AUTOMATIC FOCUS ADJUSTMENT DEVICE

摘要

PURPOSE:To attain tracking of an object and focus adjustment with high precision stably by tracing a moving object and moving a range finding visual field so as to detect or adjust a focus and deciding the size of the tracing visual field that takes a change in a focal distance of an image pickup optical system into account thereby setting the range finding visual field with an optimum size with respect to the size of the object. CONSTITUTION:A tracing gate size decision circuit 10 controls a tracking gate setting circuit 11 based on outputs of a position sensor P1 detecting an absolute position of a focus lens 1 and a position sensor P2 detecting an absolute position of a zoom system lens 2 to set variably the size of the tracing visual field. Thus, the tracing visual field with an optimum size is set to the object at all times regardless of a change in the object distance and the focal distance of the focus lens 1 and the tracking gate size decision circuit 10 controls a range finding gate setting circuit 16, then an optimum size of the range finding visual field is set to the object.