Automatic focus control device for use in a camera system

摘要

There is provided an automatic focus control device for use in a camera system comprising a focus detection control means for continuously driving a motor from the time when it is judged that a focus condition of a photograph lens can not be detected until it is judged that the focus condition can be detected, and a rotation number control means for controlling the rotation speed of said motor driven by said focus detection control means in accordance with a constant data designating a relationship between the rotation number of said motor and a unit of a defocus value. Accordingly, the moving speed of said photograph lens is controlled in accordance with defocus variation during the movement of said photograph lens, resulting in that the infocus position of the object can be detected by a low contrast search without overrunning the infocus position, even though the object is positioned far from an available range of the focus detection.