| 摘要 |
PROBLEM TO BE SOLVED: To obtain a zoom lens consisted of two lens groups in which a lens system is made small in size and thin in thickness by appropriately setting the refractive power of each lens group and also setting an aspherical lens at an optimum position, and to provide an optical equipment having the zoom lens. SOLUTION: In the zoom lens provided with 1st and 2nd lens groups having positive and negative refractive power in order from an object side, and performing variable power by changing a distance between the 1st and the 2nd lens groups, the 1st lens group is provided with a 1-1st lens group and 1-2nd group having positive refractive power in order from the object side, and the 1-1st lens group is provided with a positive lens having an aspherical surface in shape that positive refractive power gets weaker from the center of an optical axis to the periphery of the lens and a negative lens on the object side of the positive lens having the aspherical surface. The focal distances of the 1st and the 2nd lens groups are defined as f1 and f2 respectively, the focal distance of an entire system at a wide angle end is defined as (fw), and the paraxial lateral magnification of the 2nd lens group at the wide angle end and a telephoto end are defined asβ2w andβ2t respectively, and appropriately set. COPYRIGHT: (C)2004,JPO
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