| 摘要 |
A zoom lens includes a fixed first lens group having a positive refracting power, a second lens group having a negative refracting power and movable along an optical axis, a fixed third lens group having a positive refracting power, a fourth lens group having a negative refracting power and movable along the optical axis, and a fixed fifth lens group, disposed in order from the object side to the image side. The following expressions are satisfied: 0.5<f1/(fw·ft)1/2<1.8 -0.4<f3/f5<0.4 where f1, fw, ft, f3 and f5 are focal lengths of the first lens group, the entire lens system in a wide angle end state, the entire lens system in a telephoto end state, the third lens group and the fifth lens group, respectively.
|
