Anamorphic format
Anamorphic format is a cinematography technique that captures widescreen images using recording media with narrower native aspect ratios. Originally developed for 35 mm film to create widescreen presentations without sacrificing image area, the technique has since been adapted to various film gauges, digital sensors, and video formats.
Rather than cropping or matting the image and discarding visual information, anamorphic capture employs cylindrical lenses to horizontally compress or "squeeze" the image during recording. A complementary lens is then used during projection to expand the image back to its intended widescreen proportions. By utilizing the full height of the film frame or sensor, this method retains more image resolution than cropped non-anamorphic widescreen formats. Anamorphic lenses have more complex optics than standard spherical lenses, which require more light and can introduce distinctive distortions and lens flares. However, these artefacts are sometimes deliberately embraced for their aesthetic appeal.
In the late 1990s and early 2000s, the use of anamorphic formats declined as advances in film stocks and processing techniques, followed by the advent of digital intermediates, made the lower resolution associated with matting flat spherical formats such as Super 35 less of a limitation. Many productions shifted to spherical lenses, which are simpler, lighter, more cost-effective, and free from the optical distortions and artefacts characteristic of anamorphic optics. In the years that followed, the widespread adoption of digital cinema cameras and projectors contributed to a renewed interest in anamorphic formats, as digital sensors with higher base ISO sensitivity made filming in low light with anamorphic lenses more feasible.
The word anamorphic and its derivatives stem from the Greek anamorphoo, compound of morphé with the prefix aná.
Anamorphic format should not to be confused with anamorphic widescreen, a different video encoding concept that uses similar principles but different means.
History
The process of anamorphosing optics was developed by Henri Chrétien during World War I to provide a wide angle viewer for military tanks. The optical process was called Hypergonar by Chrétien and was capable of showing a field of view of 180 degrees. After the war, the technology was first used in a cinematic context in the short film To Build a Fire in 1927 by Claude Autant-Lara.In the 1920s, phonograph and motion picture pioneer Leon F. Douglass also created special effects and anamorphic widescreen motion picture cameras. However, how this relates to the earlier French invention, and later development, is unclear.
Anamorphic widescreen was not used again for cinematography until 1952 when Twentieth Century-Fox bought the rights to the technique to create its CinemaScope widescreen technique. CinemaScope was one of many widescreen formats developed in the 1950s to compete with the popularity of television and bring audiences back to the cinema. The Robe, which premiered in 1953, was the first feature film released that was filmed with an anamorphic lens.
Development
The introduction of anamorphic widescreen arose from a desire for wider aspect ratios that maximized overall image detail while retaining the use of standard cameras and projectors. The modern anamorphic format has an aspect ratio of 2.39:1, meaning the picture's width is 2.39 times its height,. The older Academy format of anamorphic widescreen was a response to a shortcoming in the non-anamorphic spherical widescreen format. With a non-anamorphic lens, the picture is recorded onto the film negative such that its full width fits within the film's frame, but not its full height. A substantial part of the frame area is thereby wasted, being occupied by a portion of the image which is subsequently matted-out and so not projected, in order to create the widescreen image.To increase overall image detail, by using all the available area of the negative for only that portion of the image which will be projected, an anamorphic lens is used during photography to compress the image horizontally, thereby filling the full frame's area with the portion of the image that corresponds to the area projected in the non-anamorphic format. Up to the early 1960s, three major methods of anamorphosing the image were used: counter-rotated prisms, curved mirrors in combination with the principle of total internal reflection, and cylindrical lenses. Regardless of the method, the anamorphic lens projects a horizontally squeezed image on the film negative. This deliberate geometric distortion is then reversed on projection, resulting in a wider aspect ratio on-screen than that of the negative's frame.
Equipment
An anamorphic lens consists of a regular spherical lens, plus an anamorphic attachment that does the anamorphosing. The anamorphic element operates at infinite focal length, so that it has little or no effect on the focus of the primary lens it's mounted on but still anamorphoses the optical field. A cameraman using an anamorphic attachment uses a spherical lens of a different focal length than they would use for Academy format, and the anamorphic attachment squeezes the image to half-width. Other anamorphic attachments existed which would expand the image in the vertical dimension, so that a frame twice as high as it might have been filled the available film area. In either case, since a larger film area recorded the same picture the image quality was improved.The distortion introduced in the camera must be corrected when the film is projected, so another lens is used in the projection booth that restores the picture back to its correct proportions to restore normal geometry. The picture is not manipulated in any way in the dimension that is perpendicular to the one anamorphosed.
