Tilt-shift is a type of photography in which camera movements are used in small and medium format cameras. Sometimes specifically refers to the use of tilt for selective focus, often for simulating a miniature scene. Nowadays the term is slightly used when the depth of field in the scene is simulated with digital post-processing techniques. Litterally, name derives from tilt-shift camera lenses required to obtain this effect when produced optically.
On this topic, we’ve found a pretty cool tutorial published by Kris on his personal blog, filmsbykris.com.
In this tutorial he explain us how to realize the tilt-shift effect or, in practice, how to use Blender defocus, a filter node which simulates the lens blur required in the scene. The tutorial is quite basic but it reaches a pretty wide number of simple but very useful functionalities.
Only for information: the posted image is realized on Blender 2.56 following this tutorial, only making a few changes for experimenting a little. Scene composition is rather different, so the camera focal lenght and therefore filter parameters.
Happy blending and thanks to Kris.