Patent ID: 8379316

Claim:
A zoom lens for projection comprising: a magnification-side lens group having negative refractive power, and which is fixed while magnification is changed; a plurality of lens groups that move along an optical axis while magnification is changed; and a reduction-side lens group having positive refractive power, and which is fixed while magnification is changed, the magnification-side lens group, the plurality of lens groups, and the reduction-side lens group being arranged in this order from the magnification side of the zoom lens, wherein the magnification-side lens group is composed of a front group having negative refractive power and a rear group having positive refractive power, which are arranged in this order from the magnification side, and wherein the rear group is composed of a positive lens, a negative lens and a positive lens, which are arranged in this order from the magnification side, and wherein focusing is performed by moving the rear group along the optical axis, and wherein the reduction side of the zoom lens is telecentric, and wherein the following formulas (1) and (2) are satisfied: 1.73 <N dRpAVE (1); and 60<ν dRn (2), where N dRpAVE is an average value of refractive indices of the positive lenses in the rear group with respect to d-line, and ν dRn is the Abbe number of the negative lens in the rear group with respect to d-line.