Field Curvature Or Why Not Everything That Should Be In Focus Is Sharp
Up front let me say “field curvature” is not that pesky problem where images with straight lines in the frame seem to bow in or out as you move towards of the corners, that would be distortion, which comes in two core flavours, barrel and pincushion, with moustache as a somewhat recalcitrant but rare third option. There is a relationship between distortion and field curvature, but we won’t be getting into that in this article....