| 摘要 |
Zoom lens of the retrofocus type comprising a negative first lens-group (G1), a positive second lens-group (G2), a negative third lens-group (G3) and a positive fourth lens-group (G4), in that order from the object side, wherein upon zooming from the short- to the long-focal length, the distance between said first lens-group (G1) and said second lens-group (G2) decreases, the distance between said second lens-group (G2) and said third lens-group (G3) increases and the distance between said third lens-group (G3) and said fourth lens-group (G4) decreases, wherein the following inequalities (1) and (3) are satisfied:
(1) -2.50 < f1 / f2 < -1.57, and
(3) 0.9 < f12t / f4 < 3.0
wherein f1 denotes the focal length of said first lens-group (G1), f2 designates the focal length of said second lens-group (G2), f12t designates the combined focal length of said first (G1) and said second lens-group (G2) at the telephoto end and f4 denotes the focal length of said fourth lens-group (G4). |
