Shutter speed – stands for the length of time a camera shutter is open to expose light into the camera sensor. If the shutter speed is fast, it can help to freeze action completely, as seen in the above photo of the dolphin. If the shutter speed is slow, it can create an effect called “motion blur”, where moving objects appear blurred along the direction of the motion. This effect is used quite a bit in advertisements of cars and motorbikes, where a sense of speed and motion is communicated to the viewer by intentionally blurring the moving wheels.
- Slow shutter speeds are also used to photograph lightnings or other objects at night or in dim environments with a tripod. Landscape photographers intentionally use slow shutter speeds to create a sense of motion on rivers and waterfalls, while keeping everything else in focus.
Motion can also be frozen to an extent with a camera flash, even at low shutter speeds. Take a look at this example:
Racheal Leonards blog 