Optical System Design-Fischer,Tadic-Galeb,Yoder Page 44 Fig3.7? 1

[Agent739]

I am just trying to interpret the illustrations correctly...what are the small circles at what appears to be the focal point in the lower three lenses supposed to represent?Is it entrance pupil?

 

[IRstuff]

It's in a section on Diffraction Limited Imagery.

The text below discusses the variation of the blur circle with respect to f/number. However, the figure shows 3 lenses with identical diameters, so you should be able to complete the thought here...

TTFN

FAQ731-376