Hi Zemaxers,

I am trying to understand a non‑paraxial optical system.

The system is a decentered lens, and I would like to determine its focal length and the chromatic focal shift.

My current understanding is that, since the system is non‑paraxial, even the “paraxial rays” need to go through the coordinate breaks. I tried this approach and obtained the results shown below. However, I am having difficulty interpreting them.

In particular, I am unsure how to evaluate the chromatic focal length shift in a non‑paraxial system.

As the software states: “This plot may not be meaningful for non‑paraxial systems.”

So I’m not sure what the correct method is.

Can you kindly give me some advice on these issues?

btw here,  Analysis...PAL/Freeform...Pupil Map  suggested by @Mark.Nicholson

https://community.zemax.com/got-a-question-7/non-paraxial-focal-length-3672

I am not sure is it similar to my issues?

best regards 

Yang