"ISO 12233 resolution chart results have been added to the Tamron 24-70mm f/2.8 Di VC USD Lens Review page.
Before making your purchase decision, I encourage you to wait for me to spend more time evaluating the Tamron 24-70mm f/2.8 Di VC USD Lens' AF performance. Neither of the two lenses I have autofocus accurately on the test chart using a Canon-calibrated EOS 1Ds Mark III. I will minimally test the second lens behind a second calibrated 1Ds III and a 5D III."
The corners do not look good at all... Even if it is a bad copy issue, two out of two is not very encouraging... Let's hope it performs better on the other bodies on which it is going to be tested...
So does this guy get paid by Canon to review pictures?
Or receiver sponsorship from Canon?
Free services from Canon?
The reason that I ask is that the above comments are pretty damning about his understanding of what it means for a lens and camera body to be accurately aligned.
I've had my Canon cameras calibrated by Canon (a service for which I paid for) and I still needed to use AFMA with any Canon lens that I hadn't sent to Canon for simultaneous calibration. So just because a lens has the word "Canon" on it means nothing with respect to its ability to accurately autofocus.
If the above tester doesn't use or understand why AFMA is appropriate and how to use it then you should take that as an indication that the reviewer is not very sophisticated and doesn't know what they are doing.