JPH05150386A - Camera provided with image frame size varying means - Google Patents

Abstract

PURPOSE:To provide a camera having an image frame size varying means in which a close photographing distance of a photographing lens is shortened and photographing angle of view at wide-angle end zoom position is enlarged as the image frame size is varied and special photographing is executed. CONSTITUTION:As to the camera having the image frame size varying means 4 by which an object image having an optional image frame size can be obtained by using the image frame size varying means 4 on a photosensitive surface 2 by the photographing lens 1; when the length of the diagonal line the image frame size is shorter, the photographing lens 1 is set so that the close photographing distance is shorter or the variable power part of the photographing lens 1 is set so that the variable power range can be more enlarged on a wide-angle side in comparison with the case where length of the diagonal line of the image frame size is long.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a camera having a screen size changing means. For example, in a 35 mm film camera, a video camera or the like, the screen size is arbitrarily changed by optical means or electric means to take a picture. This is to improve the specifications of the photographing lens while obtaining the pseudo variable magnification effect, the panoramic photographing effect, the mutual switching effect from the full size to the half size, and the like.

[0002]

2. Description of the Related Art Conventionally, a 35 mm film camera, a video camera or the like has been proposed with a camera having a screen size changing means for changing the screen size by various means such as optical means and electric means.

For example, in a 35 mm film camera, (a) the screen size is full size (36 mm x 24 mm)
The screen switching effect has been achieved by changing the horizontal direction of the film opening from the vertical half size (17 mm x 24 mm) by blocking the left and right sides of the film opening with a light blocking member. (B) The screen size is changed from full size to landscape panoramic size, and the vertical direction of the film opening is covered with a light blocking member to allow mutual change and to obtain a panoramic effect. (C) A pseudo variable magnification effect is obtained by arranging the aperture size variable member in front of the film surface and changing (smalling) the screen size in a similar manner. Etc.

[0004]

The camera provided with these screen size changing means is one in which a full-size film is used and the effective aperture diameter of the film is simply changed to various values according to the shooting conditions.

On the other hand, when the photographing distance (object distance) of a photographing lens used in a 35 mm film camera or a video camera has changed, a part or the whole of the photographing lens is moved along the optical axis for focusing. There is.

At this time, if the light beam is incident on the peripheral portion of the screen at an object distance shorter (shorter) than a certain object distance, all the light beam is vignetted by the diaphragm and the photographing lens, making it impossible to shoot.

That is, in a general camera, the closest object distance that can be photographed is regulated by the size of the entire lens system, the diameter of the front lens, and the diaphragm diameter.

In the case where a zoom lens is used as the taking lens, when the light flux tries to enter the peripheral portion of the screen at a certain zoom position on the wide angle side, the light flux is entirely vignetted due to the restriction of the effective diameter of the lens. There is. Therefore, the zoom position (wide-angle end) on the wide-angle side is one factor that is determined by the constraint of the effective diameter of the lens.

This tendency is particularly strong in a photographing lens having a variable power portion used in a lens shutter camera.

According to the present invention, when the screen size of the photosensitive surface is changed to obtain various special photographing effects, it is difficult to achieve the optical specifications because the screen size is large as a photographing lens. For example, a screen designed to improve the optical specifications of the shooting lens, such as shortening the distance to the closest object, and further enlarging the shooting angle of view to the wide-angle side when the shooting lens is a zoom lens (super wide angle). An object is to provide a camera having a size changing unit.

[0011]

A camera having a screen size changing means of the present invention is a screen size in which an object image is obtained at an arbitrary screen size by using the screen size changing means on a photosensitive surface by a taking lens. The camera having the changing means is characterized in that when the diagonal length of the screen size is short, the photographing lens is set so that the closest photographing distance is shorter than when the diagonal length is long.

In addition to the above, the camera having the screen size changing means of the present invention is a screen in which an object image is obtained at an arbitrary screen size by using the screen size changing means on the photosensitive surface by means of a taking lens having a variable power unit. In the camera having the size changing means, when the diagonal length of the screen size is short, the variable power unit is set so that the variable power range can be further expanded to the wide angle side compared to when the screen length is long. There is.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIGS. 1A, 1B and 1C are schematic views of the essential parts of an optical system according to a first embodiment of the present invention.

