Patent ID: 7558002

Claim:
A projection zoom lens comprising, in order from a magnification side: a first lens group that performs focusing with being fixed when a power of the projection zoom lens varies, the first lens group having a negative refractive power; a second lens group having a positive refractive power; a third lens group having a positive or negative refractive power; a fourth lens group having a positive refractive power; a fifth lens group having a positive or negative refractive power; and a sixth lens group that is fixed when the power of the projection zoom lens varies, the sixth lens group having a positive refractive power, wherein: the second to fifth lens groups move with a mutual relationship to compensate continuously varying of the power of the projection zoom lens and movement of an image plane caused by the continuously varying of the power of the projection zoom lens, the fifth lens group comprises a cemented lens formed by cementing a negative meniscus lens having a convex surface directed to the magnification side, a negative lens and a positive lens in order from the magnification side, and a positive lens having a convex surface directed to a reduction side, and a telephoto end position of each of the second lens group, the fourth lens group and the fifth lens group is closer to the magnification side than a wide-angle end position of each of the second lens group, the fourth lens group and the fifth lens group.