I use the 500D and the reason I chose it over extension tubes is that I use it with a zoom lens. I was told that zooming with an extension tube completely messes up focus, while zooming with a diopter changes focus a little, but not much, and mainly changes the magnification.
Check out this comparison of extension tubes and diopters. (http://people.smu.edu/rmonagha/mf/diopter.html#beat) As someone pointed out, extension tubes place the lens out of the normal focus range and magnify the aberrations of the lens. Thus, this test found that diopters were better, though there is some debate on that page over these conclusions. Tom D * **** ******* *********************************************************** * For list instructions, including unsubscribe, see: * http://www.a1.nl/phomepag/markerink/eos_list.htm ***********************************************************
