Point-and-shoot, lets face it, is simply that. The camera actually its manufacturers does most of our thinking for us. We are told that thousands of images have been analyzed and choices have been made ... for us. This is a bit like having the person who cuts your hair choose the style for your next cut. After all, they are the experts; they do it for a living.
When we graduate from P&S, or even a camera-phone, to the next level, generally called compact, we can choose our hair style. Somewhere on the camera the series of letters, P, A, S, and M, appear. They will show up on a dial, on a screen, or even a series of buttons. Lets consider what opportunities they present.
In this case the letter P stands for Programmed and is much like the mode of operation of a P&S camera. Given that you have set the ISO (like film speed) somewhere else, the camera chooses the combination of lens opening and shutter speed to cover most general situations. Many of us should set the camera there and only change it for situations when we want to take control.
The next letter is A which stands for aperture, the f number that tells how wide the lens is open. The smaller the number, the wider the opening. With a wide opening we can soft-focus the background to concentrate attention on the subject. We can also prompt the camera to pick a faster shutter speed to stop action. In auto-exposure cameras, virtually all cameras today, you pick the aperture and the camera responds by setting the shutter speed.
The converse is also true. Select S and you will have to pick the shutter speed. If you want to stop action, as in sports, pick a faster speed (higher number). If you want a blur, as in flowing water, pick a lower number. Most people can steadily hand-hold a camera at any speed of 1/100 of a second or faster with a normal, not telephoto, lens. Remember that longer (telephoto) lenses magnify camera movement, so move the speed up a notch or two for a sharp image.
Lastly, for the control freaks among us there is M for manual. In this mode the photographer picks both the shutter speed and the aperture. These choices can be aided by the use of an external light meter or the use of the cameras sensor to perform the same function. Since we can see the results immediately on digital cameras, this can be a trial and error process.
Try each of these modes in advance. Then youll be ready to take control.