A new, fully automatic exposure control system providing both iris and shutter control is explained herein. The automatic exposure control is through the taking lens without obstructing the optical path during exposure time and works with any system of iris diaphragm, i.e., linear or logarithmic f-stops, etc. The system is independent of lens focal length. The system solves the basic exposure equation and automatically compensates for all parameters including scene brightness variance, camera frame rate, shutter opening, and lens f-stop. The system is dynamic over an equivalent of 10 f-stops or more (depending on the lens used) and works over a wide range of scene brightness levels. A system is truly automatic and requires no attention from the operator once the magazine is installed on the camera. Even filters, when placed on the taking lens, are correctly compensated for Panchromatic film without any adjustments in the automatic exposure control.