size of a subject, for example. This invention relates to a lens device for imaging with unequal vertical and horizontal magnification, which is used to obtain captured images with different imaging magnifications in the vertical and horizontal directions for measurement.

[Conventional technology]

Conventionally, this type of lens device for forming images with unequal vertical and horizontal magnification has been used as an attachment in front of the camera lens of a photo camera, and is used especially for taking special effect photos of people. The company is known as Kenko Co., Ltd.). Below, this “
A conventional lens device for imaging with unequal magnification in vertical and horizontal directions called "Magic Portrait" will be described. FIG. 6 (al is a schematic longitudinal structural explanatory diagram of a conventional unequal magnification imaging lens device mounted on a photographic camera, and FIG. 6 (bl is a schematic structural explanatory diagram in the horizontal direction).

In Figure 6 fat and 6 [N (bl, 5I is 35
A photographic camera consisting of a mm format eye reflex camera, 52 is a camera lens of the photographic camera 51, and has a focal length f. = 50
mm standard camera lens. The lens device 53 for imaging with unequal vertical and horizontal magnification includes, in order from the camera lens 52 side, a lens group 54 on the camera lens side, which is made up of one cylindrical plano-convex lens having a positive focal length f1, and a lens group 54 on the camera lens side, which has a negative focal length f1. A single cylindrical plano-concave lens with f2 is arranged with the object-side lens group 55 so that the distance between the principal surfaces is d or satisfies the relationship d=L+L, and both lens groups 54 and 55 are used as camera lenses. It is assembled into a frame body 56 which can be attached to and detached from the frame body 52. In this case, both the lens groups 54 constituted by cylindrical lenses
．． As shown in the figure, both lenses 55 are arranged in a posture that has a lens effect (refraction effect) in the lateral direction perpendicular to the optical axis. Further, the cylindrical plano-concave lens constituting the subject-side lens group 55 is arranged with the concave side of its curved surface equidistant from both its front and back faces toward the subject.

Next, the imaging function of the lens device for imaging with unequal vertical and horizontal magnification having the above structure will be described below. FIG. 8 fal is an explanatory diagram of the imaging effect in the vertical plane when the vertical and horizontal unequal magnification imaging lens device 53 is attached to the camera lens 52, and FIG. It is an explanatory diagram of image effect. In both figures, the optical axis is the Z axis, the vertical direction perpendicular to the optical axis is the Y axis, and the horizontal direction perpendicular to the optical axis is the Y axis. Coordinate system x-y-
z is determined.

Figure 8 (as shown in al., in the vertical plane (in the X-Z plane)
In this case, an image of size Xl is formed on the imaging plane of the photographic camera 5I by the light beam 58X from the subject 57 whose vertical size is Xo or by the lens effect (refraction) of the camera lens 52 alone. 59X is formed. On the other hand, as shown in FIG. 8(b), in the lateral plane (Y-Z plane), two lens groups 54 and 55 using cylindrical lenses
Due to the lens effect (refraction effect), the size of the imaged object, that is, the field of view, is expanded compared to when using only the camera lens 52. In other words, in the case of only the camera lens 52, the horizontal size is Y. Luminous flux 6 from subject 60 of C
1 is imaged and an image of the size Yl is formed on the image forming surface. Due to the lens effect of both lens groups 54 and 55, Y, = M - Yoc (M is the vertical and horizontal magnification ratio described later). The corresponding value, in this case M>1), is the lateral dimension Y. A light beam 58Y from the subject 57 is formed into an image,
This will form an image 59Y on the imaging plane of the camera, which has the same size as Y1.

In this way, the vertical and horizontal magnification ratio M=(vertical direction imaging magnification)/ An image of the subject 57 with different imaging magnifications in the vertical and horizontal directions is formed, in which the value of M expressed as (imaging magnification in the horizontal direction) is other than 1. This vertical and horizontal magnification ratio M is given by the ratio of the focal length f1 of the camera lens side lens group 54 to the focal length f2 of the subject side lens group 55.

In F Magic Portrait J, which is a conventional lens device 53 for forming images with unequal vertical and horizontal magnification, the value of the vertical and horizontal magnification ratio M or M=(1/0 .8) =1.25, or M= (0,
8/ 1) = 0.8, which creates a human image with different imaging magnifications in the vertical and horizontal directions, and this creates special effects by making a thick person look slim or a thin person look plump. I try to get photographs of people (see Figure 7).

