Shutter speed simply refers to the amount of time that the camera's shutter is open. The longer the shutter is open, the more light that passes through to the camera's sensor. Conversely, the shorter the shutter is open, the less light that's able to pass through.
Shutter speed is most commonly measured in fractions of a second, like 1/200 seconds or 1/1000 seconds. Some high-end cameras offer shutter speeds as fast as 1/8000 seconds.
Shutter Speed and Motion
As noted earlier, shutter speed doesn't just control how long light is allowed to pass through the lens to your camera's sensor; it's also responsible for the appearance of motion in your photos.
Naturally, if you want to freeze the motion of a moving object, you need to use a shutter speed that's as fast or faster than whatever motion is occurring.
For example, to make the runner in the photo above appear frozen in time, the photographer used a fast shutter speed, say, 1/1000 seconds.
It's important to note that the direction of the motion in relation to the camera position will influence the needed shutter speed. Here, since the runner is perpendicular to the camera, a faster shutter speed is needed. However, had the photographer been positioned in front of the runner with her coming toward the camera, a slower shutter speed, say, 1/500 seconds, could be used.
The distance you are from the subject also impacts the speed that's needed to freeze motion. The closer you are, the faster the shutter speed is required because the subject's motion in the frame is more pronounced. This is true of the focal length of the lens you use as well - you can use a slower shutter speed with a wide-angle lens than you can with a telephoto lens, again, because the subject's size in the frame is more pronounced when using a telephoto lens.
Here's a few suggested shutter speeds for freezing the movement of different subjects:
- A person walking at a normal pace: 1/125-1/150 seconds
- A person running: 1/500-1/1000 seconds
- An animal running: 1/500-1/2000 seconds
- A bird in flight: 1/800-1/2000 seconds
- A moving vehicle: 1/500-1/8000 seconds
Of course, blurring motion requires a slower shutter speed to get the kind of movement you see in the image above.
In this case, a speed of just 1 second might be enough to get the light trails seen in the image above. For slower moving subjects, like a person walking, you might need a shutter speed of 5-10 seconds or longer to get blurred movement.
Therein lies one of the difficulties with creatively using shutter speed: the speed of the subject will, in part, dictate what shutter speed you need to ensure that the subject is either frozen or blurred. That means you'll often need some trial and error to get the right shutter speed for the visual effect you want.
Another issue with slower shutter speeds is that you cannot effectively hold the camera in your hand and get a clear, sharp photo like the one above. That means you'll need to use a tripod to stabilize your camera. A general rule of thumb is that once your shutter speed slows to about 1/60 seconds, you'll need to support the camera with something other than your hands.
Shutter Priority Mode: A Quick Explanation
Shutter priority mode (indicated at T or TV on your camera's mode dial) is a semi-automatic shooting mode that prioritizes shutter speed over the other two exposure settings (aperture and ISO).
That means that when you select this mode, you get to determine what shutter speed the camera will use (as well as the ISO), and that shutter speed will remain constant until you change it.
Even better, the camera will select an aperture value that works with the shutter speed you select to get a well-exposed image. So, you get increased creative control over your images but you don't have to be overwhelmed with choosing all three exposure settings for the shot. That makes shutter priority mode a good way to begin taking more control over your camera settings without diving straight into using fully manual mode.
For example, let's say you want to create an image like the one above in which you freeze the movement of a dog running towards you. Let's assume that a shutter speed of 1/1000 seconds is required. So, you simply turn your camera's mode dial to T or TV, dial in a 1/1000 second shutter speed, ensure the ISO is at 100 or 200, and frame up the shot. When you press the shutter button, the camera will determine the aperture that's needed to get a well-exposed image given the shutter speed and ISO settings that you've selected.
Like all things in photography, becoming adept at using shutter speed to your advantage will require that you practice using it - a lot.
To do so, try a simple exercise in which you photograph the same moving subject using varying shutter speeds in shutter priority mode.
For example, set up your camera on a tripod facing the sidewalk in front of your house. Have a friend or family member run by as you take their photo at varying shutter speeds. Start with something like 1/1000 seconds, then work your way down to a very slow shutter speed, like 1 second.
Review the series of images, noting how the motion of your subject becomes increasingly blurred as the shutter speed is extended.