| 摘要 |
<p>PROBLEM TO BE SOLVED: To reduce the size and weight of a focusing lens group, to perform quick and quiet focusing, and to satisfactorily correct various aberrations such as an axial chromatic aberration and a magnification chromatic aberration, thereby achieving excellent optical performance.SOLUTION: The zoom lens system comprises, in order from an object side, a first lens group having positive refractive power, a second lens group having negative refractive power, a third lens group having positive refractive power, and a fourth lens group having positive refractive power. When varying power from a short focal length end to a long focal length end, at least the second lens group and the third lens group are moved. The first lens group comprises, in order from the object side, a first a lens group having at least one negative lens and positive refractive power and a first b lens group comprising a positive single lens and having positive refractive power and satisfies the following conditional expression (2'): (2')νd1a<22.85, whereνd1a is the Abbe number with respect to a d-line of the negative lens located closest to the object side in the first a lens group.</p> |
