Why would I change the shutter speed on my digital camera?

Why would I change the shutter speed on my digital camera?

Mark Comon (Vice President, Paul's Photo, Torrance, CA) gives expert video advice on: What does my digital camera's "manual exposure" mode allow me to do?; How do I change the shutter speed on my digital camera?; Which is worse to overexpose or underexpose pictures on my digital camera? and more...

We change the shutter speed on our camera to affect the action-stopping ability. If I'm shooting a picture with my camera handheld, I need a shutter speed of 125 or 250. If I'm shooting moving subjects, I would change my shutter speed to a shutter speed of 500 or a thousandth of a second to stop the moving subjects. If I'm shooting pictures in low light, where I need more light to come in through the shutter, I'd set shutter speed to thirtieth or a fifteenth of a second. Now, when I set to a slow shutter speed like thirty or fifteen, action is going to blur. So, I use thirty or fifteen when there's low light or when I want the action to blur. Medium shutter speed: 125 or 250 for normal pictures. Fast shutter speed: 500 or 1000 for action. Thirtieth or a fifteenth of a second to blur action or under low light.