Tilt-shift photography
Encyclopedia
"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" 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.
s since the early days of photography; they have been available on smaller-format cameras since the early 1960s, usually by means of special lenses or adapters. Nikon
introduced a lens providing shift movements for their 35 mm SLR
cameras in 1962,
and Canon introduced a lens that provided both tilt and shift movements in 1973;
many other manufacturers soon followed suit. Only Canon currently offers four 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 camera lens can provide sharp focus on only a single plane. Without tilt, the image plane (containing the film or image sensor
), the lens plane, and the plane of focus are parallel, and are perpendicular to the lens axis; 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 in the same plane. With the lens tilted, the image plane, lens plane, and PoF intersect at a common line;
this behavior has become known as the Scheimpflug principle
. When focus is adjusted with a tilted lens, the PoF rotates about an axis at the intersection of the lens's front focal plane and a plane through the center of the lens parallel to the image plane; the tilt determines the distance from the axis of rotation to the center of the lens, and the focus determines the angle of the PoF with the image plane. In combination, the tilt and focus determine the position of the PoF.
In applications such as landscape photography
, getting everything sharp is often the objective; by using tilt, both the foreground and background can often be made sharp without the use of a large f-number
. When the PoF coincides with an essentially flat subject, the entire subject is in focus; for a subject that is not flat, obtaining foreground and background sharpness relies on the depth of field
, though the sharpness can often be obtained with a smaller f-number than would be needed without the use of tilt.
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.
Using tilt changes the shape of the depth of field (DoF). When the lens and image planes are parallel, the DoF extends between parallel planes on either side of the PoF. With tilt or swing, the DoF is wedge shaped, with the apex of the wedge near the camera, as shown in Figure 5 in the Scheimpflug principle article. The DoF is zero at the apex, remains shallow at the edge of the lens's field of view, and increases with distance from the camera. For a given position of the PoF, the angle between the planes that define the near and far limits of DoF (i.e., the angular DoF) increases with lens f-number
; for a given f-number and angle of the PoF, the angular DoF decreases with increasing tilt. When it is desired to have an entire scene sharp, as in landscape photography, the best results are often achieved with a relatively small amount of tilt. When the objective is selective focus, a large amount of tilt can be used to give a very small angular DoF; however, the tilt fixes the position of the PoF rotation axis, so if tilt is used to control the DoF, it may not be possible to also have the PoF pass through all desired points.
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".
Shift is a displacement of the lens parallel to the image plane that allows adjusting the position of the subject in the image area without moving the camera back; in effect the camera can be aimed with the shift movement.
Shift can be used to keep 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.
Shifting a lens allows different portions of the image circle
to be cast onto the image 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".
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.
Tilt-shift and perspective-control 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, there is significant curvature of field,
and sharp focus is limited to a region near the lens axis. Consequently, the Lensbaby's primary application is selective focus and "toy camera"–style photography.
It is also possible to construct a tilt-shift lens of sorts, as described in the linked article by Dennison Bertram.
Depth of field
In optics, particularly as it relates to film and photography, depth of field is the distance between the nearest and farthest objects in a scene that appear acceptably sharp in an image...
is simulated with digital postprocessing; the name may derive from the tilt-shift lens normally required when the effect is produced optically.
"Tilt-shift" encompasses two different types of movements: rotation of the lens
Lens (optics)
A lens is an optical device with perfect or approximate axial symmetry which transmits and refracts light, converging or diverging the beam. A simple lens consists of a single optical element...
plane relative to the image plane
Film plane
A film plane is the area inside any image taking device with a lens and a digital sensor or film; such as a camera. The film plane varies in distance from the lens focal point in each manufacturer...
, 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
Scheimpflug principle
The Scheimpflug principle is a geometric rule that describes the orientation of the plane of focus of an optical system when the lens plane is not parallel to the image plane. It is commonly applied to the use of camera movements on a view camera...
. 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.
History and use
Movements have been available on view cameraView camera
The view camera is a type of camera first developed in the era of the Daguerreotype and still in use today, though with many refinements. It comprises a flexible bellows which forms a light-tight seal between two adjustable standards, one of which holds a lens, and the other a viewfinder or a...
s since the early days of photography; they have been available on smaller-format cameras since the early 1960s, usually by means of special lenses or adapters. Nikon
Nikon
, also known as just Nikon, is a multinational corporation headquartered in Tokyo, Japan, specializing in optics and imaging. Its products include cameras, binoculars, microscopes, measurement instruments, and the steppers used in the photolithography steps of semiconductor fabrication, of which...
introduced a lens providing shift movements for their 35 mm SLR
SLR
The initialism SLR can refer to:* Satellite laser ranging* Scalable Linear Recording Tape Drive Backup* Self-Loading Rifle, see semi-automatic rifle.** The UK version of the Belgian FN FAL select fire battle rifle, the L1A1 SLR.* Semi-linear resolution...
cameras in 1962,
and Canon introduced a lens that provided both tilt and shift movements in 1973;
many other manufacturers soon followed suit. Only Canon currently offers four 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
Walter Iooss
Walter Iooss Jr. is a professional photographer.He is best known for his work with Sports Illustrated magazine, which has featured his photos on its cover several times and for his portraits of famous athletes such as Michael Jordan, Cal Ripken, Jr. and Ken Griffey, Jr....
