Patent ID: RE40638

Claim:
An image pickup lens system comprising a lens of a meniscus shape having a first face as a convex concave face located on the object side, and a diaphragm disposed at the object side of the lens, said lens meeting the following conditions: Y′/fl≧0.6 (1) 0.9≧Dt/Dc≧0.5 (2) 1.0≧Ap 2 /Am 2 ≧0.9 (3) wherein fl is a focal length of the entire lens system; Y′ is a maximum image height; Dt is a thickness of a thinnest portion of the lens in an area including at least one optical face; Dc is a thickness of a central portion of the lens; Ap 2 is an effective radius of a second face of the lens on the side of the image surface (a maximum radius of a portion through which effective light rays pass); and Am 2 is a maximum radius of the second face on the side of the image surface.