The D850 offers similar performance , compared Sony Alpha A7R Mark II , also features full-frame high-resolution BSI CMOS sensor.ISO figure noise starts become visible : ISO12800 ISO figure noise overwhelms image : ISO51200 Interested ? Help support ePHOTOzine using links.Amazon UK Amazon US Nikon D6 The Nikon D6 flagship DSLR Nikon professionals , size , speed , battery life toughness ideal Nikon users.Noise performance impressive , clean images ISO3200/6400 , even ISO12800 showing excellent results , although fine detail lost.Some noise starts creep ISO25600 , 's well controlled.ISO51200 give usable images , depending needs.ISO102400 could potentially useful likely need processing.At higher ( Hi1 - Hi5 ) speeds noise strong ( weird ) , speeds best avoided.Noise reduction options Off , Low , Normal , High , taken camera default setting Normal .