lentil.translation_defocus(mask, f_number, translation)[source]

Defocus error characterized by a axial translation.

  • mask (array_like) – Binary [0,1] mask defining the pupil extent to compute the wavefront over.

  • f_number (float) – System or beam f-number.

  • translation (float) – Axial translation from best focus given in the same units as the resulting OPD.


wfe – Focus error due to axial translation

Return type



Defocus is computed over a circular pupal defined by the maximum horizontal or vertical extent of the supplied mask before applying the mask. As a result, the RMS and peak-to-valley wavefront measurements of the returned OPD will be different than what was requested for non- circular masks.