| 摘要 |
A zoom lens for projection substantially consists of a negative first lens group, a positive second lens group, a positive third lens group, a negative fourth lens group, a positive fifth lens group, and a positive sixth lens in this order from a magnification side. The first lens group and the sixth lens group are fixed and the second lens group through the fifth lens group move during magnification change. A reduction side is telecentric. First through fourth lenses from the magnification side in the fifth lens group are a negative meniscus-shaped single lens with its convex surface facing the magnification side, a positive single lens, a biconcave lens and a biconvex lens, respectively, and the biconcave lens and the biconvex lens are cemented together. |
