Patent ID: 7502180

Claim:
An image-formation optical system, comprising, in order from an object side thereof, a first lens having negative refracting power, a second lens that is a meniscus lens concave on its object side, an aperture stop, and a lens group having positive refracting power, wherein said image-formation optical system satisfies the following conditions (3) and (4): 3.0≦ D r1r4 /Ih≦ 6.0 (3) 1.5≦ D r1r3 /Ih≦ 3.0 (4) where D r1r3 is a distance from an object-side surface of the first lens to an object-side surface of the second lens, D r1r4 is a distance from the object-side surface of the first lens to an image-side surface of the second lens, and Ih is a maximum image height.