| 摘要 |
PURPOSE: To obtain a high angle of view and high variable magnification ratio, to decrease the number of constituting elements, to reduce a cost and to improve mass productivity by specifying the constitution conditions of first and second lens groups. CONSTITUTION: At least one lens faces among lens faces of a first negative meniscus lens component L11 and second negative meniscus lens component L12 in the first lens group G1 are formed to aspherical faces. This zoom lens is so constituted as to satisfy conditions 0.6<=|fI|/(fw.ft)<1/2> <=1.1, 1.2<=XII/fw<=2.5, -1<=(r2+r1)/(r2-r1)<=2 where the focal length of the first lens group G1 is defined as fI; the focal length over the entire part of the lens system at the wide angle end as fw; the focal length over the entire part of the lens system at the telephoto end as ft; the max. moving amt. in the variable magnification of the second lens group G2 as XII; the radius of curvature on the extreme object side face of the second negative lens component L12 in the first lens group G1 as r1 and the radius of curvature of the extreme image side face of the second negative lens component L12 as r2.
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