Abstract: An automatic exposure camera, for example a TTL light measuring camera including a light measuring circuit, an exposed condition indicating circuit, and a light information storage circuit includes a normally open semiconductor switch connecting the circuits to a source of energizing current and actuated to a closed condition in response to a conductor being coupled across its control input terminals, at least one of which is defined by the camera manually operated shutter release members. In one form the switch input terminals are connected to mutually insulated coaxial members forming the release button and exposed at their top and in another form such terminals are connected respectively to the camera body and an electrically insulated top exposed portion of the release member. Thus, merely touching the release button by the photographer energizes and activates the respective circuits.