Can someone give a simple explanation to the AV, TV and ISO stuff.
I'll admit I'm still a newbie to this great camera, myself, but I'll post what I know and maybe other posters can fill in the blanks....
The main modes of the S3 are the P, Av, Tv and M.
P is for Program AE; it's very nearly the same as Auto, but it allows you access to the other customizable features like MyColors, Exposure Compensation and lots more (all of the options that come up when you press the Func button). In P mode, the camera automatically picks aperture, shutter speed and ISO (which you can change with the ISO button).
Av is for Aperture Priority. Setting the Aperture allow more or less light into the camera at each exposure; larger numbers mean smaller aperture. The wider the aperture, the faster the shutter speed should be. Setting wider apertures is what gets you the distinctive solidly-in-focus subject with blurred background typical of a good DSLR portrait. That blurred background is usually called bokeh (it's a Japanese word). When you use this mode, you set the aperture and the camera sets the other factors to match what you're focusing on. Controlling the aperture allows you to control the Depth Of Field; or how much of the subject is in perfect focus.
Tv is for Shutter Speed Priority. The faster the shutter speed, the more capable the camera is of freezing motion. Slow it down for darker pics, speed it up for lighter pics. Really, really slow (in the 5-10 second range) is for maximum low-light sensitivity (like my picture of the candle-lit glass, above). When you set the Shutter Speed, the camera will choose the other settings to match.
M is Manual, and you set everything yourself.
Changing ISO is for capturing higher speeds or lower light ... the higher the ISO, the more sensitive but the more grainy (or noisy). On most digital cameras, even one as good as the S3, keeping the ISO as low as possible will result in smoother/cleaner pictures. Most bad photographs people take with the S3 is the result of letting the ISO get too high (in Auto mode) without knowing that it's happening.
You start seeing noise in your pictures at ISO 400 and sometimes ISO 800 is awful. ISO 100 and 200 is fine for daytime pictures. If you're unsure which to use, let the camera choose for you in P mode, rather than Auto. If you find out that you *really* need high ISO settings, you'd be best getting a DSLR ... it's one of the many things they're very good at.
I'm still learning what combinations work best under what conditions and I expect to be learning a lot before our trip later this year....
