I take digital hockey photos with a sony 717 and have moderate success. This is for my boys' hockey teams. The most I ever enlarge is 8x10. My question is: I have nikkor lenses for my slr system and want to purchase a d70 for digital pictures; is the sigma 70-200 f/2.8 good enough to take good quality pictures with the d70? I don't want to spend the bucks for the nikon vr lens, or a used 80-200. I will be shooting at 1600 asa.