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US 4,541,703 AGranted
Electronic flash photographic device
AssigneeCanon Kabushiki Kaisha
InventorsHiroyuki Kataoka, Masanori Yamada, Nobuyuki Suzuki
Life of this patent
Estimating the term…
Abstract
In an automatic electronic flash device of the computer type for a camera, information on the F-number of full aperture of a lens mounted on the camera is transmitted to the flash device and, in the case where the full aperture F-number of the lens is larger than a predetermined full aperture F-number, the light control level of the flash device is changed according to the full aperture F-number of the lens.
Claims8
An electronic flash photographic device comprising:
- flash means for pre-emitting a flash light before a shutter release and for emitting a main flash light when a shutter is opened;
- a first control circuit for controlling an emission of the pre-emitting flash light;
- a first detecting circuit for detecting a quantity of a pre-emitting flash light reflected from an object to be photographed and for producing an aperture setting signal to set the aperture of a taking lens and a signal for determining a light termination level at which the emission of the main flash light is stopped;
- a second detecting circuit for detecting a quantity of a main flash light except for that passed through the lens and for producing a stop signal to terminate the emission of main flash light at the light termination level to be set in relation to the emission control of pre-emitting flash light;
- and
- a correction circuit for correcting the light termination level, in relation to the F-number of full aperture of the taking lens mounted on the device.
3 more elements
An electronic flash photographic device comprising:
- (A) a camera device, including:
- means for producing, at a strobo device, a full aperture signal corresponding to the F-number of full aperture of a taking lens mounted on the camera;
- and
- (B) a strobo device, including:
- flash means for pre-emitting a flash light before a shutter release and for emitting a main flash light when a shutter is opened;
- a first control circuit for controlling an emission of the pre-emitting flash light;
- a first detecting circuit for detecting a quantity of a pre-emitting flash light reflected from an object to be photographed and for producing an aperture setting signal to set the aperture of a taking lens and a signal for determining a light termination level at which the emission of the main flash light is stopped and for transmitting said aperture setting signal to said camera device;
- a second detecting circuit for detecting a quantity of a main flash light and for producing a stop signal to terminate the emission of main flash light at the light termination level to be set in relation to the emission control of pre-emitting flash light;
- and
- a correction circuit for correcting the light termination level according to said full aperture signal.
7 more elements
Dependencies are inferred from the claim text.