Patent ID: 7554748

Claim:
A zoom lens system having an object side and an image side, comprising: a negative first lens group, the first lens group comprising: a meniscus-shaped first lens with negative refracting power, the first lens having a concave surface facing the image side, and a second lens with positive refracting power; and a positive second lens group, the second lens group comprising: an aperture stop, a biconvex third lens with positive refracting power, and a meniscus-shaped fourth lens with negative refracting power, the fourth lens having a concave surface facing the object side; wherein, the first lens, the second lens, the aperture stop, the third lens and the fourth lens are coaxially disposed in that order from the object side to the image side, and the following condition is satisfied: 3.5 <T w /( f w ·tan ω w )<7.5, (1) wherein, T w is a total length of the zoom lens system at a wide-angle end, f w is a focal length of the zoom lens system at the wide-angle end, and ω w is a half angle of field of view of the zoom lens system at the wide-angle end.