The Enthusiast's Guide to Night and Low-Light Photography, 1st Edition

2. THE PROS AND CONS OF LONG EXPOSURES

THE SHUTTER SPEED controls the length of time the shutter is open, allowing light to reach the sensor in the camera. The longer the shutter is open, the more light is allowed in.

When you leave the shutter open for a long period of time, any movement by the subject or camera during the exposure can result in a blurred subject or image. This can be either a pro or a con, depending on the subject. If you are trying to freeze the action when you’re taking a concert photo, then you probably don’t want to use a long shutter speed. On the other hand, if you are trying to capture the light trails from car headlights ...