ISO has nothing to do with exposure. It digitally brightens the image after it is taken and applies it to the RAW or JPG file. Most, if not all, mirrorless cameras can "simulate" the exposure with ISO applied before you take the picture; hence, the reason people still tend to think ISO is part of the exposure.
True! It’s worth talking about though. I can’t tell you how many photographers use auto ISO and then think their camera sucks because mid-day images are noisy.
