Exposure multiple setting device for programming electric shutter

Claim 1

A control circuit for a programming electric shutter of a camera comprising: a d.c. power supply, photoconductive means for sensing the brightness of a subject to be photographed, a timing capacitor connected in series with said photoconductive means between positive and negative terminals of said power supply, trigger switch means normally short-circuiting said capacitor and operable simultaneously with the opening of the shutter to permit charging of said capacitor by current flowing through said photoconductive means, a switching circuit connected with said capacitor and responsive to the voltage level to which said capacitor is charged, shutter closing means controlled by said switching means to close the shutter when the capacitor voltage reaches a predetermined level, said photoconductive means comprises a plurality of discrete photoconductive bodies in a single unit, and switch means for selectively connecting said discrete photoconductive bodies in circuit with said capacitor to control the rate of charging of said capacitor as a function of the brightness of the subject to be photographed, thereby permitting the characteristics of said photoconductive means to be matched to the speed of the film used in the camera.