Here's another thought related to Rich's question. Think of the eyepiece as a loupe or magnifying glass (since that's really exactly what it is). The objective forms an image at the focal plane, the eyepiece magnifies that image. If you've ever looked closely at loupes, then you've noticed that the higher the power, the smaller the diameter of the lenses, for the reason (F-ratio) already discussed. And what are considered to be the highest-quality loupes? Those using triplets, essetially an orthoscopic eyepiece! The single element in orthos is typically used to increase AFOV by shortening focal length. It's the triplet that does all the work! C. __________________________________________________ Do you Yahoo!? Yahoo! Mail Plus - Powerful. Affordable. Sign up now. http://mailplus.yahoo.com