| 摘要 |
PROBLEM TO BE SOLVED: To provide a zoom lens whose entire lens system is compact and which has a high zoom ratio and high optical performance over the entire zoom range.SOLUTION: The zoom lens includes, in order from an object side to an image side, a first lens group having a negative refractive power, a second lens group having a positive refractive power, and a third lens group having a positive refractive power. When zooming, the distances between the lens groups are changed. The second lens group comprises, in order from the object side to the image side, a positive lens and a cemented lens in which a positive lens and a negative lens are cemented together. The focal length f2 of the second lens group, the focal length fT of the entire system at the telephoto end, and an average refractive index Npave of the materials of the positive lenses included in the entire system are appropriately set, respectively. |
