AyushSaran.com

Tilt-shift photography is an artistic technique where the lens is tilted relative to the attached camera. When tilted, the film or image sensor is not at a right angle to the optical axis of the lens, causing a gradient of focus. This effect can be used to direct the viewer’s gaze by blurring parts of the image the photographer wishes to de-emphasize, or can be used to simulate a smaller depth of field by bringing the foreground and/or background out of focus. It can also correct for perspective, by sharpening the focus of a foreground and background that would otherwise be outside the depth of field. One builder of a do-it-yourself tilt-shift lens noted that the lens used should be one intended for a larger film format than the the camera, so that vignetting doesn’t occur as the lens is tilted

exaples of tilt-shift images

http://www.flickr.com/photos/tags/tiltshift/

 
 
 
If you like this effect i found a few intresting tutorials on the web on achieving this effect

Make your own tilt-shift camera lens shows you how to create a tilt-shift lens on the cheap for your camera using a rubber plunger and a plastic lenscap

 
http://recedinghairline.co.uk/tutorials/fakemodel/ teaches you to fake the effect without a camera using lens blur and masks in PhotoShop