JPH0591384A - Mount conversion adapter and camera system with same - Google Patents

Abstract

PURPOSE:To provide the mount conversion adapter and the camera system having the same capable of using an exchange lens for a 35mm single-lens reflex camera for a video camera. CONSTITUTION:The mount conversion adapter provided with a mount 2 for conversion lens for single-lens reflex camera in the front and a mount 3 for video camera at the back is provided with a filter device 8 having plural filters and selecting one of them so as to be loaded on and unloaded from a light path. Thus, when falling the conversion lens from the mount conversion adapter, the previously set reference filter 9 selected from filter device is inserted into the light path.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mount conversion adapter and a camera system having the same, and for example, when mounting an interchangeable lens for a 35 mm single-lens reflex camera on an interchangeable lens video camera (camera body) for photographing. The present invention relates to a suitable mount conversion adapter and a camera system having the same.

[0002]

2. Description of the Related Art Conventionally, in addition to an interchangeable lens dedicated to a video camera, an interchangeable lens for a 35 mm single-lens reflex camera can be attached to a interchangeable video camera via a mount conversion adapter (intermediate accessory) for photographing. Various types of camera systems have been proposed.

The photographing mode of the video camera at this time is (a) a method in which a simple cylindrical mount conversion adapter for fitting the flange back is attached to the video camera. (B) A method of mounting a mount conversion adapter provided with a diaphragm driving unit that drives the diaphragm lever and changes the diaphragm diameter to control the amount of passing light. (C) A mount conversion adapter provided with a shutter means for driving the shutter film so as to prevent harmful light from entering the image sensor when the conversion lens for the 35 mm single-lens reflex camera is removed from the video camera. How to wear. Etc.

[0004]

Generally, in order to set an appropriate exposure condition in a camera system, the shutter speed and the aperture value are changed according to the brightness (luminance) of the subject,
Thereby, the sensitivity of the photosensitive material (imaging element) is adjusted.

At this time, when the brightness of the subject is high, it is necessary to control the aperture to a smaller aperture diameter because a shutter speed that is too fast cannot be obtained due to mechanical limitations of the mechanism that controls the shutter speed. However, when the diaphragm of the photographing system is narrowed down, the confusion circle becomes large due to the diffraction effect of light, and the image forming performance is greatly deteriorated.

Therefore, conventionally, a filter device having transparent glass and a plurality of ND filters is arranged near the diaphragm,
When the ND filter can be inserted and removed and the subject brightness is high and the aperture diameter must be reduced, ND with an appropriate density
A filter is placed in the optical path to prevent the aperture diameter from becoming too small.

Conventionally, in a video camera having such a filter device, when taking a picture in a place where it is not so bright such as indoors, it is preferable to selectively arrange a transparent glass of the filter device in the optical path for taking a picture. However, if the ND filter happens to be located in the optical path, the aperture diameter of the diaphragm changes with that as a reference, and there is a problem that it is not possible to shoot with an appropriate F number.

The present invention is a video camera using a mount conversion adapter capable of using a conversion lens for a 35 mm single-lens reflex camera and a filter device having a plurality of filters such as an ND filter and transparent glass. It has a mount conversion adapter and a mount conversion adapter that makes it possible to always keep the aperture diameter of the diaphragm in a good state for shooting by properly setting the reference filter that should be positioned in the optical path when the lens is removed. The purpose is to provide a camera system.

[0009]

The mount conversion adapter of the present invention is a mount conversion adapter having a mount for an interchangeable lens for a single-lens reflex camera on the front surface and a mount for a video camera on the rear surface. Is provided with a plurality of filters, one of which is selected so that the filter device can be inserted into and removed from the optical path. When the interchangeable lens is removed from the mount conversion adapter, the filter device is installed. It is characterized in that a reference filter set in advance is inserted in the optical path.

Particularly in the present invention, the reference filter is a transparent filter.

Further, the camera system of the present invention is a camera system having a mount for an interchangeable lens for a single-lens reflex camera and a video camera having an image pickup device on an image forming surface, and a plurality of filters are provided in the vicinity of the mount. Then, one filter is selected from them, and a filter device configured to be inserted and removed in the optical path is provided. When the interchangeable lens is removed from the mount, a preset reference filter is selected from the filter devices. The feature is that it is inserted in the optical path.

In particular, the present invention is characterized in that the reference filter is a transparent filter.

[0013]

1 is a schematic view of a main part of a first embodiment of a camera system of the present invention, and FIG. 2 is a schematic view of a main part of a mount conversion adapter of the present invention.

