SYSTEM FOR FOCUSING A TELEVISION CAMERA OBJECTIVE LENS

A system for focusing a zoom lens objective of a color television camera. A luminance or green video signal derived from a portion of the picture is full-wave rectified and then averaged. The sharpest focus corresponds to the highest value of that average. The signal is converted to digital form and processed by a microcomputer for automatic focusing control by finding the signal maximum with shifting of the lens focus setting. The video signal is stripped of its d.c. component before rectification, but is used with its full bandwidth.