| 摘要 |
PROBLEM TO BE SOLVED: To provide a compact zoom lens that achieves a high zoom ratio, a small diameter of the foremost lens, and a high optical performance over the entire zoom range. SOLUTION: The zoom lens system includes, in order from an object side to an image side, a first lens group having a positive refractive power, a second lens group having a negative refractive power, a third lens group having a positive refractive power, and a fourth lens group having a positive refractive power. A distance between the first lens group and the second lens group is longer at a telephoto end than at a wide angle end, a distance between the second lens group and the third lens group is shorter at the telephoto end than at the wide angle end, and a distance between the third lens group and the fourth lens group at the wide angle end is different that at the telephoto end. The first lens group is composed of one positive lens and one negative lens. The second lens group is composed of three negative lenses and one positive lens. A focal distance fw of the entire zoom lens system at the wide angle end, a focal distance f1 of the first lens group, and a focal distance f2 of the second lens group are appropriately set. COPYRIGHT: (C)2010,JPO&INPIT
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