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Aspect Ratio

With High Definition Television (HDTV) upon us, you have another factor to consider: Aspect Ratio. This is defined as the ratio of the width of the TV screen to the height. For example the standard televisions we use at present have an aspect ratio of 1.35:1 (sometimes called 4:3). That is, the TV screen is 1.35 times as wide as it is high. The aspect ratio of HDTV is 1.78:1 (often referred to as 16:9), which is slightly more rectangular. The reason this is occurring is because we are so used to seeing long rectangular images at the theater, and manufacturers feel that the new technology should include a facelift, namely a more rectangular shape.

Films at the theater vary in aspect ratio. In the United States, they are usually either 1.85:1 or 2.35:1. The former is the more common, basically because it is less expensive. The process involves shooting the motion picture on standard 35mm film, at an aspect ratio of 1.33:1 (this is called being filmed "spherical" or "flat") 2001-01-aspect-ratio-primer-aspect43-1and then, when it is shown at the theater, small metal plates in the projector crop the top and bottom of the image so that it is projected on the screen at 1.85:1. This is called "Soft Matting" 2001-01-aspect-ratio-primer-aspect1851-2.jpg(not standardized terminology, but it is descriptive and serves a useful purpose here). Occasionally, the film is shot spherically on 35mm film and then cropped to 2.35:1. Such was the case for "Terminator 2", "Apollo 13", and many others. 2001-01-aspect-ratio-primer-aspect2351crop-3.jpgOf course, when the director is shooting the picture, there are marks in the camera viewfinder as to what will be seen at the theater and what will be cropped. Sometimes, when the motion picture is finally shown on television, the parts of the imag2001-01-aspect-ratio-primer-backfuture2crop-4.jpge that were cropped at the theater are allowed to be seen, in order that the entire TV screen will be filled. For example, "Back to the Future 2" was shown at the theater soft matted at 1.85:1, but when broadcast on TV, it was shown without the soft matting.You might remember an occasional film on TV where you can see the microphone at the top, and you wonder, "How did they miss seeing that when they made the movie?" Well, they did see it, but it was cropped at the theater.2001-01-aspect-ratio-primer-backfuture2full-5.jpg
Movies filmed at 2.35:1 (it is more like 2.40:1, but most literature states it at 2.35:1) aspect ratio (CinemaScope ® and Panavision ®) are usually made by squeezing the long rectangular image sideways onto the standard 35mm film space using what is called an "anamorphic lens". 2001-01-aspect-ratio-primer-squeezed-6At the theater, another anamorphic lens on the front of the projector unsqueezes the image so that it is appears normal when shown on the screen. These high aspect ratio anamorphic movies were begun in the early 1950s because people were staying home to watch television instead of going to the theater. Color and stereophonic 2001-01-aspect-ratio-primer-aspect2351ana-7.jpgsound helped make this a great success. For additional information on anamorphic photography, see the diagram in the article by Panavision.

 

Originally, television was designed with an aspect ratio of 1.35:1 (4:3) so that movies, which, at the time, had virtually the same ratio, could be shown without cropping any of the picture. However, when CinemaScope movies were shown on TV, only about half the rectangular image could be shown, in order to fill the TV screen. This is called "Pan and Scan". It had to be done this way because, unlike the soft matting technique described above, there was no image at the top and bottom of the film to add back in when it was shown on TV. About 20% of theater movies are filmed anamorphically at 2.35:1, and the rest are filmed spherically and shown (mostly) at 1.85:1. HDTV, with its aspect ratio of 1.78:1 (16:9) does not match either of these formats, but engineering limitations dictated that this would be as high an aspect ratio that could be designed into the HDTV picture tubes.

The rectangular shaped images we see at theaters are called "widescreen" or "letterbox", as most movies are released 2001-01-aspect-ratio-primer-bigtrail1a-8.jpgnowadays in the original high aspect ratio on laser disc, DVD (Digital Video Disc or Digital Versatile Disc), a few on video tape, and some on cable TV. There is a great deal of interest in seeing films in their original widescreen aspect ratio, as shown at the theater, and Turner Classic Movies, as well as American Movie Classics cable channels routinely show them. 2001-01-aspect-ratio-primer-bigtrail4a-9.jpgThe interesting thing is that widescreen movies started long before "The Robe" in the early 1950s. In fact, Hollywood was experimenting with them in the 1920s, and 1930s. One of John Wayne's first movies, "The Big Trail", was released in 1930, and in 70mm. Unfortunately, the stock market crashed in 1929, and theaters could not afford to show it. So, widescreen films had to wait until TV was keeping viewers at home before they would emerge en masse.

