As a general guideline, the shutter speed should be 1/1 [Focal Length]. As a result, if you're using a 500mm lens, you should set your shutter speed to 1/500 or greater. If you're using a DSLR with a crop factor, multiply by the crop factor. For example, if you have a 24MP camera, then your shutter speed should be 1/24 or faster.
Setting the shutter speed too low will cause a photo to be under-exposed. This is because any objects in front of the camera that are still when the picture is taken will appear blurry due to motion blur from the shutter speed being too slow. Setting the shutter speed too high will cause a photo to be over-exposed. Since only certain types of photography benefit from using a high shutter speed (action photos, for example), this book focuses on medium-low shutter speeds.
When you shoot moving subjects, it's important to use a fast shutter speed. Otherwise, the subject will appear blurry. A fast shutter speed also allows you to take pictures of fleeting moments. So, generally speaking, try to use a shutter speed of at least 1/200th of a second for candid photos.
There are two ways to go about setting the shutter speed: manually and automatically. With autoexposure, the camera selects the proper shutter speed based on the light available at the time of the shot.
The shutter speeds accessible to you will vary based on the type of camera you are using, but a DSLR will normally range from 1/4000 to 30 seconds. You'll find a useful reference chart further down this page that illustrates all of the typical options in between.
A fast shutter speed allows you to take photos of moving objects or subjects who have a tendency to wander away from your ideal shooting location. These photos would otherwise be too blurry to be worth taking. Slower shutter speeds allow you to capture more detail in an image, such as the swirls in a pond at twilight or the clouds rolling by during a storm.
When you press the shutter button, the camera will use a mechanical mechanism to open and close the lens aperture. This allows light to pass through the lens and reach the sensor, but prevents anything from reaching the film inside the body of the camera. The amount of time it takes for the shutter to open and close is how long the camera takes to take one photo. The faster this process can be done, the more photos you can take before you need to reload. A slow shutter speed may be required to prevent movement from ruining your picture. For example, if there's a bird outside your window and it wanders away while the shutter is closed, when you reopen it later that bird will be gone.
Shutter speed is referred to as an exposure value.
1/300 To avoid camera shake, set the shutter speed equal to your focal length when hand holding your camera. In other words, while using a 300mm lens, your shutter speed should be 1/300 or quicker, 1/20 or faster when using a 20mm lens, and so on. Be careful not to make your shutter speed too slow though; if it's too slow, you'll get blurry images.
Shutter speeds work by allowing enough time for all of the objects within your scene to pass through the aperture without being captured by the camera sensor. The shorter the exposure time, the more pictures that can be taken before another object crosses the screen. Longer exposures allow objects to blur as they move across the frame.
A tripod is essential for getting clear photos at slower shutter speeds because even slight movements of the camera will produce blurred images. A wide-angle lens helps to minimize subject matter that falls outside of the frame, which reduces the need for scrolling through photographs later in post-processing.
When photographing landscapes or abstract scenes, where subtle changes in light intensity are important, a longer exposure time may be needed to capture everything you want to show with one shot. A long exposure also allows objects to move slightly if they're moving at all, producing some interesting effects such as star trails around the Milky Way Galaxy or waves on still waters.