Anamorphic format is the cinematography technique of shooting a widescreen picture on standard 35 mm film or other visual recording media with a non-widescreen native aspect ratio. It also refers to the projection format in which a distorted image is "stretched" by an anamorphic projection lens to recreate the original aspect ratio on the viewing screen. (It should not be confused with anamorphic widescreen, a different video encoding concept that uses similar principles but different means.) The word anamorphic and its derivatives stem from the Greek words meaning "formed again". As a camera format, anamorphic format is losing popularity in comparison to "flat" (or "spherical") formats such as Super 35 mm film shot using spherical lenses; however, because most film movie projectors use anamorphic projection format, spherical format negatives are commonly converted into anamorphic prints for projection.
In the years since digital cinema cameras and projectors have become commonplace, anamorphic has experienced a considerable resurgence of popularity, due in large part to the higher base ISO sensitivity of digital sensors, which facilitates shooting at smaller apertures.
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 Construire un Feu (To Build a Fire, based on the 1908 Jack London story of the same name) 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 cinemas. The Robe, which premiered in 1953, was the first feature film released that was filmed with an anamorphic lens.
The introduction of anamorphic widescreen arose from a desire for wider aspect ratios that maximised overall image detail while retaining the use of standard (4 perf per frame) cameras and projectors. The modern anamorphic format has an aspect ratio of 2.40:1, meaning the (projected) picture's width is 2.4 times its height, (technically it is 2.39:1, but it is known professionally as 2.40:1 or "two-four-oh"). The older Academy format 35 mm film (standard non-anamorphic full frame with sound tracks in the image area) has an aspect ratio of 1.37:1, which, when projected, is not as wide (or, equivalently, is taller).
Anamorphic widescreen was a response to a shortcoming in the non-anamorphic spherical (a.k.a. "flat") 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 so does its full height. A substantial part of the frame area is thereby wasted, being occupied (on the negative) by a portion of the image which is subsequently matted-out (i.e. masked, either on the print or in the projector) 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 stretch the image vertically, thereby filling the full (4 perf) 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 (e.g. Ultra Panavision), curved mirrors in combination with the principle of Total Internal Reflection (e.g. Technirama), and cylindrical lenses (lenses curved, hence squeezing the image being photographed, in only one direction, as with a cylinder, e.g. the original CinemaScope system based on Henri Chrétien's design). Whichever method is used, the anamorphic lens leaves the image recorded on the film negative looking as if it has been stretched vertically (because it has been). This deliberate geometric distortion is then reversed on projection, resulting in a wider aspect ratio on-screen than that of the negative's frame.
An anamorphic lens consists of a regular spherical lens, plus an anamorphic attachment (or an integrated lens element) 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 (distorts) the optical field. A cameraman using an anamorphic attachment uses a spherical lens of a different focal length than he would use for Academy format (i.e. one sufficient to produce an image the full height of the frame and twice its width), and the anamorphic attachment squeezes the image (in the horizontal plane only) to half-width. Other anamorphic attachments existed (that were relatively rarely used) which would expand the image in the vertical dimension (e.g. in the early Technirama system mentioned above), so that (in the case of the common 2-times anamorphic lens) 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 better.
The distortion (vertical stretching) introduced in the camera must be corrected when the film is projected, so another lens is used in the projection booth that expands the picture back to its correct proportions (or, in the case of the now obsolete Technirama system, squeezes the image vertically) to restore normal geometry. It should be noted that the picture is not manipulated in any way in the dimension that is orthogonal to the one anamorphosed.
It may seem that it would be easier to simply use a wider film for recording movies. However, 35 mm film was already in widespread use, and it was more economically feasible for film producers and exhibitors to simply attach a special lens to the camera or projector, rather than invest in an entirely new film format, with the attendant cameras, projectors, editing equipment and so forth.
Cinerama was an earlier attempt to solve the problem of high-quality widescreen imaging, but anamorphic widescreen eventually proved more practical. Cinerama (which had an aspect ratio of 2.59:1) consisted of three 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 three projectors, a 6-perf-high frame, four times as much film, and three cameras (eventually just one camera with three lenses and three streaming reels of film and the attendant machinery), plus 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 due to its similar aspect ratio and its lack of the disadvantages of Cinerama's complexities and costs.
The anamorphic widescreen format in use today is commonly called 'Scope' (a contraction of the early term CinemaScope), or 2.35:1 (the latter being a misnomer born of old habit; see "2.35, 2.39 or 2.40?" below). 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. (CinemaScope films seldom used full facial closeups, because of a condition known as CinemaScope mumps, which distored faces as they got closer to the camera.)
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. It has become associated with a certain cinematic look, and is in fact sometimes 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.
Another characteristic of anamorphic lenses, because they stretch the image vertically, is that out-of-focus elements tend to blur more in the vertical direction. An out-of-focus point of light in the background (called bokeh) appear as a vertical oval rather than as a circle. When the camera shifts focus, there is often a noticeable effect whereby objects appear to stretch vertically when going out of focus. However, the commonly cited claim that anamorphic lenses produce a shallower depth of field is not entirely true. Because of the cylindrical element in the lens, anamorphic lenses take in a horizontal angle of view twice as wide as a spherical lens of the same focal length. Because of this, cinematographers often use a 50 mm anamorphic lens when they would otherwise use a 25 mm spherical lens, or a 70 mm rather than a 35 mm, and so on.
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 (whether cylindrical, prismatic or mirror-based). 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 (using Chrétien's off-the-shelf lenses) suffered from this. The first company to produce an anti-mumps system was Panavision in the late 1950s.
Panavision used a second lens (i.e. an add-on adapter) 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.
