Hehe bro. Some corrections. Actually, The lens is sharp from 17 all the way to 70mm. I was saying that the F2.8 is only applicable till max about 19mm only. Hehe.Hey finally! I've been reading how convenient this lens is, it is sharper than the 18-200 VR apparently but as you said only at those ranges. However, I've also been hearing how most people have upgraded to the 17-50. I'd like to seek other options to the Tamron which is why I'm looking at this Sigma.