Johnson R B
Appl Opt. 1993 Jul 1;32(19):3494-6. doi: 10.1364/AO.32.003494.
When all aberrations are absent other than third-order astigmatism and Petzval, it is demonstrated that selection of a flat tangential astigmatic field is optimum if the smallest maximum spot size is desired over the entire field of view. With balanced sagittal and tangential fields the spot size is observed to be smaller than the flat-tangential-field case until the field angle reaches √? of the full-field angle. Comparisons of the spot sizes and shapes for these cases and the flat-sagittal-field case are made for flat and optimally curved image surfaces.
当除了三阶像散和匹兹伐尔像差外不存在其他像差时，结果表明，如果希望在整个视场中获得最小的最大光斑尺寸，那么选择一个平坦的切向像散场是最优的。对于平衡的弧矢场和切向场，在视场角达到全场角的√?之前，观察到光斑尺寸比平坦切向场的情况要小。针对平坦和最佳弯曲的像面，对这些情况与平坦弧矢场情况的光斑尺寸和形状进行了比较。
