Hello,

            I am using the extended polynomial to create a lens and am trying some simple optimization.  I noticed that the radius of curvature and focal length are not matching up as I would usually expect; focal length should be *roughly* twice the radius of curvature.  I am wondering if I am looking at the analysis incorrectly?  I used the EFLX and POWF operands and they seem to agreed with the analysis windows and EFFL.

A plano-convex lens focal length using a material with index 1.5 would normally be twice the radius of curvature as a first approximation.  So does optimizing the polynomial surface change the focal length that much compared to the radius of curvature?

Thanks in advance for the advise.