Although the anamorphic widescreen format is still in use as a camera format, it has been losing popularity in favour of flat formats, mainly Super 35 mm film. (In Super 35, the film is shot flat, then matted, and optically printed as an anamorphic release print.) There can be several reasons for this:
Anamorphic 'scope as a printed film format, however, is well established as a standard for widescreen projection. Regardless of the camera formats used in filming, distributed prints of a film with a 2.39:1 theatrical aspect ratio is always in anamorphic widescreen format. This is not likely to soon change because movie theaters around the world don't need to invest in special equipment to project this format--all they need is an anamorphic projection lens, which has long been standard equipment.
Other widescreen film formats (commonly 1.85:1 and 1.66:1) are simply cropped (i.e. portions of the image are omitted) to produce a widescreen effect, a technique known as masking or matting. This can occur either during filming, where the framing is masked in the camera's gate, or in the lab, which can optically print a matte mask onto the prints. Either method produces a frame similar to that in Figure 1, and is known as a hard matte. Many film prints today have no matte, although the film is intended to be shown in a widescreen aspect ratio in motion picture theaters; this approach is called full-frame filming, since most spherical 4-perf cameras retain the silent gate. In these, the negative captures additional information that is masked out during projection (by an aperture mask in the projector's gate), and this is known as soft matte. This approach allows filmmakers the freedom to include the additional picture in an open matte 4:3 transfer of the film and thereby avoid the drawbacks of pan and scan, by protecting the frame for possible 4:3 presentation.
One common misconception about the anamorphic format concerns the actual width number of the aspect ratio, as 2.35, 2.39 or 2.4. Since the anamorphic lenses in virtually all 35 mm anamorphic systems provide a 2:1 squeeze, one would logically conclude that a 1.375:1 full academy gate would lead to a 2.75:1 aspect ratio when used with anamorphic lenses. Due to differences in the camera gate aperture and projection aperture mask sizes for anamorphic films, however, the image dimensions used for anamorphic film vary from flat (spherical) counterparts. To complicate matters, the SMPTE standards for the format have varied over time; to further complicate things, pre-1957 prints took up the optical soundtrack space of the print (instead having magnetic sound on the sides), which made for a 2.55:1 ratio.
The initial SMPTE definition for anamorphic projection with an optical sound track down the side (PH22.106-1957), issued in December 1957, standardized the projector aperture at 0.839 × 0.715 inches (21.3 × 18.2 mm) (aspect ratio 1.17:1). The aspect ratio for this aperture, after a 2x unsqueeze, is 2.3468...:1, which rounded to the commonly used value 2.35:1. A new definition issued in October 1970 (PH22.106-1971) specified a slightly smaller vertical dimension of 0.700 in. for the projector aperture, to help make splices less noticeable to film viewers.
Four-perf anamorphic prints use more of the negative's available frame area than any other modern format, which leaves little room for splices. As a consequence, a bright line flashed onscreen when a splice was projected, and theater projectionists had been narrowing the vertical aperture to hide these flashes even before issuance of PH22.106-1971. This new projector aperture size, 0.838 × 0.700 inches (21.3 × 17.8 mm), aspect ratio 1.1971...:1, made for an un-squeezed ratio of 2.39:1 (and commonly referred to by the rounded value 2.40:1 or 2.4:1). The most recent revision, from August 1993 (SMPTE 195-1993), slightly altered the dimensions so as to standardize a common projection aperture width (0.825-inch, or 21.0 mm) for all formats, anamorphic (2.39:1) and flat (1.85:1). The projection aperture height was also reduced by 0.01" in this modern specification to 0.825 × 0.690 inches (21.0 × 17.5 mm), aspect ratio 1.1956...:1 (and commonly rounded to 1.20:1), to retain the un-squeezed ratio of 2.39:1. The camera's aperture remained the same (2.35:1 or 2.55:1 if before 1958), only the height of the "negative assembly" splices changed and, consequently, the height of the frame changed.
Anamorphic prints are still often called 'Scope' or 2.35 by projectionists, cinematographers, and others working in the field, if only by force of habit. 2.39 is in fact what they generally are referring to (unless discussing films using the process between 1958 and 1970), which is itself usually rounded up to 2.40 (with a false precision as compared to the mathematically correct 2.4). With the exception of certain specialist and archivist areas, generally 2.35, 2.39, and 2.40 mean the same to professionals, whether they themselves are even aware of the changes or not.
There are numerous companies that are known for manufacturing anamorphic lenses. The following are the well known in the film industry:
Although many films projected anamorphically have been shot using anamorphic lenses, there are often aesthetic and technical reasons that make shooting with spherical lenses preferable. If the director and cinematographer still wish to retain the 2.40:1 aspect ratio, anamorphic prints can be made from spherical negatives. Because the 2.40:1 image cropped from an Academy ratio 4-perf negative causes considerable waste of frame space, and since the cropping and anamorphosing of a spherical print requires an intermediate lab step, it is often attractive for these films to use a different negative pulldown method (most commonly 3-perf, but occasionally Techniscope 2-perf) usually in conjunction with the added negative space Super 35 affords.
However, with advancements in digital intermediate technology, the anamorphosing process can now be completed as a digital step with no degradation of image quality. Also, 3-perf and 2-perf pose minor problems for visual effects work. The area of the film in 4-perf work that is cropped out in the anamorphosing process nonetheless contains picture information that is useful for such visual effects tasks as 2D and 3D tracking. This mildly complicates certain visual effects efforts for productions using 3-perf and 2-perf, making anamorphic prints struck digitally from center cropped 4-perf Super 35 the popular choice in large budget visual effects driven productions.