After I tried one the other day and was unhappy with its one shot centre point AF performance we have done some further testing with the examples available to us.
I'm not going to go into the details of the testing for the pixel peeping fools except to say a variety of lenses and shooting situations were used and experienced professional photographers took the shots.The results were disappointing to say the least and I'm sorry to say that all 4 of the cameras exhibited unacceptable AF performance in both one shot and AI servo modes regardless of settings used. 2 of the cameras were markedly better at one shot AF then the other 2 but all 4 were exhibiting the issues spoken about in AI servo mode.
The issue seems to be the camera not being able to "hold" its focus rather then failing to acquire focus as often it was noted the camera click into focus quite quickly and then after a second or so began to "hunt" for focus again. This happened most often on stationary targets and occurred both in one shot and AI servo mode.

So I've read there are some good , some bad Mk III's with 40% being bad. Well all I can say is we have a 100% dud rate at the moment and I think the AF issue probably applies to all Mk III's.

My conclusion .... yep Canon's got a issue and its serious enough to require some kind of fix to be made available as soon as possible as its the kind of issue that can seriously damage a workflow for a operation like ours when such a large % of shots are OOF.

Our current solution is to use the Mk III only for situations where the opportunity for several shots of the same scene is possible. Not something a so called sports camera should be restricted to.

I am well aware that over the years I've been a unabashed supporter of Canon's DSLR's and lens system and that hasn't changed. The chip in the Mk III is superb and more then capable of producing the finest low noise digital images ever produced from a DSLR and the camera ergonomics and operations have evolved nicely but I'm afraid this AF issue is going to put a stain on what otherwise is a wonderful camera.

Canon needs to fix this issue and fix it fast.

Canon also needs to look at the (new) way its been testing its cameras. If their testing failed to pick up a serious flaw like this then they need to consider their testing methods a failure. The old way would have picked this up months before production began.







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'Stop it now or you will go blind'