Preventing Dark (underexposed) Photos

An incorrect shutter speed/aperture combinations are a major cause of dark images. What shutter speed and apertures you can use in a given situation are dictated by the available light, not by what you need to capture the subject. Even though you may want a 1/1000th of a second shutter and a f22 aperture to capture the action at a football game, it will not properly capture the scene at night. The faster you set your shutter speed, the less time light will have to imprint on the film/sensor. Likewise, if you use a small aperture, less light can move through the lens to reach the film/sensor. In order to ensure a properly exposed image when setting the shutter speed/aperture yourself, it is vital that you use your light meter.