Tilt-shift Photography

Whereas the image circle of a standard lens usually just covers the image frame, a lens that provides tilt or shift must allow for displacement of the lens axis from the center of the image frame, and consequently requires a larger image circle than a standard lens of the same focal length.
Applying camera movements
On a view camera, the tilt and shift movements are inherent in the camera, and many view cameras allow a considerable range of adjustment of both the lens and the camera back. Applying movements on a small- or medium-format camera usually requires a tilt-shift lens or perspective control lens. The former allows tilt, shift, or both; the latter allows only shift. With a tilt-shift lens, adjustments are available only for the lens, and the range is usually more limited.