| 摘要 |
PURPOSE:To make a device light in weight and low in cost by controlling selectively the engagement relation between the first transmitting means which drives a focusing means with a motor and the second transmitting means which drives a variable power means with the motor, and performing focusing and magnification varying with the same motor. CONSTITUTION:The power of a motor 24 is transmitted to a focus ring 22, which is provided in the front part of a lens unit 21, through a focus ring driving mechanism 23 incorporating a speed reduction mechanism, and the focus ring 22 is turned and is moved in the direction of the optical axis to perform focusing. Meanwhile, a zoom lens 25 is provided in the rear part of the lens unit 21 and is driven through a zoom lens driving mechanism 26 by the motor 24. The signal from an encoder incorporated in the focus ring 22 and the signal from a distance measuring circuit 28 are compared with each other by an out-of-focus detecting circuit 29; and if they do not coincide with each other, the focus ring driving mechanism 23 is operated by a control circuit 30 and the motor 24 is rotated through a motor driving circuit 31. |
