| 摘要 |
PROBLEM TO BE SOLVED: To obtain a sufficient lens brightness with a small F-value in a negative and positive two-group zoom lens system, while utilizing an advantage easy to curb costs with a simple mechanical mechanism, and to correct various corrections such as coma, spherical aberration, astigmatism, distortion and chromatic aberration, and to attain excellent optical performance.SOLUTION: A zoom lens system comprises, in order from an object side, a negative first lens group and a positive second lens group, and when a magnification is changed from a wide end to a telephoto end, a distance between the first lens group and the second lens group decreases. The second lens group comprises, in order from the object side, a positive 2A lens group, an aperture stop and a positive 2B lens group. The zoom lens system satisfies the following conditional expression (1). (1) 0.65<f2A/f2B<1.0, where f2A denotes a focal distance of the 2A lens group, and f2B denotes a focal distance of the 2B lens group. |
