Electronic flash system for a camera with a focal-plane shutter

摘要

A flash photography system is adapted for the combination of an electronic flashlight unit and a photographic camera with a shutter which, as in the case of the two-plate slotted shutter, exposes the film by means of a slot which sweeps over or scans the film surface at at least a few shutter speeds. In order to enable the film to be completely exposed for a scene which is illuminated by the flashlight, the electronic photoflash tube is controlled so as to emit light at a constant intensity for a period which suffices to cover the time during which the shutter slot completes its motion. The flashlight emission is set in operation in synchronism with the operation of the shutter, i.e. with the start of the scanning or sweeping of the shutter slot. The flashlight can be emitted before the operation of the shutter in order to determine a camera shutter aperture. The shutter is controlled electrically.