Tilt-shift photography

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Tilt-shift photography refers to the use of camera movements on small- and medium format cameras; it usually requires the use of special lenses.

"Tilt-shift" actually encompasses two different types of movements: rotation of the lens 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 change the line of sight while avoiding the convergence of parallel lines, as when photographing tall buildings.

In many cases, "tilt-shift photography" refers to the use of tilt and a large aperture to achieve a very shallow depth of field.

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[edit] History and use

Movements have been available on view cameras since the early days of photography. Nikon introduced a lens providing shift movements for their 35 mm SLR cameras in the mid 1960s,[1] and Canon introduced a lens that provided both tilt and shift movements in 1973; [2] many other manufacturers soon followed suit. Canon and Nikon each currently offer several lenses that provide both movements. Such lenses are frequently used in architectural photography to control perspective, and in landscape photography to get an entire scene sharp.

Some photographers have popularized the use of tilt for selective focus in applications such as portrait photography. The selective focus that can be achieved by tilting the plane of focus is often compelling because the effect is different from that to which many viewers have become accustomed. Walter Iooss Jr. of Sports Illustrated, Vincent Laforet, Ben Thomas, and many other photographers have images using this technique on their web sites.

A similar technique, known as Smallgantics, applies the same effect of miniaturizing the subject as seen in tilt-shift photography, but is a motion-picture technique that is accomplished in post-production using digital effects software. It was first seen in the 2006 Thom Yorke music video "Harrowdown Hill," directed by Chel White.

[edit] Camera movements

Main article: Camera Movements

[edit] Tilt

24mm lens that tilts (as seen above) as well as shifts

On a regular camera, the image plane (containing the film or image sensor), lens plane, and object plane are parallel, and objects in sharp focus are all at the same distance from the camera. When the lens plane is tilted relative to the image plane, the plane of focus (PoF) is at an angle to the image plane, and objects at different distances from the camera can all be sharply focused if they lie on a straight line. With the lens tilted, the image plane, lens plane, and PoF intersect at a common line;[3] this behavior has become known as the Scheimpflug principle.

When the PoF coincides with an essentially flat subject, the entire subject is sharp; in applications such as landscape photography, getting everything sharp is often the objective.

The PoF can also be oriented so that only a small part of it passes through the subject, producing a very shallow region of sharpness, and the effect is quite different from that obtained simply by using a large aperture with a regular camera. It can be used to make a large scene appear much smaller, as the shallow depth of field is similar to that achieved by a macro lens on miniature subjects.[4]

View camera users usually distinguish between rotating the lens about a horizontal axis (tilt), and rotation about a vertical axis (swing); small- and medium-format camera users often refer to either rotation as "tilt".

35 mm lens that shifts

[edit] Shift

In a subject plane parallel to the image plane, parallel lines in the subject remain parallel in the image. If the image plane is not parallel to the subject, as when pointing a camera up to photograph a tall building, parallel lines converge, and the result sometimes appears unnatural, such as a building that appears to be leaning backwards. Shift is a movement of the lens parallel to the image plane that allows the line of sight to be changed while keeping the image plane (and thus focus) parallel to the subject; it can be used to photograph a tall building while keeping the sides of the building parallel. The lens can also be shifted in the opposite direction and the camera tilted up to accentuate the convergence for artistic effect.

Lenses designed for shifting have a much wider field of vision than a standard lens of the same focal length. Whereas the image frame fits tightly in a standard lens, the shifting lens has an imaging area many times wider. Shifting the lens allows different portions of the image circle to be cast onto the sensor plane, similar to cropping an area along the edge of an image.

Again, view camera users usually distinguish between vertical movements (rise and fall) and lateral movements (shift or cross), while small- and medium-format users often refer to both types of movements as "shift".

[edit] Applying camera movements

Use of lens shift to control distortion

On a view camera, the lens and camera back are connected by a bellows, and many view cameras allow a considerable range of adjustment of both the lens and the camera back, so the tilt and shift movements are inherent in the camera. Applying tilt on a small- or medium-format camera usually requires a tilt-shift lens or perspective control lens; shift can be applied with the same type of lens or with a lens that offers only the shift movement.

Tilt-shift and perspective-correction lenses are available for many SLR cameras, but most are far more expensive than comparable lenses without movements. The Lensbaby SLR lens is a low-cost alternative for providing tilt and swing for many SLR cameras, although the effect is somewhat different from that of the lenses just described. Because of the simple optical design, aberrations are significant, and sharp focus is limited to a region near the lens axis. Consequently, the Lensbaby's primary application is selective focus. If that is the objective, however, the Lensbaby may be a perfectly acceptable choice.

It is also possible to construct a tilt-shift lens of sorts, as described in the linked article by Dennison Bertram.

[edit] Uses of effect

Lensbaby demonstrating selective focus

By blurring, the viewer's gaze may be directed away from parts of the image the photographer wishes to de-emphasize.

A smaller depth of field can be simulated by bringing the foreground and/or background out of focus.

[edit] Miniature faking

Main article: Tilt-shift miniature faking
Tilt-shift Miniature Example

Miniature faking is a post-processing technique, which involves selectively blurring a photo to simulate the narrow depth of field found in macro photography and some tilt-shift photography, making the image appear to be of a miniature model.[5]

[edit] See also

[edit] References

  1. ^ Sato, Haruo. "Tale Seventeen : PC-Nikkor 28 mm f/4". Nikon Corporation. http://imaging.nikon.com/products/imaging/technology/nikkor/n17_e.htm. Retrieved on 2008-07-10. 
  2. ^ Canon TS 35 mm f/2.8 SSC lens. Canon Camera Museum. Retrieved on 2008-07-10.
  3. ^ Wilson, Andrew (May 1, 2006). "Shift/tilt lenses bring new perspectives". Vision Systems Design. http://vsd.pennnet.com/Articles/Article_Display.cfm?Section=ARTCL&ARTICLE_ID=254651&VERSION_NUM=2&p=19. Retrieved on 2008-05-19. 
  4. ^ Rodrigues, Vailancio (2008-11-16). "50 Beautiful Examples of Tilt-Shift Photography". Smashing Magazine. http://www.smashingmagazine.com/2008/11/16/beautiful-examples-of-tilt-shift-photography/. Retrieved on 2008-11-19. 
  5. ^ Segal, David (2007-02-07). "Can Photographers Be Plagiarists?". Slate. http://www.slate.com/id/2159172/. Retrieved on 2007-02-07. 

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