| 摘要 |
PROBLEM TO BE SOLVED: To provide a zoom lens which offers a high zoom ratio and wide view angle, has a front lens whose effective diameter is kept small, and provides good optical performance over an entire zoom range from the wide angle end to the telephoto end.SOLUTION: The zoom lens includes, in order from the object side to the image 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 rear group comprising one or more lens groups. The second lens group and a lens group of the rear group located on the most object side moves when zooming. The first lens group is stationary when zooming and comprises a negative lens and three positive lenses arranged in order from the object side to the image side. Focal lengths f1, f2 of the first lens group and the second lens group, respectively, curvature radii R1, R2 of an object-side surface and an image-side surface, respectively, of the negative lens of the first lens group, and a shape factor SFG1 defined as SFG1=(R1+R2)/(R1-R2) are each set appropriately. |