In the figure, reference numeral 101 denotes a lens unit for a 35 mm single lens reflex camera, which is composed of a zoom lens. Reference numeral 102 denotes a mount conversion adapter, which is provided with a mount 2 for a 35 mm single-lens reflex camera on the front surface,
A mount 3 for a video camera is provided on the rear surface. 1
Reference numeral 03 is a video camera (camera body).

FIG. 1 shows the mount conversion adapter 10 of FIG.
2 is a lens unit 101 in front, and a video camera 10 is in the rear.
The case where 3 is attached is shown.

First, the mount conversion adapter 102 will be described. 1 is the adapter body. 2 is 35 mm
A mount 3 for mounting an interchangeable lens for a single lens reflex camera and a mount 3 for mounting on the video camera 103.

Reference numeral 8 denotes a filter device, which has a filter disc 8a holding a plurality of filters such as an ND filter 10 and a transparent glass (transparent filter) 9 in a turret type. Reference numeral 5 denotes a motor as a driving unit, which rotates the filter disk 8a around the rotation shaft 8b via the gear 5a.

Reference numeral 6 denotes a control means (CPU) which controls the drive of the motor 5 based on signals from the video camera 103 and external operation means (not shown). The control unit 6 exchanges various signals with the control unit 19 on the lens unit 101 side and the control unit 21 on the video camera 103 side.

Reference numeral 7 is an encoder, which is a filter disc 8a.
The position (rotation position) of is detected. Reference numerals 4a and 4b denote contacts, which exchange various signals with the lens unit 101 and the video camera 103 and supply power.

Reference numeral 29 denotes a detection pin, which is biased to the left by spring means (not shown) and detects whether or not the interchangeable lens is mounted on the mount 2 by using the switch 28. That is, when the interchangeable lens is mounted on the mount 2, the detection pin 29 is pressed to the right, and the other end 27 turns on the switch 28. When the interchangeable lens is removed from the mount 2, the detection pin 29 is moved leftward by the spring means, so that the other end 27 is separated from the switch 28 and the switch 28 is turned off.

The ON / OFF state of the switch 28 is input to the control means 6. The switch 28 of the control means 6 is OFF
In this case, the drive unit 5 is driven so that the reference filter, for example, the transparent filter 9 is inserted into the optical path from the filter device 8.

Next, the lens section 101 will be described.

Reference numeral 11 denotes a focus lens (focusing lens), which is driven by the focus drive section 11a. 1
Reference numeral 2 denotes a variable power lens group, which is driven by a variable power driver 12a. Reference numeral 13 is a diaphragm means, and the diaphragm diameter is changed by a diaphragm driving portion 13a. Reference numeral 14 is a relay lens group. Reference numeral 19 is a control means (C
PU) and a focus drive unit 11a and a magnification drive unit 12
a, the diaphragm drive unit 13a and the like are drive-controlled.

Next, the video camera 103 will be described.

Reference numeral 15 is an image pickup device (CCD). Reference numeral 16 denotes a piezo element, which drives the image pickup element 15 back and forth with a predetermined amplitude in the optical axis direction. As a result, the focus signal for the front focus or the rear focus of the lens unit 101 is obtained from the video signal obtained from the image sensor 15.

Reference numeral 23 denotes a piezo drive unit, which is a piezo element 16
Drive operation. A video signal processing circuit 26 processes the video signal from the image sensor 15 to obtain, for example, a focus signal (AF signal). A focusing signal processing circuit 25 detects the focusing state of the lens unit 101 using a signal from the video signal processing circuit 26.

A diaphragm control circuit 24 obtains a diaphragm signal for optimizing the exposure light to the image sensor 15 based on a signal from the image sensor 15, and inputs the diaphragm signal to the control means 21. The control means 21 processes the image signal from the image pickup device 15, the diaphragm signal from the diaphragm control circuit 24, the focusing signal from the focusing signal processing circuit 25, and the like through the controlling means 6 of the mount conversion adapter 102 and the contact 4b. We exchange various signals.

Next, the operation of this embodiment will be described.

When the power of the video camera 103 is turned on, the control means 19 of the lens section 101 causes the control means 6 of the mount conversion adapter 102 to change various initial information such as the open F number, the focal length, the focus position and the aperture value of the lens section 101. (Signal) is input and similar information is input to the control means 21 of the video camera 103 via the control means 6.

The control means 19 of the lens unit 101 detects the zoom position of the variable power lens group 12, and the focus lens 1
In addition to controlling the driving speed of No. 1, the diaphragm driving unit is driven based on the diaphragm signal from the control means 6 of the mount conversion adapter 102 to control the diaphragm 13 to an appropriate aperture diameter.

