| 摘要 |
PROBLEM TO BE SOLVED: To obtain the small sized wideangle lens thin in total thickness of the lens systm at the time of housing it and excellent in performance by specifying the relationships among refractive powers of each lens lens component. SOLUTION: A first lens component L1 is constituted of a single biconcave lens L(1, 1) having a negative refractive power:ϕ1 . A second lens component L2 is constituted of a positive lens L(2, 1) and a negative lens L(2, 2) and has a positive refractive power:ϕ2 as a whole. A third lens component L3 is conotituted as that a negative lens L(3, 1), a positive lens L(3, 2) and a negative lens L(3, 3) are arranged successively from the object side, and has a positive refractive power:ϕ3 as the lens component. Moreover, a fourthe lens component L4 is constituted of a negative lens L(4, 1) and has a negative refractive power:ϕ4 . Then, refractive powersϕ1 toϕ4 satisfy conditional equations 0.7<ϕ1 /ϕ4 <2.5 and 1.8<ϕ2 /ϕ3 <7.0.
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