Video camera exposure control apparatus for controlling iris diaphragm and automatic gain control operating speed
 Disclosed is an exposure control device for a video camera having automatic gain control by which both stability and instantaneous regulation of exposure can be satisfied in accordance with a photographing scene. The exposure control device for the video camera has an iris diaphragm control which receives an electric signal output an image sensor through a preamplifier as an iris diaphragm detection signal and which controls the iris diaphragm based on the iris diaphragm detection signal. An automatic gain control circuit receives an electric signal output from an automatic gain control amplifier disposed subsequent a preamplifier as an automatic gain control detection signal and controls the gain of the automatic gain control amplifier based on the automatic gain control detection signal. A determination circuit determines the various states of a photographing scene based on a change of an electric signal output the image sensor caused by lapse of time. An operating speed control circuit simultaneously increases or decreases the respective operating speeds of the iris diaphragm control and the automatic gain control based on the state of the photographing scene determined by the determination circuit. 
Fuji Photo Film Co., Ltd.
H H
H04N H04N
inventional inventional
Yoshihiko
Mori