"...I've read posts that say they will work, they won't work, and they CAN work."
Your question needs a caveat. They may mount and they may work but are they worth using. Some older lenses have been significantly upgraded with newer design that produce much better photos. Just because it mounts on your camera doesn't mean it is a good lens.
EB
EOS 1D, EOS 1D MK IIn, EOS 1D MK III, EOS 1Ds MK III, EOS 1D MK IV and EOS 1DX and many lenses.
