| 摘要 |
PROBLEM TO BE SOLVED: To provide a compact zoom lens which has a high zoom ratio, and high optical characteristics over its whole zoom range. SOLUTION: This zoom lens includes a first lens group of positive refractive power, a second lens group of negative refractive power, a third lens group of positive refractive power, and a fourth lens group of positive refractive power, all arranged in this order from the object side to the image side. It moves the second lens group and fourth lens group on the optical axis when zooming. The third lens group is composed of a third A lens group of negative refractive power, and a third B lens group of positive refractive power moving in a direction having the component perpendicular to the optical axis to move the image, both arranged in the order from the object side to the image side. The third B lens group includes a cemented lens made by jointing a positive and negative lenses, and satisfies 5<¾(R3A+R3B)/(R3A-R3B)¾<30 when representing the curvature radiuses of the object side surface and the image side surface of this cemented lens by R3A, R3B respectively. COPYRIGHT: (C)2011,JPO&INPIT |
