| 摘要 |
PURPOSE:To attain rapid and smooth focusing by calculating a focusing distance on the basis of a focus voltage obtained at the time of photographing an object and a focus voltage obtained after the passage of prescribed time to control a focusing lens position. CONSTITUTION:A focus voltage E(X) corresponding to the focusing distance X of a high frequency component in a video signal obtained through a detector 10 at the time of photographing the object and a focus voltage E(X+m) obtained after the passage of the prescribed time required when a focusing lens 1 is moved by a distance (m) are supplied to a microcomputer 3 through an A/D converter 11. The focusing distance (X) is calculated by operation based upon the equality I and converted into a lens movement control signal. Thus, the automatic focusing of the lens 1 can be rapidly and smoothly executed without vibrating movement. In the equation, (a) is a constant factor relating to the inclination of a focus voltage curve. |
