I've been having an upswing in wedding business, which is great. However, I've come to the conclusion that the while I love my prime lenses, there are times when the zoom is better suited. So I walk into my favorite local camera shop yesterday with the intention of getting some hands on with the fast primes I've been researching - namely the Tamron 15-30, 24-70, and 28-85 f/2.8. Why Tamron? Quality to price ratio... And it is what is in the budget for me at the time. So, I'm looking at the 15-30, and this thing is monstrous in size. Big, fat, heavy.... But the price you pay for the optic quality it provides. I'm wanting to use this on the Df, and it doesn't feel right, plus there price is out of range. I start looking at the other 2 Tamron lenses and the guy helping me and, "Any reason you are not considering the Nikon 24-70?". I explain to him my price ceiling, and he responds. " We have a generation 1 used in the back!" My ears perk a little... But then drop down again... It's probably out of the price range as well. I ask anyway to see it. It has such a good price on it, then I traded my Nikon 24/2.8 and Tamron 90/2.8 primes for it and got it for a great price. So now I've got the 24-70 and the 80-200 f/2.8 primes to round out my Nikon kit. Went right from the camera store to the Columbus Zoo. Very happy with the wide open performance in low light, both in AF speed and sharpness. Gotta say, I'm glad I ran into this deal.