Noise low ISO40 way ISO1600.At ISO3200 noise still low , fine detail reduced slightly.At ISO6400 noise still low , another reduction fine detail.At ISO12800 noise becomes noticeable , fine detail drops.Detail drops ISO25600 noise increases.However , level detail still considered relatively impressive , giving slightly better results 20mp FF sensor found Canon EOS-1D X Mark III.As well detail reduced ISO51200 , colour saturation also drops.Noise strong ISO speeds ISO51200.ISO409600 best avoided entirely.These shots taken default settings noise reduction.ISO figure noise starts become visible : ISO25600 ISO figure noise overwhelms image : ISO204800 Interested ? Help support ePHOTOzine using links.Amazon UK Amazon US Sony A9 II The noise performance A9 Mark II good , good results , usable including ISO6400 .