Patent ID: 7209300

Claim:
A wide-angle lens system comprises a positive front lens group, a diaphragm, and a positive rear lens group, in this order from an object, wherein said front lens group comprises a negative first-sub-lens group and a positive second-sub-lens group, in this order from the object; wherein said negative first-sub-lens group comprises a negative lens element, a positive lens element, and a negative lens element, in this order from the object; and wherein said front lens group satisfies the following conditions: 0.5< f/|f 1a |<0.75 0.5 <| f 1a |/f 1b <1.0 0.35 < f/f 1bi <0.6 wherein f designates the focal length of the entire lens system; f 1a designates the focal length of said negative first-sub-lens group (f 1a <0); f 1b designates the focal length of said positive second-sub-lens group (f 1b >0); f 1bi designates the focal length of the most image-side surface of said positive second-sub-lens group (f 1bi =r 1bi /(1−N 1bi )); r 1bi designates the radius of curvature of the most image-side surface of said positive second-sub-lens group (r 1bi <0); and N 1bi designates a refractive index of the most image-side lens element of said positive second-sub-lens group.