Zoom lens for video projector

摘要

The zoom lens includes a first negative enlargement lens group (I) and second, third and fourth positive enlargement lens groups (II,III,IV). The first, second, and third lens groups are axially movable in a preset relation to each other and to the fixed forth lens group. The focal length of the zoom lens can be adjusted and varied. The zoom lens satisfies the condition 1.6 < D34w/Fw < 2.8. D34w is the axial space between the third and fourth lens group when the lens is in a wide-angle position. Fw is the focal length of the entire zoom lens when the lens is in the wide-angle position.