Definition: Shutter lag is any delay between the time the shutter button in a digital camera is fully depressed and the time the image sensor actually records the image. Shutter lag varies from model to model among digital cameras.
Even though shutter lag is only a fraction of a second most of the time, it still can cause photographers to sometimes miss spontaneous photos. Shutter lag problems increase when the photographer is farther from the subject, when using a fully extended optical zoom lens, and when shooting in low-light conditions. To avoid some of the effects of shutter lag, photographers can use the focus lock feature on their digital cameras to speed up the autofocus process, by depressing the shutter button halfway.