Jr. of Sports Illustrated
Sports Illustrated
Sports Illustrated is an American sports media company owned by media conglomerate Time Warner. Its self titled magazine has over 3.5 million subscribers and is read by 23 million adults each week, including over 18 million men. It was the first magazine with circulation over one million to win the...
, Vincent Laforet, Ben Thomas, and many other photographers have images using this technique on their web sites.
Tilt
Image sensor
An image sensor is a device that converts an optical image into an electronic signal. It is used mostly in digital cameras and other imaging devices...
), the lens plane, and the plane of focus are parallel, and are perpendicular to the lens axis; 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 in the same plane. With the lens tilted, the image plane, lens plane, and PoF intersect at a common line;
this behavior has become known as the Scheimpflug principle
Scheimpflug principle
The Scheimpflug principle is a geometric rule that describes the orientation of the plane of focus of an optical system when the lens plane is not parallel to the image plane. It is commonly applied to the use of camera movements on a view camera...
. When focus is adjusted with a tilted lens, the PoF rotates about an axis at the intersection of the lens's front focal plane and a plane through the center of the lens parallel to the image plane; the tilt determines the distance from the axis of rotation to the center of the lens, and the focus determines the angle of the PoF with the image plane. In combination, the tilt and focus determine the position of the PoF.
In applications such as landscape photography
Landscape photography
Landscape photography is a genre intended to show different spaces within the world, sometimes vast and unending, but other times microscopic. This popular style of photography is practiced by professionals and amateurs alike. Photographs typically capture the presence of nature and are often free...
, getting everything sharp is often the objective; by using tilt, both the foreground and background can often be made sharp without the use of a large f-number
F-number
In optics, the f-number of an optical system expresses the diameter of the entrance pupil in terms of the focal length of the lens; in simpler terms, the f-number is the focal length divided by the "effective" aperture diameter...
. When the PoF coincides with an essentially flat subject, the entire subject is in focus; for a subject that is not flat, obtaining foreground and background sharpness relies on the depth of field
Depth of field
In optics, particularly as it relates to film and photography, depth of field is the distance between the nearest and farthest objects in a scene that appear acceptably sharp in an image...
, though the sharpness can often be obtained with a smaller f-number than would be needed without the use of tilt.
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
Aperture
In optics, an aperture is a hole or an opening through which light travels. More specifically, the aperture of an optical system is the opening that determines the cone angle of a bundle of rays that come to a focus in the image plane. The aperture determines how collimated the admitted rays are,...
with a regular camera.
Using tilt changes the shape of the depth of field (DoF). When the lens and image planes are parallel, the DoF extends between parallel planes on either side of the PoF. With tilt or swing, the DoF is wedge shaped, with the apex of the wedge near the camera, as shown in Figure 5 in the Scheimpflug principle article. The DoF is zero at the apex, remains shallow at the edge of the lens's field of view, and increases with distance from the camera. For a given position of the PoF, the angle between the planes that define the near and far limits of DoF (i.e., the angular DoF) increases with lens f-number
F-number
In optics, the f-number of an optical system expresses the diameter of the entrance pupil in terms of the focal length of the lens; in simpler terms, the f-number is the focal length divided by the "effective" aperture diameter...
; for a given f-number and angle of the PoF, the angular DoF decreases with increasing tilt. When it is desired to have an entire scene sharp, as in landscape photography, the best results are often achieved with a relatively small amount of tilt. When the objective is selective focus, a large amount of tilt can be used to give a very small angular DoF; however, the tilt fixes the position of the PoF rotation axis, so if tilt is used to control the DoF, it may not be possible to also have the PoF pass through all desired points.
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".
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 displacement of the lens parallel to the image plane that allows adjusting the position of the subject in the image area without moving the camera back; in effect the camera can be aimed with the shift movement.
Shift can be used to keep 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.
Shifting a lens allows different portions of the image circle
Image circle
The image circle, or circle of illumination, of a lens is the circular area in the image plane formed by the cone of light transmitted by the lens . Within this circle is the smaller circle for which image definition is acceptable, the circle of good definition ; however, some authors make no...
to be cast onto the image 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".
Lens image circle
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.Tilt-shift and perspective-control lenses are available for many SLR cameras, but most are far more expensive than comparable lenses without movements. The Lensbaby
Lensbaby
Lensbaby is a line of camera lenses for SLR cameras that combine a simple lens with a bellows or ball and socket mechanism for use in special-effect photography. A lensbaby can give effects normally associated with view cameras...
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, there is significant curvature of field,
and sharp focus is limited to a region near the lens axis. Consequently, the Lensbaby's primary application is selective focus and "toy camera"–style photography.
It is also possible to construct a tilt-shift lens of sorts, as described in the linked article by Dennison Bertram.