Originally posted by dwssas I am looking for opinions on the reliability of auto ISO. I would use the 200-800 setting. I believe the ability to use exposure comp. would be lost in this mode. Are there any other downsides to it?
On the K100D, you mean?
The AutoISO is part of the same exposure calculation as shutter speed and aperture, so it's as accurate as the rest of the camera's programmed exposure. (Which is to say, good enough in normal use.)
In my experience, it does a good job of balancing all three variables to keep shutter speed decent and still give you a reasonably low ISO. In fact, good enough that I had no qualms about putting it to 200-1600 (with the viewfinder warning at 1600). Better to get an ISO 1600 shot that works than a too-blurry ISO 800 one.
You don't really "lose" the ability to use exposure compensation, but rather, when you activate any EV + or -, the AutoISO is disabled and you're stuck into 200. (The K10D doesn't have this, er, "feature".)