| 摘要 |
PROBLEM TO BE SOLVED: To solve the problem in which more reduction in a F number in a conventional optical system and more reduction in the size of the optical system increase influence on various aberrations, particularly on a coma aberration.SOLUTION: A zoom lens includes, 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. When zooming from a wide angle end to a telephoto end, the first lens group is fixed, the second lens group moves to an image surface side, the third lens group is fixed, and the fourth lens group moves. During focusing, the fourth lens group moves. The zoom lens satisfies the following conditional expressions (1) and (2): 0.35<(&bgr;34T/&bgr;34 W)/(&bgr;2T/&bgr;2 W)<1.2 ...(1) 3.0<&bgr;2T/&bgr;2 W<fT/fW ...(2). |
