Ok Gang got a question . Here in the near future I will have about $1500 for a new lense. My camera is a Nikon D5100 that I like a lot. I don't plan on going full frame ever but might upgrade to a 7100 in a year or so. I mostly shoot wildlife and some road racing. The lenses that have caught my eye are Nikon F4 70-200 $1396 or maybe one of the aftmkt 70-200 f2.8's like the new Tamron at the top of my range. Would you trade the light stop difference for the Nikon lenses quality?? Any other ideas are appreciated.