| 摘要 |
PROBLEM TO BE SOLVED: To obtain a rear focus type zoom lens which possesses four lens groups as a whole, at which focusing is executed by a lens group on the rear side of a variable power system, by which entire lens system is miniaturized and whose variable power ratio is about 10. SOLUTION: This lens orderly possesses four lens groups of the first group L1 of positive refracting power, the second group L2 of negative refracting power, the third group L3 of the positive refracting power and the fourth group L4 of the positive refracting power from an object side, and variable power from a wide angle end to a telephoto end is executed by moving the second group L2 to an image surface side, and image surface fluctuation in accordance with the variable power is corrected by moving the fourth group L4, and also focusing is executed by moving the fourth group, so that the lens constitution of each lens group is appropriately set.
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