Quote Originally Posted by Fouad
Bryan's fine description of these two lenses leaves me not sure as to which of these two may have the better image quality, even if by a small margin.

That's easy. 300mm f/2.8. The ultimate test of any lens is astrophotography. Lenses like the 200mm f/2 which seem pretty sharp for daytime use begin to reveal serious flaws when they try to focus a single star into a point. Here one such review of the 200mm f/2 (scroll down):


http://www.welsh-house.net/andy/review200f2.html


The 300mm f/2.8 does a bit better. But as others said, the difference is so small for daytime photography that no one (in practice) will be able to tell the difference.