| 摘要 |
PROBLEM TO BE SOLVED: To provide a compact zoom lens having image forming performance sufficiently coping with a high-density and high-pixel solid-state image pickup element. SOLUTION: This zoom lens is equipped with a first lens group I having positive refractive power, a second lens group II having negative refractive power, a diaphragm 12 and a third lens group III having positive refractive power in order from an object side. The first lens group is fixed, the third lens group performs variable power action, and the second lens group corrects the fluctuation of an image surface and performs focusing, and the diaphragm moves integrally with the third lens group. The third lens group has a doublet IIIa consisting of a meniscus lens 5 and a biconvex lens 6, a doublet IIIb consisting of a biconvex lens 7 and a biconcave lens 8 and a doublet IIIc consisting of a biconvex lens 9 and a meniscus lens 10 in order from the object side, and is constituted to satisfy 0.7<|f2|/f3<1.1, 3<(D7w+D8)/fw<4.5, N8-N7>=0.2,ν7-ν8>=18 and (D12+D13)/fw>=0.65.
|
