Canon Rebel xti and I was happy with my Sigma kit (18x50 & 55x200), that is until I put a borrowed Canon lens on that puppy. Images so crisp they remained so until 300% in ACR. I loved it.
I use a tripod 95% of the time and mainly do mountain landscape and the occasional critter that jumps out of the woods. I figure the range I had will work, maybe bump it up to 300mm, still using a pair of lenses. I should point out that my pockets aren't that deep so be gentle with your advice. Used doesn't hurt my ego.
So, will Tamaron glass give that crisp image or do I have to stick with Canon, or ??