Flash photography system
First Claim
1. A flash device comprising:
- (a) input means for receiving a flash light start signal from a photographic camera;
(b) means for effecting emission of flash light from the flash device in response to said flash light start signal received by said input means;
(c) means for stopping emission of the flash light by a flash light stopping signal from the photographic camera(d) means for receiving an aperture control value a film speed value from the photographic camera for flash light photographing in series in a digitalized bit-by-bit manner in synchronism with a clock pulse train fed from the photographic camera;
(e) maximum light quantity output means for producing a signal representing a maximum light quantity which can be emitted from the flash device;
(f) calculating means for calculating a maximum photographing distance covered by the flash light for effecting a correct exposure on the photographic object for flash light photographing on the basis of said aperture control value, said film speed value and said maximum light quantity;
(g) means for introducing said clock pulse train from the photographic camera;
(h) means for manually selecting between a first unit of distance and a second unit of distance; and
(i) display means for displaying the maximum photographing distance from the output of the calculating means in accordance with a selected unit of distance, said displaying means including common displaying elements usable both in said first and second units of distance.
1 Assignment
0 Petitions
Accused Products
Abstract
A flash photography system for a photographic camera and a flash device adapted to be connected thereto with the camera providing an aperture value output for flash light photography and a flash light stop signal obtained from an integrated output of the light reflected from a photographic object to terminate flash light emission when the integrated value reaches a predetermined value. The flash device calculates a maximum photographing distance covered by the flash light for effecting a correct exposure of the photographic object from the maximum flash light value and the aperture value from the camera. The maximum photographing distance is displayed by a suitable display visible to the camera operator.
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Citations
7 Claims
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1. A flash device comprising:
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(a) input means for receiving a flash light start signal from a photographic camera; (b) means for effecting emission of flash light from the flash device in response to said flash light start signal received by said input means; (c) means for stopping emission of the flash light by a flash light stopping signal from the photographic camera (d) means for receiving an aperture control value a film speed value from the photographic camera for flash light photographing in series in a digitalized bit-by-bit manner in synchronism with a clock pulse train fed from the photographic camera; (e) maximum light quantity output means for producing a signal representing a maximum light quantity which can be emitted from the flash device; (f) calculating means for calculating a maximum photographing distance covered by the flash light for effecting a correct exposure on the photographic object for flash light photographing on the basis of said aperture control value, said film speed value and said maximum light quantity; (g) means for introducing said clock pulse train from the photographic camera; (h) means for manually selecting between a first unit of distance and a second unit of distance; and (i) display means for displaying the maximum photographing distance from the output of the calculating means in accordance with a selected unit of distance, said displaying means including common displaying elements usable both in said first and second units of distance.
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2. A flash device comprising:
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(a) a first terminal for receiving a flash light start signal from a photographic camera; (b) flash light emitting means for emitting flash light in response to said flash light start signal; (c) maximum light quantity output means for producing a signal representing a maximum light quantity for illuminating the photographic object from said flash light emitting means; (d) output means for producing a signal representing emission of the flash light to start light measurement of reflected light from the photographic object on the basis of said flash light start signal; (e) means for transferring said maximum light emission quantity to a photographic camera; (f) means for receiving a flash stop signal from the photographic camera; (g) means for stopping emission of said flash light; (h) means for reading a maximum photographing distance covered by the flash light for effecting a correct exposure of the photographic object, said maximum photographing distance being calculated and output from the photographic camera; and (i) means for displaying said maximum photographing distance on the basis of the output of said reading means. - View Dependent Claims (3, 4)
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5. A flash device comprising:
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(a) DC battery power source means; (b) boosting means for boosting the output voltage of said battery means; (c) a capacitor charged with the output of said boosting means; (d) a flash light emitting means for emitting flash light enabled by the charge of said capacitor; (e) means for outputting a charge completion signal by determining whether or not the charged voltage across said capacitor reaches a predetermined value, reversing the polarity of said charge completion signal when the voltage across said capacitor reaches said predetermined value; (f) means for outputting digital signals including said charge completion signal in series in a bit-by-bit manner in synchronism with a clock pulse train fed from a photographic camera; (g) a first terminal for receiving a signal produced by closure of a synchronizing switch of the photographic camera; (h) means, connected to said first terminal, for starting emission of flash light from said flash light emitting means upon closure of said synchronizing switch; (i) means for producing a light measurement start signal for starting measurement of light upon closure of said synchronizing switch; (j) a second terminal for outputting said digital signals and said light measurement start signal; (k) means for stopping emission of flash light in response to a flash light stopping signal derived from the photographic camera; and (l) a third terminal for receiving said clock pulse train and said flash light stopping signal.
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6. In a flash photography system having an electronic flash device and a photographic camera in communication with the flash device by means of digital signals, the electronic flash device comprising:
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(a) means for supplying power; (b) a DC-DC converter connected to the power supplying means; (c) means for storing an electric charge derived from said DC-DC converter; (d) means for emitting flash light enabled by the charge of said storing means; (e) means for receiving a signal produced by closure of a synchronizing switch of the photographic camera; (f) means, connected to said receiving means, for starting emission of flash light from said emitting means; (g) means for communicating with the photographic camera by said digital signals; (h) digital circuit means connected with said communicating means; (i) means for enabling said DC-DC converter; and (j) means for detecting an appearance of at least one digital signal at said communicating means to automatically actuate said enabling means.
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7. A flash device comprising:
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(a) DC battery power source means; (b) boosting means for boosting the output voltage of said battery means; (c) a capacitor charged with the output of said boosting means; (d) a flash light emitting means for emitting flash light enabled by the charge of said capacitor; (e) means for outputting a charge completion signal by determining whether or not the charged voltage across said capacitor reaches a predetermined value, reversing the polarity of said charge completion signal when the voltage across said capacitor reaches said predetermined value; (f) means for outputting digital signals including said charge completion signal in series in a bit-by-bit manner in synchronization with a clock pulse train fed from a photographic camera; (g) receiving means for receiving a signal produced by closure of a synchronizing switch of the photographic camera; (h) means, connected to said receiving means, for starting emission of flash light from said flash light emitting means upon closure of said synchronizing switch; (i) means for stopping emission of the flash light by a flash light stopping signal from the photographic camera; (j) means for receiving an aperture control value and a film speed value from the photographic camera for flash light photographing in series in a digitalized bit-by-bit manner in synchronism with a clock pulse train fed from the photographic camera; (k) maximum light quantity output means for producing a signal representing a maximum light quantity which can be emitted from the flash device; (l) calculating means for calculating a maximum photographing distance covered by the flash light for effecting a correct exposure of the photographic object for flash light photographing on the basis of said aperture control value, said film speed value and said maximum light quantity; (m) means for introducing said clock pulse train from the photographic camera; (n) display means for displaying the maximum photographing distance from the output of the calculating means; (o) means for outputting said digital signal to the photographic camera; and (p) means for receiving said flash stopping signal.
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Specification