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HISTORY Beginning in the late 1980s, Sony began marketing the concept of "electronic cinematography", utilizing its analog HDTV cameras. The effort met with very little success. In 1998, with the introduction of HDCAM recorders and 1920 × 1080 pixel digital Video cameras based on CCD technology, the idea, now re-branded as "digital cinematography", finally began to gain traction in the market. In May 2002 became the first high-profile, high-budget movie released that was shot on 24 frame-per-second high-definition digital video, using a Sony HDW-F900 camera. The lesser-known 2001 movie Vidocq was shot with the same camera. In parallel with these developments in the world of traditional high-budget cinematography, a digital cinema revolution was occurring from the bottom up, among low budget filmmakers outside of the Hollywood system. Beginning in the mid-1990s, with the introduction of Sony's DCR-VX1000, the digital MiniDV format began to emerge. MiniDV offered much greater quality than the analog formats that preceded it, at the same price point. While its quality was not considered as good as film, these MiniDV Camcorder s, in conjunction with Non-linear Editing software that could run on Personal Computer s, allowed a large number of people to begin making movies who were previously prevented from doing so by the high costs involved with shooting on film. Today, cameras from companies like Sony, Panasonic , JVC and Canon offer the prosumer market a variety of choices for shooting high-definition video with less than $10,000 worth of camera equipment. At the high-end of the market, there has been an emergence of cameras aimed specifically at the digital cinema market. These cameras offer resolution and dynamic range that exceeds that of traditional video cameras, which are designed for the limited resolution and dynamic range of broadcast television. TECHNOLOGY Digital cinematography captures motion pictures digitally, in a process analogous to Digital Photography . While there is no clear technical distinction that separates the images captured in digital cinematography from Video , the term "digital cinematography" is usually applied only in cases where digital acquisition is substituting for film acquisition, such as when shooting a feature film. The term is not generally applied when digital acquisition is substituting for analog video acquisition, as with live broadcast television programs. Sensors Digital cinematography cameras capture images using CMOS or CCD sensors, usually in one of two arrangements, depending on their primary market. High-end cameras designed specifically for the digital cinematography market often use a single sensor (much like Digital Photo Cameras ), with dimensions similar in size to a 35mm film frame. An image can be projected onto a single large sensor exactly the same way it can be projected onto a film frame, so cameras with this design can be made with PL , PV and similar mounts, in order to use the wide range of existing high-end cinematography lenses available. Their large sensors also let these cameras achieve the same shallow Depth Of Field as 35mm movie cameras, which is important because many cinematographers consider selective focus an essential visual tool. Prosumer cameras and professional cameras designed primarily for the broadcast market typically use three 1/3" or 2/3" sensors in conjunction with a Prism , with each sensor capturing a different color. This has benefits in terms of color reproduction, but renders these cameras incompatible with traditional cinematography lenses and incapable of achieving 35mm depth of field. These cameras are sometimes used in conjunction with Depth-of-field Adaptors to overcome these limitations. However, such adaptors degrade image quality and result in a loss of light, making cameras which can natively accept 35mm format lenses preferable if such lenses are to be used. Note that Sony's CineAlta cameras, despite being designed and marketed specifically for high-end digital cinematography, nonetheless use a design based around three 2/3" sensors. Panasonic also has cameras designed for digital cinematography which follow this pattern. This design decision is probably attributable to the long history these companies have making cameras for the broadcast market. Acquisition Formats While many people make movies with MiniDV camcorders and other consumer and Prosumer products that have lower resolutions or shoot Interlace d video, cameras marketed as digital cinematography cameras typically shoot in progressive HDTV formats such as 720p and 1080p , or in higher-end formats created specifically for the digital cinematography market, such as 2K and 4K . To date, 1080p has been the most common format for digitally acquired major motion pictures. No major motion picture has been shot at 4K. However, due to the availability of new cameras in 2007 which may make 4K acquisition more practical, this is likely to change. Data Storage Tape vs. Data-Centric Broadly, there are two paradigms used for data storage in the digital cinematography world. Many people, particularly those coming from a background in broadcast television, are most comfortable with Video Tape based workflows. Data is captured to video tape on set. This data is then ingested into a computer running Non-linear Editing software, using a Deck . Once on the computer, the footage is edited, and then output in its final format, possibly to a film recorder for theatrical exhibition, or back to video tape for broadcast use. Original video tapes are kept as an archival medium. The files generated by the non-linear editing application contain the information necessary to retrieve footage from the proper tapes, should the footage stored on the computer's hard disk be lost. Increasingly, however, digital cinematography is shifting toward "tapeless" workflow, where instead of thinking about digital images as something that exists on a physical medium like video tape, digital video is conceived of as data in files. In tapeless workflow, digital images are usually recorded directly to files on Hard Disk or Flash Memory based "digital magazines". At the end of a shooting day (or sometimes even during the day), the digital files contained on these digital magazines are downloaded, typically to a large RAID connected to an editing system. Once data is copied from the digital magazines, they are erased and returned to the set for more shooting. Archiving is accomplished by backing up the digital files from the RAID, using