JPH037181B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a video camera that uses an automatic diaphragm as a shutter that also serves as an aperture when shooting still images, and shoots still images at various exposure times.

A conventional video camera is, for example, the one shown in FIG. 1, in which a lens body L is provided with an automatic aperture 10 and an automatic aperture drive circuit 20, and a body body B is provided with a recording control drive circuit 40. Also,
The automatic aperture 10 is used as an aperture shutter when photographing still images. In addition, in the figure, "automatic aperture"
is shown as AI.

The video camera mentioned above shoots one screen every 1/60 second or 1/30 second, and by continuously projecting this shooting screen, it can be viewed as a moving image. There is. Therefore, each of the above screens is a still image.

However, with the conventional video camera described above, still images cannot be taken using various exposure times. In other words, as mentioned above, the shutter speed of conventional video cameras is 1/60
The shutter speed is fixed at 1/30 seconds or 1/30 seconds, and still images cannot be taken at other shutter speeds. Therefore, in order to be able to shoot moving images and still images with various exposure times using a single video camera, it is necessary to simply combine the conventional video camera and still camera described above. It is possible to make one. However, in this case, there are problems in that the overall shape is large, the weight is large, and handling is complicated.

The present invention has been made by focusing on the above-mentioned conventional problems, and is a video camera that can take still images with various exposure times, and which has almost the same shape and weight as the conventional one. The purpose is to provide a video camera that is easy to handle.

In addition, a video camera configured to achieve the above purpose is provided with a new circuit different from the conventional one, and in order to connect this new circuit, a signal is provided between the lens body L and the body body B. It is expected that the number of lines will increase.
Therefore, an object of the present invention is to minimize the increase in the number of signal lines.

In order to achieve these objects, the present invention provides an automatic diaphragm in the lens section, the lens section and the camera section are separable, and the automatic diaphragm is used as a shutter for still image shooting. In a video camera capable of taking still images, the lens unit includes a programmable exposure time control circuit that outputs an exposure time control signal, and the camera includes a still control circuit that outputs a still control signal that transmits the start and end of still image shooting. A first signal control circuit and a second signal control circuit are provided in the camera section and the lens section, respectively, and control the flow of bidirectional signals consisting of the exposure time control signal and the still control signal. The two-way signals are time-divided and transmitted to each other on a single signal line during still image shooting.

Hereinafter, the present invention will be described in detail based on embodiments shown in the accompanying drawings. Incidentally, in FIG. 1, the same reference numerals are given to the same members as those shown, and the explanation thereof will be omitted. FIG. 2 is a block diagram showing one embodiment of the present invention. The still control circuit 50 outputs a still signal that conveys the start and end of still image shooting, and also generates a still signal for a predetermined period of time after receiving a still trigger signal. This still signal is a signal indicating that a still image is being photographed. The still trigger signal is a signal for switching from video shooting to still image shooting. The programmable exposure time control circuit 60 detects the amount of light from the subject, calculates the optimal exposure amount at that time, and outputs the result as a signal (exposure time control signal) related to the exposure time of the automatic aperture. be.

The gate circuit 70 receives the exposure time control signal and the still signal, and outputs an automatic aperture shutter control signal that controls opening and closing of the automatic aperture during still image shooting. This automatic aperture shutter control signal opens and closes the automatic aperture 10 through the automatic aperture drive circuit 21, and the automatic aperture shutter control signal opens and closes the automatic aperture 10 for a predetermined period of time from when the still signal is output.
This is a signal that causes the automatic diaphragm 10 to gradually open for a predetermined time period after the predetermined time period has elapsed, and for a predetermined time period after the program exposure time elapses. .

Further, the recording control drive circuit 41 records the image pickup signal obtained by opening the automatic diaphragm 10 during still image shooting on a predetermined recording medium as described above, and also records the image signal obtained by opening the automatic diaphragm 10 during still image shooting. After the time has elapsed, a recording completion signal is sent to the still circuit 50.

FIG. 3 is a circuit diagram in which a circuit is added to reduce the number of signal lines for connecting the circuits which has been increased in the embodiment shown in FIG.

First, in the main body B, there is a recording control drive circuit 4.
1, a still control circuit 50, and a first signal control circuit 80. On the other hand, the lens body L is provided with a programmable exposure time control circuit 60, a gate circuit 70, a second signal control circuit 90, and a signal conversion circuit 95. The lens main body L and the body main body B can be separated.

Further, the first signal control circuit 80 and the second signal control circuit 90 are circuits that control the flow of bidirectional signals consisting of an exposure time control signal and a still control signal, and there is a single line between the two circuits 80 and 90. They are connected by one signal line 100. Further, during still image shooting, these bidirectional signals are time-divided and transmitted to the body B or the lens body L.

FIG. 4 is a circuit diagram showing the embodiment shown in FIG. 3 in more detail. An OR gate 51 is used as the still control circuit 50. A switch 1 (a switch interlocked with a release button) that is turned on when photographing a still image is provided, and a one-shot multivibrator 2 is provided between the switch 1 and an OR gate 51. The other input terminal of the OR gate 51 is connected to the recording control drive circuit 4.
1 recording completion signal is received. This recording completion signal is a signal that indicates that recording on the recording medium has been completed.

