Well we can agree to disagree. My markIII, and the markIII\'s of many people work just fine. Internet banter is a small sampling of real life at times.
No, what you have is a camera under which the conditions you shoot doesn\'t show the problem - nothing more.
I have tested over a hundred different Mark IIIs from colleagues who say they don\'t have the problem and I have been able to replicate it for them after a day of shooting.
Ship me your Mark III and I\'ll prove you have a flawed camera too. If I can\'t you can have my 600/4 IS.
You\'re right about internet banter: except that it\'s working in reverse for you - the banter is from people who claim their camera is fine.