[Invention or problem to be solved]

The conventional lens device for unequal vertical and horizontal magnification introduced above is
On the imaging plane of the camera through the camera lens, the vertical and horizontal magnification ratio M is 1 compared to M = ll when only the camera lens is used.
．． This is to form an image of the subject at a low value of 25 (or 0.8). Therefore, when attempting to form an image with a high vertical and horizontal magnification ratio M for measuring the size and shape of an object, detecting defects, etc., in the conventional lens device described above, both the front and back surfaces of the lens group on the subject side are This conventional configuration causes aberrations in the image of the object formed, because the concave side of the curved surface faces the subject. There is a problem with the blurring of the image due to this.

This invention was made to solve the above problems, and when attached to a camera, it can display an image of a subject having a high vertical and horizontal magnification ratio on the imaging plane of the camera without blurring the image. It is an object of the present invention to provide a lens device for forming an image with unequal magnification in the vertical and horizontal directions.

[Means to solve the problem]

In order to achieve the above object, the present invention includes two lens groups arranged in front of a camera lens with a predetermined distance between principal surfaces, each group consisting of one or more lenses. Both lens groups are composed of cylindrical lenses that have a lens effect in the horizontal direction perpendicular to the optical axis or in the vertical direction, while the focal length on the camera lens side is f1, and the object The focal length of the side is f2
When , there is a relationship of fl・f2×0, and both lens groups produce an image of the subject with different imaging magnifications in the vertical and horizontal directions on the imaging plane of the camera via the camera lens. In a lens device for imaging with unequal magnification in vertical and horizontal directions, the cylindrical lens constituting the lens group on the subject side of both the lens groups has an equidistant surface or a curved surface from both the front and back surfaces, and this curved A technical measure has been taken in which the convex side of the surface faces the subject.

[For production]

In the lens device for imaging with unequal vertical and horizontal magnification according to the present invention, the cylindrical lens constituting the lens group on the object side, or a curved surface or an equidistant surface from both the front and back sides thereof, is used.
Since this curved surface is placed facing either the convex side or the subject side, aberrations at the periphery of the field of view are removed, making it possible to form blur-free images even when forming subject images with a high vertical-to-horizontal magnification ratio. .

〔Example〕

The present invention will be explained below based on examples.

First Embodiment FIG. 1 is a schematic perspective view showing the overall configuration when a lens device for imaging with unequal vertical and horizontal magnification according to an example of the present invention is applied to video camera photography of a person, and FIG. 2 is similar to FIG. 1. FIG. 2 is a schematic explanatory diagram for explaining a photographed image obtained by the example shown. Fig. 3 fal is a diagram for explaining the schematic structure in the vertical direction and its imaging action of the lens device for imaging with unequal magnification in the vertical and horizontal directions shown in Fig. 1; These are diagrams for explaining the schematic structure in the lateral direction of a lens device for equal magnification imaging and its imaging function, and in both figures, the optical axis is shown with respect to the imaging plane of a video camera (not shown). The Z axis, the vertical direction perpendicular to the optical axis is the X axis, and the horizontal direction perpendicular to the optical axis is the Y axis, defining an orthogonal coordinate system X-Y-Z.

In Fig. 1, 1 is a video camera having an image forming surface with a length of 6 mm and a width of 8 mm, and 2 is a video camera l of this video camera.
is a camera lens having a focal length fo==12 mm. The lens device 3 for imaging with unequal vertical and horizontal magnification includes a camera lens side lens group 4 and a subject side lens group 5 in order from the camera lens 2 side to a frame (not shown) that can be attached to and detached from the video camera 1, that is, the camera lens 2 thereof. Distance between main surfaces d
It is attached to the camera lens 2. The camera lens side lens group 4 is composed of one cylindrical biconvex lens having a focal length f = 90 mm. The object-side lens group 5 is composed of two cylindrical plano-concave lenses each having a focal length of -60 mm and forming an equidistant surface or a curved surface from both the front and back surfaces, and the combined focal length is f2.
=-30mm. These two cylindrical plano-concave lenses are both arranged with their curved surfaces facing either the convex side or the object side. Both lens groups 4.5 configured in this way satisfy the relationship of distance between their principal surfaces d = f + 10 f 2 = 60 mm, and both have a lens effect (refraction effect) in the lateral direction perpendicular to the optical axis. It is placed in a holding position. 7 is a person as a subject.

