Well i picked up mine earlier today and so far am pretty impressed it.I was testing it against my 100-400 and must say at 400mm wide open they're very close. Granted ill have to do some more controlled test but heres a shot taken indoors wide open@400mm. Can you guess which lens?
Canon on the right.
After owning multiple Tamron's and comparing them to the BEST Canon lenses I can now clearly pick out the Tamrons color vs the Canon.
No brainer on this one.
EDIT: Now they are stacked on my quote. so should be the BOTTOM is canon. Much better colors.
EDIT: exposure is off on both. I take it back and canot really predict. Top is darker bottom is brighter. Not fair comparison