Does anyone else here with a Canon EOS 60D and a Tamron A16E (17-50mm f/2.8 non-VC) find theirs tends to back-focus at 17mm? On mine, I find it's spot-on at 50mm, and I obtain proper focus at 17mm by focusing at 50mm and then zooming back out (using the AF-ON and AE-lock functions).
The 60D has been recently independently calibrated and focuses correctly with my other four lenses (three Canon, one Sigma). I don't think it's anything to do with the 60D's high-sensitivity AF sensor (same behaviour on all AF points, no problems with the 50mm/1.4), or too-shallow-depth-of-field (target's out of focus even with lens stopped down to f/4).
Oddly, the Tamron lens seems to work without problems on my old 400D. (Is there some slight difference in the EF protocol in the newer camera that could be causing this? Some colour-relate quirk?)