In the present embodiment, when the screen size is reduced by special photography (when the diagonal length of the screen is reduced), the focus portion of the photographing lens is moved more than when the screen size is large. The figure shows a case in which the object distance that can be photographed (extended) is shortened.

In the figure, reference numeral 1 denotes a taking lens, which moves the entire lens system for focusing. Reference numeral 2 denotes a photosensitive surface, which is made of, for example, a 35 mm film. 3 is a diaphragm, 4 is a light shielding member as a screen size changing means,
It is arranged in front of the photosensitive surface 2.

1A and 1B are full-size screen sizes of the photosensitive surface 2, and FIG. 1A is an optical path diagram when the projection lens 1 focuses on an object at infinity.
(B) is an optical path diagram when the taking lens 1 is focused on the closest object at the object distance L1. FIG. 1C shows a case where the photosensitive surface 2 is made smaller by the screen size changing means 4. This figure shows an optical path diagram when the taking lens 1 is further extended to the object side as compared with FIG. 1B, and the object distance L2 is shorter than the object distance L1.

When the object at infinity shown in FIG. 1A is focused, the light beam L2a incident on the peripheral portion 2a of the screen passes through the diaphragm 3 in a relatively large amount even when the diaphragm 3 is made small.

It is assumed that the taking lens 1 is extended from the state shown in FIG. 1A and focused on the object distance L1 shown in FIG. 1B. At this time, the light beam L2b incident on the peripheral portion 2a of the screen is slightly vignetted by the lens system and the diaphragm 3, but a certain amount of light beam passes through the diaphragm 3. Even when the diaphragm 3 is made small, a small amount of light flux passes through the diaphragm 3. Therefore, even if the distance L1 in FIG. 1B is narrowed down by the diaphragm 3, the luminous flux is incident on the peripheral portion 2a of the screen and is the closest object distance that can be photographed.

That is, from the state shown in FIG. 1B, the taking lens 1 is further extended and the object distance L shorter than the object distance L1.
Try to focus on 2. At this time, as shown in FIG. 2, the light flux L2b incident on the peripheral portion 2a of the screen passes through the diaphragm 3 although it is slight when the diaphragm 3 is open. However, since the light flux L2d incident on the peripheral portion 2a of the screen does not pass through the center of the diaphragm 3, if the diaphragm 3 is made to be a small diaphragm, all the vignetting will occur due to the diaphragm 3 and photography will not be possible.

On the other hand, as shown in FIG. 1 (C), when performing a special photographing with a small screen size, the photographing field angle is reduced by reducing the screen size. The rate of vignetting of the light beam incident on the part becomes smaller.

For example, in the case of FIG. 2 as well, if the screen size is made small as shown in FIG. 1C, the light beam L2c incident on the peripheral portion 2a of the screen slightly passes through the diaphragm 3 even if the diaphragm 3 is made small. Come to do.

According to the present invention, when the screen size is reduced by utilizing such an optical property, the interlocking mechanism moves the focus portion of the photographing lens more than when the screen size is large. And the closest object distance that can be photographed is made shorter.

That is, when the screen size is changed by the screen size changing means 4, the maximum amount of extension of the taking lens 1 is increased in association with it.

When a video camera is used in this embodiment, the screen size changing means may be configured to electrically change the image pickup range.

FIG. 3 is a system diagram according to this embodiment.
In the figure, reference numeral 11 denotes a distance measuring circuit, which measures the distance D to the subject by a known distance detecting means. Reference numeral 12 is a control circuit such as a microcomputer, 13 is a close warning display circuit, 31 is a camera release switch, and 32 is a switch for setting a panorama mode.

Next, the operation of this embodiment will be described with reference to the flow chart of FIG.

