| 摘要 |
PROBLEM TO BE SOLVED: To make a wide-angle zoom lens have a high lightness at the wide-angle end, a wide angle of view, and a thin thickness at the telephotographic end, by making each lens form and conditional formulae to be a specified form and to be in a specified in range, in a compact wide-angle zoom lens consisting of positive and negative two lens groups. SOLUTION: A first lens group consists of a first biconcave negative lens L1, a cemented lens of a second negative lens L2 and a third positive lens L3, and a fourth biconvex positive lens L4, and a second lens group consists of a fifth lens L5 having a aspherical surface, a sixth lens 6 positive meniscus formed and facing its convex plane to an image side, and a seventh lens L7 negative meniscus formed and facing its convex plane to the image side. Moreover, the following conditions are satisfied: 0<(r3+r4)/(r3-r4)<3.5, 0.5<(r11+r12)/(r11-r12)<4.5, 0.9<|r5/r4|<2.3, n1>1.65, n4<1.57.
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