ZDC thanks Eddie Judd of Davin Optronics for many useful discussions, and Robin Hull, also of Davin Optronics, for permission to use his test image in this article.

Imagine you were tasked with designing some imaging optics for a customer who was not an optics specialist. You may produce three designs: a singlet, a doublet, and a 5-element eyepiece. Each design has its own price/performance point.

Now, your customer understands price very well: but how do you communicate things like vignetting, field curvature, astigmatism etc to a non-optics specialist? The Geometric Bitmap Image Analysis (GBIA) feature in ZEMAX is extremely helpful in showing customers what images will look like when you "look-through" the built lens. It communicates far more directly than ray-fan plots and the like.

A note on Versions: the GBIA feature has been in ZEMAX for many years. However, the August 2006 and subsequent versions benefit from a greatly improved sampling algorithm that gives results with better signal/noise ratio for fewer rays traced. This article was written with the August 2006 release. Users of earlier versions will be able to get the same results, but will require substantially longer time to do so.