Anamorphic widescreen
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Template:Cleanup-date Anamorphic widescreen is a cinematography and photography technique for capturing a widescreen picture on standard 35mm film. It can also refer to a related technique for maximizing picture quality in DVD video recordings.
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Background
Anamorphic widescreen in cinematography was first popularized with CinemaScope, which was one of many widescreen formats developed in the 1950s. The Robe was the first feature film released to use anamorphic photography, premiering in 1953. The need for anamorphic widescreen arose due to an incompatibility between the aspect ratio of the photographic film, and that of the resulting picture. The modern anamorphic widescreen format has an aspect ratio of 2.39 to 1, meaning the picture width is 2.39 times its height. "Academy format" 35mm film (standard non-anamorphic full frame with sound) has an aspect ratio of 1.37 to 1, which is not as wide (or, conversely, is too tall). In conventional spherical ("flat") 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; this lens effectively stretches the picture vertically so that it fills the available film area (Figure 2). Since a larger film area is being used to project the same picture, quality is increased. (The film frame itself is also very slightly larger.) The distortion introduced in the picture must be corrected when the film is played back, so another lens is used during projection that returns the picture to its correct proportions.
It may seem that it would be easier to simply use a wider film for recording movies; however, 35mm 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, and editing equipment.
Cinerama was an earlier attempt to solve the problem of high quality widescreen imaging, but anamorphic widescreen eventually proved to be more practically viable. Cinerama preceded anamorphic films, but consisted of three projected images side-by-side; the images never blended together perfectly and it required three projectors, a 6 perf high frame, which required four times the film, and three cameras (eventually just one camera with three lenses). Nonetheless, the format was popular enough with audiences to spur studios to the widescreen developments of the early 1950s. Anamorphic widescreen was attractive to studios because of its similar high aspect ratio (Cinerama was 2.59) without the disadvantages that came with the Cinerama format's simultaneous reels. Recently part of the Cinerama formula has come back into consideration for future widescreen projection. It is the 6 perf pull-down, which with digital sound, eliminates the sound track and makes a 1.6 times increase in the frame size prior to anamorphic, 2 to 1 width expansion. That process is called "Cine 160", and is also useful for better 3D projection. This format is about 20 times cheaper to impliment than 4K digital, that will likely be the digital successor to regular 35mm theater projection. Current interest in 3D may spur on the use of the new film format.
The common anamorphic widescreen film format in use today is commonly called "'Scope" or 2.35 (the latter being a misnomer born of old habit; see "2.35, 2.39, or 2.4?" 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 than 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.
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. An anamorphic lens will also have a more shallow depth of field compared to a spherical lens for a given aperture.
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:
- An anamorphic lens can create artifacts as described above.
- An anamorphic lens is more expensive than a spherical lens.
- Because the anamorphic scope camera format does not preserve any of the image above and below the scope frame, it may not transfer as well to more narrow aspect ratios such as 4:3 or 16:9 for full screen television.
- Film grain is less of a concern because of the availability of higher quality film stocks and digital intermediates, although the anamorphic format will always yield higher definition.
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 theatrical aspect ratio will always be in anamorphic widescreen format. This is not likely to soon change because cinemas 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.
Many directors and cinematographers who use the anamorphic format swear by it, shooting most if not all of their films this way. Directors known for their loyalty to the anamorphic format include Clint Eastwood, Wes Anderson, John McTiernan, Jan de Bont, Mel Gibson and Michael Bay. Many of the world's most reknowned cinematographers, such as Donald McAlpine, Vilmos Zsigmond, Laszlo Kovacs and John Schwartzman, shoot anamorphic every chance they get.
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 hard matte. This can occur either during filming, where part of the picture is masked out 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. Many film prints today have no matte, though the film is framed for the intended aspect ratio; this approach is called full frame filming. In these, the film captures additional information that is masked out during projection in the projector gate, known as soft matte process. This approach allows filmmakers the freedom to include the additional picture in a 4:3 transfer of the film and avoid pan and scan, though doing so may introduce areas of the picture that were not intended for viewing, such as microphone booms or other filming accessories that would not have been visible in the widescreen frame. For this reason, often productions will "protect for 4:3" by making certain the frame is clear of these objects, even though that part of the image will not remain visible in the theater.
2.35, 2.39, or 2.4?
