Patent ID: 8638507

Claim:
A fisheye lens system comprising, in an order from an object to an image: a first lens group comprising at least three lenses and having negative refractive power; a second lens group having positive refractive power; and an aperture disposed between the first lens group and the second lens group, wherein the at least three lenses included in the first lens group comprise a first lens, a second lens, and a third lens, in the order from the object to the image, and satisfy conditions below: 0.4 <SF 1<0.6; 0.5 <SF 2<1.0; and 1.3 <SF 3<5.5, and wherein SFi=(R 1 i −R 2 i )/(R 1 i +R 2 i ) is a shaping factor of an i th lens (I=1, 2, or 3), R 1 i is a radius of curvature of a surface of an object side of the i th lens, and R 2 i is a radius of curvature of a surface of an image side of the i th lens, and wherein the second lens group comprises an aspheric lens.