When people think of tilt-shift photography at all they tend to think of pictures like this
Miniature faking Photography (source) - Often mistaken as Tilt-shift photography
We call this Miniature faking, and although it does use a tilt function it is not an true example. This photo is also post produced in Photoshop which as I explain below, is not always needed or in some cases desirable. You can read up more on Fake Tilt Shift Photography here.
So what is tilt-shift photography?
This is best broken down into two components. The tilt is when the lens is tilted towards the item you want to photograph but the film plane (the area between the lens and the image sensor in your digital camera) stays the same. The shift is when a lens is moved in parallel to the image plane (up or down but still parallel). This is often done to capture an area which is not easily viewed in the default position such as a church tower or perhaps the bottom of a canyon.
Like the image above it is very popular photo-effect for architectural photography to create striking effects.source)
By tilting and shifting the lens so we can focus on an area that we wouldn't necessarily capture in the original film plane. Alternatively, as happens in Landscape Photography, we might utilise tilt-shift to sharpen the image overall to make it more detailed and lifelike.
More popular at least, maybe to movie-goers is what is known as Selective Focus: this is where a small part of an image is focused to the point of blurring the rest of the larger picture like keys on a floor
Tilt-shift imaging is used in the movie industry as well. Janusz KamiÅski, the Director of Photography for Minority Report deliberately did not use tilt-shift in Photoshop because he felt it made the image less real and more artificial.
How do I take a Tilt-shift Photograph?
You normally need a tilt-shift lens to take these photos which probably explains why composing them in Photo-editing software is popular as you can take any digital image and manipulate it. It also, like all great photography requires a lot of moving around of the lens and the camera body itself. If done well though, you can create some truly memorable photos.