A diaphragm signal and a focus signal are input to the control means 21 of the video camera 103 from the diaphragm control circuit 24 and the focus signal processing circuit 25. At this time, the piezo drive unit 23
In this way, the piezo element 16 is driven to reciprocally drive the image pickup element 15 in the optical axis direction, and the focus signal is detected.

At this time, the driving amplitude of the image pickup device 15 is driven with a large amplitude because the depth of field becomes deep if the diaphragm aperture of the diaphragm means 13 is small. Also, the amplitude becomes smaller as the diaphragm opening becomes larger and closer to the opening side. In this embodiment, the direction of whether the focus lens group 11 is to be driven forward or backward is determined by swinging the image sensor 15 in the front-back direction.

In this embodiment, the amplitude of the reciprocating drive of the image pickup device 15 in the optical axis direction at this time is set within the range in which the image pickup angle of view of the image does not change.

Normally, the F number of the lens unit 101 is F
Smaller apertures than about 8.0 are not made to correspond, and at this time, even if the piezo element 16 is driven with the maximum amplitude, the direction detection becomes slow. Therefore, when the aperture diameter of the aperture means 13 is smaller than F8.0, the mount conversion adapter 102
The drive unit 6 is operated via the control means 6 of (1) to place the ND filter 10 instead of the transparent glass 9 of the filter device 8 in the optical path. That is, when the diaphragm means 13 is a small diaphragm, the speed at which the piezo element 16 is driven to detect the focusing direction becomes slow because the depth of focus becomes deep.

Therefore, in this embodiment, in such a case, the ND filter is automatically positioned in the optical path,
This prevents the diaphragm diameter of the diaphragm means 13 from becoming smaller than a certain value, that is, from preventing the depth of focus from becoming deep, thereby preventing delay in the detection speed in the focusing direction.

In this embodiment, the detection pin 29 detects whether or not the interchangeable lens is mounted on the mount 2. When the interchangeable lens is not attached to the mount 2, that is, when the interchangeable lens is removed from the mount 2, a reference filter (transparent filter) is inserted into the optical path from the filter device. A flowchart of the control method at this time is shown in FIG.

Thus, when the video camera is used in a relatively dark place, for example, indoors, it is possible to prevent the aperture opening diameter of the aperture means 13 from increasing while the ND filter is inserted in the optical path and obtain a good image. I am allowed to do so.

[0038]

According to the present invention, as described above, a video camera using the mount conversion adapter capable of using the interchangeable lens for the 35 mm single-lens reflex camera and the filter device having a plurality of filters such as an ND filter and transparent glass. Mounted so that the aperture diameter of the diaphragm can always be kept in a good state by setting the reference filter that should be positioned in the optical path when the interchangeable lens is removed from the video camera. A conversion adapter and a camera system having it can be achieved.

[Brief description of drawings]

FIG. 1 is a schematic view of a main part of a first embodiment of a camera system of the present invention.

FIG. 2 is a schematic view of a main part of a mount conversion adapter according to a first embodiment of the present invention.

FIG. 3 is a flowchart of a camera system according to the present invention.

[Explanation of symbols]

 101 lens part 102 mount conversion adapter part 103 video camera part 1 adapter body 2 mount for single-lens reflex camera 3 mount for video camera 4a, 4b contact point 5 drive part 6,19,21 control means 7 encoder 8 filter device 9 transparent glass 10 ND filter 13 Aperture means 15 Image sensor 16 Piezo element 28 Switch 29 Detection pin

Claims (4)

[Claims] 1. A mount conversion adapter in which a mount for an interchangeable lens for a single-lens reflex camera is provided on the front surface and a mount for a video camera is provided on the rear surface, and a plurality of filters are provided in a part of the mount conversion adapter, and one of them is used. A filter device that is configured so that it can be inserted into and removed from the optical path by selecting a filter, and when the interchangeable lens is removed from the mount conversion adapter, a reference filter that has been preset from among the filter devices is placed in the optical path. A mount conversion adapter characterized by being inserted. 2. The mount conversion adapter according to claim 1, wherein the reference filter is a transparent filter. 3. A camera system having a mount for an interchangeable lens for a single-lens reflex camera and a video camera having an image sensor on an image forming surface, wherein a plurality of filters are provided in the vicinity of the mount, one of which is provided. Provided is a filter device configured to be selectable in the optical path so that it can be inserted / removed in the optical path, and when the interchangeable lens is removed from the mount, a preset reference filter is inserted in the optical path from the filter device. A camera system characterized by the above. 4. The camera system according to claim 3, wherein the reference filter is a transparent filter.