Patent ID: 7023628

Claim:
A fisheye objective lens for receiving light from an object and for forming an image of the object on an image plane, the objective lens comprising: a first lens element having a convex object surface facing the object and a concave image surface facing the image plane, a second lens element having a convex object surface facing the object and a concave image facing the image plane, a third lens element having a positive power, and a positively powered lens group having a positively powered cemented doublet lens pair and a singlet lens element having a positive power, the lens group having an object surface facing the object and an image surface facing the image, the fisheye objective lens having an optical axis, the first, second, third and the lens group being coaxially aligned on the optical axis; and wherein, the fisheye objective lens has a height to focal length ratio within a range 8<TT/fo<15, where TT designates the distance between the vertex of the first lens element convex object surface and the image plane when focused at infinity, and where fo designates the focal length of the fisheye objective lens.