Back when I first began using an SLR camera, one of the first rules that I learned was to maintain a fast enough shutter speed to eliminate blur when shooting handheld. The formula that my high school photography teacher (Mr. Cresop, I wonder where he is now) taught was to use the lens focal length to determine the shutter speed (for example, for a 50mm lens the minimum shutter speed would be 1/50 second). This advice is still good to use today. Even with things like image stabilization, a fast shutter speed equates a sharper image.
On occasion though, a longer shutter speed can add an interesting blur to the image. In today’s image, my friend Kenneth Linge borrowed my camera to demonstrate this recently in downtown Salt Lake City. He had the model stand very still while photographing her as a couple guys walked past. The relatively long shutter speed of 1/10 second gave a nice motion blur to the onlookers. By bracing himself on a lamp pole, he was able to minimize the camera movement and keep the model acceptably sharp.
This is another example of when breaking the “rules” of photography can work in the photographer’s favor.
Canon 5D, Canon 24-105 f/4L lens – 1/10 second, f/25, ISO 160