| 摘要 |
A zoom lens of the telephoto-type comprises, in order from the object side, a first group (10) having a positive refractive power, a second group (20) having a negative refractive power, an aperture stop (St), a third group (30) having a positive refractive and a fourth group (40) following the third group. While zooming from wide-angle end to telephoto end, the second group is moved along the optical axis toward the image side with the first and third groups fixed with respect to the optical axis and the fourth group is moved along the optical axis to perform correction of the image plane position and for focusing.
The first lens group (10) consists of a first lens (L11) and a second lens (L12) being both positive and a negative third lens (L13).
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