| 摘要 |
PROBLEM TO BE SOLVED: To provide a large-diameter, high variable power ratio zoom lens with high optical performance over the whole variable power range and the whole focusing range while adoping an inner-focusing four-group zoom lens. SOLUTION: In the zoom lens provided with a 1st lens group whose refractive power is positive, a 2nd lens group whose refractive power is negative and which is moved at varying the power, a 3rd lens group which is moved at the time of varying the power and a 4th lens group whose refractive power is positive arranged in this order from an object side, the 1st lens group is provided with a 11th lens group which is fixed at focusing and a 12th lens group whose refractive power is positive and which is moved at focusing, and the 11th lens group is provided with at least one 1st positive lens, at least one negative lens, both lens surfaces of which are concave, and at least one 2nd positive lens.
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