a Sigma or nikon?
I have a nikon d80 camera which I'm looking for a new lense. I think I narrow it down to the Sigma 70 200mm f/2.8 or nikon 80 200mm f/2.8. I take pictures of high school football and basketball for the coaches. I am using nikon 85mm f/1.8. Confused, which one is more suitable for me, any suggestion?