| 摘要 |
PURPOSE: To provide a zoos lens having high optical performance over a whole variable power range by comprising five lens groups as a whole and properly setting refractive powers of the respective lens groups and moving conditions accompanied by power variation, etc. CONSTITUTION: This zoom lens has, in order from the object side, five lens groups of a first group L1 of positive refractive power, a second group L2 of negative refractive power, a third group L3 of positive refractive power, a fourth group L4 of positive refractive power and a fifth group L5 of negative refractive power, at the time of varying the power from the wide-angle end to the telescopic end, the respective lens groups are moved so that an interval between the first group L1 and the second group L2 is increased, an interval between the second group L2 and the third group L3 is decreased and an interval between the third group L3 and the fourht group L4 is decreased and the image forming magnificationβ2W at the wide-angle end of the second group L2 for an object at infinity is properly set.
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