| 摘要 |
A zoom lens comprises, from object to image side: a positive first-lens unit (L1); a negative second-lens unit (L2); a positive third-lens unit (L3); and a positive fourth-lens unit (L4); the third-lens unit (L3) comprising a negative 3a'th-lens sub-unit (L3a) and positive 3b'thlens sub-unit (L3b); the second-lens unit (L2) and fourth-lens unit (L4) moving on the optical axis when zooming; the 3b'th-lens sub-unit (L3b) moving in a direction having a component perpendicular to the optical axis, thereby displacing an image perpendicular to the optical axis; the 3a'th-lens sub-unit (L3a) comprising a negative-lens element G3an whose both surfaces are spherical, and a positive-lens element whose both surfaces are spherical; the 3b'th-lens sub-unit (L3b) including a positive-lens element G3bp including an aspherical lens surface, and a negative-lens element; wherein, assuming that the indices of the materials of the negative-lens element G3an and the positive-lens element G3bp are NG3an and NG3bp respectively, 0.21 < NG3an - NG3bp is satisfied. |
