| 摘要 |
PURPOSE:To increase a focusing speed and to improve the convergence near the focal position by dividing a zooming region with respect to the determination of the coefft. of movement of a zoom lens. CONSTITUTION:An out-of-focus (d) is determined from the ray from an object past a focusing lens 11 by a mechanism for detecting a focal length in a zooms. The position where said ray belongs to any of the divided zoom regions is identified by a mechanism 13 for transmitting the coefft. of movement of the zoom region and the out-of-focus (d) is converted to the extent of the movement of the lens by a mechanism 15 for determining the extent of the movement of the lens to which the selected coefft. (m) of the movement and the signal from a mechanism 14 for generating a specified quantity of pulse generating a specified quantity of pulse signal in all the zoom region are inputted. A mecanism 16 for moving the focusing lens is operated by the same. If the out-of-focus remains, the above-mentioned operation is repeated. The focusing speed is thus increased and the convergence near the focal position is improved. |