In step # 101, the release switch 3
It is detected whether 1 is turned on. Release switch 3
When 1 is turned on, the process proceeds to step # 102 and the distance measuring circuit 11 measures the distance D to the subject. Step # 103
Then, it is determined by the release switch 32 whether or not the special photographing, for example, the panorama mode is set. Since the release switch 32 is OFF when the screen size is full size, the process proceeds to step # 105, and the distance D and the close range D1 in full size are set.
When the distance D is shorter than the distance D1, the process proceeds to step # 106 to issue a close warning, and then the release operation is performed.

When the panorama mode is selected and the release switch 32 is ON, the routine proceeds to step # 104, where the distance D and the shortest distance D2 in panorama size (D2 <D
When the distance D1 is shorter than the distance D2, the process proceeds to step # 106 to issue a close warning, and then the release operation is performed.

In this embodiment, when the screen size is changed as described above, the closest shooting distance is changed to improve the specifications of the shooting lens.

FIGS. 5A, 5B, and 5C are schematic views of the essential parts of the optical system according to the second embodiment of the present invention.

In the present embodiment, when the zoom lens is used as the photographing lens and the screen size is reduced by special photographing (when the diagonal length of the screen becomes short), the zooming portion of the zoom lens has a large screen size. In comparison with, the case of moving the optical axis a lot more to perform zooming to expand the viewable angle of view and achieve a super wide angle of view is shown.

Reference numeral 51 in the figure denotes a photographing lens, which is composed of, for example, a zoom lens proposed in Japanese Patent Laid-Open No. 57-201213. That is, it is composed of two lens groups, a first lens group 51a having a positive refractive power and a second lens group 51b having a negative refractive power, and both lens groups are independently moved to the object side (image plane side) to obtain a wide-angle end (telephoto end). Zooming from the end) to the telephoto end (wide-angle end).

Reference numeral 2 denotes a photosensitive surface, which is made of, for example, a 35 mm film. 53 is a diaphragm, and 4 is a light-shielding member as a screen size changing means, which is arranged in front of the photosensitive surface 2.

5A and 5B, the screen size of the photosensitive surface 2 is full size, and FIG. 5A shows the zoom lens 51.
Fig. 5 (B) showing the optical path when is in the zoom position at the telephoto end
Shows an optical path diagram when the zoom lens 51 is at the wide-angle end zoom position. FIG. 5C shows a case where the photosensitive surface 2 is made smaller by the screen size changing means 4.

In the same figure, an optical path diagram is shown when the zooming portion of the zoom lens 51 is moved further to the wide-angle side than in FIG. 5B to perform zooming and zooming to the zoom position at the ultra-wide-angle end. ing.

At the zoom position at the wide-angle end in FIG. 5B, the luminous flux L55a incident on the peripheral portion 2a of the screen is restricted by the effective diameters of the lower portion 55a of the lens system 51a and the upper portion 55b of the lens system 51b.

In FIG. 5B, the lens system 5 is
When the lenses 1a and 51b are further moved to the image plane side and the magnification is changed to a wide angle of view, the light beam L55a becomes the upper portion 55b of the lens system 51b.
Then almost all of them are vignetting and I can't shoot anymore. That is, when the screen size is full size, FIG.
Is the widest angle zoom position at the wide-angle end.

On the other hand, as shown in FIG. 5C, when the special image is taken by reducing the screen size, the screen size is reduced so that the lens system 51b shown in FIG. The rate of vignetting of the light beam incident on the portion 2b becomes smaller. That is, as shown in FIG. 5C, when the screen size is reduced, the light flux L55c incident on the screen peripheral portion 2b is not reflected by the lens system 51b even if the lens system 51b is moved further to the image plane side as compared with FIG. 5B. The upper part 55b will pass without vignetting.

According to the present invention, when the screen size is reduced by utilizing such optical properties, the zooming portion of the photographing lens (zoom lens) is increased to the wide angle side by the interlocking mechanism as compared with the case where the screen size is large. I am trying to move it.
Then, the zoom position to the wide-angle side where variable magnification is possible is enlarged to achieve a super wide angle of view.

That is, when the screen size is reduced by the screen size changing means 4, the maximum amount of movement of the zooming portion of the taking lens 1 is increased in association with it. As a result, in the present invention, as a special photographing, for example, when a panoramic effect is to be obtained, a wide angle of view in the horizontal direction of the screen is more effectively achieved.

