I've read that the ISO adjustment on a digital camera just ups the gain, like turning up the volume on a radio, and has the same effect of increasing noise along with volume. Someone suggested an alternate way, that is to just underexpose however many stops instead, and then correct the exposure in post processing (raw conversion I believe). The point was that the M8 is so good at picking up shadow detail that it is recoverable even if underexposed several stops. I tried it just once, with mixed results, but probably because I'm not very skilled at doing it. Would be curious to hear from someone who really knows how to do it, if it looks better than shooting @ high ISO and then fussing around with Noise Ninja and others.