The higher the ISO the more noisy the shot becomes

; DX sensor bodies are smaller (since the DX sensor is smaller than the FX sensor) but their images are more noisy than that of and FX body-Noise is when a picture looks like there are grains of sand on it or white particles.(Noise is genernally unpleasant)-ISO is light sensitivity

Even at that very high ISO, noise is acceptable (compared to no picture or being forced into flash when you don't want it)