Exposure control mechanism

摘要

A camera having an adjustable mechanism to set an exposure aperture, a shutter to control the duration of an exposure and a member movable in a first range to initiate adjustment of the mechanism and movable in a second range to actuate the shutter to open the exposure aperture, includes a single electromagnet effective to become energized and subsequently de-energized to control the mechanism to set a desired exposure aperture and effective to be energized during an open condition of the shutter to hold the shutter open until de-energization thereof. The electromagnet is connected in a control circuit that has a photosensor exposed to scene brightness and switches controlled by the movable member to operatively connect the photosensor to the electromagnet. The circuit is effective upon actuation of the switches during movement of the member in the first range to energize or to energize and then quickly de-energize the electromagnet to establish the desired exposure aperture in accordance with scene brightness, and during movement of the member in the second range to re-energize the electromagnet and after an exposure of duration related to scene brightness to de-energize the electromagnet to initiate shutter closure.