I was comparing Nikon's 70-200mm f/2.8 vrii with Sigma's 70-200mm f/2.8 EX DG OS HSM lens on a D610. When I checked out the results of the Nikon lens on a D600, the overall score increased from 27 (D600) to 28 (D610). Why would it be different if nothing pertinent was changed in the D610? Scroll...