Patent ID: 8305693

Claim:
A high zoom ratio wide-angle zoom lens system comprising: a first lens group comprising a first lens of biconcave, a second lens of positive meniscus, a third lens of biconvex, and a fourth lens of biconvex wherein the first lens and the second lens are lenses not cemented together by adhesive; a second lens group comprising a fifth lens of positive meniscus, a sixth lens of biconcave, a seventh lens of biconvex, and an eighth lens of plano-concave; a third lens group comprising a ninth lens of biconvex; and a fourth lens group comprising a tenth lens of biconvex, an eleventh lens of plano-concave, a twelfth lens of biconvex, and a thirteenth lens of aspheric; wherein the zoom lens system satisfies the following conditions (a)-(e): (a): −20.03<R1/R2<−1.89; (b): 0.13<f w /f 1 <0.14; (c): −0.6<f w /f 2 <−0.53; (d): 0.11<f w /f 3 <0.14; and (e): 0.18<f w /f 4 <0.21 where R1 is a curvature of a first surface of the first lens, R2 is a curvature of a second surface of the first lens, f w is a focal length of the overall system at a wide angle, f 1 is a focal length of the first lens group, f 2 is a focal length of the second lens group, f 3 is a focal length of the third lens group, and f 4 is a focal length of the fourth lens group.