| 摘要 |
<p>A zoom lens system includes a positive first lens group, a negative second lens group, and positive third and fourth lens groups. Upon zooming from the short to long focal length extremities, the distance between the first and second lens groups increases and the distance between the second and third lens groups decreases. The first lens group includes a positive first sub-lens group which remains at a stationary position during focusing and a positive second sub-lens group which moves during focusing. Condition (1) is satisfied: 0.35<f1b/f1a<0.57 (1), wherein f1b and f1a designate the focal length of the second and first sub-lens groups, respectively.</p> |
