| 摘要 |
PROBLEM TO BE SOLVED: To provide a zoom lens in which aberrations such as spherical aberration and coma aberration are satisfactorily corrected, and which has a wide angle of view, is compact and achieves high optical performance.SOLUTION: The zoom lens includes, in order from the object side: a first lens group having a positive refractive power; a second lens group having a negative refractive power; a diaphragm; a third lens group having a positive refractive power; and a fourth lens group having a positive refractive power. When zooming, the first lens group and the third lens group are fixed, and the distance between the diaphragm and the third lens group is changed. The fourth lens group has at least one negative lens. The zoom lens satisfies the following conditional expressions: (1) 0.5<f3/f4<1.45, and (2) 0.1<msa/m2<0.8, where f3 is the focal distance of the third lens group, f4 is the focal distance of the fourth lens group, msa is the amount of movement of the diaphragm from the position closest to the objet side to the position closest to the image side, and m2 is the amount of movement of the second lens group from the wide angle end to the telephoto end. |
