Actually, they are simply referred to as camera movements - it can be tilt (tip forward or back), shift (move up, down, left or right) or it can be a swing (pivot left or right) of the film back, or it can be tilt, shift or swing of the lens ... or it can be any combination of all six. And, while a correction of keystoning is a common use in architectural photography, it is equally as often (if not more) used for maximizing or minimizing depth of field in a photograph in fields such as product or landscape photography. Most often, it was used to help maximize depth of field due to the fact that, when using larger formats for image recording, the depth of field becomes much more pronounced and shallow, hence the use of smaller and smaller apertures (including apertures as small as f/128 or smaller). This led to the name of the "f/64 Club" referring to Ansel Adams and other landscape photographers of the day who commonly worked in large format, at small aperture.
Using the movements of the front or rear standard of large format cameras allowed them to bring important elements of the scene parallel with the film plane, resulting in them rending those elements in focus in the final image. One great example is using a forward tilt of both lens and film standards to bring the scene more parallel to the film plane, allowing a foreground of flowers to render just as sharply as distant mountains without the need to use tiny apertures, which inevitably degrades image quality due to the effect of refraction at those small apertures and adds the additional challenge of longer shutter speeds which can allow elements (such as flowers swaying in a breeze) to blur.
Obviously, MAXIMIZING DOF is not an issue in a 3D rendered landscape as, by default, everything is sharp! However, the movements could just as easily be used to MINIMIZE DOF resulting in razor thin areas of sharp focus in an image by tilting or swinging the lens or film planes so that only a small portion of the film plane intersects with the plane of focus.
This has been most recently re-popularized with the "diorama" style photography of towns and cities using a Tilt Shift lens on a 35mm style camera. These lenses offer Tilt and Shift capabilities, but typically no swing movements.
It would certainly be interesting to see effects such as these emulated in a renderer! I don't know how useful
, but interesting all the same.
~Micheal
