The shutter speed determines the length of your exposure time, and affects the way that motion is recorded by your camera
The shutter speed is, along with the aperture, one of the two primary controls available to adjust the amount of light that reaches the sensor.
But while the aperture controls the intensity of light, the shutter speed determines the duration for which the sensor is exposed to it.
To compare a camera with an oven, the aperture represents the temperature, and the shutter speed is akin to the cooking time.
Creating a perfect picture, just like cooking a perfect pie, involves getting the right combination of these two controls.
Shutter speed: Controlling exposure
Longer shutter speeds allow more light to reach the sensor; short ones allow less light to pass.
The lower the prevailing light level, the longer the shutter needs to remain open in order to record a correctly exposed shot.
Just like the aperture, the shutter speed range is measured in stops, with each stop doubling or halving the exposure value. Unlike apertures though, the numerical relationship is more obvious. So a speed of 1/2000sec lets in half the amount of light of 1/1000sec, but double that of 1/4000sec.
Shutter speed: Shutter Speed Scale
The shutter speed range available on a camera varies: top of the range DSLRs may offer speeds from1/8000sec to 30 seconds.
In addition there will be a setting called ‘B’ in which the shutter will stay open for as long as you hold it down (or locked open using a remote release), which is ideal for night photography.
Compact cameras have a much shorter range of speeds.
Shutter speed: Avoid camera shake
Your shutter speed choice also affects the overall sharpness of your image.
You may not be aware of it, but the natural movement in your hands transfers to the picture, resulting in camera shake. The degree of shake varies depending on many factors and it may not be visible till you enlarge the shot.
The more telephoto your lens, the greater this problem is magnified, so to reduce the risks, a good rule of thumb is to ensure that your shutter speed is at least equal to the focal length of the lens.
So if you’re using an 18-55mm lens at the 55mm end, don’t let the speed go below 1/60sec, and if you’re using a 200mm lens, keep it to 1/250 or above. If there isn’t enough light to use these speeds, raise the ISO or use a tripod.
Shutter speed: Freezing motion
Shutter speeds have a profound effect on how the camera records moving subjects.
A fast shutter speed stops fast motion in its tracks as though the subject is frozen in time. You’ve all seen shots of high jumpers suspended in mid-air above the bar. That’s done with fast shutter speeds.
Shutter speed: Blurring motion
Using slower speeds will cause some motion blur but this may be desirable. A racing car ‘frozen’ on the track will look like it’s parked, whereas a speed that allows a controlled amount of subject blur will better convey its motion.
Shutter speed: Panning
One useful technique employed by many sports photographers is to move the camera with the subject, keeping it in the same position in the frame. This is known as panning, and the effect is to keep the subject relatively sharp but blur the background with streaking.
The precise speeds to use vary depending on your subject, and the effect desired, so you’ll need to experiment.