| 摘要 |
PROBLEM TO BE SOLVED: To provide a zoom lens barrel applying a cam frame for advance/ retreat driving and a cam follower, realizing miniaturization and having simple structure. SOLUTION: In this zoom lens barrel, a 1st group frame 5 for a 1st group lens coupled through a helicoid screw is driven to advance/retreat with the rotation of a cam ring 4, and a 2nd group holding frame 8 for a 2nd group lens and a 3rd group frame 9 for a 3rd group lens are respectively driven to advance/retreat through cam followers 15 and 16 fit in the cam grooves 4d and 4e of the cam ring 4 at the time of zoom driving. The cam grooves 4d and 4e are formed on the cam ring 4 so that the relative positions of the cam followers 15 and 16 in an optical axis O direction may be inverted at the time of performing extending operation between a wide end position and a telephoto end position, and the diameter of the cam ring 4 is made smaller and the cam followers 15 and 16 are smoothly driven.
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