| Aspect Ratio (image) |
Article Index for Aspect Ratio |
Website Links For Ratio |
Information AboutAspect Ratio (image) |
|
The aspect ratio of an Image is its displayed width divided by its height (usually expressed as "''x'':''y''" or "''x''×''y''," with the joining colon or multiplication symbol articulated as the preposition "by" or sometimes "to"). Currently, the most common motion picture and European Digital Television . Historically, many other aspect ratios no longer in general use have existed in both film and video. Conversion between formats with unequal ratios can be accomplished by either cropping the image to fit the receiving format's ratio or adding black bars (letterboxing or pillarboxing) to retain the original format's ratio. Film ratios tend to be formatted to end with ":1", while video ratios usually prefer to be denoted with whole numbers on both sides of the ratio. The most common Still Camera aspect ratios are 4:3 and 3:2, though other ratios such as 5:4, 7:5 and the square format 1:1 are also still found. THE EVOLUTION OF FILM AND TV ASPECT RATIOS . The most square-like box (red, 4:3) is the format used in Standard Definition Television .]] Practical limitations The size of the image in motion picture formats is dictated by the physical size of the film area between the perforations. The universal standard, as established by William Dickson and Thomas Edison in 1892, is a frame that is four perforations high. The film itself is 35 mm wide (1.38 in), but the area between the perforations is 24.89 mm by 18.67 mm (.980 in by .735 in).Burum, Stephen H. (ed) (2004). ''American Cinematographer Manual'' (9th ed). ASC Press. ISBN 0-935578-24-2 With a space designated for the standard Optical Soundtrack , and the frame size reduced to maintain a picture that was wider than taller (more mimicking human vision), this resulted in the Academy aperture of 22 mm by 16 mm (.866 in by .630 in) or 1.37:1. Cinema terminology Within the Motion Picture Industry , the convention is to assign a value of 1 to the image height, so that, for example, an anamorphic frame is described as 2.40:1 or just "2.40" (pronounced "two four oh"). The most common projection ratios in American theaters are 1.85:1 and 2.40:1. Some European countries use 1.66:1 as a widescreen standard. 1.33:1 was used for all theatrical films up until the 1950s when 1.85:1 became the standard for US theatrical projection. Movie camera systems Development of various camera systems must therefore ultimately cater to the placement of the frame in relation to these lateral constraints of the perforations and the optical soundtrack area. One clever widescreen alternative, VistaVision , used standard 35 mm film running sideways through the camera gate, so that the sprocket holes were above and below frame, resulting in a larger horizontal negative size per frame as the vertical size was now restricted by the perforations. However, the 1.5 ratio of the initial VistaVision image needed to be cropped down to 1.85 and optically converted to a vertical print (on standard 4-perforation 35 Mm Film ) to show in the projectors available at theaters. Though the format was briefly revived by Lucasfilm in the 1970s for special effects work that required larger negative size (due to image degradation from the optical printing steps necessary to make multi-layer composites), it went into obsolescence largely due to better cameras, lenses, and film stocks available to standard 4-perforation formats, in addition to increased lab costs of making prints in comparison to more standard vertical processes. (The horizontal process was later adapted to 70 mm film by IMAX .) Super 16 Mm film is frequently used for television production due to its lower cost, lack of need for soundtrack space on the film itself (as it is not projected but rather transferred to video), and aspect ratio similar to 16:9 (Super 16 mm is natively 1.66 whilst 16:9 is 1.78). It also can be blown up to 35 mm for theatrical release and therefore is also used for feature films. CURRENT VIDEO STANDARDS 4:3 standard The 4:3 ratio for standard television has been in use since television's origins and many as a standard after the advent of optical Sound-on-film . By having TV match this aspect ratio, films previously photographed on film could be satisfactorily viewed on TV in the early days of the medium (i.e. the '40s and the '50s). When Cinema attendance dropped, Hollywood created Widescreen aspect ratios (such as the 1.85:1 ratio mentioned earlier) in order to differentiate their industry from the TV. 16:9 standard 16:9 (generally named as: ''"Sixteen-by-Nine"'') is the international standard format of before sending the image to the TV. Wider ratios such as 1.85:1 and 2.40:1 are accommodated within the 16:9 DVD frame by additional black bars within the image itself. The 228 Million . VISUAL COMPARISONS PREVIOUS AND PRESENTLY USED ASPECT RATIOS See List Of Common Resolutions for a listing of computer resolutions and aspect ratios. See List Of Film Formats for a full listing of film formats, including their aspect ratios. ASPECT RATIO RELEASES Original aspect ratio (OAR) Original Aspect Ratio (OAR) is a altering the aspect ratio to the television standard of 1.33:1. Because of the varied ways in which films are shot, IAR (Intended Aspect Ratio) is a more appropriate term, but is rarely used. Modified aspect ratio (MAR) Modified Aspect Ratio is a home cinema term for the aspect ratio or dimensions in which a film was modified to fit a specific type of screen, as opposed to original aspect ratio. Modified aspect ratios are usually either 1.33:1 (historically), or (with the advent of widescreen television sets) 1.78:1 aspect ratio. 1.33:1 is the modified aspect ratio used historically in VHS format. A modified aspect ratio transfer is achieved by means of Pan And Scan or Open Matte , the latter meaning removing the cinematic matte from a 1.85:1 film to open up the full 1.33:1 frame. CRITICISM image]] Multiple aspect ratios create additional burdens on filmmakers and consumers, and confusion among TV broadcasters. It is not uncommon for a widescreen film to be presented in an altered format (cropped, letterboxed or expanded beyond the Original Aspect Ratio). It is also not uncommon for . Both PAL and NTSC have provision for some data pulses contained within the video signal used to signal the aspect ratio (See ITU-R BT.1119-1 - Wide-Screen signalling for broadcasting). These pulses are detected by television sets that have widescreen displays and cause the television to automatically switch to 16:9 display mode. When 4:3 material is included (such as the aforementioned commercial), the television switches to a 4:3 display mode to correctly display the material. Where a video signal is transmitted via a European SCART connection, one of the status lines is used to signal 16:9 material as well. For many artists, however, aspect ratio is determined not by the constraints of the technology or medium, but by the content or the story. Indeed, as long ago as the early 20th century, film directors such as D. W. Griffith , one of the early giants in film, would sometimes change the picture aspect ratio within the film. In "Intolerance", for example, a single shot where a character falls from a high wall has the sides of the vista greatly cropped to enhance the dramatic height of the fall. Today, Directors of Photography are often forced to compose the shot to keep the essential subjects in the "sweet spot" of the frame as a compositional compromise between the intended aspect ratio and the potential future alternate ratios to be presented. STILL PHOTOGRAPHY Common aspect ratios in still photography include 4:3 (1.33) used by most -H high definition mode; 3:1 used by APS-P panoramic mode; and 1:1 (square) in a variety of cameras. Common print sizes in the U.S. (in Inch es) include 4x6 (1.5), 5x7 (1.4), 4x5 and 8x10 (1.25), and 11x14 (1.27); Large-format cameras typical use one of these aspect ratios. Medium-format cameras typically have format designated by nominal sizes in Centimeter s (6x6, 6x7, 6x9, 6x4.5), but these numbers should not be interpreted as exact in computing aspect ratios. SEE ALSO
REFERENCES EXTERNAL LINKS
|
|
|