On my P&S (C**n) it works like this:
AUTO ISO gives you ISO 50 unless you use flash and the subject would be out of range for proper illumination. In this case it will increase ISO to the necessary value to get a properly exposed shot.
The one exception is when you set the camera mode to "Fast Shutter" - here AUTO ISO will alter the ISO speed in order to give you a hand-holdable shot shutter speed.
Bruce Dayton wrote:
So instead of just altering shutter speed or aperture, the camera may change the ISO value instead. My opinion is that this kind of feature is something that you would see on a P&S rather than on a more sophisticated camera. One who is in control of metering and exposure probably wouldn't welcome the behavior. On top of that, Pentax made it the default setting.
