Patent ID: 8780463

Claim:
An image-forming lens comprising, from an object side to an image side in order: a first lens group; an aperture; and a second lens group with a positive refractive power, the first lens group including, from the object side in order: a first F lens group with a negative refractive power; and a first R lens group with a positive refractive power, the first F lens group including, from the object side in order: a first negative lens which has a surface on the image side having a large curvature; and a second negative lens which has a surface on the object side having a large curvature, and the first R lens group including: any one of a positive lens and a cemented lens with a positive refractive power as a whole, wherein a distance from a surface on a most object side of the first lens group to an image plane in a state of focusing on an object at infinity: L, a maximum image height: Y′, a curvature radius of the surface on the object side of the second negative lens: r 21 , and a curvature radius of a surface on the image side of the second negative lens: r 22 satisfy Conditional expression 1: 2.8<L/Y′<4.3 and Conditional expression 2: −7.0<(r 21 +r 22 )/(r 21 −r 22 )<−0.7, and the second lens group includes, from the object side to the image side in order: a second F lens group with a positive refractive power where a biconvex lens and a biconcave lens are cemented to each other; a second M lens group having a concave shape on a surface on a most object side and a convex shape on a surface on a most image side; and a second R lens group of a positive lens.