Camera shake
Camera Shake is a fault in a photograph caused by the camera not being held still enough whilst the exposure was made. The result is a blurred, or sometimes a double image. Camera shake is more probable in low light, where slow shutter speeds are necessary, and when using long (telephoto) lenses.
Camera shake can be reduced by using a support - e.g. a tripod, holding the camera braced against something solid (such as the photographer!), or using a higher shutter speed, faster film or shorter lens.
Some cameras - such as the "chocolate bar" format common on 110 film cameras (e.g. the Haking 220 EF or Kodak Pocket Instamatic 60) are awkward to hold steady; a light weight camera can also make camera shake more likely. The trend of holding digital cameras at arm's length, using the LCD display as a viewfinder is another common cause of shake.
Of course, sometimes camera shake is done deliberately, for effect.
