Watson, Cole, Grindle & Watson
Automatic diaphragm control and mirror release devices for cameras
 In a camera automatic diaphragm control device of the type wherein scene light is measured through the diaphragm aperture during the stopping-down operation thereof, which is arrested when the measured light value reaches a given level with respect to manually set exposure parameters, thereby determining the diaphragm aperture, structure is provided for positively ensuring that the diaphragm aperture is left fully open when the set exposure parameters and the measured light require such diaphragm aperture setting. The diaphragm aperture control device is employed in a single lens reflex camera with a reflex mirror retractable from a viewing position at selected times in dependence on whether the diaphragm aperture remains fully open or is reduced. 
Minolta Camera Kabushiki Kaisha
G G
G03B G03B
inventional inventional
Keiji
Yamazaki