Exposure control with retarder on shutter drive - has combined aperture control and shutter release giving trapezoidal exposure diagram

摘要

An exposure control using a retarding mechanism on the shutter drive has a combined timing circuit for the aperture setting and shutter release. The aperture runs from a max. to a min. setting at a constant rate. When the selected aperture is reached, a retarder holds the setting while the shutter is opened and closed. This provides a trapezoidal characteristic on the exposure diagram. The point at which the aperture is held is calculated taking into account the rise time of the shutter opening. Accurate exposure control is obtained using simple control circuits.