JPH0418299Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Field of Application of the Invention] The present invention relates to a photographing system such as a television camera or a video camera having an imaging means such as an image pickup tube or a CCD, and is particularly suitable for photographing a high-speed moving object. The present invention relates to an adapter with a built-in shutter for obtaining a good image with less motion blur and distortion by intermittently applying instantaneous exposure to an imaging means using a shutter means.

[Background of the idea]

Conventionally, in imaging systems such as television cameras and video cameras (generally referred to as television cameras) that obtain images by scanning the imaging surface with a scanning beam, a high-speed moving object that is faster than the scanning time of one frame is Photographs are taken by intermittently exposing the imaging surface. As a result, the imaging surface can be exposed at a shutter speed that is substantially faster than the scanning time per frame, and a clear image can be obtained that prevents motion blur when photographing a high-speed moving object.

An example of a shutter means is one in which a rotary disc type shutter having a translucent part is rotated in front of the photographic lens so that the light beam from an object that is incident on the photographic lens is transmitted intermittently for a short period of time. There is. Although this method has fewer spatial restrictions for arranging the shutter means, since the diameter of the light beam incident on the photographic lens is large, the diameter of the rotary shutter must be increased, which has the drawback of increasing the size of the entire device.

Another example of shutter means is one in which the light beam is interrupted by a rotating shutter near the imaging plane of the photographic lens.In this method, the shutter means consisting of the rotating shutter and the drive device that drives it can be made smaller. However, it is mechanically very difficult to arrange this shutter means at or near the imaging surface.

Therefore, the present applicant first developed an optical device for photographing a high-speed moving object in Japanese Patent Application Laid-open No. 160779/1983, which has two optical systems, a first optical system and a second optical system, and is used for normal photographing. When photographing a high-speed moving object, the intermediate image of the object formed by the first optical system is re-imaged on the imaging means by the second optical system. An optical device is provided in which a rotary shutter is disposed near a position where an intermediate image is formed at this time. However, with this configuration, the image on the imaging means surface is reversed between the normal case of photographing using only the first optical system and the case of photographing a high-speed moving object using the second optical system and a rotary shutter. Therefore, when using the second optical system, special operations such as attaching the camera body in the opposite direction or electrically reversing the scanning direction of the imaging means are required. Furthermore, since the image formed by the first optical system is re-imaged by the second optical system, the overall length of the optical system becomes long.

[Purpose of invention]

SUMMARY OF THE INVENTION The object of the present invention is to eliminate the drawbacks of the prior art described above and provide a compact adapter with built-in shutter for television cameras that does not cause image reversal.

[Summary of the invention] The adapter with built-in shutter of the invention has a built-in shutter that interrupts the light beam passing through the photographic lens, and is detachably attached between the photographic lens and the television camera. has a diverging lens section (this is placed closer to the imaging lens side than the imaging plane of the imaging lens) and a converging lens section in order from the imaging lens side, so that it is substantially equal to the flange back length of the imaging lens. The flange back length is the same as the flange back length.

[Example of idea]

FIG. 1 shows an optical system according to an embodiment of the present invention,
1 is a photographing lens; 7 is a known television camera including a color separation prism 8 and an image sensor 9; and 2 is a detachable shutter built-in adapter based on the present invention. Reference numerals 10 and 11 are mounts for attachment. During normal photography in which fast-moving objects are not photographed, the photographing lens 1 and television camera 7 are used in combination without attaching the built-in shutter adapter 2. When photographing a high-speed moving object, a built-in shutter adapter 2 is attached between the photographing lens 1 and the television camera 7 as shown in the figure.

The built-in shutter adapter 2 has a diverging lens section 3.
and a convergent lens section 4, and has a shutter means. In this embodiment, a rotary shutter 5 driven by a motor 6 is used as the shutter means. The rotary shutter 5 consists of a disc having a transparent window 5' as shown in FIG. In addition to a rotary shutter, physical elements such as a liquid crystal shutter can also be used as the shutter means.

FIG. 3 shows an embodiment of the optical system portion of the adapter 2 with built-in shutter. As shown,
The converging light beam from the photographing lens 1 is converted into almost parallel light, weakly diverging light, or weakly converging light by the action of the diverging lens group 3, which is arranged closer to the photographing lens than the imaging plane of the photographing lens, and is arranged behind it. By converging with the convergent lens group 4,
The flange back length of the shutter built-in adapter 2 is configured to be the same length as the flange back length of the photographic lens 1. The flange back length is the distance from the mount reference plane of the lens barrel to the image focal point. That is, in the configuration of the optical system of this embodiment described above, when the photographing lens 1 is directly mounted on the camera 7 with the mount 11 without inserting the adapter 2 in FIG. The distance to the focal point (where the surface of the image sensor 9 is placed) and the distance from the reference plane of the mount 11 of the adapter 2 to the image focal point when the adapter 2 with the photographing lens 1 attached is attached to the camera 7 with the mount 11. This means that the distances are the same. By configuring the optical system in this way, even when the built-in shutter adapter 2 is attached, an image can be focused on the same surface of the photographing element 9 as when it is not attached.

It is most preferable to arrange the shutter 5 in the space between the diverging lens group 3 and the converging lens group 4 since it does not require wasted space, but of course if there is space, it can be placed in front of the diverging lens group 3 A shutter may be arranged behind the converging lens group 4.

With the configuration described above, it is possible to combine the lens 1 and camera 7 for normal shooting without inserting the adapter 2, or use the built-in shutter adapter only when a shutter is required, such as when photographing a high-speed moving object. 2 can also be inserted to take a picture, and in either case, it is possible to correctly form an image on the image sensor in the camera 7.

Note that if the final surface of the lens protrudes from the flange surface toward the image side, the final surface of the lens
In order to avoid the possibility of collision with the internal elements, in addition to making the flange back lengths equal as described above, the back focus length of the adapter 2 is also configured to match the back focus length of the photographing lens. The back focus length here refers to the distance from the vertex of the final surface of the lens to the image focal point.

[Effect of idea]

According to the present invention, the adapter with built-in shutter can be inserted between the photographic lens and the camera and used only when a shutter is necessary, such as when photographing a high-speed moving object, without making any modifications to the photographic lens or camera. Furthermore, an image can be formed on the surface of the imaging means in the camera both when the shutter built-in adapter is inserted and when it is not inserted. Moreover, according to the present invention, since the shutter is placed between the photographic lens and the camera, the shutter is placed in front of the photographic lens, unlike the conventional technology described in the background section of the invention. It is possible to avoid the increase in the size of the lens and mechanical difficulties when arranging the shutter near the imaging surface. You can avoid problems.

[Brief explanation of drawings]

Figure 1 is a schematic diagram showing one embodiment of the present invention;
The figure is a front view of the rotary shutter in the same embodiment.
FIG. 3 is an illustrative diagram of the optical system of the shutter built-in adapter in the same embodiment. 1... Shooting lens, 2... Shutter built-in adapter, 3... Diverging lens section, 4... Converging lens section, 5... Rotating shutter, 6... Motor, 7
...TV camera, 9...imaging device.

Claims (1)

[Scope of utility model registration request] This adapter has a built-in shutter that interrupts the light beam passing through the photographic lens, and is removably attached between the photographic lens and the television camera. (This is arranged closer to the taking lens than the imaging plane of the taking lens) and has a flange back length that is substantially the same as the flange back length of the taking lens due to the converging lens section. An adapter with a built-in shutter.