What is exposure and how do I set my exposure?
Good question! According to the dictionary it is how much light reaches the photosensitive surface inside your camera. Says a lot, huh!?
Actually what it means to you is, that is how dark or bright your picture ends up. When it is right your photo looks natural. Underexposure is when your picture looks too dark and overexposure is when things are washed out.
As for how you set it; in any program mode your camera automatically sets it according to choices you make.
While in a program mode, the only time you have to worry about exposure is if your pictures are consistently coming out too dark or too light. In that case go here for an adjustment.
There are generally three possible settings available for your camera to decide how to expose a given shot. The exposure adjustment is known as light metering. Each metering setting covers a different area of your viewfinder when the camera is deciding the correct exposure.
When in the matrix (full screen) setting the camera uses the lighting in your entire viewfinder to decide what exposure is right.
In center weighted metering your camera uses approximately the center third of your viewfinder to decide.
In spot metering the camera just uses a tiny part in the center of your viewfinder.
The camera will expose your shot based on the lighting within the specific area you have chosen as your metering area. It ignores the lighting in the rest of the picture.
When you use a point & shoot camera you usually have a screen on the back of it which you can use as you take a picture. You can see how the camera is metering before you snap the picture.
As you move the camera around, the screen will get darker and lighter. This gives you the opportunity to see how your picture is going to look even before you shoot it.
You do not have this luxury with a DSLR. Using a DSLR you will have to take the shot, then go into playback mode and see the result. With a point & shoot you just verify what you saw.
"Exposure" is 2 pages.