| 摘要 |
PROBLEM TO BE SOLVED: To provide a zoom lens barrel which does not cause the divergence of focus by preventing a cam barrel from rotating even when external impact is given to the lens barrel and restoring it to a previous position where load is imposed when the load is eliminated, while restraining cost rising and realizing miniaturization. SOLUTION: In the zoom lens barrel, a 1st group 2 holding at least the partial lens group of a photographic optical system is moved in an optical axis direction along a straight-advance barrel 4 by rotating the cam barrel 5 along the machined surface of a cam groove 50 on an object side. The lens barrel is equipped with a spring 8 energizing the 1st group 2 toward the machined surface of the cam groove 50 on the object side and a plane formed in a state where at least a part of the surface of the cam groove opposed to the machined surface of the cam groove 50 is orthogonal to an optical axis. COPYRIGHT: (C)2004,JPO
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