Patent ID: 7408725

Claim:
A single focus lens comprising: in order from an object side of the single focus lens, a first lens having positive power and having a convex surface on the object side; a second lens of a negative meniscus lens and having a concave surface of the object side on its paraxial axis; and a third lens of an aspherical lens having a convex surface on the object side on its paraxial axis, wherein the single focus lens satisfies conditions (1) to (7): 0.6 <f 1 /f <1.5 (1) 69 <νdA (2) 24 <νdB <32 (3) NdA<1.55 (4) 1.48 <NdB <1.65 (5) L/D <1.8 (6) 0.30 <RA/f <0.40 (7) wherein f represents a focal length of the single focus lens; f1 represents a focal length of the first lens; νdA represents Abbe number of the first lens; νdB represents Abbe number of the second lens; NdA represents a refractive index at the d-line of the first lens; NdB represents a refractive index at the d-line of the second lens; RA represents a paraxial radius of curvature of an object-side surface of the first lens; L represents a distance along an optical axis between the object-side surface of the first lens and an image-forming position; and D represents a maximum image height.