First Looks at Tamron 24-70mm f/2.8 Di VC USD Lens Image Quality

ISO 12233 resolution chart results have been added to the Tamron 24-70mm f/2.8 Di VC USD Lens Review page.
 
I have two of these lenses right now. Unfortunately, the first lens I received needs to go back.
 
After spending 10 hours or so completing testing the lens on the ISO chart, it became clear that the lens was not working properly at the longer focal lengths. Image quality was unacceptable at 70mm. Tamron confirmed that the results were not as they expected.
 
The second lens performs much better optically. These are the results now presented on the 24-70 VC 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.
 
Stay tuned for more information.