Tilt–shift photography is the use of camera movements that change the orientation or position of the lens with respect to the film or image sensor on cameras.
Sometimes the term is used when a shallow depth of field is simulated with digital post-processing; the name may derive from a perspective control lens (or 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.
History and use Movements have been available on view cameras 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. Canon and Nikon currently offer 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. Ben Thomas, Walter Iooss Jr. of Sports Illustrated, Vincent Laforet and many other photographers have used this technique.
Perspective-control lenses
In photography, a perspective-control lens allows the photographer to control the appearance of perspective in the image; the lens can be moved parallel to the film or sensor, providing the equivalent of corresponding view camera movements. This movement of the lens allows adjusting the position of the subject in the image area without moving the camera back; it is often used to avoid convergence of parallel lines, such as when photographing a tall building. A lens that provides only shift is called a shift lens, while those that can also tilt are called tilt–shift lenses. The terms PC and TS are also used by some manufacturers to refer to this type of lens.
Short-focus perspective-control (PC) lenses (i.e., 17 mm through 35 mm) are used mostly in architectural photography; longer focal lengths may also be used in other applications such as landscape, product, and closeup photography. PC lenses are generally designed for single-lens reflex (SLR) cameras, as rangefinder cameras do not allow the photographer to directly view the effect of the lens, and view cameras allow for perspective control using camera movements.
A PC lens has a larger image circle than is required to cover the image area (film or sensor size). Typically, the image circle is large enough, and the mechanics of the lens sufficiently limited, that the image area cannot be shifted outside of the image circle. However, many PC lenses require a small aperture setting to prevent vignetting when significant shifts are employed. PC lenses for 35 mm cameras typically offer a maximum shift of 11 mm; some newer models offer a maximum shift of 12 mm.
The mathematics involved in tilt lenses are described as the Scheimpflug principle, after an Austrian military officer who developed the technique for correcting distortion in aerial photographs.
The first PC lens manufactured for an SLR camera in any format was Nikon's 1961 35 mm PC-Nikkor; it was followed by an 35 mm PC-Nikkor (1968), an 28 mm PC-Nikkor (1975), and an 28 mm PC-Nikkor (1981). In 1973, Canon introduced a lens, the TS 35 mm SSC, with tilt as well as shift functions.
Other manufacturers, including Venus Optics Laowa, Olympus, Pentax, Schneider Kreuznach (produced as well for Leica), and Minolta, made their own versions of PC lenses. Olympus produced 35 mm and 24 mm shift lenses. Canon currently offers 17 mm, 24 mm, 50 mm, 90 mm and 135 mm tilt/shift lenses. Nikon currently offers 19 mm, 24 mm, 45 mm, and 85 mm PC lenses with tilt and shift capability. Venus Optics Laowa offers a 15 mm shift lens with an extremely good optical distortion control. Fujifilm announced the 30 mm and 110 mm medium format tilt/shift lenses on Sept. 12 2023.
Shape control When the camera back is parallel to a planar subject (such as the front of a building), all points in the subject are at the same distance from the camera, and are recorded at the same magnification. The shape of the subject is recorded without distortion. When the image plane is not parallel to the subject, as when pointing the camera up at a tall building, parts of the subject are at varying distances from the camera; the more distant parts are recorded at lesser magnification, causing the convergence of parallel lines. Because the subject is at an angle to the camera, it is also foreshortened.
When the camera back is not parallel to a planar subject, it is not possible to have the entire subject in focus without the use of tilt or swing; consequently, the image must rely on the depth of field to have the entire subject rendered acceptably sharp.
With a PC lens, the camera back can be kept parallel to the subject while the lens is moved to achieve the desired positioning of the subject in the image area. All points in the subject remain at the same distance from the camera, and the subject shape is preserved. If desired, the camera back can be rotated away from parallel to the subject, to allow some convergence of parallel lines or even to increase the convergence. Again, the position of the subject in the image area is adjusted by moving the lens.
Adapters Low-cost tilt/shift adapters are available. However, they can only be used with SLR lenses on mirrorless cameras that have a short enough flange focal distance in order to provide infinity focus. Thus, they are not available for all lens/camera combinations. The image circle of the lens must be larger than the sensor in the camera, in order to avoid vignetting.
Aperture control
Most SLR cameras provide automatic aperture control, which allows viewing and metering at the lens's maximum aperture, stops the lens down to the working aperture during exposure, and returns the lens to maximum aperture after exposure. For perspective-control and tilt–shift lenses, the mechanical linkage is impractical, and automatic aperture control was not offered on the first such lenses. Many PC and TS lenses incorporated a feature known as a "preset" aperture, which lets the photographer set the lens to working aperture, and then quickly switch between working aperture and full aperture without looking at the aperture control. Though slightly easier than stopped-down metering, operation is less convenient than automatic operation.
When Canon introduced its EOS line of cameras in 1987, the EF lenses incorporated electromagnetic diaphragms, eliminating the need for a mechanical linkage between the camera and the diaphragm. Because of this, the Canon TS-E tilt–shift lenses include automatic aperture control.
In 2008, Nikon introduced its PC-E perspective-control lenses with electromagnetic diaphragms. Automatic aperture control is provided with the D300, D500, D600/610, D700, D750, D800/810, D3, D4 and D5 cameras. With some earlier cameras, the lenses offer preset aperture control by means of a pushbutton that controls the electromagnetic diaphragm; with other earlier cameras, no aperture control is provided, and the lenses are not usable.
Camera movements
Tilt
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.
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
If a subject plane is 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 changing the camera angle; in effect the camera can be aimed with the shift movement. A transcription is available on the Large Format Page. 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.