| 摘要 |
PROBLEM TO BE SOLVED: To obtain a large-aperture wide-angle zoom lens having higher performance by making a 1st lens group have at least two aspherical surfaces and satisfying a specified conditional expression. SOLUTION: This zoom lens is equipped with a 1st lens group G1 having negative refractive index, a 2nd lens group G2 having positive refractive index, a 3rd lens group G3 having negative refractive index and a 4th lens group G4 having positive refractive index in order from an object side. At least two aspherical surfaces are arranged in the 1st lens group G1, and the conditional expression: 1.0>|f1/f2|>0.0 is satisfied, provided that f1 is the focal distance of the lens positioned nearest to the object side out of the lenses having the aspherical surface in the 1st lens group G1 and f2 is the focal distance of the lens positioned second from the object side out of the lenses having the aspherical surface in the 1st lens group G1. Thus, the curvature of field and distortion aberration on a wide-angle side are easily compensated and further aspherical amount per surface is made small, then necessary cost in terms of manufacture is reduced.
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