A zoom lens system includes a first lens group, a second lens group, a third lens group and a fourth lens group. Zooming is performed by moving each lens group in the optical axis direction. The zoom lens system satisfies the following conditions:
0.35<log(fT23/fW23)/log(ft/fw)<0.55 (1);
0.4<(LDW−LDT)/(ft/fw)<0.7 (2);
wherein
[0001]- f23W: the combined focal length of the second and the third lens groups at the short focal length extremity;
[0002]- f23T: the combined focal length of the second and the third lens groups at the long focal length extremity;
[0003]- ft: the focal length of the entire zoom lens system at the long focal length extremity;
[0004]- fw: the focal length of the entire zoom lens system at the short focal length extremity;
[0005]- LDw: the distance from the most object-side surface of the first lens group to the most image-side surface of the fourth lens group at the short focal length extremity; and
[0006]- LDT: the distance from the most object-side surface of the first lens group to the most image-side surface of the fourth lens group at the long focal length extremity.