For lowest noise best detail possible would recommend using ISO64 ISO3200 , images low levels noise good levels detail.Noise extremely low , n't really begin show reach ISO6400.ISO32 shows lower dynamic range.For lower light situations ISO6400 ISO12800 still provides good results , although noise increases detail reduced.ISO25600 still shows usable results , good noise control , depending intended use.At ISO51200 noise levels become strong would recommend avoiding setting possible , colour saturation drops , although results may still useful resized used web.ISO102400 best avoided noise highest high.Noise reduction options available Off , Low , Normal , High.We took photos using default setting Normal , users previous Nikon DSLRs may want reduce Low , default setting quite strong noise reduction.The D850 gives improved noise performance , compared Nikon D810 , whilst also giving increased resolution .