JPS6424574A - Auto-focus video camera - Google Patents

Abstract

PURPOSE:To suppress the fluctuation of a focus evaluation value during the zooming, to prevent the oscillating of a lens due to a re-activating and to attain a stable auto-focus action by changing a focus area in accordance with a zoom position. CONSTITUTION:An image formed by a lens 1 goes to a luminance signal by an image pick-up circuit 4 having an image pick-up element and inputted to a focus evaluation value generating circuit 5. The focus evaluation value generat ing circuit 5 inputs a zoom position detecting signal from a zoom position detecting circuit 19 to a gate control circuit, a sampling area is changed based on a zoom position detecting signal by the gate control circuit, the focus evalua tion value for one field is outputted and a focusing action is executed. Thus, in the focusing condition at the time of photographing a same subject, zooming is executed, and even then, it can be prevented that a focus motor is operated erroneously and the lens is oscillated and the stable auto-focus action can be executed.