Sometimes you have to understand F-stops, shutter speeds, and ISO to get good photos, but great photos comes from the person behind the camera.

Here's an example, say your shooting at full telephoto of 560mm and you want a sharp/non-blurry shot. You would look at the shutter speed and hope that it's at least 1/500th sec or else you'll have to rely on the IS, which you could probably get by with 1/125th sec shutter speed. If the camera is choosing a shutter speed of 1/60th of a second then you will have to open the aperture until you get the desired shutter speed or kick up the ISO until you get the desired shutter speed.

The auto modes are not mind readers and base the suggestions off of general rules and not applicable to many situations.

Low light on stage is pretty much a crap shoot for almost any point and shoot. You can pretty much forget superzoom cameras for that. Even with a DSLR, a person has to buy expensive lens to get those shots.

If you want the most zoom in a point and shoot that does very good in low light, for a point and shoot, then look at the Canon G11. It's telephoto range only extends to 140mm, compared to 560mm for the SX20, so it'll zoom to less than 1/3rd the distance that the SX20 could, but the sensor is much better in low light and the lens has a larger aperture.