Variable exposure shutter for cine camera - has variable shutter blade rotating with main blade and set by separate motor

摘要

The variable exposure shutter has a rotating segment shutter (1) whose dark period represents the min. dark time required for the claw to index the film. A second segment (2) is pivotted coaxially and is driven by a stepping motor (4) mounted on the shutter drive shaft. The stepping motor provides a direct control of the dark period of the shutter cycle, from min. to fully closed. It replaces the costly and noisy differential drive for mechanical shutter control. Electronic control circuits provide the shutter drive controls while photocells monitor the exposure value of the shutter setting.