| 摘要 |
PROBLEM TO BE SOLVED: To provide a zoom lens wherein a camera shake can be corrected by shifting an image by an optical system which is movable so as to have a component orthogonal to an optical axis, and the refractive power of each lens group is appropriately set so that the performance deterioration is reduced while attaining high variable power, and to provide an optical device having the zoom lens and a variable power method. SOLUTION: The zoom lens includes: a first lens group G1 with a positive refractive power; a second lens group G2 with a negative refractive power; a third lens group G3 with a positive refractive power; and a fourth lens group G4 with a positive refractive power, which are arranged in the order staring from the object side. The distances between each of the lens groups change as the magnifying power is changed from a wide-angle end state to a telescopic end state. The third lens group G3 has a positive lens group G31 with a positive refractive power and a negative lens group G32 with a negative refractive power, which are arranged in the order starting from the object side. If the negative lens group G32 is moved to have a component orthogonal to the optical axis, and the focal distance of the second lens group G2 is denoted as f2 and the focal distance of the third lens group G3 is denoted as f3, then the following relationship, 0.38<(-f2)/f3<0.50, must be satisfied. COPYRIGHT: (C)2010,JPO&INPIT
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