| 摘要 |
PROBLEM TO BE SOLVED: To lighten a burden imposed on control in focusing and adjustment, to make reliability high and to perform accurate focusing by providing adjusting areas where a focus lens group is simply to be moved in an optical axis direction without spoiling a focusing function on both sides of the respective steps of a cam groove. SOLUTION: The adjusting areas Z2a are provided at both ends of each step groove Z2-i (i=1 to 8), and a shifting area Z2b is provided between the adjusting areas Z2a. In the adjusting area Z2a, focusing operation in each step groove Z2-i is performed all the same even when adjustment is performed inside the adjusting area Z2a in order to obtain the moving amount of a two-group lens L2 consisting of a focusing factor. Since the adjusting areas Z2a where the focusing lens group is simply moved in the optical axis direction without spoiling the focusing function are provided on both sides of the respective steps of the can groove, the burden imposed on the control in the focusing and the adjustment is lightened, the reliability is made high and the accurate focusing is performed.
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