Since Woodward’s ambiguity function contains all the optical transfer functions with varying focus error, it can be applied to display visually the tolerance to focus error. We compare the tolerance to defocus of a transparent but finite extended pupil and a pupil with a central obscuration.
© 1984 Optical Society of America
H. Bartelt, J. Ojeda-Castañeda, and Enrique E. Sicre, "Misfocus tolerance seen by simple inspection of the ambiguity function," Appl. Opt. 23, 2693-2696 (1984)