| 摘要 |
PURPOSE:To eliminate trouble in focusing or zooming operation by generating a warning when a focusing lens is in an area wherein the lens can not be focused on a short-distance subject continuously during the movement of a power varying lens group from the telephoto side to the wide-angle side. CONSTITUTION:A lens position controller moves a lens group 4B for focusing in the short-distance direction and from the shot distance side to the infinite- distance side by the power varying operation of lens groups 1 and 2 for power variation from the telephoto end to the wide-angle end, thereby maintaining an in-focus state. Then the focusing lens group 4B is never positioned in the area wherein the lens can not be focused continuously on the short-distance subject at the time of the movement of the lens groups 1 and 2 for power variation from the telephoto end to the wide-angle end and if the lens group is positioned in the area, the lens group is moved out of the area or a warning is generated to eliminate trouble in the focusing operation and zooming operation. |
