Abstract: A television camera lens diagnostic system for diagnosing the state of operation of a movable mechanism in a lens unit has a start button which generates a start signal for commanding initiation of the diagnosis when pushed and a diagnostic action commanding circuit commands the movable mechanism to take a predetermined action for the diagnosis upon receipt of the start signal. Potentiometers detects the actual action of the movable mechanism and a microcomputer determines whether the movable mechanism has trouble on the basis of the actual action of the movable mechanism detected by the potentiometers and the extent and the condition of the trouble are displayed.

Abstract: An automatic focus detecting device comprising an image sensor for electrically converting distributions of two images of an object which are formed by two restricted light beams passed through different areas in a zooming lens system into time sequence video signals which in turn are extracted at predetermined extraction intervals and directed to a correlator for deciding the degree of agreement between the two images. The video signal extraction is effected in two operation modes; one is for a high accuracy focus detection and the other for a rough accuracy focus detection. In the former operation mode, a time sequence video signal of a narrow image is extracted at short intervals and on the other hand, in the latter operation mode, a time sequence video signal of a wide image is extracted at long intervals.