| 摘要 |
PURPOSE:To maintain invariably accurate focusing by setting the reference position of a focusing lens so that deviation in the relation between the position and focal length of a focusing lens is absorbed even when the relation has the deviation slightly, and making the focusing point of an infinite-distance subject invariably constant on a wide-angle side. CONSTITUTION:As for an inner type focusing device, a position detection switch 5 detects a 2nd lens group reaching the reference position and sends a detection signal and when the detection signal is sent, position data held in a lens position holding means are updated with reference position data indicating the reference position, and after the focal length is varied to the wide-angle end in position adjustment mode, a focusing means 2 performs focusing operation. After the focusing operation ends, the 2nd lens group is moved in a farther-distance direction by a specific quantity and stopped and the position of the position detection switch 5 is so adjusted so that the detection signal is sent when the 2nd lens group reaches the stop position. |