Using wider film for movies seemed easier, but 35mm's widespread use made it more cost-effective to add special lenses to cameras and projectors rather than invest in a new format and equipment.
Naming
was an earlier attempt to solve the problem of high-quality widescreen imaging, but anamorphic widescreen eventually proved more practical. Cinerama consisted of three simultaneously projected images side by side on the same screen. However, in practice the images never blended together perfectly at the edges. The system also suffered from various technical drawbacks, in that it required a film frame that was 6 perf in height, three cameras, and three projectors, which resulted in a host of synchronization problems. Nonetheless, the format was popular enough with audiences to trigger off the widescreen developments of the early 1950s. A few films were distributed in Cinerama format and shown in special theaters, but anamorphic widescreen was more attractive to the Studios since it could realize a similar aspect ratio and without the disadvantages of Cinerama's complexities and costs.The anamorphic widescreen format in use today is commonly called 'Scope', or 2.35:1. Filmed in Panavision is a phrase contractually required for films shot using Panavision's anamorphic lenses. All of these phrases mean the same thing: the final print uses a 2:1 anamorphic projector lens that expands the image by exactly twice the amount horizontally as vertically. This format is essentially the same as that of CinemaScope, except for some technical developments, such as the ability to shoot closeups without any facial distortion.
Optical characteristics
There are artifacts that can occur when using an anamorphic camera lens that do not occur when using an ordinary spherical lens. One is a kind of lens flare that has a long horizontal line, usually with a blue tint, and is most often visible when there is a bright light in the frame, such as from car headlights, in an otherwise dark scene. This artifact is not always considered a problem, and even has become associated with a certain cinematic look, and often emulated using a special effect filter in scenes shot with a non-anamorphic lens. Another common aspect of anamorphic lenses is that light reflections within the lens are elliptical, rather than round as in ordinary cinematography. Additionally, wide-angle anamorphic lenses of less than 40 mm focal length produce a cylindrical perspective, which some directors and cinematographers, particularly Wes Anderson, use as a stylistic trademark.File:Cavendish House Leicester.jpg|thumb|left|upright=1.5|Many wide-angle anamorphic lenses render a cylindrical perspective, as simulated by this stitched panorama of Cavendish House, Leicester. Contrast the straight vertical plane with the curved horizontal plane.
Another characteristic of anamorphic lenses is that the cylindrical glass effectively creates two focal lengths within the lens. This results in out-of-focus points of light appearing as vertical ovals rather than circles, as well as an increase in horizontal angle of view, both in proportion to the squeeze factor. A 50mm anamorphic lens with a 2x squeeze will have the horizontal view of a 25mm spherical lens, while maintaining the vertical view and depth of field of a 50mm. This has led to the common claim that anamorphic lenses have shallower focus, as the cinematographer must use a longer lens to obtain the same horizontal coverage.
A third characteristic, particularly of simple anamorphic add-on attachments, is "anamorphic mumps". For reasons of practical optics, the anamorphic squeeze is not uniform across the image field in any anamorphic system. This variation results in some areas of the film image appearing more stretched than others. In the case of an actor's face, when positioned in the center of the screen faces look somewhat like they have the mumps, hence the name for the phenomenon. Conversely, at the edges of the screen actors in full-length view can become skinny-looking. In medium shots, if the actor walks across the screen from one side to the other, he will increase in apparent girth. Early CinemaScope presentations in particular suffered from this. Panavision was the first company to produce an anti-mumps system in the late 1950s.
Panavision used a second lens which was mechanically linked to the focus position of the primary lens. This changed the anamorphic ratio as the focus changed, resulting in the area of interest on-screen having a normal-looking geometry. Later cylindrical lens systems used, instead, two sets of anamorphic optics: one was a more robust "squeeze" system, which was coupled with a slight expansion sub-system. The expansion sub-system was counter-rotated in relation to the main squeeze system, all in mechanical interlinkage with the focus mechanism of the primary lens: this combination changed the anamorphic ratio and minimized the effect of anamorphic mumps in the area of interest in the frame. Although these techniques were regarded as a fix for anamorphic mumps, they were actually only a compromise. Cinematographers still had to frame scenes carefully to avoid the recognizable side-effects of the change in aspect ratio.