| 摘要 |
<P>PROBLEM TO BE SOLVED: To improve performance by suppressing deterioration of optical performance caused by an assembly error without increasing manufacturing cost. <P>SOLUTION: A first lens group having positive refractive power, an aperture stop, and a second lens group having positive refractive power are arranged in this order from an object side to an image side, and in the first lens group, a negative meniscus lens, a positive lens, and a negative lens are arranged in this order from the object side to the image side, so that the following conditional expressions (1), (2), and (3) are satisfied: (1) 0°≥θg3<1°, (2) 500<f1, and (3) 30<f2<35, where θg3 is an emission angle of an on-axis light flux emitted from the negative lens arranged closest toward the image side in the first lens group, f1 is the focal length of the first lens group, and f2 is the focal length of the second lens group. <P>COPYRIGHT: (C)2012,JPO&INPIT |
