JPH06125489A - Lens adaptor for camera - Google Patents

Abstract

PURPOSE:To pick up a frame picture and a field picture with high picture quality without need of troublesome processing and to simplify the lens operation by providing a shutter switching an incident optical path to the lens adaptor. CONSTITUTION:The system is provided with a replacement lens 1 having an image pickup lens, a camera main body 2 having an image pickup device such as a CCD, and a lens adaptor 3. Then the lens adaptor 3 is made up of a rear converter lens used being mounted to a rear part of the replacement type camera lens, for example, and has a focus correction optical system 32 comprising a shutter 31, a concave lens 321 and a convex lens 322 in its inside. An existing replacement lens is freely used by forming the lens adaptor 3 integrating the shutter 31 to the rear converter lens having the focus correction optical system 32 and a limitation of making the surrounding dark or the like is not required for the use of a strobo and a frame picture and a field picture with high picture quality are obtained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lens adapter having a shutter function used for video cameras and the like.

[0002]

2. Description of the Related Art Generally, a video camera, as shown in FIG. 4 (a), includes an interchangeable lens 1 equipped with an imaging lens and a C
It consists of a camera body 2 equipped with an imaging device such as a CD (Charge Coupled Device), and as shown in FIG. 4 (b),
It is configured by joining the interchangeable lens 1 to the joining portion 21 of the camera body 2.

In such a structure, as shown in FIG. 5, the light emitted from an image pickup object (not shown) is condensed by the interchangeable lens 1 to form an image forming surface 22a of the image pickup device 22.
To form an image of the object. An actual imaging lens is used by combining a plurality of lenses, but in FIG.
This is represented by a single lens. Further, when a still image is taken using such a video camera, a CCD shutter (electronic shutter) has been conventionally used.

[0004]

However, with the above-mentioned electronic shutter, although there is no problem in obtaining a still image of a frame, the field image cannot be picked up and the image quality is inferior to the frame image. In addition, it is necessary to darken the surroundings when shooting with a flash, which requires a troublesome work for shooting.

It is possible to attach a shutter to the front surface of the lens, but it is necessary to prepare several kinds of shutters according to the aperture of the lens, and in order to synchronize the image and the shutter, the camera body and the shutter are Since there is a need to connect a signal line between them, there is a drawback that it interferes with lens operation.

The present invention has been made in view of the above circumstances, and an object thereof is to take a frame image and a field image of good image quality without requiring troublesome work, and to easily operate a lens for a camera. To provide an adapter.

[0007]

In order to achieve the above object, the present invention provides a camera for condensing light emitted from an object to be imaged by an imaging lens and forming an image on a light receiving element arranged on the main body side. A lens adapter used, which is arranged in an incident light path to the light receiving element, wherein the lens adapter has a shutter for opening and closing the incident light path.

In the present invention, the lens adapter is inserted between the image pickup lens and the camera body.

In the present invention, the lens adapter has means for correcting the focal position of the image pickup lens.

In the present invention, the lens adapter has a signal contact for receiving an electric signal from the camera body, and the shutter is driven by the electric signal input from the signal contact.

[0011]

According to the present invention, the lens adapter is mounted in the incident light path to the light receiving element arranged in the camera body, and
The shutter provided on the lens adapter is actuated by an external mechanical or electrical stimulus, whereby the incident light path is opened and closed as necessary.

According to the present invention, the lens adapter has one side connected to the unit of the imaging lens and the other side connected to the camera body.

According to the present invention, the image forming position of the image pickup lens which is displaced by interposing the lens adapter is corrected by the correcting means. As a result, the image of the object is focused on the light receiving surface of the light receiving element.

According to the present invention, the electric signal from the camera body is input to the lens adapter through the signal contact, and this electric signal is supplied to the drive unit of the shutter. As a result, the shutter is opened and closed according to the input electric signal.

[0015]

1 is a schematic diagram showing a video camera equipped with a lens adapter according to the present invention, and FIG. 2 is a configuration diagram showing an embodiment of the lens adapter according to the present invention, which is the same as the configuration of FIG. The components are represented by the same symbols. That is,
Reference numeral 1 is an interchangeable lens equipped with an imaging lens, 2 is a camera body having an imaging device such as a CCD, and 3 is a lens adapter.

The lens adapter 3 is composed of, for example, a rear converter lens mounted on the rear part of an interchangeable camera lens for use, and inside thereof, as shown in FIG. 2, a focus composed of a shutter 31, a concave lens 321, and a convex lens 322. A correction optical system 32 is arranged. A concave lens coupling portion 33 that is coupled (screwed) with the interchangeable lens 1 is formed on the front side on the left side of the lens adapter 3 in the figure, and is coupled with the coupling section 21 of the camera body 2 on the rear side on the right side of the figure ( A convex lens coupling portion 34 that is screwed) is formed. Further, when the lens coupling portion 34 is coupled to the coupling portion 21 of the camera body 2, the lens coupling portion 34 is joined to an electric contact (not shown) provided on the front portion of the camera body 2 at a predetermined position on the periphery of the lens coupling portion 34. An electric contact portion 35 is provided. The electric contact portion 35 is
It is connected to the drive mechanism section of the shutter 31 by internal wiring (not shown).

