Shutter speed is the amount of time that the shutter is open for. Whilst the shutter is open light is being let into the camera to make a still image.  The shutter speed can be changed depending on the light quality in the scene, it can also be changed to create different artistic effects. Shutter speed is measured in fractions of a second, the smaller the fraction the faster the shutter speed. I took the two images above using different shutter speeds to show how it can be used in different situations. A fast shutter speed is useful for capturing moving objects as a frozen image, for example this water splash happened quickly therefore a fast shutter speed was needed to freeze the moment in time. A slow shutter speed can be used to enhance motion, for example in this image on the right I shook the camera creating a distorted effect.