Tamron 18 - 270mm wide angle focus problem

See here:

http://forums.dpreview.com/forums/readflat.asp?forum=1034&message=35681364&changemode=1

PDAF is generally not very reliable at wide angel if you want critical sharpness, regardless of maker. The tolerance for "in focus" is fairly relaxed at wide angel. Superzoom lens are even more complicated because of their focal range and focus breathing at close range.

These problem has always existed, it's just your average superzoom lens user are not critical enough to see the difference.

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