Self timer

A self timer is a device on a camera that gives a delay between pressing the shutter release and the shutter's firing. It is most commonly used to let photographers to take a photo of themselves (often with family), hence the name.

The self-timer is also used to reduce camera shake when taking photographs in low light or with long (telephoto) lenses. The timer's delay gives the photographer time to steady the camera before the shutter fires, and allows vibrations from the mirror flipping up (on SLRs) to die out. It also eliminates any photographer-induced camera motion when the shutter button is pressed.