| 摘要 |
A zoom lens system having three lens units, that is, a negative lens unit, a positive lens unit, and a negative lens unit. The idea of floating system is introduced into the rear focusing system to minimize the degree of aberration fluctuation at a short object distance with a simple lens arrangement, thereby stabilizing the optical performance during focusing at a short object distance. The zoom lens system includes a 1-st lens unit (G1) having a negative refractive power, a 2-nd lens unit (G2) having a positive refractive power, and a 3-rd lens unit (G3) having a negative refractive power, and effects zooming from the wide end to the tele end by varying the spacing between each pair of adjacent lens units. With the 2-nd lens unit (G2) defined as a focusing lens unit, focusing is effected by varying the axial air spacing between a lens component (LF) of the 2-nd lens unit (G2) that is the closest to the image side and the remaining lens component (LF').
|
