| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a zoom lens which has the zoom ratio easily increased, has the angle of view easily widened, and has an entire system easily made small-sized and light-weight. <P>SOLUTION: The zoom lens comprises, in order from the object side to the image side, a positive first lens group which is not moved for zooming, a negative second lens group which is moved for zooming, a positive third lens group which is moved for zooming, and a positive fourth lens group which is not moved for zooming. The first lens group comprises, in order from the object side to the image side, a negative lens G1 having a meniscus shape having a convex surface facing the object side, a positive lens G2, a positive lens G3, a positive lens G4, and a positive lens G5 having a meniscus shape having a convex surface facing the object side. Curvature radiuses G1R1 and G1R2 of lens surfaces on the object side and the image side of the negative lens G1, a focal length fG1 of the negative lens G1, curvature radiuses G5R1 and G5R2 of lens surfaces on the object side and the image side of the positive lens G5, a focal length fG5 of the positive lens G5, and a focal length f1 of the first lens group are properly set respectively. <P>COPYRIGHT: (C)2012,JPO&INPIT |
