| 摘要 |
PURPOSE:To automatically control a zoom lens so as to maintain the size of an object within an image plane to be nearly definite at the time of manual focusing or automatic focusing. CONSTITUTION:A zooming device 1A is provided with a focusing mechanism 2A, a zooming mechanism 3, an automatic sizing mechanism 4A; and reference object distance L1 and optical magnification M1 at the time of presetting the size of the object H and current object distance L2 after presetting are obtained corresponding to the position information of a focusing lens 2a and the zoom lens 3a at the time of the manual focusing and the automatic focusing by the automatic sizing mechanism 4A so cps to calculate the controlled variable (moving quantity) and the control direction of the zoom lens 3a so that the size of the object H preset may be kept nearly definite. |
