| 摘要 |
PURPOSE:To improve image pickup effect and to facilitate operation by varying the moving speed of a focusing lens according to the level of a defocus signal. CONSTITUTION:Incident light from a subject enters an image pickup device 2 through a video lens body 3. An automatic focusing sensor 9 is arranged at a position equivalent to the image pickup device 2 to detect the extent of deforcusing of the subject. Its output is inputted to a defocusing arithmetic circuit 12 through an A/D converter 11 to calculate the extent of defocusing. Then, a defocusing extent judging circuit 13 judges an in-focus state and when it is judged that the subject is not in focus, the focusing lens 4 is moved in an optical axis direction under the command of a control circuit 14 through a motor driving circuit 15, focusing motor 16, and lens driving gear 17. A defocusing extent signal, on the other hand, is supplied from the circuit 13 to a D/A converter 18 and the driving voltage of the motor 16 is controlled through a buffer 19 to control the moving speed of the lens 4. |
