| 摘要 |
PURPOSE:To make it possible to perform automatic focusing operation with rapidity and stability by controlling a device so that an image forming optical system may always follow up a moving object based on an image surface moving speed. CONSTITUTION:The timing of starting/ending charge storage is transmitted to a control means 109 by a focus detecting means 104 for detecting the focusing state of a photographic lens 101. A period from the end of the charge storage to the start of the succeeding charge storage is applied to charge transfer and the calculation of a defocusing amount. The calculated defocusing amount is also transmitted to the control means 109. The image surface moving speed of the image forming optical system on the image surface position accompanying the movement of the object is calculated based on plural defocusing amounts calculated by the focus detecting means 104, the amount due to the movement of the image forming optical system and an interval of the storage time which is the base for the calculation of plural defocusing amounts. And a future image surface position is predicted based on the image surface position and the image surface moving speed at a prescribed time, and the image forming optical system is driven toward the predicted future image surface position. |