Hereinafter, first, a case will be described in which a person 7 is photographed by a video camera l equipped with a camera lens 2 having an fo of 12 mm. When photographing a person 7 with a height of 1.7 m at a photographing distance of 4 m, the vertical and horizontal magnification ratio N1 is N1-1, and the imaging magnification n is n.
= 12/4000 = 0.003, 1.7m
An image having a size of xn=5.1 mm is formed on the imaging plane of the video camera 1, and a captured image as shown at +al in FIG. 2 is obtained.

Next, a case will be described in which the lens device 3 for imaging with unequal vertical and horizontal magnification having the above configuration is attached to the video camera 1 and a person 7 is photographed. As shown in Fig. 3 fat, in the vertical plane (X-Z plane), an image is formed by the light beam 8X from the object space including the person 7 or by the lens effect (refraction effect) across the camera lens. , an image 9X thereof is formed on the imaging plane of the video camera l. On the other hand, as shown in FIG. 3(b), in the horizontal plane (YZ plane), 2
Due to the lens effect of the two lens groups 4.5, the field of view is expanded more than when using only the camera lens 2, and the light beam 8Y from the object space including the enlarged person 7 is formed into an image of the video camera 1. The image 9Y is formed on the imaging plane. As a result, as shown in Ib+ in FIG. 2, the vertical dimension length of the human image is the same as when the video camera 1 is used alone, and the captured image is obtained by reducing the horizontal dimension length. It will be done.

In this case, the vertical and horizontal magnification ratio N1 is given by M = l f, /f21, and the vertical and horizontal magnification ratio M = 190/ (-30)
l = 3, and the human figure shown in Fig. 2(b) has the horizontal dimension length reduced to 1/3 compared to that shown in Fig. 2(al). has been obtained,
Furthermore, the field of view in the horizontal direction of the captured image in FIG. 2(b) is three times as wide as that in FIG. 2(a).

Even when obtaining a subject image with a higher vertical/horizontal magnification ratio than the conventional one and changing the horizontal imaging magnification, the cylindrical lens constituting the subject side lens group 5 can be curved or equidistant from both the front and back surfaces. Since the convex side of this curved surface was arranged to face the subject side, aberrations in the peripheral part of the field of view were removed, making it possible to form an image without blur.

Second Embodiment FIG. 4 is a schematic perspective view showing the overall configuration when a lens device for imaging with unequal vertical and horizontal magnification according to another embodiment of the present invention is applied to video camera photography of a person, and FIG. FIG. 4 is a schematic explanatory diagram for explaining a photographed image obtained by the example shown in FIG. 4;

In FIG. 1, 1) is a video camera having an image forming surface measuring 6 mm in length and 8 mm in width, and 12 is the camera lens, which has a focal length f. =6mm. The lens device 13 for imaging with unequal vertical and horizontal magnification includes a camera lens side lens group 14 and a subject side lens group 1 in order from the camera lens 12 side, in a frame (not shown) that is detachable from the video camera 1).
5 are fitted with a distance d between their principal surfaces, and are attached to the camera lens 12. The camera lens side lens group 14 is composed of one cylindrical concave lens having a focal length f=-40 mm. The subject-side lens group 15 is composed of two cylindrical convex lenses each having a focal length of 160 mm and forming an equidistant surface or a curved surface from both the front and back surfaces, and the combined focal length is f2. = 80mm. These two cylindrical convex lenses are both arranged with their curved surfaces facing either the convex side or the object side. The distance between the principal surfaces of both lens groups 14 and 15 configured in this way is d=L+f2=, t.

They are arranged in a posture that satisfies the relationship of mm and both have a lens effect (refraction effect) in the vertical direction perpendicular to the optical axis. 17 is a person as a subject.

Focal length f. = Video camera equipped with a camera lens 12 of 6 mm 1) When photographing a person 17 with a height of 1.7 m at a shooting distance of 4 m, the vertical and horizontal magnification ratio M is M = 1, and the imaging magnification n is n = 6 / 4000. = 0.0015, and an image with a size of 1.7 m x n = 2.55 mm is formed on the imaging plane of the video camera 1), and is
A captured image as shown in 1 is obtained. On the other hand, when the vertical and horizontal unequal magnification lens device 13 configured as described above is attached to the video camera 1), the lens effect in the vertical direction of the two lens groups 14 and 15 causes the fifth
As shown in Figure (b), the horizontal dimension length of the human image is the same as when using the video camera 1) alone, and the captured image is enlarged to twice its vertical dimension length. . In this case, the vertical and horizontal magnification ratio M is M=l f.

