| 摘要 |
<p>PROBLEM TO BE SOLVED: To provide a zoom lens easily achieving excellent optical performance over a wide variable power range and over the whole projection distance while having a simple configuration.SOLUTION: The zoom lens includes, in order from an enlargement conjugate side to a reduction conjugate side, a first lens group having a negative refractive power, a second lens group having a positive refractive power, a third lens group having a negative refractive power, a fourth lens group having a positive refractive power, and a fifth lens group having a positive refractive power. During zooming from the wide angle end to the telephoto end, the second lens group and the fourth lens group move to the enlargement conjugate side along the same locus, and the third lens group moves to the enlargement conjugate side along a locus different from that of the second lens group and the fourth lens group. During focusing, the third lens group moves.</p> |
