Anamorphic format is a term that can be used either for: the cinematography technique of capturing a widescreen picture on standard 35 mm film, or other visual recording media, with a non-widescreen native aspect ratio; or a photographic projection format in which the original image requires an optical anamorphic lens to recreate the original aspect ratio. It should not be confused with anamorphic widescreen, which is a very different electronically based video encoding concept that uses similar principles to the anamorphic format but different means. The word "anamorphic" and its derivatives stem from the Greek words meaning formed again, due to reshaping the image onto the film or recording media.
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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 Pour Construire un Feu (To Build a Fire) in 1927 by Claude Autant-Lara.[1]
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.[2]
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.[1] 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 development of anamorphic widescreen arose due to a desire for wider aspect ratios. The modern anamorphic widescreen format has an aspect ratio of 2.40:1, meaning the picture width is 2.40 times its height, (technically it is 2.39:1, but it is known professionally as 2.40:1 or "two-four-oh"). 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 is not as wide (or, conversely, is too tall). In non-anamorphic spherical (flat) widescreen imaging, the picture is recorded on film so that its full width fits within the film frame, and substantial film frame area is wasted on portions that will be matted out by the time of projection, either on the print or in the projector, in order to create a widescreen image in the theater (Figure 1).
To make full use of the available film, an anamorphic lens is used during recording. 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, and hence squeezing the scene being photographed, in only one direction, as per a cylinder, e.g., the original CinemaScope system based on Henri Chrétien's design). Whatever the method used, the anamorphic lens leaves the image on film looking as if it had been stretched vertically. This deliberate geometric distortion is then reversed upon projection, resulting in a wider aspect ratio on-screen than that of the frame as recorded on film.
An anamorphic lens consists of a regular spherical lens, plus an anamorphic attachment (or 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 prime camera lens onto which it is mounted), but still nevertheless anamorphoses the optical field. When you use an anamorphic attachment, you use a spherical lens of a different focal length than you would for 1.85:1 (one sufficient to produce an image the full height of the frame and twice the width), and then the anamorphic attachment squeezes 2x horizontally. Specialized reverse anamorphic attachments existed that were relatively rarely used on projection and camera lenses to expand the image in the vertical space (e.g., the early Technirama system mentioned above), so that (in the case of the common two-times anamorphic lens) a frame twice as high as it might have been filled the available film area. Since a larger film area needed to be used to record the same picture, quality was increased.
The distortion introduced in the picture must be corrected when the film is played back, so another lens is used during projection that either expands the picture back to its correct proportions or (as in the case of the now defunct 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 complementary dimension to the one anamorphosed (horizontally squeezed or vertically stretched).
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 investing in a new film format, along 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 to be more practicable. Cinerama preceded anamorphic films, but consisted of three projected images side-by-side on the same screen: the images never blended together perfectly at the edges, and it required three projectors; a 6-perf-high frame, which required 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, which presented synchronization problems). Nonetheless, the format was popular enough with audiences to spur studios to the wide screen developments of the early 1950s. A few films were distributed in Cinerama format and shown in special theaters. Anamorphic widescreen was attractive to studios because of its similar high aspect ratio (Cinerama was 2.59), without the disadvantages of Cinerama's added complexities and costs.
The common anamorphic widescreen film format in use today is commonly called Scope 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 at the time of CinemaScope, except for minor technical developments.
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, such as from car headlights, in the frame with an otherwise dark scene. This artifact is not always considered to be a problem. It has come to be associated with a certain cinematic look and is in fact sometimes emulated using a special effect filter in scenes that were not shot using an anamorphic lens. Another common aspect of anamorphic lenses is that light reflections in the lens will be elliptical rather than round, as they are in spherical 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 camera lenses is that out-of-focus elements tend to be blurred more vertically. An out-of-focus point of light in the background will appear as a vertical oval rather than a circle. When the camera shifts focus, there is often a noticeable effect where elements 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 will often use a 50 mm anamorphic lens when they would otherwise use a 25 mm spherical lens, a 70 mm rather than a 35 mm, and so on.
