| 摘要 |
PURPOSE:To obtain the stable quantity of light during magnification variation by rotating an aperture ring with an aperture knob through plural endless wires and relay pulleys, and providing a wire sag absorbing means to an intermediate endless wire. CONSTITUTION:The aperture knob 4 is rotated to rotate the 2nd relay pulley 10 through an endless wire 15, and the 1st relay pulley 9 is therefore rotated through an endless wire 13. The wires on both sides of the endless wires 13 are guided in press contact with two guide pulleys 6 and 14 fixed on the same shaft, so when a lens 2 moves, sag is absorbed by the same extent instantaneously and torque is generated at neither the 1st relay pulley 9 nor the 2nd pulley 10. Therefore, the rotation of the aperture knob 4 is rotated to the aperture ring 1 in 1:1 proportion, which never varies by the movement of the lens 2. |
