What Is A Cable Release?
A cable release is a shutter button on a hand unit that can be attached to a camera by a short cable. Some manufacturers have a dedicated cable release port on the side of the camera, and some use the USB port to offer the shutter control. Make sure you refer to your camera manual to find out what kind of cable release works with your camera as each manufacturers often has several models that vary depending on the size of the camera.
Why Use A Cable Release?
There’s several situations where a cable release can be an invaluable tool. When the camera is set to bulb mode, you can use the cable release to hold the shutter open for as long as you want by locking the cable release switch in the down position. This allows you to create photos with an extremely long exposure time which is great for astrophotography and star trails. The second most common usage for a cable release is in landscape photography when you you are seeking absolute critical sharpness. When the camera is on a tripod and exposure times are quite long, pressing the shutter button on the camera can induce vibrations into the camera that have a small effect on image sharpness. Using a cable release means that you do not have to touch the camera to take the photos.
The third reason to have a cable release is for timelapse photography. Most manufacturers offer two types of cable release; one that simply has a shutter button, and one that has a screen and several other controls. These other controls allow you to set an interval time between repeating shots, and you can also set how many photos you want to take. For example, you might set it to take 300 photos, each with a 5 second exposure. These can then be combined into a timelapse video on a computer.