One of three elements that affect a photograph's exposure (along with ISO and aperture), shutter speed determines the amount of time that passes while a single image is being taken, or the amount of time that passes while the shutter is open. When the shutter is open, a picture is being taken, when it closes, the image is complete. The button that takes the photo is called the shutter release, because it opens the shutter to take the image.
Shutter speed has a direct effect on how much light is in an image. When the shutter is open for a longer period of time, more light is let in, so the image will be brighter. The opposite is also true—shorter shutter speeds mean less light is let in, so the image is darker. Of course, the amount of light, or the image's exposure, can also be adjusted through aperture and ISO.
Shutter speed is written in seconds, or fractions of seconds that indicate how long the shutter is open. For example, a one second shutter speed is much slower than 1/500. On most cameras, the slowest shutter speed is called Bulb—this isn't actually a speed, but under this setting, the shutter will remain open until you press the shutter release a second time.
Most cameras will use a number instead of a fraction to indicate the shutter speed inside the viewfinder or on the LCD screen to save space. A 1/500 shutter speed is often designated in the viewfinder as 500, for example. Shutter speeds that are not fractions (i.e. a second or longer) are accompanied by a quotation mark: 1” in the viewfinder is a one-second shutter speed.
How Does Shutter Speed Impact Blur?
So, if a slower shutter speed lets in more light, it makes sense that, for low light pictures, you should use a slow shutter speed. But there's more to choosing a shutter speed than just light: Any object that moves while the shutter is open will be blurred. Sometimes, the blur is intentional, but other times you want a crisp subject frozen in time with zero blur.
Most of the time, blur is unwanted, so a fast shutter speed is used. When taking pictures of sports or snapping shots of kids, for example, a fast shutter speed is usually best. The faster the subject is moving, the faster the shutter speed should be to freeze the action. Since the best shutter speed depends on the speed of your subject, there's no hard and fast rule as to what setting to use. For fast subjects, try starting out at 1/500. Check your shots in the LCD screen and increase if you have some blur, or decrease if the subject is sharp but too dark.
Sometimes, blur can be a good thing. Blur can give an image a sense of movement. Many waterfall images, for example, use a slow shutter speed so the water appears as a smooth, white blur. Intentionally using a slow shutter speed to blur motion is called long exposure photography—it's great for smoothing out water, showing the motion of traffic or people or photographing fireworks, just to name a few. Just like freezing the action, there's no hard, fast rule for the right shutter speed to use for a long exposure.
You can start at one second, then increase or decrease from there to add more or less blur. Bulb mode (set on most cameras by turning your shutter speed all the way down) allows you to choose based on the motion you see, stopping when the action is complete.
To (successfully) take an image with a slow shutter speed, you'll need a tripod. Since any motion while the shutter is open becomes blur, if the entire camera moves, even just slightly, the whole image will be blurry. A tripod prevents unwanted blur by keeping the camera steady during the entire exposure. To further prevent camera shake, you can also use the camera's self timer or a remote so that touching the camera to take the picture doesn't move the camera either.
What shutter speeds require a tripod? Well, it depends on a few factors. Image stabilization allows you to shoot at one to three settings slower before needing a tripod, compared to cameras (or lenses) without stabilization. Zoom also plays a role—more zoom requires a faster shutter speed. As a general rule for DSLR and mirrorless users, the minimum handheld shutter speed = 1/focal length. What does that mean? Remember the focal length is how far your lens is zoomed in. So if you are shooting at 50mm, your shutter speed should be at least 1/50. If you are using as 300mm telephoto, you'll want a much faster 1/300. This guideline just applies to using the camera without a tripod—remember you'll want to increase the speed for faster subjects.
How to Set Shutter Speed
Ready to try it out? Shutter speed can be set in two ways. Manual mode allows you to set the shutter speed as well as the aperture and ISO—allowing the photographer to have complete control over the image. But managing all three at once can be rather daunting for beginners—if you are new to shutter speed, start by using Shutter Priority mode. In Shutter Priority, the user sets the shutter speed, the camera will automatically select the aperture and ISO for the proper exposure. That way, you can focus on mastering shutter speed before throwing in the other two elements to exposure.
In Shutter Priority, the shutter speed is typically adjusted by using the control wheel at the back of the camera. Some advanced compacts don't have a control wheel at all and the shutter speed is adjusted using the arrow keys or a touchscreen. When shooting in manual mode, the camera has to have controls dedicated to aperture as well. If your camera has only one control wheel, a function button typically lets you swap between the two. Cameras with two wheels will have one dedicated to each function for faster adjustments. If you're not sure, check your camera's manual for specifics on your model.
Shutter speed allows you to control whether an image has blur or whether it's sharply frozen in time, as well as affecting exposure. As one of three parts of the exposure triangle, understanding shutter speed is essential to mastering manual modes and taking complete control over your photography.