Patent ID: 7817351

Claim:
A zoom lens system comprising, in order from the object side: a first lens group having negative refractive power, the first lens group comprising, in order from the object side to the image side, a first lens having negative refractive power and a second lens having positive refractive power; a second lens group having positive refractive power, the second lens group comprising, in order from the object side to the image side, a third lens having positive refractive power, a fourth lens having negative refractive power, and a fifth lens having negative refractive power; and a third lens group having positive refractive power, the third lens group comprising a sixth lens having positive refractive power, wherein the zoom lens system satisfies the following conditions: ND3>1.8; (1) ( ND 3 −ND 4)<0.1; (2) TTL/fw<= 1.3; and (3) R 6/ fw> 0.70, (4) wherein, ND 3 is the refractive index of the third lens, ND 4 is the refractive index of the fourth lens, TTL is the sum of the thickness of the first lens group, the thickness of the second lens group, and the thickness of the third lens group, fw is a focal length of the zoom lens system at a wide-angle position, R 6 is the radius of curvature of a surface of the third lens facing the object side of the zoom lens system.