与分析窗口相比，FCGS和FCGT的值更稳定。

这在 The Analyze Tab (sequential ui mode) > Image Quality Group > Aberrations (Image Quality Group) > Field Curvature and Distortion 提到：Strictly speaking, the field curvature and distortion plots are only valid for rotationally symmetric systems with plane object and image surfaces. However, OpticStudio uses a generalization of the field curvature and distortion concepts to give reasonable results for some, but not all, non-rotationally symmetric systems. Caution should be used when interpreting these data for non-rotationally symmetric systems or systems with object and/or image surfaces that are not planes.

FCGS和FCGT对非旋转对称系统有更合理的结果。

如果系统是旋转对称的，FCGT和FCGS操作数数值跟分析图列出的那些值一致。以库克镜头为例：