Noise becomes visible ISO25600 camera still produces usable images.At ISO51200 drop colour saturation , may want use images without processing ( resizing ) .ISO102400 ( Hi1 ) show highest levels noise , well visibly processed image settings may best avoided.There High ISO NR ( Noise Reduction ) options High , Normal , Low , Off.We took default setting Normal.The D780 gives noticeably improved noise performance compared D750 , much better detail higher ISO speeds ( ISO3200-6400 ) , higher ISO speeds ( ISO12800-ISO25600 beyond ) vastly improved.ISO figure noise starts become visible : ISO6400 ISO figure noise overwhelms image : ISO102400 Interested ? Help support ePHOTOzine using links.Amazon UK Amazon US Nikon D850 The Nikon D850 everything could ask Digital SLR , whether want high-resolution images high-speed shooting , , without complaining .