thanks , that would have been an easy solution - but the problem is, the 12-24 works well on bright days and even on dim lit areas when shooting from a far,
its when the subject is close and dim that it happens and it still focuses sharp every so often - so, its not just an AF micro adjustment issue -
while im on this - i just thought about using my 5D2 and 1D2N for the 12-24 and see how it goes.
theres some new issues that my 1DX has given me as well, including the new 600RT
i noticed that when using the 600rt on camera as master paired with a couple of 580ex's that some feautures will make the 580ex not function properly. sometimes, i noticed the 580 would change settings to strobe mode on the back of the lcd.
although this is not scientific tests by any means - i have noticed irregularities in operation compared to the purely 580ex setup without mix flashes (600rt)