JP2887482B2 - Still video camera - Google Patents

Description

Description: BACKGROUND OF THE INVENTION The present invention relates to a still video camera for recording a still image on a video floppy disk.

[Related Art] Recently, still video cameras with a built-in strobe have been commercialized by various companies. Also, in this type of still video camera, since the latitude of the exposure range of a solid-state image sensor such as a CCD is narrower than that of a silver halide film, the following method is used to obtain the optimum exposure. ing. That is, 1) a photometric operation is performed from the output of the external photometric element to determine the aperture and the shutter speed.

2) Temporary exposure is performed at the determined aperture and shutter speed, and the video signal output level is read into the microcomputer.

3) The exposure is recalculated according to the video signal output level, and the shutter speed in the main exposure for recording is determined.

4) Main exposure is performed at the aperture and shutter speed determined by the exposure recalculation, and recording is performed on a video floppy disk.

Such a technique to obtain the optimum exposure is called “re-reading photometry”.
(Feedback photometry). At this time, in the provisional exposure in the above item 2), the mechanical shutter has a simple configuration by utilizing the electronic shutter function of the image sensor.

[Problems to be solved by the invention]

However, such an electronic shutter function forcibly clears the charge of an image pickup device such as a CCD, so that unlike the normal clearing, the charge often remains, and in the subsequent main exposure, In the case of frame recording, there is a problem that the difference occurs accidentally and causes frame flicker.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-described problems of the conventional still video camera, and has as its object to reduce the possibility of occurrence of frame flicker as described above.

[Means for solving the problem]

For this reason, in the present invention, the "read-out photometry"
When the exposure recalculation is not required, the above object is achieved by prohibiting the exposure by the electronic shutter.

[Action]

With the above-described configuration of the present invention, when exposure re-calculation by “rereading photometry” is not required, exposure by the electronic shutter is not performed, and thus the occurrence of frame flicker as described above is eliminated.

〔Example〕

 Hereinafter, the present invention will be described based on examples.

(Configuration) FIG. 1 is a block diagram showing the configuration of a still video camera according to an embodiment of the present invention. Reference numeral 1 denotes a microcomputer (hereinafter abbreviated as μ-computer) for performing sequence control of the still video camera of the present invention. 2 is an optical system lens of an imaging system, 3 is an aperture, 4 is a mechanical shutter for exposure, 5 is a solid-state imaging device such as a CCD, 6 is a signal processing system,
Reference numeral 7 denotes a recording circuit.

8 is a built-in flash, 9 is an AF (auto focus) type distance measuring element, 10 is an AE (automatic exposure) type light measuring element, 11 is an EF (strobe) type light adjusting element, and 12 is AWR (auto white balance). ) Element, 13 is a display LED in the viewfinder, 14 is a display LC
D and 15 are drivers for driving the optical systems 2, 3, and 4, and 16 is a driver for driving the deck system. 17 is a magnetic head for recording, 18
Is a sheet motor for driving the video floppy disk 19.

Reference numeral 20 denotes a battery for driving the camera, 21/22 denotes SW1 / SW2 of the release switch, 23 denotes a set button for mode setting, 24 denotes a field / frame switch, and 25 denotes a field / frame switch.
Is the select button for mode setting, 26 is the up button,
27 is a down button, 28/29 is a shooting mode setting button such as self / single continuous shooting, and 30 is a switch SW1 / SW2 2
Lock switch that prohibits 1/22 release operation.

31/32 are built-in flash mode switches, 33 is a simple exposure compensation button, 34 is a write protect switch that detects the presence or absence of a video floppy erroneous write prevention claw, 35 is a video floppy disk 19 loading completion switch, and 36 is This is a 52 track switch for knowing the absolute track position of the magnetic head 17.

