AUTOMATIC FOCUS CONTROL SYSTEM FOR VIDEO CAMERA

摘要

Described in an automatic focus control system for video cameras in which a part of object light being conducted towards an image pickup surface through an optical main system is conducted through an optical sub-system to a detecting unit the output signals of which are used for controlling focusing of the optical main system. The output signals from the detecting unit are used for variably controlling diaphragm means in the sub-system. Focused state of the optical main system is sensed in such a manner that the depending on whether the optical main system is in considerably defocused state or approximately focused approximately focused state, the effective diameter of the diaphragm in the optical sub-system is reduced or enlarged, respectively.