Abstract: Apparatus provides for reducing drain on an electrical power source in a camera and also provides for convenient manual operation in connection with relatively long-exposure-time photographing by controlling the closing of a power switch that switchably connects the power source to an exposure control circuit.

Abstract: A single lens reflex camera which measures internally-received light and which has a circuit for automatically determining exposure time and including a capacitor which stores an electrical quantity corresponding to the amount of received light, this capacitor being connected to a light-measuring device through an automatic switch. The latter switch normally opens automatically in connection with swinging up of the mirror of the camera just prior to exposure so that the capacitor will store an electrical quantity corresponding to the measured light. The operator of the camera can optionally operate a manually operable structure for manually opening the latter switch, and this manually operable structure may also be connected with a power switch closed in order to render the automatic circuit operative just prior to manual opening of the switch connected to the memory capacitor, an additional power switch being provided as is conventional to be operated by manipulation of the shutter-tripping plunger.

Abstract: For use in a single lens reflex camera having a swingable mirror, a device for associating the film winding and shutter release in a manner free from error, characterized in that an arresting lever is so arranged that the book portion thereof is in association with the arresting portion of a cam plate associated with the film winding lever and the opposite end of the arresting lever is in opposition to one end of an intermediate art lever as well as to the tapered surface formed on one end of a member associated with the shutter button. The operation of the shutter is automatically prevented by the arresting lever until the film winding operation is completed. Likewise, the film winding operation is automatically prevented by the arresting lever until the shutter button operation is automatically prevented by the arresting lever until the shutter button operation is completed.