Birch, Stewart, Kolasch & Birch, LLP
Imaging lens and image pickup apparatus
An imaging lens comprises, in order from an object side: a first lens that has a negative refractive power and is convex toward the object side; a second lens that has a positive refractive power and is a meniscus lens convex toward the object side; a stop; a third lens that has a positive refractive power and is convex toward an image side; and a cemented lens that has a positive refractive power as a whole and is formed by cementing a fourth lens and a fifth lens, wherein assuming that an Abbe number of the second lens with respect to d-line is ν2, a distance on an optical axis from a vertex of a surface of the first lens facing toward the object side to an image plane of the imaging lens is L, a focal length of the imaging lens is f, and a back focus of the imaging lens is Bf, the following conditional expressions (1) to (3) are satisfied:ν2>30  (1),2.5<L/f<4.0  (2), and0.5<Bf/f<1.3  (3).
Fujinon Corporation
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G02B G02B
inventional inventional
Taro
Asami