| 摘要 |
<p>PURPOSE:To obtain desired exposure corresponding to an intention of composition, by providing a flash light emission quantity setting part on the electronic flash side, so that light emission of the electronic flash can be continued even after the exposure to a main object to be photographed has become correct. CONSTITUTION:By a photodetector 15, the light emission quantity of a xenon discharge tube 10 is detected, and an optical current corresponding to the light emission quantity is generated in the photodetector 15. Charging voltage of an integral capacitor 18 is an integral compressed value of the optical current of the photodetector 15, and is inputted to one input terminal of a buffer memory 23, a capacitor 27 for a light emission quantity memory, and a comparator 28. On the other hand, from a point B of a negative pole side of a constant-voltage source 30, voltage being lower by prescribed amount is inputted to a + input terminal of the comparator 28 in accordance with a corrected value of the flash light emission quantity from an output of a buffer 23, that is to say, point A voltage. When light emission of the xenon discharge tube 10 is continued, and charging voltage of the capacitor 18 rises by an optical current generated by the photodetector 15, and light emission of 4 times of the light emission quantity stored in the capacitor 27 is executed, voltage of the point B becomes equal to capacitor storage voltage, and when an output of the comparator 28 is inverted to a high level, light emission of the xenon discharge tube 10 is stopped.</p> |