One common misconception about the anamorphic format concerns the actual number of the aspect ratio itself. Since the anamorphic lenses in virtually all 35mm 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 frame area than any other modern format) when projected. This new aperture size, 0.838 in by 0.7 in, (1.19:1) makes for an unsqueezed ratio of 2.39:1. The most recent revision, from August 1993 (SMPTE 195-1993), slightly altered the dimensions so as to standardize a common aperture width (0.825 in) for all formats, anamorphic and flat. At these modern dimensions (0.825 in by 0.690 in - 1.19:1), the unsqueezed ratio remains at 2.39:1. Template:Ref
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 sometimes rounded up to 2.4. With the exception of certain specialist and archivist areas, generally 2.35, 2.39, and 2.4 mean the same to most professionals, whether they themselves are even aware of the changes or not.
Lens Makers
There are numerous companies that are known for manufacturing anamorphic lenses. The following are the best known in the film industry:
- Panavision - The most commonly used source of anamorphic lenses by far, they have several series of lenses which range from 20mm to a 2,000mm anamorphic telescope.
- Joe Dunton Camera - Manufacturer and rental house based in England and North Carolina, carries the most extensive range of focal lengths available anywhere.
- Rodenstock, makers of Hawk Lenses, used on Star Wars: Episode 1 - The Phantom Menace
- Elite Optics, manufactured in Russia and considered among the highest quality anamorphic lenses available. They are sold in the United States by Slow Motion, Inc.
- Schneider Optics, makers of the most widely-used anamorphic projection lenses in the world.
Super 35 and Techniscope
Although many films projected anamorphically have been shot using anamorphic lenses, there are often aesthetic and technical reasons which make shooting with spherical lenses preferable. If the director and cinematographer still wish to retain the 2.39 aspect ratio, anamorphic prints can be made from spherical negatives. Because the 2.39 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.
DVD video
A similar anamorphic technique is used to store video on DVD. DVDs using anamorphic widescreen make effective use of the available resolution, as well as allowing a film to automatically expand to fit widescreen television sets. Anamorphic widescreen DVDs store a stretched picture, to make more optimal use of vertical resolution, that is to avoid or decrease wasted lines of resolution on the black letterboxing bars. Sources that are close to 16:9 can be transferred to DVD taking up the entire 16:9 frame with no wasted space. However, sources that are wider than 16:9, such as 1.85:1 or 2.39:1 video, must still be letterboxed into the 16:9 frame with varying amounts of black bars.
When a DVD is inserted into a player, the player will do one of two things depending on the type of television set in use: If the DVD player is set up to output a widescreen image, the player will send a signal to the TV that the video is anamorphic, and then sends the video, still horizontally squeezed, to the television, which will stretch it horizontally to fill the screen. The combination of this squeeze-and-stretch restores the video back to its original widescreen aspect ratio, minimizing the loss of quality. If the DVD player is set up to output a letterboxed picture, the DVD player compresses the picture vertically to restore the correct aspect ratio, and adds letterbox-style "black-bars" before sending the signal to the display device.
This technique is not used on all DVD discs; some use the standard letterboxing technique. Those that do use the anamorphic technique typically specify "anamorphic widescreen", "enhanced for 16x9", "enhanced for widescreen televisions" or a similar statement on the packaging, though there is currently no widely accepted standard for such labeling. If a DVD claims to be widescreen, but does not have a label like one of the previous, it may use the standard letterbox technique, resulting in decreased resolution for widescreen pictures. Some DVD packaging explicitly mentions that the lower-quality letterbox technique is used; when viewing such a letterboxed DVD on a widescreen display, it may be necessary to zoom in on the picture in order to utilize the full width of the screen.
Anamorphic lens enhancement
Image:DVD-Video enhancement using anamorphic lens.gif Since the anamorphic widescreen standard for DVD disks includes letterboxing for aspect ratios wider than 16:9, the display device will still lose some resolution to the display of black bars for wider formats such as 2.39:1 films. This wasted resolution can be eliminated by using a front projector in conjunction with an anamorphic lens and a video processor: first, the video processor or scaler (such as an HTPC) stretches the video up to the full resolution of the projector, eliminating the wasted resolution but also distorts the image vertically. As the distorted image is projected, it passes through an anamorphic lens which will either shrink the video vertically or expand it horizontally, restoring the original aspect ratio in both casesTemplate:Ref. Depending on the quality of the scaler and the lens, the end result is potentially a smoother video due to increased vertical resolution. If the anamorphic lens shrinks the image vertically, there is an added advantage of increased brightness, since light output has been condensed. In contrast, an anamorphic lens which stretches the image horizontally will also decrease its brightness. A similar approach can be used to convert a 4:3 projector into a 16:9 projectorTemplate:Ref, or a 16:9 projector into a 4:3 projector (by rotating an anamorphic lens by 90 degrees).
References
- Template:Note prismasonic.com - Screen size calculator for conversion by anamorphic lens
- Template:Note "Of Apertures and Aspect Ratios", Widescreen Museum