Patent ID: 8891174

Claim:
A zoom lens comprising, in order from an enlargement side to a reduction side: a first lens unit having positive refractive power and not moving for zooming; a second lens unit having negative refractive power and moving for zooming; a stop; a zooming lens unit having positive refractive power and moving for zooming; and a final lens unit having positive refractive power and not moving for zooming, wherein during zooming from a wide-angle end to a telephoto end, the second lens unit moves to the reduction side and the zooming lens unit moves to the enlargement side, the zooming lens unit includes a cemented lens, the cemented lens has a negative lens and a positive lens cemented in order from the enlargement side, and a cemented surface of the cemented lens has a convex shape on the enlargement side, the zoom lens satisfies 0.15 <Nn−Np< 0.35 where a refractive index of the negative lens is denoted by Nn and a refractive index of the positive lens is denoted by Np, and the zoom lens satisfies 0.15 <e 12 w/L< 0.25 0.15 <e 2 w/L< 0.25 0.25 <e 12 t/L< 0.40 0.03 <e 2 t/L< 0.11 where a distance between a principal point of the first lens unit and a principal point of the second lens unit at the wide-angle end is denoted by e12w, a distance between the principal point of the second lens unit and the stop at the wide-angle end is denoted by e2w, a distance between a principal point of the first lens unit and a principal point of the second lens unit at the telephoto end is denoted by e12t, a distance between the principal point of the second lens unit and the stop at the telephoto end is denoted by e2t, and a distance between a surface vertex on the enlargement side of a lens disposed on the most enlargement side and a surface vertex on the reduction side of a lens disposed on the most reduction side is denoted by L.