Patent ID: 7663814

Claim:
An imaging lens system comprising: a negative first lens that is disposed on a most object side, has a concave surface directed toward the object side and has a meniscus shape; a cemented lens that is disposed on a most image side, a most object side surface of the cemented lens being a convex surface; and a stop that is disposed just in front of the object side of the cemented lens, wherein the following conditional expressions are satisfied: 0.05<( R 2− R 1)/( R 1+ R 2)<0.25 (1) vd 1− vd 2>15 (2) where R 1 denotes a radius of curvature of an object side surface of the first lens, R 2 denotes a radius of curvature of an image side surface of the first lens, vd 1 denotes an Abbe number of a lens, which is located on the most object side among lenses constituting the cemented lens, at the d-line, and vd 2 denotes an Abbe number of a lens, which is located on the most image side among the lenses constituting the cemented lens, at the d-line.