| 摘要 |
PURPOSE:To judge focusing position in accordance with a cumulate value and control a lens to the focusing position unfailingly by providing a means to detect evaluation value after detecting middle and high area component levels during image pickup signaling, and a cumulate means by means of finding a differential value of an evaluation value of an image pickup element or a lens wobbling back and forth. CONSTITUTION:The position of a four group lens F4 is made movable by virtue of a focus drive motor 6 which is controlled by a system controller 14 through a driver 15. An AF detecting signal, formed from a middle area component level in process of image pickup signaling, is detected from an optical detector 13, which is regarded as an evaluation value. The differential value of an evaluation value when the lens F4 is wobbled back and forth is cumulated and, by controlling the position of the lens F4 so as the cumulated value will [0], the lens F4 can be controlled to the focusing position with assurance even in case the S/N ratio of the evaluation value is bad. |
