PURPOSE: To control camera elements at high speeds and with high precision, by using a counter to count pulses generated in relation to camera elements and giving information of the counter to a microprocessor to control camera elements when the counted value coincides with a set value.

CONSTITUTION: At the photographing sequence start, the lock due to a diaphragm stop pin is released by the electromagnetic force of a magnet, and the restoring foce of a spring is utilized to start stopping-down. A microprocessor 5 set a preset value to a counter 4. The quantity of rotation corresponding to one pit of a slit 1a of a Siemens' star 1 rotated synchronously with stopping-down corresponds to 0.1EV of stopping-down. A photodiode 3 is turned on and off repeatedly by the rotation of the Siemens' star 1, and the set value of the counter 4 is counted down by 1 for every input of a pulse; and when contents of the counter 4 become 0, a carry signal is sent to the microprocessor 5 to stop the stopping-down. Other camera elements are controlled similarly at a high speeds and with high precision.