Shutter speed allows you to either slow down or speed up your shutter. Slowing your shutter down allows for more light and movement, while speeding it up allows for less light but also a much sharper image. Shutter Speed can be automatically decided by your device as well by tapping .
Tap to manually set your shutter speed.
Then move the slider left or right. This adjustment will give you a faster or slower shutter speed. The marker will tell you the fraction of a second at which your shutter speed is set. Your final product with a slow shutter speed will show movement, additional light or both.