I know that it is possiblel to set ISO values as low as 1 via CHDK override menu but that the actual ISO value used by the camera will not go lower than a certain value. Does the original camera firmware know what this is? What I mean is that on my Canon G9, when I set an ISO value of 20 via CHDK menu, for example, the camera diplays a native ISO of 32 (i.e. it always displays an ISO value, even without CHDK upload but I was surprised to see that it showed this lower value). Does this mean the camera is working at ISO 32 or is it just confused and the lowest ISO possible will ber determined by something else?
Thanks for any help and I hope my question makes sense!