With a standard 4:3 television, widescreen movies leave blank space at the top and bottom of the screen. This is the only 2001-01-aspect-ratio-primer-demetrius235-10.jpgway to fit the rectangular widescreen image onto the more square-like 4:3 TV screen. Although some people get the feeling they are being cheated when they see a widescreen movie on TV, with so much blank space, it is really just a matter of how the movie was composed when it was filmed. If you compare a2001-01-aspect-ratio-primer-demetrius43-11.jpg closeup scene in a widescreen movie with one filmed at 4:3 aspect ratio, you will find that the director usually moves the camera back farther from the subject in a widescreen film, in order to maintain a similar field of view height. In particular, people will often be filmed from just above the head to below the shoulders in closeups, regardless of the aspect ratio. Other than closeups, there is usually a bit more on the sides and a bit less at the top and bottom in a widescreen scene vs. a similar scene from a movie filmed at 4:3. When CinemaScope came out in 1953, the first few movies were filmed in the widescreen 2.35:1 format and also in the conventional 4:3 format just in case the movie audiences didn't like widescreen. Note the rare comparison of the same movie scene ("Demetrius and the Gladiators") filmed in CinemaScope (photo on the left) as well as standard 4:3 (photo on the right). The studio had to do different takes with the two different cameras.

High aspect ratio (2.35:1) movies do appear a bit odd (blank areas at the top and bottom of the TV screen) when seen on TV2001-01-aspect-ratio-primer-benhur-12 in the original ratio, probably because they were filmed for viewing on large theater screens. For example, "Ben Hur" is available at its almost 3:1 aspect ratio on home video. When compared to an old movie, like "The Sea Hawk", 2001-01-aspect-ratio-primer-seahawk-13which was filmed at 1.33:1, "Ben Hur" can have a strange effect when the image is the same width but smaller height as the old movie. "The Sea Hawk" and "Ben Hur" are two of my favorite movies, and when I saw "Ben Hur" for the first time, in a Cinerama theater, it was breathtaking. I watch it at home with my feet practically resting on the base of the TV, because the widescreen image is so small. Two other examples of an old movie vs. a Panavision movie on a TV at the same width can be seen by clicking here to view a frame from "Sands of Iwojima" next to a frame from "The Longest Day". When a film that was made anamorphically and shown in letterbox form at the theater, such as "The Untouchables", t2001-01-aspect-ratio-primer-untouchableswide-14.jpghen is shown on broadcast TV, it is usually modified to fit your TV screen, called "Pan & Scan" (P&S). Some people don't like the widescreen versions at home for one reason or another. H2001-01-aspect-ratio-primer-untouchablesfull-15.jpgowever, the letterbox versions are the only way to see everything that the director intended. HDTV will alleviate the Pan & Scan problem, because they are 16:9 in shape. Widescreen movies will be shown at full width, while the 4:3 images will occupy the center of the screen. (All screen shots copyright respective studios.) For those consumers who hate widescreen movies, preferring the P&S, even if it means missing some of the picture, many new DVD players will let you enlarge the image so just the center part of the movie is seen, filling the TV screen.

There are several 16:9 NTSC TVs on the market, but they are not designed to receive HDTV, so you need to be careful when shopping for that new television. If you want HDTV, make sure that is what you are getting. Just because it is 16:9 does not mean it is HDTV. These NTSC 16:9 TVs receive standard broadcast signals (NTSC stands for National Television Systems Committee), with the standard 525 scanning lines (remember, only 483 lines are actually shown), and you can adjust the image to fit the screen shape. The 625 scanning lines for Europe is called PAL. If you want to watch a standard 4:3 image, it is formed in the center of the rectangular screen, and there is some blank space at the sides. You can zoom the 4:3 image to fill the screen, giving it a movie theater appearance, but a portion of the image is cropped off the top and bottom. Some people like this effect, and it is a matter of preference. If you plan to watch a lot of letterboxed movies, and want a low profile TV, this might be a choice to consider. The regular 4:3 TV image will be of a satisfactory size, and the letterbox movie will be nice and big (wide), the way it is supposed to be, without much blank area at the top and bottom.

Many DVD movies are stored on the disc in anamorphic format. This means the image occupies nearly the full height of the screen, but is squeezed side-to-side. When unsqueezed by the image expansion feature on 16:9 TVs, the picture nearly fills the screen instead of having large blank bars at the top and bottom. Irrespective of how the film is stored on the DVD, the 2001-01-aspect-ratio-primer-thepostman2351withovallights2-16.jpgmovie may or may not have been filmed with anamorphic lenses. You can tell if it has by looking at out of focus lights behind the actors in night scenes when the lens apertures are large. If the lights appear as vertical ovals, then the movie was filmed anamorphically. An example of this is shown on the right, which is a screen shot from "The Postman".