That is, in the panorama mode, since the vertical direction of the screen of 35 mm film size is shielded by the light shielding member, the screen size in the horizontal direction of the screen is almost the same as the full size. Therefore, if the angle of view is further widened in the panorama mode, the angle of view in the left-right direction is widened, and a further panoramic effect can be obtained.

It should be noted that such an effect is not limited to the zoom type shown in FIG. 5, and the same effect can be obtained in a general zoom lens in the present invention.

FIG. 3 is a system diagram according to this embodiment.
In the figure, reference numeral 61 is a control circuit by a microcomputer and the like, and 62 is a zoom motor drive circuit, which drives and controls a motor 63. The motor 63 drives the variable power unit. Reference numeral 64 denotes a focal length detecting means, which detects the focal length (zoom position) of the entire system due to the zooming of the zooming unit. S1, S2, S
3 is a switch, respectively.

The switch S1 is turned on to set a special photographing mode, for example, a panorama mode. The switch S2 is turned on to change the magnification changing portion to, for example, the telephoto side. Switch S
No. 3 is turned on and the zooming portion is zoomed to the wide-angle side.

In this embodiment, the control circuit 61 uses the switch S1.
When is OFF, that is, when the switch S2 or the switch S3 is turned ON when the screen size is normal (full size), the focal length detecting means 64 detects the zoom range. Then, the zoom motor drive circuit 62 drives the motor 13 to perform zooming in a normal zooming range up to the telephoto end or the wide-angle end.

On the other hand, when the switch S1 is ON, it is in the panoramic mode in which the screen size has changed, and when the switch S3 is ON, the wide-angle side drive is performed. After the end zoom position is detected, the zooming unit is driven so as to zoom further toward the wide-angle side. That is, the zoom motor drive circuit 12 and the motor 13 drive the zooming portion to the wide-angle side, thereby zooming to the ultra-wide-angle end in the panorama mode.

When the switch S1 is on and the switch S2 is on, the switch S1 is off because the drive is on the telephoto side.
Magnification is performed up to the normal telephoto end in the same manner as.

[0048]

According to the present invention, when each element is set as described above to change the screen size of the photosensitive surface to obtain various special photographing effects, the screen size is large as a photographing lens. Optical specifications that were difficult to achieve, such as shortening the closest object distance and further widening the shooting angle of view to the wide-angle side when the shooting lens is a zoom lens (ultra-wide angle), etc. It is possible to achieve a camera having a screen size changing means for improving the optical specifications of the taking lens.

[Brief description of drawings]

FIG. 1 is a schematic view of a main part of an optical system according to a first embodiment of the present invention.

FIG. 2 is an optical path diagram of the closest object distance of a conventional taking lens.

FIG. 3 is a system diagram of Embodiment 1 of the present invention.

FIG. 4 is a flowchart of the first embodiment of the present invention.

FIG. 5 is a schematic view of a main part of an optical system according to a second embodiment of the present invention.

FIG. 6 is a system diagram of a second embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Photographing lens 2 Photosensitive surface 3,53 Aperture 4 Screen size changing means 11 Distance measuring circuit 12,61 Control circuit 13 Close warning display circuit 51 Zoom lens 62 Zoom motor drive circuit 63 Motor 64 Focal length detecting means

Claims (2)

[Claims] 1. A camera having a screen size changing means for obtaining an object image at an arbitrary screen size by using the screen size changing means on a photosensitive surface by a taking lens, when the diagonal length of the screen size is short. A camera having a screen size changing means, characterized in that the photographing lens is set so that its close-up photographing distance is shorter than that when the photographing lens is long. 2. A camera having a screen size changing unit adapted to obtain an object image at an arbitrary screen size by using the screen size changing unit on the photosensitive surface by a taking lens having a variable power unit, wherein a diagonal line of the screen size is used. A camera having a screen size changing means, characterized in that when the length is short, the variable power section is set so that the variable power range can be further expanded to the wide-angle side as compared with the long time.