Patent ID: 7443612

Claim:
A wide-angle lens comprising four lens groups, arranged in order along an optical axis from an object side toward an image side and with no intervening lens component, as follows: a first lens group having negative refractive power; a second lens group having positive refractive power; a third lens group having positive refractive power; and a fourth lens group having negative refractive power; wherein said first lens group includes a lens element having negative refractive power and having a concave surface on the object side of said first lens group and said concave surface has a curvature larger in absolute value than the absolute value of the curvature of the surface on the image side of said lens element; said second lens group includes no more than two lens elements, no more than one of which has positive refractive power, and includes a convex surface on the object side; said third lens group includes at least one aspheric surface and an image-side lens component having positive refractive power that has a convex image-side surface; said fourth lens group has a concave object-side surface and includes at least one aspheric surface; and the following conditions are satisfied: 1.7 <F NO <2.8 0.77 <Y/f <1.1 where F NO is the f-number of the wide-angle lens; Y is the maximum image height at the image plane of the wide-angle lens; and f is the focal length of the wide-angle lens.