>>3473354>but the FF sensor can really be helpful above 3200 ISO, I almost saw no noise in AC's picture. Her skin tone and skin texture is also pretty good for the iso.I think you're probably just overestimating the amount of noise that cameras in general have in that ISO range.
Pic related--crop sensor, also at ISO 5000. You can see the noise in the shadows (e.g., the dark parts of the suits and the hair), but the skin is bright enough that it doesn't show the noise that much at all, especially at web resolutions. If you were to zoom in to 100%, you could definitely see noise a-plenty, but resized for 4chan looks pretty clean.
People are more afraid of high ISO than they should be.