The fly in that ointment is future compatibility, particularly with AF systems. Doesn't matter for Zeiss, of course, and Sigma's Dock is a great solution. But what about Tamron and Tokina? Tamron was impacted not too long ago, several of their lenses including the popular 17-50/2.8 were found to activate the 8 off-center cross-type AF points of the 40D/50D/60D/7D as single-orientation lines instead of crosses. I don't know if that issue also affects the subsequent bodies that inherited those AF systems (70D/T4i/T5i). Canon acknowledged the problem, which affected some really old Canon lenses from which Tamron 'borrowed' the LensID code, but they didn't say they fixed it, AFAIK. They may not have seen a need, certainly not for Tamron's benefit.





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