3 ms·
There are good technical reasons for it: https://en.wikipedia.org/wiki/Petzval_field_curvature https://en.wikipedia.org/wiki/Petzval_field_curvature
by cma 6y ago
There are good technical reasons for it: https://en.wikipedia.org/wiki/Petzval_field_curvature https://en.wikipedia.org/wiki/Petzval_field_curvature