StaaleS
Established
For the record:
Canon XXXD/Rebels and XXD and the new 7D have a crop factor of 1.6
Canon 1D, 1D mk II, 1D mk III have a crop factor of 1.28
Canon 5D, 1Ds, 1Ds mk II, 1Ds mk III have full-frame 35mm sensors. No crop factor.
The 1D and 1Ds series, 5D, 7D, 40D, 50D have user-replaceable focus screens and Canon sells a variety of screens for them - the 1D/Ds have a greater selection of screens than the others. Other models do not have user-replaceable screens, as such, but the only practical implication of this is that the release latch for the focus screen is a bit more fiddly to access. The screen can still be replaced, but of course Canon does not offer anything except the standard matte for them.
Canon XXXD/Rebels and XXD and the new 7D have a crop factor of 1.6
Canon 1D, 1D mk II, 1D mk III have a crop factor of 1.28
Canon 5D, 1Ds, 1Ds mk II, 1Ds mk III have full-frame 35mm sensors. No crop factor.
The 1D and 1Ds series, 5D, 7D, 40D, 50D have user-replaceable focus screens and Canon sells a variety of screens for them - the 1D/Ds have a greater selection of screens than the others. Other models do not have user-replaceable screens, as such, but the only practical implication of this is that the release latch for the focus screen is a bit more fiddly to access. The screen can still be replaced, but of course Canon does not offer anything except the standard matte for them.