An electrically operated extrinsic coordinating system for the light metering and exposure controlling circuits of a photographic camera, the camera also having incorporated therein an intrinsic coordinating system for those circuits, comprises first and second electronic switches connected in the respective power supply circuits for the light metering and exposure controlling circuits through respective interconnection channels to shunt the first and second switches of the intrinsic coordinating system, a delay circuit connected between the first and second electronic switches, and an operating switch arranged to be accessible from the outside of the camera and cooperative with the first electronic switch upon manual closure of the operating switch to actuate the light metering and exposure controlling circuits for the power supply in predetermined time-displaced relation to each other independently of the intrinsic coordinating system.