The shutter 31 comprises a shutter blade 311 that opens and closes an optical path of the light condensed by the interchangeable lens 1 to the image pickup device, and a drive mechanism portion 312 for driving the shutter blade 311. Is arranged substantially at the center in the optical axis direction. As described above, the drive mechanism section 312 is connected to the electric contact section 35 by the internal wiring (not shown), inputs the electric signal sent from the camera body 2 through the electric contact section 35, etc., and receives this input signal. Accordingly, the shutter blade 311 is opened and closed.

As described above, the focus correction optical system 32 is composed of the concave lens 321 and the convex lens 322, and the concave lens 321 is on the lens coupling portion 33 side of the front portion of the adapter and the convex lens 322 is on the rear portion of the adapter, with the shutter blade 311 sandwiched therebetween. Are arranged on the side of the lens coupling portion 34 so that their optical axes coincide with the adapter axis. The focus correction optical system 32 includes the interchangeable lens 1 when the lens adapter 3 is inserted and coupled between the interchangeable lens 1 and the camera body 2.
The distance between the camera body 2 and the camera body 2 changes, so that the image formed by the interchangeable lens 1 is no longer formed on the image forming surface 22a (FIG. 3) of the image pickup device 22.

FIG. 3 is a view showing the principle of this focus correction, and the image forming operation of the video camera equipped with the lens adapter with shutter 3 will be described with reference to FIG. Figure 3
As shown in FIG. 3, light emitted from an imaging object (not shown) is condensed by the interchangeable lens 1 and is incident on the concave lens 321 of the lens adapter 3. In the concave lens 321, the optical path of incident light is changed to a direction substantially parallel to the optical axis. That is, here, correction is performed to set the focal position of the interchangeable lens 1 to be longer. The light subjected to the optical path changing action is incident on the convex lens 322 via the shutter blade 311, is condensed here, and is imaged on the imaging surface 22 a of the imaging device 22.

In the shutter 3 built in the lens adapter 3, an electric signal sent from the camera body 2 is input to the drive mechanism section 312 via the electric contact section 35 and the like, and the shutter is released in response to this input signal. The blade 311 is opened and closed.

As described above, according to this embodiment,
Since the lens adapter 3 is configured by incorporating the shutter 31 in the rear converter lens provided with the so-called focus correction optical system 32, it becomes possible to freely use the existing interchangeable lens, and it is possible to use a strobe to darken the surroundings. It is possible to obtain high-quality frame images and field images without any restrictions such as Further, since the lens adapter 3 is provided with the signal electric contact portion 35 that is joined to the contact on the camera body 2 side, a complicated connecting work can be avoided and the lens operation is obstructed even when connecting externally. It can be arranged so as not to become.

In the present embodiment, an example in which a shutter that is electrically controlled is arranged as the shutter incorporated in the lens adapter 3 is shown, but the shutter is not limited to this, and a mechanical element from the outside is used. It is also possible to apply one that is activated by stimulation. Further, when using an electronic viewfinder in an electronic still camera, for example, it is desirable that the shutter 31 be always open and closed only during shooting.

[0023]

As described above, according to the present invention,
It becomes possible to freely use existing interchangeable lenses,
It is possible to obtain high-quality frame images and field images without being restricted by the use of a strobe such as making the surroundings dark. Further, since the adapter is provided with the signal contact, it is possible to avoid a complicated connecting work, and it is possible to arrange it so as not to interfere with the lens operation even when the connection is made externally.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing a video camera equipped with a lens adapter according to the present invention.

FIG. 2 is a configuration diagram showing an embodiment of a lens adapter according to the present invention.

FIG. 3 is an optical path diagram for explaining an image pickup operation of the video camera of FIG.

FIG. 4 is a schematic diagram of a general video camera.

5 is an optical path diagram for explaining an image pickup operation of the video camera of FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Interchangeable lens 2 ... Camera main body 21 ... Bonding part 22 ... Imaging device 22a ... Imaging surface 3 ... Lens adapter 31 ... Shutter 311 ... Shutter blade 312 ... Drive mechanism part 32 ... Focus correction optical system 321 ... Concave lens 322 ... Convex lens 33 , 34 ... Lens coupling part 35 ... Electric contact part

Claims (4)

[Claims] 1. A lens used in a camera for collecting light emitted from an image pickup object by an image pickup lens to form an image on a light receiving element arranged on the main body side, and the lens being arranged in an incident optical path to the light receiving element. A lens adapter for a camera, characterized in that the lens adapter has a shutter for opening and closing the incident optical path. 2. The lens adapter for a camera according to claim 1, wherein the lens adapter is inserted between the imaging lens and a camera body. 3. The lens adapter for a camera according to claim 1, wherein the lens adapter has means for correcting the focal position of the imaging lens. 4. The lens adapter according to claim 1, 2 or 3, wherein the lens adapter has a signal contact for receiving an electric signal from the camera body, and the shutter is driven by an electric signal input from the signal contact. Lens adapter for camera.