Exposure controlling system

Abstract

Abstract PURPOSE:To control the quantity of expresure regardless of subject reflection or light source luminance by a method wherein the time for shutter closing signal generation is corrected by a certain number of pulses corresponding to the shutter action delay time. CONSTITUTION:A correcting timer 13 responding to a V/F converter 7 yields only the action delay time interval t2-t3 of a sutter 4. The timer 13 output and the converter 7 output are put into an AND circuit 15 and the number of pulses corresponding to the action delay time t2-t3 is determined in a counter 14. A total counter 8 output and the correcting counter 14 output are added at a point 16. The sum obtained at the point 16 is compared in a comparator 9 with a proper exposure value from an exposure setter 10. The output of the comparator 9 is transmitted through a shutter on/off director 11 and shutter driving circuit 12, resulting in a proper control of the shutter 4. This ensures that shutter closing signals t2 and t4 result in optimum exposure time periods t1-t2 and t1-t6 even when luminance is the maximum or half the maximum, causing no underexposure.

Inventors

• 👤 Mitsugi Yamamura

Bibliographic Details