| 摘要 |
PROBLEM TO BE SOLVED: To obtain a zoom lens having a high optical performance, in a range extending over the entire zoom range to the entire object distance. SOLUTION: The zoom lens has at least N (N is an integer of 5 or larger) lens groups. Here, an (N-1)th lens group from the object side has positive refractive power, and the Nth lens group has negative refractive power. When zooming is carried out, the plurality of lens groups other than the (N-1)th lens group move; when focusing is carried out from an infinite-distance object to a close-distance object, at least the Nth lens group moves to the image side; and the inequality expression: 0.1<¾fN/fT¾<1.0 is satisfied, if fN is defined as the focus distance of the Nth lens group, and fT is the focal distance, at the telephoto end of the system as a whole. COPYRIGHT: (C)2011,JPO&INPIT
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