Independent check of ghost-path enumeration on 10 lens designs

Challenge

Standard sequential ghost operands cannot model a reflection between a lens surface and the sensor. A sequential ghost-path enumerator still has to match OpticStudio on the paths both methods can see.

Approach

An independent ghost-analysis tool enumerated two-bounce ghost paths on the same 10 imaging lens prescriptions used in Zemax OpticStudio. The designs ran from a singlet through a 100° wide-angle and a zoom. Custom programs and scripts compared the path lists and the ghost-focus positions.

Result

The check enumerated the same two-bounce ghost paths as OpticStudio on every design, about 450 paths in all. The largest ghost-focus position difference was under 0.2%. Lens-to-sensor reflection ghosts ranked in the top 5 on 9 of 10 designs.

Key figures

• ~450

  two-bounce ghost paths matched to OpticStudio on every design

• <0.2%

  largest ghost-focus position difference versus OpticStudio

• 9 of 10

  designs where lens-to-sensor ghosts ranked in the top 5