Photography – Flash system responsive to focal length or distance
Patent
1998-07-27
2000-09-12
Perkey, W. B.
Photography
Flash system responsive to focal length or distance
396161, 396182, G03B 1505
Patent
active
061189448
ABSTRACT:
A flashlight control apparatus having a device for emitting flashlight towards a subject and a device for receiving the light reflected from the subject through a photographing lens. An output is generated which corresponds to the received light which is time-integrated in order to calculate the amount of light received. An optimum integration level is calculated which is to be integrated. This optimum integration level corresponds to an optimum quantity of flashlight to be emitted by the emitting means, based on film speed information. A time limit is also calculated, which is shorter, by a predetermined length of time, than an optimum emission time of the emitting device. This optimum emission time is based on aperture value information and object distance information. The emitting device is controlled to stop emitting flashlight when the time limit elapses, in the case where a quantity of light received by the light receiving devices has reached an optimum quantity before the time limit elapses.
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Matsudo Nobuhiko
Sato Osamu
Asahi Kogaku Kogyo Kabushiki Kaisha
Perkey W. B.
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