| 摘要 |
<P>PROBLEM TO BE SOLVED: To solve the problem that an influence of various aberrations, in particular, an influence of a coma aberration when an F number is further reduced and the size of an optical system is reduced in a conventional optical system. <P>SOLUTION: In the zoom lens has, in order from an object side, a positive first lens group, a negative second lens group, a positive third lens group, a positive fourth lens group, and a positive final lens group, the first lens group is fixed, the second lens group is moved to the image surface side, the third lens group is fixed, and the fourth lens group is moved in varying magnification from a wide angle end to a telephoto end, and the fourth lens group is moved in focusing, and the second lens group comprises: in order from the object side, an object side negative lens having the surface on the image side having a strong curvature; a lens having a small refractive power; and a cemented lens of a negative lens and a positive lens, and the following conditional expression is satisfied: (1) 0.07<¾f2¾/fT<0.35. <P>COPYRIGHT: (C)2013,JPO&INPIT |
