| 摘要 |
PURPOSE:To perform focal length adjustment and focus adjustment mutually irrespectively by fixing the foremost lens to a shaft slidable in the optical axis direction in a zoom lens barrel, and using the shafts for zooming as guides thereby perfoming focus adjustment. CONSTITUTION:The lens frame 9 of the foremost lens group 3b is fixed to a shaft 10, and are guided and supported by shafts 11, 12 for zooming slidably in the optical axis direction. The trailing end of the shaft 10 projects from a stationary lens barrel 8, and is brought in pressure contact with a cam 15 having a manual adjusting knob 28. With this constitution, at the time of zooming, a ring 24 is turned, and pins 18, 20 are adjusted of positions by cam grooves 19, 21, by which movable lens groups 4, 5 are moved. At this time, the shaft 10 does not displace at all. At the time of focus adjustment, the knob 28 is turned, then the lens group 3b is displaced by the turning of the cam 15 so that the focus is adjusted irrespectively of the zooming. Thereby, the focus adjustment and the zooming are carried out mutually irrespectively. |
