Oh opticians!

On Sun, 24 Apr 2005 21:39:33 -0400, RichA wrote:

How is this possible? We all know how f-ratio is determined,
take the focal length of the scope, divide by the diameter of
the objective and you have it.
But how, (and I've seen this) can a 300mm focal length camera lens,
with a front aperture of about 60mm have an f-ratio of f2.8??
-Rich

Sorry, make that 420mm at f2.8!!!

http://www.wrotniak.net/photo/e10/tcon-300.html