/f, l = l (-40) /80 l =
The field of view in the vertical direction of the photographed image of (bl in Fig. 5) is 1/2 compared to that of (al) in Fig. 5.
The result is something that has been narrowed down to twice as much.

Even when obtaining a subject image with a higher vertical-to-horizontal magnification than the conventional one, the cylindrical lens constituting the subject-side lens group 15 can be curved or equidistant from its front and back surfaces. Since the convex side of this curved surface was arranged to face the subject, aberrations in the peripheral part of the field of view were removed, and an image without blur could be formed.

Incidentally, in both of the above embodiments, an example was explained in which the lens devices 3 and 13 for unequal magnification in the vertical and horizontal directions are applied to a video camera 1.1). However, it can also be applied to photographic cameras in the same way as before.

〔Effect of the invention〕

As explained above, the lens device for imaging with unequal vertical and horizontal magnification according to the present invention is arranged in front of the camera lens with a predetermined distance between the main surfaces, and has an imaging magnification of unequal magnification in both the vertical and horizontal directions. Of the two lens groups, the camera lens side lens group and the subject side lens group, which are composed of cylindrical lenses for forming images of different subjects, the cylindrical lenses that make up the subject side lens group are attached to both the front and back surfaces. Since the structure is such that the convex side of this curved surface is placed toward the subject side, it has a higher vertical and horizontal magnification ratio than conventional ones, and can be used both vertically and horizontally. When forming subject images with different imaging magnifications, aberrations in the peripheral areas of the visual field are removed, and images without blur can be formed.

That is, according to the present invention, it is possible to provide a lens device for imaging with unequal vertical and horizontal magnification, which can be applied to measurement of the size and shape of objects, defect detection, etc., which require a higher vertical and horizontal magnification ratio than conventional ones. .

[Brief explanation of drawings]

FIG. 1 is a schematic perspective view showing the overall configuration when a lens device for imaging with unequal magnification in vertical and horizontal directions according to an example of the present invention is applied to video camera photography of a person, and FIG. FIG. 3 is a schematic explanatory drawing for explaining the photographed image that is taken. FIG. , and FIG. 4 are schematic perspective views showing the overall configuration when a lens device for imaging with unequal vertical and horizontal magnification according to another embodiment of the present invention is applied to video camera photography of a person, and FIG. A schematic explanatory diagram for explaining the photographed image obtained by the example shown in the figure, FIG. 6(a) and FIG. Structure explanatory diagrams, and FIG. It is an explanatory diagram of the imaging effect when the imaging lens device is attached to the camera lens. 1.1) -- Video camera, 2, 12 -- Camera lens, 3.13 -- For imaging with unequal magnification in vertical and horizontal directions. Lens device, 4.1
4 Camera lens side lens group, 5-Subject side lens group consisting of two cylindrical plano-concave lenses, 15-Subject side lens group consisting of two cylindrical convex lenses, 7, 17-
Person as subject, 8X, 8Y, - single beam of light, 9X, 9
Y image, 51-1 photographic camera, 52-camera lens, 53-lens device for imaging with unequal vertical and horizontal magnification, 54-camera lens side lens group, 55-subject side lens group, 56
Frame body, d-distance between main surfaces. Patent applicant Kobe Steel, Ltd.

Claims (1)

[Claims] (1) Two lens groups are arranged in front of the camera lens with a predetermined distance between principal surfaces, and one group is composed of one or more lenses, and both lens groups are Both groups are composed of cylindrical lenses that have a lens effect in the horizontal direction perpendicular to the optical axis or in the vertical direction, and when the focal length on the camera lens side is f_1 and the focal length on the subject side is f_2, f_1・f_2<0
Both lens groups form an image of the subject with different magnifications in the vertical and horizontal directions on the imaging plane of the camera via the camera lens. In this lens device, the cylindrical lens constituting the lens group on the subject side of both the lens groups has surfaces equidistant from both the front and back surfaces forming a curved surface, and the convex side of this curved surface is directed toward the subject side. A lens device for imaging with unequal vertical and horizontal magnification, characterized in that the lens device is arranged in a vertical and horizontal direction.