Joe,

Think of the light coming from the lens as a cone. When you focus at infinity the cone is at its shortest length, and the diameter of image it provides is its smallest. As mentioned above, it you can fit it on the camera (lensboard large enough) and focus it (long enough bellows draw) you can use a lens with more coverage than the format needs when the camera is "squared up".

It is much easier to get a bigger (longer focal length lens) to cover a given format than a shorter lens. You will generally find wide angle lenses more expensive, or not as good image quality for the same money as a longer one that covers the format.

As we focus closer, we need more bellows, but also the cone gets bigger and can cover more area. This is why one can use a small enlarger lens for macro work, even it it will not cover the format at infinity. Or sometimes use lenses not able to cover the format at infinity, when photographing at portrait distances.

The excess coverage (more than required for a squared up camera) is used when we want to change the composition or the plane of focus.

Ideally we take our image out of he centre of the lens, as that would be the best image quality, but that is not a requirement. We can chose to take the image (i.e. place the film) anwhere in the area the cone presents an image (rise or shift). That is essentially what is done when the image is shifted. Think of photographing the top of a tall building without getting keystoning, or getting a photograph straight on a mirror without being in the picture.

To focus closer we move the lens away from the film. By changing the angle of lens axis or film plane (tilt or swing), we can focus both close and far at the same time, on another plane.

And that is why you will find so many ways of adjusting your Graphic View monorail...

That should provide you something to think about until you get your hands on your camera again.

Enjoy,

Len