| 摘要 |
PURPOSE:To move a zoom lens securely at a specified speed, vary the movement speed of the zoom lens, and move the zoom lens at a high speed even in the case of an inner focus lens, irrespective of temperature characteristic. CONSTITUTION:Reference data are set with reference data setting means 20. Detecting the position of a zoom lens by means of a potentiometer 10, movement speed of the zoom lens is detected by the displacement of the zoom lens within a specified period of time. Comparing the movement speed of the zoom lens with the reference movement speed by means of speed and direction setting means 21, the amount of speed error is obtained. The rotation speed of a zooming motor 9 is controlled according to the speed error amount. The zoom lens is moved securely at a specified speed because the zoom lens is moved according to the comparison output obtained by comparing the movement speed of the zoom lens with the reference movement speed. The movement speed of the zoom lens can be varied by changing the reference data. The zoom lens can be moved at a high speed even in the case of an inner focus lens. |
