PURPOSE: To provide the lens which has an about 60° field angle and luminance of F number 2 by composing the lens of a positive meniscus lens which is convex to the object side, a biconcave lens, a biconvex lens, and a negative meniscus lens which is convex to the image side in order from the object side, and satisfying specific conditions.

CONSTITUTION: This lens consists of the front group composed of the positive meniscus lens L1 which is convex to the object side, biconcave lens L2, biconvex lens L3, and the rear group composed of the negative meniscus lens L4 which is convex to the image side. Then the conditions shown by inequalities (1)-(5) are satisfied. Here, f1 is the radius of curvature of the object-side surface of the positive meniscus lens, r4 the radius of curvature of the image-side surface of the biconcave lens, r8 the radius of curvature of the image-side surface of the negative meniscus lens, d5 the on-axis thickness of the biconvex lens, d6 the on-axis air interval between the biconvex lens and negative meniscus lens, f12 the composite focal length of the positive meniscus lens and biconcave lens, and (f) the composite focal length of the whole system.