Recently I learned about a whole aspect of photography I'd never even heard of before: movements. I'd seen the various Canon TS-E tilt/shift lenses (such as the TS-E 45mm f/2.8) but never understood what the hell the tilt/shift meant. I finally found a page that explains it very well: Understanding Camera Movements at Luminous Landscape.

The reason I'd never heard of camera movements is that they are not often used in 35mm photography; they are more a feature of large-format view cameras, which support movements in their basic design. Essentially, it's the simple process of offsetting the lens (a.k.a. front standard) with relation to the film plane (a.k.a. rear standard). A shift means moving the lens up, down, left, or right relative to the film, which offsets the image produced. A tilt is actually angling the lens so that it is not parallel with the film plane. Both of these techniques allow you to produce images that are physically impossible in a system where the lens is rigidly mounted to the camera.

One cool use of shifts is to take a picture of something above the camera, like tall trees or a building, without having to tilt the camera itself upward, thus distorting perspective. By keeping the film plane parallel to the object you're photographing, perspective remains straight and vertical lines remain vertical, yet you aren't limited to only what's directly in front of the camera.

What I find really interesting is tilts, which allow you to take photos that appear to have infinite depth of field. The really weird Scheimpflug Principle states that if the front standard and rear standard (i.e. lens and film plane) are not parallel, then if you find the imaginary point where the two standards would intersect, any other plane intersecting that point will always be in focus. There's a good diagram on the Luminous Landscape page above that explains it better. The end result, though, is that you can produce photos like this one, which would be physically impossible with a standard fixed lens. Weird.

I've been getting really interested in optics lately. I find stuff like the above really interesting. I've also been enjoying reading these tales from Nikon optics engineers describing the effort, thought process, and compromises that went into the development of some of Nikon's more interesting lenses. Heh, as usual, I take interest in the technical details beneath the surface, rather than the art itself, which some would say is the real point.