It's quite clear we are never going to agree on the validity of the EF-S concept. To me it appears that despite the theoretical advantages claimed for short back focus - about which I'm equally unconvinced - the 3rd party manufacturers are producing lenses as good or better than the Canon models and at a lower price. If Canon were to do the same they would not need the extra complication involved in back-shifting the mirror fractionally and the mirror mechanism would not be quite so loud...

To my mind all the EF-S system has done is add a compatibility issue to a system that was largely free of them (the flash control method excepted) for a claimed 'advantage' that largely does not appear to exist.......