Optics Conventions

• also has a conic constant. 0 = sphere, -1 = paraboloid, <-1 = hyperboloid, >0 = oblate ellipsoid.
• has polynomial coefficients:
  • Array length must not exceed 20th-order term, ie. array length <= 10
  • Trailing zero terms are omitted

Sanity check (light traveling left → right):

• A biconvex lens has R₁ > 0 (first surface bulges toward incoming light) and R₂ < 0 (second surface bulges toward outgoing light).
• A biconcave lens has R₁ < 0 and R₂ > 0.

Thickness

The Thickness in the Lens Data Editor is the axial distance from the current surface vertex to the next surface vertex along +Z.

• Positive thickness: next surface is ahead in the propagation direction (normal case).
• Negative thickness: next surface is behind (used in folded layouts or when reversing the propagation direction).