On axis, the reference sphere is just a perfect sphere with radius equal to the exit pupil position, which you can get via EXPP. The ‘Wavefront’ of the system, is the real wavefront at the EXPP with the reference sphere subtracted.

Off axis this definition is much the same but there is some complexity due to the tilt aberration. OpticStudio uses the tilt-removed reference sphere, which gives the physically meaningful wavefront that controls image quality. 

• Mark

Hi Mark,

Thank you very much for your answers.
Then can I obtain the optical path data of the reference sphere on the exit pupil surface in any way, including on-axis and off-axis?

Sincerely 

Nancy 

Hi Sandrine Auriol

Thanks for your reply! The File really work for me！I love you so much！

Sincerely 

Nancy 

Thank you!

Hi Sandrine Auriol

Thanks again for your file！ I found that I still have some questions about this file: Are there any practical uses for the optimized operands OPDM and OPDX, why and how to calculate them? Actually I cannot fully understand the explanation of these two operands in the help manual.

Best，Nancy