| 摘要 |
PURPOSE:To prevent the impossibility of distance measurement due to compentition between close and far distances on the wide-angle side while securing the use range in the telephoto side, by varying the use range of a light receiving sensor with a sensor mask which is interlocked with a zoom operating member. CONSTITUTION:If a variator moving ring 5 of a zoom lens equipped with an active auto-focus mechanism approaches the front element side and the zoom position is in the wide-angle side, a bending-up part 14a of a sensor mask 14 is brought into contact with the variator moving rint 5 to move the sensor mask 14 forward in the direction of the optical axis, and a part of a light receiving sensor 15 is masked to cut a luminous flux which causes the competition between close and far distances. Thus, the impossibility of distance measurement due to the competition between close and far distances in the wide-angle side is prevented with a simple constitution. |
