| 摘要 |
PURPOSE:To enable rapid change to an exact magnification by providing plural ranges where a zoom lens group does not make zoom motion even if a zoom driving member moves to an interlock mechanism for the motion of the zoom driving member and the zoom motion in the optical axis direction of the zoom lens group. CONSTITUTION:This zoom lens barrel is constituted by loosely fitting a 1st lens group zoom frame 2 and a 2nd lens group holding frame 3 into the bore of a stationary barrel and loosely fitting a zoom cam barrel 4 onto the outside diameter of the barrel 1 turnably around the optical axis. Pins 2P, 3P embedded to the zoom frame 2 and the holding frame 3 respectively are engaged respectively slidably with guide grooves 1G2, 1G3 in the optical axis direction provided on the barrel 1 and cam grooves 4C2, 4C3 provided on the zoom cam barrel 4. The zoom frame 2 and the holding frame 3 are, therefore, moved in the optical axis direction by turning a pinion 5 intermeshed with the gear part on the outside diameter of the barrel 4 by a forward and backward running motor (not shown in the figure) or the like to turn the barrel 4 around the optical axis. Then, the 1st lens group L1 and the 2nd lens group L2 make the zoom motion.
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