Photometric device

Abstract

Abstract PURPOSE:To obtain an image pickup with exposure fitted for the brightness of an object in a wide-angle image pickup time, and the image pickup with the optimum exposure in a telephoto image pickup time, by setting a small area at the center part of a picture as a photometry range, or making larger a weighting in the wide-angle image pickup time, and setting a large area including the center part of the picture as the photometry range, or making small the weighing in the telephoto image pickup time. CONSTITUTION:A mean value circuit 11 detects the mean value of a supplied video signal, and supplies a detected signal to a diaphragm control circuit 12, and the diaphragm control circuit 12 generates a diaphragm control signal corresponding to the detected signal, and supplies it to a diaphragm opening/closing mechanism from a terminal 13, thereby the opening/ closing control for a diaphragm is performed. Thus, it is possible to perform the image pickup with the exposure fitted for the brightness of the object existing within the photometry range because the photometry range is set at the small area at the center part of the picture in the wide-angle image pickup time, and also, in the telephoto image pickup time when the greater part of the picture is occupied by the object, the photometry range is the large area including the center part of the picture, therefore, it is possible to perform the image pickup with the optimum exposure for the picture. In such a way, it is possible to perform the image pickup with the exposure fitted for the brightness of the object in the wide-angle image pickup time, and also, to perform the image pickup with the optimum exposure in the telephoto image pickup time, and to perform the image pickup with the optimum exposure regardless of a zooming operation.

Inventors

• 👤 Hiroyuki Miyahara
• 👤 弘之 宮原

Bibliographic Details