Shutter speed is the length of time the camera shutter is open, exposing light onto the camera sensor. Essentially, it’s how long your camera spends taking a photo. This has a few important effects on how your images will appear. When you use a long shutter speed (also known as a “slow” shutter speed), you end up exposing your sensor for a significant period of time. The first big effect of it is motion blur. If your shutter speed is long, moving subjects in your photo will appear blurred along the direction of motion. This effect is used quite often in advertisements of cars and motorbikes, where a sense of speed and motion is communicated to the viewer by intentionally blurring the moving wheels.
Motion blur
Slow shutter speeds are also used to photograph the Milky Way or other objects at night, or in dim environments with a tripod. Landscape photographers may intentionally use long shutter speeds to create a sense of motion on rivers and waterfalls while keeping everything else completely sharp.
Shutter speed: 5 seconds (a long shutter speed)
On the other hand, shutter speed can also be used to do just the opposite – freeze motion. If you use an especially fast shutter speed, you can eliminate motion even from fast-moving objects, like birds in flight, or cars driving past. If you use a fast shutter speed while taking pictures of water, each droplet will hang in the air completely sharp, which might not even be visible to our own eyes.
Shutter speed: 1/1600th second (a fast shutter speed)
All of the above is achieved by simply controlling the shutter speed. In summary, quick shutter speeds freeze action, while long ones create an effect of motion when you photograph moving objects.