| 摘要 |
An imaging lens includes, in order from an object side, a first lens G 1 , a second lens G 2 , a third lens G 3 , an aperture stop St and a fourth lens G 4 . The first lens is a negative lens having a meniscus shape with a convex surface directed to the object side. The second lens is a negative lens. The third lens is a positive lens having a convex surface directed to the object side. The fourth lens is a biconvex lens. The following conditional expression is satisfied: <?in-line-formulae description="In-line Formulae" end="lead"?>1.5<f4/fa<2.7 (1)<?in-line-formulae description="In-line Formulae" end="tail"?> where fa denotes a focal length of the whole lens system, and f 4 denotes a focal length of the fourth lens.
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