| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a zoom lens which has excellent optical performance over the entire power variation range by excellently compensating a power chromatic aberration varying as the power is varied and is suitable to, for example, a liquid crystal projector. <P>SOLUTION: The zoom lens has a 1st lens group with negative refracting power, a 2nd lens group with positive refracting power, a 3rd lens group with negative refracting power, and a 4th lens group with positive refracting power in order from an enlargement conjugation side. At least one of the respective lens groups has at least one diffraction optical element. The 3rd lens group is composed of one negative lens and the 1st lens group and 4th lens group are stationary for power variation from a wide-angle end to a telephoto end. The 2nd lens group moves on the optical axis and the 3rd lens group moves from the enlargement conjugation side to a reduction conjugation side. A conditional expression 0.05<M3/f3<0.20 is satisfied, where M3 is the movement quantity of the 3rd lens group and f3 is the focal length of the 3rd lens group. <P>COPYRIGHT: (C)2003,JPO |
