ok i will admit i dont fully understand ISO and i stil shoot jpeg! I will be honest when i change the ISO i notice little or no difference in the exposure. I comprehend aperture , shutter etc but the same shot on various iso's seem to make little or no difference..why is this? Also i notice when i set my io to say 200, on the exif data on my camera the iso reads 1600, in red text? I can assume that he shot is 200 becaus there is no noise so why does the readout say a another iso to that i have set?