An image of a camera viewfinder

The viewfinder and rear screen (in live view) of your camera will look similar to this. Using the Disp or Info button (dependent on camera) will display other types of information, but these are the most important.

Some cameras may not have an exposure meter in the viewfinder, but may have it on the screen in live view (or vice versa). If you are in the process of buying a camera, it is best to have one that has the meter in the viewfinder and on live view. The exposure meter allows you to see and adjust how much light is coming into the camera.