This has been a good and informative read, thanks guys for promoting the knowledge base! I have a Minolta 50mm 1.7 I got from some guy on here, and wow it is a great lens!, and so far my only prime, got to work on that. I have been very pleased with my tamron's so far, but as that is what I started out with I don't really have much to compare them against. The 17-50 is a very nice lens and has great color I think, it's a little to short for alot of what I do, but i am trying to learn to use it more. The Tamron 70-200 is amazing, but at soccer and football when the lights come on I do find myself saying I wish it would focus faster.