The basic idea of tethering is that you hook your camera up to a computer and the computer becomes involved in the image capturing process. There are two ways that the computer might be involved: storing the images and controlling the capture.

The simplest use of tethering is to immediately download the pictures you take onto your computer. Normally, images are stored on an SD card (or similar storage device) in your camera. You can see them on the tiny LCD screen, but if you want to preview a larger version of the image you’ll have to pop the card out, import the pictures to your computer, and then open them up. This can be time consuming. Tethering cuts out the middle man, immediately downloading the image to your computer. More to come on how to set this up, but with Lightroom 3 it is insanely simple.

A more complex use of tethering invovles some kind of software created by your camera’s manufacture, like EOS Capture. This gives you the ability to control your camera from the computer. Let’s say, for example, you’re taking a picture of a product. You set everything up on a tripod and you have all your lights set up. With tethering, you can use the computer to focus, take a picture, or alter the camera settings. You basically have complete control of the camera (other than physically moving it around). This can be a bit more complicated.

In the next few days, I’ll write up a quick tutorial on how to use Lightroom 3 to perform tethered captures with Canon cameras. You might not think you need to, but once you try it… it’s cool.