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I have an asphere lens setup in NSC, and want to see the effect of adding an astigmatism to the lens. The only way I see is to use the biconic Zernike surface with all Zernike coefficients set to 0. When enter the lens prescription into the aspheric surface or Zernike surface, I get the correct results. As soon as I switch to the biconic Zernike the results look incorrect. Any ideas on why they do not match?
 

Spot at 100mm

 

Hi Chris,
 
I already emailed you the response, but I post it here as well in case other users come up with the same question.
The Biconic Zernike Surface is described by the following sag equation:
 
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which is not necessarily the same as the Aspheric surface sag given the higher order aspheric terms (X^4 and Y^4 in your model):
 
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This can be seen by superposition of the two surfaces in the 3D Layout:
 
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That's why the illumination patterns are different with Biconic Zernike and Aspheric Surfaces.

Best regards,

Moj


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