Paul Jolly Photography Chapter 16

Remote shutter

Pressing the shutter on the camera vibrates your equipment at the very time you need it to be stable. Using a remote shutter release stops movement from your hand from vibrating the camera. Clearly the camera will not be hand held for this and will either be on a tripod or you will be using another method of holding the camera steady.
A mechanical remote shutter removes some vibration. An electrical wired remote shutter is much better and a radio triggered remote shutter (RF radio frequency or IR infra red) is best as there is no physical connection at all.
If you have to use a mechanical or wired remote shutter, attaching the activator to a second, independent, tripod will help in reducing transmitted vibration. Beware of dangling the remote cable in the air - turbulent air (is there any other kind?) pushing on the cable will also cause your camera to move; to reduce this clip the cable down the tripod leg.