| 摘要 |
PURPOSE:To shorten the object distance of a zoom lens, consisting of four groups of positive, negative, positive, and positive lenses (focal length; f1, f2, f3, and f4) from the object side, by moving out the 1st group. CONSTITUTION:The four-group zoom lens consists of positive and negative (variator), positive (compensator), and positive (relay lens) elements; and the 1st group is composed of a positive lens (focal length f1F; radii r1 and r2 of curvature of the 1st and 2nd surfaces) and positive-negative cemented positive lens (focal length f1R; radii r3 and r5 of curvature of surfaces at the object side and image side), and equations should be satisfied. The longest and shortest focal lengths of the whole system are denoted as fT and fW. |
