JPH0444464B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in an imaging device combined with an image monitoring device.

Conventionally, when using a monitor device connected to a camera that handles video signals, if the camera's exposure conditions (for example, aperture value) change, the brightness of the image signal changes accordingly. This can also be visually recognized on the screen.

On the other hand, when trying to capture still images with a video camera, various parameters related to the exposure amount during shooting (aperture, accumulation time, shutter speed, strobe photography conditions, light intensity of the illumination light source, etc.) are required. There is a degree of freedom in setting as appropriate.

However, when performing manual settings for such parameters, for example, even if movie (moving image) is captured immediately before still shooting and this movie image information is checked on the monitor, the parameters cannot be changed during still (still image) capturing. The disadvantage is that it is difficult to know what kind of image will be obtained because the images are switched. This is a drawback that naturally occurs in monitors using conventional optical viewfinders.

The present invention provides an improved imaging device that can overcome the drawbacks of the prior art as described above, and its main feature is to set imaging conditions related to the amount of exposure when capturing a still image with a camera. The present invention is characterized in that the brightness of the display on the monitor during moving image capturing is adjusted in accordance with the set imaging conditions. Other features will become apparent through the following description and drawings.

FIG. 1 is a diagram showing an embodiment of the present invention.
is an optical system for imaging, 2 is a mechanical or physical aperture, 3 is a mechanical or physical shutter, 4 is an imaging means such as a semiconductor image sensor or an image pickup tube, and 5 is a monitor for the output of this imaging means. A process circuit 6 for converting into a signal suitable for the present invention is a gain control circuit according to the present invention, and may be provided outside the monitor, or may also serve as an AGC circuit within the monitor.
Reference numeral 7 denotes a monitor means such as a cathode ray tube, a liquid crystal display, or a plasma display. 8
9 is an aperture control means for controlling the aperture amount of the aperture 2; 9 is a shutter control means for controlling opening and closing of the shutter 3;
10 is a driving means for driving the imaging means 4; 11;
12 is a setting means for manually setting the amount of light emitted from the illumination device 17, aperture value, shutter speed, image storage time in the image pickup means, etc. when capturing a still image, and 12 is each circuit 8 to 10 based on the setting value in the setting means. At the same time, the output of the distance information means 19, which will be described later, and the amount of emitted light set by the setting means are calculated, and the switch 18, which will be described later,
When it is ON, it is a mode control circuit that controls the gain of the gain control circuit 6 based on the result of this calculation.

Further, this control circuit outputs a predetermined set value different from the set value of the setting circuit 11 when the switch 18 is ON. 13 is a gate circuit for inputting or disabling the output value of the mode control circuit to the circuits 8 to 10, and 14 is a sequence controller for controlling the sequence of the entire imaging apparatus. Also 15
is a monitor start switch, and when this switch is turned on, power supply to each circuit is started, the mode is set to moving image capturing mode, the image capturing means is scanned periodically, and the moving image signal is sent to the monitor means 7 via the process circuit 5.
The moving image is displayed.

Further, the output of the process circuit 5 is configured to be led to a recording circuit (not shown). Reference numeral 16 denotes a still image pickup switch. When the switch 16 is turned on, the gate circuit 13 is opened, and the aperture 2, shutter 3, and image pickup means 4 are controlled by the output of the setting means 11, and one field is controlled. Alternatively, the image signal for one frame is guided to the recording device. Again 1
7 is a lighting device, and a standby switch 1
8 is turned on, it is put into a ready state, and is triggered by switch 16. Further, the gain control circuit 6 is controlled so that the gain corresponds to the setting value in the setting means 11 until the switch 16 is turned on. or,
By turning on the switch 16, the gain of the gain control circuit is controlled to a predetermined level while one image is being captured as a still image. Reference numeral 19 denotes distance information means for setting object distance information in the optical system 1, which may output a signal indicating the state of the optical system, for example, or may output a distance signal from a distance measuring device. Also good.

Next, the operation of this embodiment will be explained. Standby switch 18 is OFF, switch 16 is OFF
At this time, by turning on the monitor switch 15, power supply to each circuit is started, image information from the imaging means is periodically read out, and a moving image imaging mode is entered.
Furthermore, the formation of a new image begins with this readout.

Therefore, the monitor means 7 displays periodically updated moving images. At this time, the gate circuit 13 is closed, so the aperture value set in advance for still image capture,
Shutter speed, accumulation time, etc. are not input to each circuit 8-10.

For example, in this embodiment, the switch 15 is turned on,
While the switch 16 is off, the shutter is always open, the accumulation time is constant, and the aperture is controlled in accordance with the output level of the process circuit 5 so that the amount of light incident on the imaging means is constant.

On the other hand, in this state, the gain in the gain control circuit 6 is controlled by the output of the mode control circuit 12 so as to be at a level corresponding to the setting value of the setting circuit 11.

Next, switch 15 is turned on and switch 16 is turned on.
OFF, and when the switch 18 is ON, it means that still photography using the auxiliary light source is being prepared, so the mode control circuit 12 sends the setting means 11
A different setting value is output. For example, a signal is output to fully open the aperture, set the shutter speed to 1/60 seconds, and set the accumulation time to 1/60 seconds. However, since gate circuit 13 is closed, no signal is input to circuits 8-10.

Then, these set values, distance information, and amount of emitted light are further calculated, and the gain of the gain adjustment circuit 6 is controlled based on the calculation results.

In other words, the monitor displays what kind of brightness the screen will have when auxiliary lighting is actually used. Of course, conventional methods simply display objects that require auxiliary lighting on a screen with a constant brightness, which is too dark to be useful.

Next, switch 15 is turned on and switch 18 is turned off.
When the switch 16 is turned on at this time, the gate 13 opens and imaging is performed at the preset aperture value, shutter speed, and accumulation time. At the same time, the gain in the gain adjustment circuit becomes the aforementioned predetermined level.

Also, switch 15 is ON, switch 18 is ON
When the switch 16 is turned on at this time, the gate 13 opens and the circuits 8 to 10 are controlled by a set value different from the set value in the setting means 11. Also, the lighting circuit 17 is activated to provide lighting for a short period of time.

As explained above, according to the present invention, when capturing a still image, it is possible to monitor in advance an image in almost the same state as the still image that should actually be obtained, so that various shooting parameters etc. when capturing a still image can be monitored. When setting, it is possible to select the most appropriate photographing conditions.

In this embodiment, the display state is changed by controlling the gain, but the same effect can be obtained by changing the clamp level during the horizontal blanking period.

[Brief explanation of drawings]

FIG. 1 is a diagram showing an embodiment of the present invention. 6... Gain control circuit, 7... Monitor, 11... Parameter setting circuit, 15... Monitor start switch, 16
...Still imaging switch, 17...Lighting circuit.

Claims (1)

[Scope of Claims] 1. An imaging device having a moving image imaging mode and a still image imaging mode, comprising: imaging means for converting an optical image into a video signal; and displaying an image corresponding to the video signal from the imaging means. a setting means for setting imaging conditions related to the amount of exposure to the imaging means in the still image imaging mode; and a setting means for setting imaging conditions regarding the amount of exposure to the imaging means in the still image imaging mode; An imaging device comprising: means for adjusting the level of the video signal to provide brightness that corresponds to imaging conditions.