QUOTE(auhckw @ Oct 31 2008, 10:18 PM)
Guys, I'm quite new to all these... Is my below explanation correct?
ISO (Lighting)
-The lower the number the darker it is.
-The higher the number the brighter it is but noiser.
Shuttle (Freezing)
-The lower the number the brighter it is cause shuttle close faster. Close faster can also mean image freeze. Faster Shuttle.
-The higher the number the darker it is cause shuttle close slower. Close slower can also mean image blurry. Slower Shuttle.
Aperture (Sharpness)
-The lower the number the blurer focus on the background.
-The higher the number the sharper focus on the background.
U r right about ISO in general, but wrong about "Shutter speed" (not shuttle, a shuttle goes to space

) and Aperture.
Shutter speed is how long your "shutter" (flaps that close and open to let light into the camera sensor) opens and therefore determines the amount of light that comes into the camera. A fast shutter speed (smaller number, i.e. 1/2000s) can freeze action, but lets in much less light compared to a slower shutter speed.
Aperture on the other hand, is the size of the opening of ur shutter. A bigger aperture (e.g. f/2.0) lets in more light per second compared to a smaller aperture (e.g. f/8.0). And in terms of camera and lens effects, aperture controls "Depth of field" (DOF), which determines how blurry "out of focus" stuff are in ur shot. Whether the background is blur or the foreground is not determined by aperture, but by your "focus distance". Remember that u can blur the foreground and background and keep only the mid range sharp and focused.
So shutter speeds, ISO & aperture are all related to each other in terms of "exposure".
Each having it's own weaknesses and strengths when used.
Increasing ISO increases ur exposure, but adds noise.
Decreasing shutter speed increases exposure, but chances of blurred shots are higher.
Increaing aperture increases exposure, but reduces DOF.
Depending on ur style and the effects u want, u will have to play around balancing all 3 to find ur perfect setting.
Hope my noob comments help!