| 摘要 |
A zoom lens barrel wherein its cam ring has three sets of three cam grooves for advancing or retracting a first group frame, a focus frame and third group frame. The three cam grooves include a cam follower introducing groove connected to ends of two cam grooves for the focus frame and a third group frame and a joint groove for joining two cam grooves for the first group frame and the focus frame. When inserting a cam follower of the first group frame into the cam groove, after it is inserted into the introducing groove, it is passed through the cam groove for the focus frame and then, passed through the joint groove and fit to the cam groove for the first group frame. Further, when inserting the cam followers of the focus frame and third group frame into the cam groove, after it is inserted from the introducing groove, it can be fit to the focus frame and third group frame separately. Therefore, the assembly is facilitated and it is possible to provide a zoom lens barrel ensuring an excellent space efficiency and achieving reduction of the size and compactness.
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