The first signal control circuit 80 includes switches 81 and 82.
and an inverter 83. When the output signal of the OR gate 51, that is, the still control signal, is H, only the switch 81 is turned on, and when the still control signal is L, the switch 81 is turned on.
Only 2 is turned on. The second signal control circuit 90 includes switches 91 and 92 and an inverter 93. When the output signal of the programmable exposure control circuit 60, that is, the exposure time control signal, is H, only the switch 92 is turned on, and when the exposure time control signal is L, only the switch 91 is turned on.

Further, the gate circuit 70 includes an inverter 71 and an AND gate 72. The inverter 71 inverts the exposure time control signal, and the AND gate 72 receives the output signal of the inverter 71 and the still signal.

Next, the operation of the above embodiment will be explained.
In explaining this, the timing chart shown in FIG. 5 will be used. First, when switch 1 is open, no still signal is generated and AND gate 72 is not output, so automatic aperture drive circuit 2
1 is controlled only by the signal from the automatic aperture control circuit 30, and video shooting is performed.

Next, when switch 1 is turned on, a still trigger signal is generated, which causes one-shot multivibrator 2 to generate one pulse. As a result, the OR gate 51 outputs the still control channel. In this case, since the output of the OR gate 51 is H, the switch 81 is turned on and the switch 82 is turned on.
turns off. On the other hand, since no exposure time control signal is generated at this time, switch 91 is turned on and switch 92 is turned off. Therefore, the still control signal of OR gate 51 is sent to T flip-flop 96 as signal converter 95 via switch 81, single signal line 100, and switch 91. This causes the T flip-flop 96 to output an output signal, which will be referred to as a still signal.

In this way, the programmable exposure time control circuit 60 does not elute for a predetermined period of time T1 from the time it receives the still signal. For this purpose, the inverter 71
outputs during the predetermined time T1. Therefore, during the time T1, the automatic aperture shutter control signal is output, and the automatic aperture control circuit 21 closes the automatic aperture 10 during the time T1.

When the T1 time has elapsed, T2
Since the time and exposure time control circuit 60 outputs, the AND gate 72 no longer outputs, and as a result, the automatic aperture 10 gradually begins to open from the beginning of time T2. The above-mentioned time T2 is determined according to the amount of light in the field at that time.

When the exposure time control signal is output, switch 9
2 is turned on and switch 91 is turned off. Also, at this time, since the still control signal has disappeared, the switch 82 is turned on and the switch 81 is turned off. Therefore, the exposure time control signal is sent to the recording control drive circuit 41 via the switch 92, the single signal line 100, and the switch 82.

After the above-mentioned time T2 has elapsed, the exposure time control signal disappears, so the automatic aperture shutter control signal is output in the same way as the time T1, and this time is designated as T3. During this period, the automatic diaphragm 10 begins to open rapidly and then remains closed during T3. During this time, the video signal related to the still image shooting is recorded on the recording member. Then, when the T3 time has elapsed, a recording completion signal is generated from the recording control drive circuit 41, and in response to this, the still signal disappears, the still image shooting by the video camera is completed, and the video camera moves to the moving image shooting operation. That is, the automatic diaphragm 10 is controlled by the automatic diaphragm control circuit 30.

Also, two signals, the exposure time control signal and the still control signal, pass through the single signal line 100 without any problem. This is because the generation times of both signals are different.
This is used to selectively use time-division transmission.

As described above, the present invention is a video camera that can take still images with various exposure times, but it can also have a shape and weight that are almost the same as conventional ones, and it can also be used to take still images. Since switching is done by simply turning on the switch 1, it has the advantage of being easy to handle. Furthermore, a new circuit different from the conventional one is provided, and in order to connect this new circuit, the lens body L and the body body B are connected.
Although it is expected that the number of signal lines provided between the two will increase, this also has the effect of minimizing the increase in the number of signal lines.

[Brief explanation of the drawing]

Fig. 1 is a block diagram showing a conventional video camera, Fig. 2 is a block diagram showing one embodiment of the present invention, Fig. 3 is a block diagram showing another embodiment of the invention, and Fig. 4 is a block diagram showing the above embodiment. FIG. 5, which shows an example more specifically, is a time chart of the above embodiment. 10...Automatic aperture, 21...Automatic aperture drive circuit, 50...Still control circuit, 60...Programmed exposure time control circuit, 70...Gate circuit, 8
0...First signal control circuit, 90...Second signal control circuit, 100...Single signal line.

Claims (1)

[Claims] 1. In a video camera capable of taking still images, in which the lens part is equipped with an automatic diaphragm, the lens part and the camera part are separable, and the automatic diaphragm is used as an aperture shutter when taking still images, an exposure time control signal is provided. The lens section is provided with a programmable exposure time control circuit that outputs still image shooting, and the camera section is provided with a still control circuit that outputs still control signals that communicate the start and end of still image shooting, and those exposure time control signals and a first signal control circuit that controls the flow of a bidirectional signal comprising a still control signal;
A second signal control circuit is provided in the camera section and the lens section, respectively, and when shooting a still image, the bidirectional signals thereof are time-divided and transmitted to each other on a single signal line. .