Week 7 - Tilt Shift

Definition:
"Tilt-shift photography" refers to the use of camera movements on small- and medium-format cameras, and sometimes specifically refers to the use of tilt for selective focus, often for simulating a miniature scene. Sometimes the term is used when the shallow depth of field is simulated with digital postprocessing; the name may derive from the tilt-shift lens normally required when the effect is produced optically.
"Tilt-shift" actually encompasses two different types of movements: rotation of the lens plane relative to the image plane, called tilt, and movement of the lens parallel to the image plane, called shift. Tilt is used to control the orientation of the plane of focus (PoF), and hence the part of an image that appears sharp; it makes use of the Scheimpflug principle. Shift is used to adjust the position of the subject in the image area without moving the camera back; this is often helpful in avoiding the convergence of parallel lines, as when photographing tall buildings.

Scheimpflug Principle
a useful rule when using camera movements is that when the planes of the subject, the lens panel, and the image are made to coincide at a single line, everything will be in focus.

 Tilt

The axis of the lens is normally perpendicular to the film (or sensor). Changing the angle between axis and film by tilting the lens standard backwards or forwards is called lens tilt or just tilt. Tilt is especially useful in landscape photography. By using the Scheimpflug principle, the “plane of sharp focus” can be changed so that any plane can be brought into sharp focus. When the film plane and lens plane are parallel as is the case for most 35 mm cameras, the plane of sharp focus will also be parallel to these two planes. If, however, the lens plane is tilted with respect to the film plane, the plane of sharp focus will also be tilted according to geometrical and optical properties. The three planes will intersect in a line below the camera for downward lens tilt. The tilted plane of sharp focus is very useful in that this plane can be made to coincide with a near and far object. Thus, both near and far objects on the plane will be in focus.

Shift



Moving the front standard left or right from its normal position is called lens shift or simply shift. This movement is similar to rise and fall, but moves the image horizontally rather than vertically. One use for shift is to remove the image of the camera from the final image when photographing a reflective surface.

Swing

 Altering the angle of the lens standard in relation to the film plane by swiveling it from side to side is called swing. Swing is similar to tilt, but in the horizontal axis. Swing may be used to achieve sharp focus along the entire length of a picket fence, for example.

How to: Straighten Buildings (perspective control)

Architectural photographers can use the shifting ability to correct the perspective distortion when photographing tall buildings and interiors.

Links

Great link with perspective calculator, information about perspective control and tilt-shift panoramas.
http://www.cambridgeincolour.com/tutorials/tilt-shift-lenses1.htm

Info about perspective control
http://photo.net/equipment/canon/tilt-shift


Other:
http://cow.mooh.org/projects/tiltshift/
http://www.usa.canon.com/dlc/controller?act=GetArticleAct&articleID=2826