Patent ID: 8228621

Claim:
An image pickup lens comprising four or more lens blocks, wherein each of the lens blocks is an optical element comprising a lens substrate being a parallel flat plate, and a lens portion or lens portions having positive or negative power and formed on at least one of an object-side surface and image-side surface of the lens substrate, the lens substrate is different in material from the lens portion or lens portions in each of the lens blocks, the lens blocks include, in order from an object side, a first lens block, a second lens block, a third lens block, and a fourth lens block, the first lens block has positive power, the second lens block has negative power, a lens block arranged at a closest position to an image side has a concave shape facing the image side in a paraxial region, at least one of lens portions each having a concave shape in the paraxial region satisfies the following conditional expression (1), and the first lens block satisfies the conditional expression (3): νn<40 (1) 0.5 <f 1/ f< 1.5 (3) where νn is an Abbe number of a lens portion having a concave shape in the paraxial region, f1 is a composite focal length of the first lens block, and f is a composite focal length of a total system of the image pickup lens.