| 摘要 |
The invention concerns a zoom system, having various materials (glass types) and variable air spaces, for example for a surgical (stereo)microscope, constructed from four symmetrically arranged lens groups (2 through 5), each two lens groups (2, 5; 3, 4) being arranged identically and in mirror-image fashion with respect to one another. As a result of the special selection of glass types having anomalous partial dispersion, and the specific design features, a high zoom factor is achieved with a short overall length, as well as good correction of the secondary spectrum, astigmatism, and field curvature.
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