So what are shutter speeds?

What you can do with shutter speed is freeze motion with a fast shutter speed or capture movement with a slow shutter speed. Flowing water looks silky smooth at speeds slower than 1/8th of a second (with a tripod), while you can freeze water in time with fast shutter speeds. The same thing goes for hip hop dancers.


Also, an important side note is that there is a rule for getting sharp images: 1/focal length. So if you have a 50mm lens then you'd need at least 1/50th of a second for your picture to not be blurry, and if you're using a digital SLR then there is a crop value (minus a few exceptions) of 1.5/1.6 so your 50mm lens is a 75~80mm lens, which means that you need a shutter speed of at least 1/80th of a second to get a sharp image.

Summary: Fast shutter speed = freeze action. Slow shutter speed (w/ tripod) = silky flowing water.