| 摘要 |
PROBLEM TO BE SOLVED: To provide a novel zoom lens which is suitable as an image capturing lens for a digital camera and offers compactness, a large aperture, high performance, and a wide view angle.SOLUTION: A zoom lens comprises a positive first lens group I, a negative second lens group II, a positive third lens group III, and a positive fourth lens group IV arranged in order from the object side toward the image side with an aperture stop S placed between the second lens group II and the third lens group III. When zooming from a short focus end to a long focus end, a distance between the first lens group and the second lens group increases and a distance between the second lens group and the third lens group decreases while a distance between the third lens group and the fourth lens group varies. The first lens group I comprises a single positive lens. A focal length f1 of the first lens group and a focal length of the entire system at the short focus end fw satisfy a conditional expression: (1) 15<f1/fw<30. |
