| 摘要 |
<p>In an optical system including a front lens unit having negative refractive power, a stop, and a rear lens unit having positive refractive power in order from an enlargement side to a reduction side, the front lens unit has a combination lens in which a negative lens and a positive lens are adjacently arranged in order from the enlargement side to the reduction side, and a focal length of the negative lens f N , an Abbe number ½ N and relative partial dispersion ¸ N of a material of the negative lens, an Abbe number ½ P and relative partial dispersion ¸ P of a material of the positive lens, and a focal length of the entire optical system f W are appropriately set.</p> |
