Flash exposure control system
AssigneeCanon Kabushiki Kaisha
InventorsTakashi Uchiyama, Zenzo Nakamura, Shohei Ohtaki
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Abstract
The present invention relates to a device for flash light photography and, more particularly, to a device for flash light photography for adjustable light stroboscope. A major feature of the present invention is that the adjustable light condition of the stroboscope is rendered to be adjusted, based on the film speed and diaphragm value, independently of each other. Thus, when the film speed is made high, the responsive distance for light adjustment is elongated.
Claims6
A computer flash light device usable with a camera having an aperture control circuit which controls the aperture size on the basis of the value of the diaphragm aperture signal from the computer flash light device comprising:
- (a) flash means for producing a flash light;
- (b) exposure information setting means including:
- (1) a non-movable plate provided with aperture value marks;
- (2) a first movable member provided so as to be movable relative to the non-movable plate, said member being set at a desired aperture value mark on the non-movable plate;
- and
- (3) a second movable member provided so as to be movable relative to the non-movable plate, said member being provided with film sensitivity marks so as to set the film sensitivity by setting the determined film sensitivity mark at the aperture value mark selected by the first movable member;
- (c) a flash light amount control circuit for controlling the amount of the flash light emitted by the flash means;
- (d) adjusting means coupled to said flash light amount control circuit, said adjusting means for adjusting said amount of the flash light controlled by the light amount control circuit as a function of the displacement position relative to the non-movable plate of the second movable member;
- and
- (e) a diaphragm aperture value signal forming circuit having an aperture value adjusting means which is coupled with the first movable member so as to adjust the aperture value as a function of the displacement position relative to the non-movable plate of the first movable member, said diaphragm aperture value signal forming circuit producing a diaphragm aperture signal having a value corresponding to the aperture value adjusted with the adjusting means.
A camera system comprising:
- (A) a computer flash light device including:
- (a) flash means for producing a flash light;
- (b) exposure information setting means including:
- (1) a non-movable plate provided with aperture value marks;
- (2) a first movable member provided so as to be movable relative to the non-movable plate, said member being set at a desired aperture value mark on the non-movable plate;
- and
- (3) a second movable member provided so as to be movable relative to the non-movable plate, said member being provided with film sensitivity marks so as to set the film sensitivity by setting the determined sensitivity mark at the aperture mark selected by the first movable member;
- (c) a flash light amount control circuit for controlling the amount of the flash light emitted by the flash means;
- (d) adjusting means for adjusting the amount of the flash light controlled by said light amount control circuit as a function of the displacement position relative to the non-movable plate of the second movable member;
- and
- (e) a diaphragm aperture value signal forming circuit having an aperture value adjusting means which is coupled with the first movable member so as to adjust the aperture value as a function of the displacement position of the first movable member relative to the non-movable plate, said diaphragm aperture value signal forming circuit producing the aperture value signal having a value corresponding to the adjusted aperture value;
- (B) a camera usable with the flash light device including:
- (a) a diaphragm aperture;
- and
- (b) a diaphragm aperture control circuit to control the diaphragm aperture for defining the aperture value, said circuit controlling the diaphragm aperture based on the signal from the diaphragm aperture value signal forming circuit.
Dependencies are inferred from the claim text.