| 摘要 |
PROBLEM TO BE SOLVED: To obtain a high zoom magnification and sufficient brightness over the entire zoom range and achieve a sufficiently wide imaging field angle.SOLUTION: A zoom lens has a lens group structure including, in order from the object side to the image side, positive, negative, positive and positive lens groups. When zooming from the wide angle end to the telephoto end, the first lens group is fixed with respect to the imaging plane, and the second lens group is moved in the optical axis direction to the image side so that the distance to the third lens group is decreased. The third lens group includes, in order from the object side to the image side, a positive lens, a negative lens, and a cemented lens made up of a positive lens located on the object side and a negative lens located on the image side and having a positive refractive power. In the zoom lens, the following conditional expression (1) is satisfied: (1) -0.95<fg3_neg/fg3<-0.5, where fg3_neg is the focal length of the second negative lens from the object side in the third lens group, and fg3 is the focal length of the third lens group. |
