| 摘要 |
This variable power optical system has: a first lens group (G1) having positive refractive power and being arranged farthest towards the object side; a negative lens group (G2) having negative refractive power and being arranged to the image side from the first lens group; a positive lens group (G4) situated to the image side from the negative lens group, the positive lens group (G4) including at least one lens arranged to the image side from the aperture stop, and having positive refractive power; and a focus group (G3) arranged between the negative lens group and the positive lens group. When varying the power, the first lens group moves with respect to the imaging plane, the gap between the first lens group and the negative lens group changes, and the gap between the negative lens group and the positive lens group changes; and during focusing, the gap between the focus group and a lens arranged at a position facing the object side of the focus group changes, and the gap between the focus group and a lens arranged at a position facing the image side of the focus group changes. The focus group is composed of a single lens component, and the lens component farthest towards the imaging plane side from the positive lens group has negative refractive power and satisfies a prescribed conditional expression. |
