I have been waiting to get a diigital back for my contax money being the issue.I ahve been thinking of getting rid of my contax with a35 55 80 and 145 lenses for a sony a900 with a few sony zeiss lenses. I have a full canon system and a leica M9 system. The canon lenses 16-35 and 24-105 are the ones most likely to be supplanted are the zeiss 24-70 and 16-35 much better then the canon? Are the corners sharper then the canon lenses. Also thinking of the 70-400 witht he is built in might be a nice lens. Is it uch better then the canon 100-400 which I had and did not like. PS I hate the 5d mk11 autofocus and that is my only full frame body.I have 1d mk 1v bodies which are very nice but heavy. Thanks in advance
David
David