| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a photographic optical system in which various aberrations including color aberration may be corrected while a weight of a lens may be reduced. <P>SOLUTION: A photographic optical system comprises: a first lens group L1 having positive refractive power, a second lens group L2 having positive or negative refractive power and a third lens group L3 having positive or negative refractive power arranged in this order from an object side to an image side with the second lens group moved for focusing; and at least one diffraction optical element DOE and at least one optical element NL made of a solid material disposed in positions closer to the object side than an intersection between a pupil paraxial ray and an optical axis. A focal length fDOE of merely a diffraction component of the diffraction optical element, a focal length fNL of the optical element made of the solid material, a focal length f1 of the first lens group and an abnormal partial dispersion ratio ΔθgF<SB POS="POST">NL</SB>of a material for the optical element made of the solid material are respectively appropriately set. <P>COPYRIGHT: (C)2013,JPO&INPIT |
