I've birded most of my life with glasses including full time sunglasses as well as the photograys/transitions/whatever. I've never had any problem mainly because I don't worry about color matching - I'm looking at patterns of light and dark. But with that said, I don't see any noticeable shifts in colors or picking out colors. And that's across four continents in all kinds of light conditions!
+++++++++++++++++++++++++++++++++++++++++++++++ Chuck & Jaye Otte mailto:<otte2...> 613 Tamerisk Junction City Kansas USA 66441 785-238-8800