Here are 5 important concepts about shutter speed, which you must understand to take good photographs in a wide range of conditions. 1. What is shutter speed? The magic of photography happens when light touches the film or CCD: an image is captured. However, just the right amount of light must enter the camera. The shutter is basically a sheet covering the film or CCD and protecting it from the light coming into the lens. When you take a picture, the shutter opens briefly, allowing light to hit the film or CCD and create your picture. The length of time that the shutter is open is what we adjust when we change the shutter speed. 2. How is shutter speed expressed? A shutter speed could be expressed as 1/8th of a second. A common range of shutter speeds on a camera would look like this: 1, 1/2, 1/4, 1/8, 1/15, 1/30, 1/60, etc., with each one being a fraction of a second. 3. Check the light meter to determine the right shutter speed The light meter in your camera, which is often a series of lights or a gauge inside the viewfinder, will let you decide what shutter speed to use. For example, if the meter is saying that it is too bright, you will want to use a fast shutter speed such as 1/250 so that the shutter will quickly open and close so that too much light doesn't get in. If the meter says that it is too dark, you will want to use a slower shutter speed such as 1/30 so that the shutter will stay open longer in order to collect enough light to create a picture. Adjust your shutter speed faster and slower until your light meter is telling you that just the right amount of light is being let into the camera. 4. When to use slow shutter speeds You may want to choose a slower shutter speed that provides just the right amount of blur in order to display speed in the subject. However, remember that a shutter speed slower than 1/30 makes it difficult to hold the camera totally still for the whole time the shutter is open. Moving the camera slightly while the shutter is open is known as "camera shake," and it can result in the entire image looking a bit blurry. A general rule is not to hold the camera in your hands if you plan to use shutter speeds slower than 1/30. Instead, rest it on something or use a tripod. 5. When to use fast shutter speeds Using slow shutter speeds to shoot moving subjects can cause them to appear blurry. A passing car can look like a streak of color across the photograph rather than a car. The faster the object you are photographing, the faster the shutter speed needed. If you want to capture fast-paced sports action, it is a good idea to use a faster shutter speed, perhaps around 1/500 or 1/1000.