(Operation) Next, the operation of the still video camera will be described. When the μ-computer 1 detects "ON" of the switch SW121, the AF distance measuring element 9 measures the distance to the subject. Also, a photometric output is obtained by the AE photometric element 10, and the aperture and shutter speed are determined by the operation of the μ-computer 1. And switch SW2
When "on" of the switch 22 is detected, the lens 2 is driven via the driver 15 based on the distance information. Then, the aperture 3 is set, the shutter 4 is actuated to expose the CCD 5 by photometric calculation, and recording is performed on the video floppy disk 19 by the magnetic head 17 via the signal processing system 6 and the recording system 7. .

(“Re-reading photometry” operation) Next, the “re-reading photometry” will be described first with reference to FIG. 3 showing an operation sequence flowchart of a conventional example. In step S1, the release switch SW
When "on" of the signal 121 is detected (Yes), the process proceeds to step S2, in which the distance is measured by the photometric element 9, and the process returns to step S1 until "on" is detected (No). Next, in step S3, the photometric element
Photometry is performed according to 10, and a shutter speed and aperture calculation are performed based on the photometry in step S4. Then, proceeding to step S5, when "ON" of the switch SW222 is detected (Yes),
Proceed to step S6. On the other hand, SW2 is turned on in step S5
If is not detected (No), the flow returns to step S3 to perform photometry. When switch SW2 is detected to be “on”, step S
In step 6, the lens 2 is driven, and in step S7, the lens 2 is set to the aperture 3 determined by the photometric calculation. Then, the process proceeds to step S8, and outputs an electronic shutter pulse at the shutter speed determined in step S4. And
In step S9, the video signal is read. If the output is equal to or lower than a certain level, the shutter speed is determined in step S10 by performing correction in accordance with the level. The conventional camera has been configured to proceed to step S11 to run the shutter 4 to perform exposure, and to perform recording in step S12.

On the other hand, an operation sequence of "rereading photometry" of the embodiment of the present invention will be described next with reference to a flowchart of FIG. From the start to step S7, the process proceeds in the same manner as in FIG. 3, and each step is indicated by the same S number. In the next step S8a, when the shooting is flash shooting (Yes)
To step S11. In this case, the electronic shutter pulse is not output as in the conventional example shown in FIG.
Then, the shutter 4 is operated and driven to perform stroboscopic photography and record. On the other hand, in step S8a, if it is not flash photography (No), the recording proceeds to steps S8, S9, S10, S11, and S12 in the same manner as in FIG.

That is, since the electronic shutter pulse function does not work during flash photography, the occurrence of frame flicker in this case as in the conventional example can be eliminated.

(Other Embodiments) In the above embodiment, the case where the exposure using the electronic shutter pulse function is prohibited only when the strobe is used has been described. However, the same applies to the case of BLC (backlight control) and manual exposure correction. Of course, the prohibition may be performed.

〔The invention's effect〕

As described above, according to the present invention, the exposure by the electronic shutter is prohibited when the exposure re-calculation by the "re-reading photometry" is not required, so that the frame flicker in those cases is eliminated. Became possible.

[Brief description of the drawings]

FIG. 1 is a block diagram showing the configuration of an embodiment of a still video camera according to the present invention, FIG. 2 is an operation sequence flowchart of "rereading photometry" in FIG. 1, and FIG. 3 is a conventional "rereading photometry". It is a flowchart of an example of the operation sequence of "". DESCRIPTION OF SYMBOLS 1 ... microcomputer (arithmetic means) 2 ... lens 3 ... aperture 4 ... shutter 5 ... CCD 8 ... strobe 9 ... distance measuring element 10 ... light measuring element 11 ... light adjusting element 19 ... video floppy disk

Claims (1)

(57) [Claims] An external photometric device, an arithmetic device for determining an aperture and a shutter speed from the photometric output, a temporary exposure device for performing a temporary exposure prior to a main exposure during recording,
A still video camera having an arithmetic unit for calculating the shutter speed of the main exposure according to the video signal output level at the time of the temporary exposure, and a strobe device, wherein at the time of strobe shooting, A still video camera comprising a prohibition unit for prohibiting control of an imaging circuit.