EXPOSURE CONTROL APPARATUS FOR A STILL VIDEO CAMERA HAVING AN ELECTRONIC VIEWFINDER

摘要

A still video camera includes an electronic image sensor as a signal source either for an electronic viewfinder or for a still image processed by the camera and recorded upon a magnetic disk. Since the viewfinder operates in a movie mode (with a fixed exposure time), the light intensity required for a viewfinder display ordinarily differs from that required for a still exposure. By commonly determining the correct exposure conditions for both the viewfinder display and the still exposure, time can be saved in shifting from the movie mode to the still mode. A sample of image light in the movie mode is diverted to a microprocessor-controlled exposure circuit, which integrates the light to determine the correct diaphragm aperture for both modes of operation. The movie aperture is directly input to a diaphragm driver while the still aperture is saved until a still exposure is requested.