Yes, it should be weakest at the 28mm end but even at 28mm I have no complaints.
Very low CA overall and for such a lens nice that it is optimized at the wide angle end. I have the 24-70/4 S which I could switch to if I need to take a lot of 28mm pictures.
I think many discard this lens because it is a Tamron design?
The lens handling is very good. I like that it has internal zoom. The 24-70/4 has not

but the new 24-70/2.8 II has
