Abstract: An exposure time control circuit for a camera shutter having a light-responsive element that controls charging of a capacitor as a function of the intensity of the light from a scene to be photographed. The charge of the capacitor at a certain level activates a switching circuit that initiates closing of the camera shutter. A light-intensity indicating circuit is directly connected to the light-responsive element for indicating the intensity of the light received from a scene to be photographed so that the camera shutter speed may be set accordingly. Photographic exposure and light readings are taken independently with control switches that need not make use of a change-over switch for connecting and disconnecting the light-intensity indicating circuit to the light-responsive element.

Abstract: An electronic camera shutter having a single spring that biases an armature lever in a direction for applying an electromagnet armature supported thereon against the electromagnet until the electromagnet, which is a part of an exposure time control circuit, is energized so that the armature is attracted. This same spring cooperates with a holding lever biasing it in a direction for engaging with the armature lever and driving it in a direction for separating the armature from the electromagnet to initiate closing of the shutter upon de-energization of the electromagnet at the end of the exposure time period controlled by the exposure time control circuit.