Patent ID: 8659841

Claim:
A superwide-angle lens system comprising a negative first lens group, an aperture diaphragm, and a positive second lens group, in that order from the object side, wherein said first lens group is provided with a negative meniscus lens element having a convex surface on the object side, a negative meniscus lens element having a convex surface on the object side, and a positive lens element, in that order from the object side, wherein said second lens group is provided with a cemented lens having a negative lens element and a positive lens element; and a positive lens element, in that order from the object side, and wherein the following conditions (1) and (2) are satisfied: −1.45 <f 12 /f<− 1.15 (1), and 1.4 <SF 2<2.4 (2), wherein f 12 designates the combined focal length of the two said negative meniscus lens elements provided in said first lens group, f designates the focal length of the entire said superwide-angle lens system, SF 2 designates the shaping factor of the negative meniscus lens element provided on the image side of the two said negative meniscus lens elements provided in said first lens group, SF 2=( r 21 +r 22)/( r 21 −r 22), r 21 designates the radius of curvature of the surface on the object side of said negative meniscus lens element provided on the image side, and r 22 designates the radius of curvature of the surface on the image side of said negative meniscus lens element provided on the image side.