| 摘要 |
A wide-angle zoom lens is disclosed having five lens groups of negative, positive, positive, negative, and positive refractive power, respectively, in sequential order from the magnification side. The first lens group is fixed during zooming and is formed of first and second subgroups, each of negative refractive power. Each subgroup moves relative to the other subgroup, as well as along the optical axis, during focusing. Further, the second, third and fourth lens groups are each moved along the optical axis such that the spacing between these lens groups varies for zooming and correction of what would otherwise be excessive curvature of field caused by zooming, and the fifth lens group is fixed during zooming. Various conditions are satisfied so as to favorably correct aberrations, provide an image angle of about 70° at the wide-angle end, and provide room on the reducing side for the insertion of a beam-combining prism.
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