| 摘要 |
PURPOSE:To determine an ideal extension amount for the closest photographing by providing a cam groove of a zooming cam cylinder and a driven member. CONSTITUTION:When an operating ring 55 is moved forward and backward, a straight ring 56 and a driving frame 60 go straight on by engagement of helicoids 55b, 56a and a driving vertical groove 57a. As the driving frame goes straight on, a cam cylinder 59 is rotated, and zooming is executed by moving a variator frame 61 and a compensator frame 63 to a position where a variator vertical groove 57b coincides with a variator groove 59b, and to a position where a compensator vertical groove 57c coincides with a compensator groove 59c, respectively. The operating ring 55 rotates basing on the straight ring 56, rotates a helicoid cylinder 65 through a focusing frame 67, a focusing lens group 51 moves on an optical axis by engagement of helicoids 57b, 65a, and zoom focusing and focusing for the closest photographing are executed. Also, an extension range of the focusing lens group 51 for the closest photographing becomes (l). |
