| 摘要 |
PROBLEM TO BE SOLVED: To provide a compact, high-performance variable magnification optical system and an imaging apparatus equipped with the optical system. SOLUTION: The variable magnification optical system for forming an optical image of an object on the light receiving surface of an imaging element with variable magnification includes, in order from the object side, a first lens group Grl having positive power, a second lens group Gr2 having negative power, a third lens group Gr3 having positive power, a fourth lens group Gr4 having positive power and a fifth lens group Gr5. In varying the magnification from a wide angle end (W) to a telephoto end (T), the first lens group Grl, the third lens group Gr3 and the fifth lens group Gr5 are kept in fixed positions, and the second lens group Gr2 and the fourth lens group Gr4 are moved. The third lens group Gr3 includes, in order from the object side, a biconvex positive lens Lp and a negative lens Ln having a concave meniscus shape on the image side or a concave planar shape on the image side, and the negative lens Ln has an aspherical surface. COPYRIGHT: (C)2007,JPO&INPIT |