A third characteristic, particularly of simple anamorphic add-on attachments to prime lenses, is "anamorphic mumps". For reasons of practical optics, the anamorphic squeeze is not uniform across the image field in any system, 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 in the center of the screen their faces look somewhat like they had 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 they walk across the screen from one side to the other, they increase in apparent girth. Early Cinemascope presentations in particular (using Chrétien's off-the-shelf lenses) suffered from it. The solution was to link the anamorphic squeeze of the add-on adapter to the focus position of the prime lens, so that as focus changed the anamorphic ratio changed along with it, resulting in a normal-looking geometry in the area of interest on-screen. In early prismatic systems such as Panavision's Ultra-Panavision system, the angle of counter-rotation between prisms was linked by a mechanical system to the focus ring of the prime lens. In later cylindrical lens systems, the change in aspect ratio required between focus positions was achieved by combining two sets of anamorphic optics in one: a robust "squeeze" system 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 prime lens. The combination of squeeze and expansion changed the anamorphic ratio to the extent required to minimize the effect of anamorphic mumps in the area of interest in the frame. Though these techniques were regarded as a fix for the anamorphic mumps, they were a compromise. Cinematographers still needed to be careful with their framing of the scene so that effects of the change in aspect ratio were not readily apparent. The first company to produce an anti-mumps system was Panavision in the late 1950s.
While the anamorphic scope widescreen format is still in use as a camera format, it has been losing popularity in favor of flat formats, mainly Super 35 mm film. (In Super 35, the film is shot flat and can then be 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, the distributed prints of a film with a 2.39:1 theatrical aspect ratio will always be 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 that is required is an anamorphic projection lens, which has long been considered standard equipment.
Other widescreen film formats (commonly 1.85:1 and 1.66:1) are simply cropped in vertical size to produce the widescreen effect, a technique known as masking or matting. This can occur either during filming, where the framing is masked in the gate, or in the lab, which can optically create a matte 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, though the film is framed for the intended aspect ratio; this approach is called full-frame filming, since most spherical 4-perf cameras retain the silent gate. In these, the film captures additional information that is masked out during projection using an aperture mask in the projector gate, and 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 avoid pan and scan, by protecting the frame for 4:3.
One common misconception about the anamorphic format concerns the actual width number of the aspect ratio, as 2.35, 2.39 or 2.40. Since the anamorphic lenses in virtually all 35 mm anamorphic systems provide a 2:1 squeeze; one would logically conclude that a 1.37:1 full academy gate would lead to a 2.74:1 aspect ratio, if used with anamorphic lenses. However, due to a difference in the camera gate aperture and projection mask sizes for anamorphic films, 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 first SMPTE definition for anamorphic projection with an optical sound track down the side (PH22.106-1957), made in December 1957, standardized the aperture to 0.839 in by 0.715 in (1.17:1). The aspect ratio for this aperture, after a 2x unsqueeze, rounds to 2.35:1. A new definition was created in October 1970 (PH22.106-1971) which made the vertical dimension slightly smaller in order to make splices less noticeable (as anamorphic prints use more of the negative's frame area than any other modern format) when projected. This new aperture size, 0.838 by 0.700 inches (21.3 by 17.8 mm), or 1.19:1, makes for an unsqueezed ratio of 2.39:1 (more commonly referred to as 2.40:1). The most recent revision, from August 1993 (SMPTE 195-1993), slightly altered the dimensions so as to standardize a common aperture width (0.825-inch, or21.0 mm) for all formats, anamorphic and flat. At these modern dimensions, of 0.825 × 0.690 inch (21.0 × 17.5 mm), or 1.20:1, the unsqueezed ratio remains at 2.39:1.[3]
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 incorrectly rounded up to 2.40 (instead of the correct 2.4). With the exception of certain specialist and archivist areas, generally 2.35, 2.39, and 2.40 mean the same to most 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 contains nonetheless picture information which is useful for such visual effects tasks as 2D and 3D tracking. This mildy 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.
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