Patent ID: 8072690

Claim:
A projection zoom lens system comprising, in order from a magnification side of the projection zoom lens: a first lens group having a negative refractive power; a second lens group having a positive refractive power; a third lens group having a positive refractive power; a fourth lens group; and a fifth lens group having a positive refractive power, wherein during a power variable operation, the first lens group and the fifth lens group remain stationary, and the second lens group, the third lens group, and the fourth lens group are moved along an optical axis, wherein the fourth lens group includes, in order from the magnification side of the projection zoom lens, a negative lens having at least one aspheric surface, a positive lens, a negative lens concave toward the magnification side of the projection zoom lens, a positive lens convex toward a reduction side of the projection zoom lens, and a positive lens, and wherein the fifth lens group is formed of one lens, and satisfies the following conditional expression (1): 3 <f 5 /f w <8â€ƒâ€ƒ(1), where f 5 is a focal length of the fifth lens group, and f w is a focal length of the whole system of the projection zoom lens at a wide-angle end of the projection zoom lens.