ISO51200 best avoided images lose colour saturation , noise becomes excessive.There options Low , Standard High noise reduction.We took photos Standard setting.ISO figure noise starts become visible : ISO6400 ISO figure noise overwhelms image : ISO25600 Interested ? Help support ePHOTOzine using links.Amazon UK Amazon US Canon EOS R3 Big , beautiful ready kind photographic assignment , Canon EOS R3 tackle job environment , efficiently reliably.The ISO range much greater many older Canon cameras , offering basic range ISO 100-102400 , expandable ISO 50 and204800.Where noise levels become problem individual judgement , ISO 3200 images clean sharp.ISO 6400 12800 still quite usable , albeit bit noise starting creep in.ISO 25600 sees contrast suddenly dropping noise taking gradually , beyond things pretty much lost cause .