What the camera may or may not be good at is deciding what the subject IS. The problem is, a lot of times you want to compose a picture in an interesting way, where the thing that has to be most sharply in focus is not at the center. For example, a picture of a person with something in the background is often more interesting if the person is off to the side rather than smack dab in the middle. But the problem is, the camera usually wants to focus on what’s in the middle. Even SLRs. If you just compose the picture and then press the button, the person (or whatever is the important thing that really should be most sharply focused will be out of focus).

The solution to this is simple. First, point the camera straight at the person (or at the thing that should be sharply in focus). Then, half-press the shutter button. The camera will focus on the person (or whatever). When the camera is focused, it will usually give you a little green light or a beep or something. Now, keep that button half-pressed, because if you take your finger off the camera will just re-focus when you press the button again. Now, re-compose the picture (point the camera in a slightly different direction so that the person is now a little off to the side).