standard practices and equipment for data backup from the Information Technology industry, often to Data Tape . Compression Digital cinema cameras are capable of generating extremely large amounts of data; often hundreds of Megabyte s per second. To help manage this huge data flow, many cameras or recording devices designed to be used in conjunction with them offer Compression . Prosumer cameras typically use high Compression Ratio s in conjunction with Chroma Subsampling . While this allows footage to be comfortably handled even on fairly modest Personal Computer s, the convenience comes at the expense of image quality. High-end digital cinematography cameras or recording devices typically support recording at much lower compression ratios, or in uncompressed formats. Additionally, digital cinematography camera vendors are not constrained by the standards of the consumer or broadcast video industries, and often develop proprietary compression technologies that are optimized for use with their specific sensor designs or recording technologies. Lossless vs. lossy compression A lossless compression system is capable of reducing the size of digital data in a fully reversible way -- that is, in a way that allows the original data to be completely restored, byte for byte. This is done by removing redundant information from a signal. Digital cinema cameras rarely use only lossless compression methods, because much higher compression ratios (lower data rates) can be achieved with lossy compression. With a lossy compression scheme, information is discarded to create a simpler signal. Due to limitations in human visual perception, it is possible to design algorithms which do this with little visual impact. Chroma subsampling See Also: Chroma subsampling Some digital cinematography systems further reduce data rate by subsampling color information. Because the human visual system is much more sensitive to luminance than to color, lower resolution color information can be overlaid with higher resolution luma (brightness) information, to create an image that looks very similar to one in which both color and luma information are sampled at full resolution. This scheme may cause pixilation or color bleeding under some circumstances, however, and the highest quality digital cinematography systems are capable of recording full resolution color data (4:4:4). Bitrate Video and audio compression systems are often characterized by their bitrates. Bitrate describes how much data is required to represent one second of media. One cannot directly use bitrate as a measure of quality, because different compression algorithms perform differently. A more advanced compression algorithm at a lower bitrate may deliver the same quality as a less advanced algorithm at a higher bitrate. Intra- vs. Inter-frame compression Most compression systems used for acquisition in the digital cinematography world compress footage one frame at a time, as if a video stream is a series of still images. Inter-frame compression systems can further compress data by examining and eliminating redundancy between frames. This leads to higher compression ratios, but displaying a single frame will usually require the playback system to decompress a number of frames that precede it. In normal playback this is not a problem, as each successive frame is played in order, so the preceding frames have already been decompressed. In editing, however, it is common to jump around to specific frames and to play footage backwards or at different speeds. Because of the need to decompress extra frames in these situations, inter-frame compression can cause performance problems for editing systems. Inter-frame compression is also disadvantageous because the loss of a single frame (say, due to a flaw writing data to a tape) will typically ruin all the frames until the next keyframe occurs. In the case of the HDV , format, this may result in as many as six frames being lost. Digital acquisition codecs compared Distribution Formats Movies shot digitally may be released theatrically or on DVD or VHS . Digital Theatrical Distribution See Also: Digital cinema For the relatively small number of theaters with digital projectors, digital films may be distributed digitally, either shipped to theaters on hard drives or sent via the Internet or satellite networks. Digital Cinema Initiatives, LLC , a joint venture of Disney, Fox, MGM, Paramount, Sony Pictures Entertainment, Universal and Warner Bros. Studios, is working to establish standards for digital cinema projection. In July of 2005, they released v.1.0 of the Digital Cinema System Specification , which encompasses 2K and 4K theatrical projection. They also offer compliance testing for exhibitors and equipment suppliers. Distributors prefer digital distribution, because it saves them the expense of making film prints, which may cost as much as $2000 each. Digital projection also offers advantages over traditional film projection such as lack of jitter, flicker, dust, scratches, and grain. Theater owners have balked at the high cost of installing digital projection systems, however, and while the number of digital venues is growing, growth is slower than many people anticipated. New payment models in which distributors would bear some of the cost of digital projection systems may result in the number of digital screens expanding faster in the future. Film-based Theatrical Distribution Most theaters do not yet have digital projection systems, so even if a movie is shot digitally, it must be transferred to film if a large theatrical release is planned. Typically, a Film Recorder will be used to print digital image data to film, to create a 35mm Internegative . This internegative is then treated much as a camera negative from a film camera, and the same traditional optical processes are used to generate release prints from it. DIGITAL CINEMATOGRAPHY CAMERAS Professional There are a number of video cameras on the market designed specifically for high-end digital cinematography use. These cameras typically offer relatively large sensors, selectable frame rates, recording options with low compression ratios or in some cases with no compression, and the ability to use high-quality optics. With the possible exception of the Red One and the noX (which has not yet been released), these cameras are priced well out of the range of self-funded low-budget filmmakers. Some cannot be purchased at all, and are only available for rental at rates of thousands of dollars a day. Some professional digital cinema cameras include: MODULA HD CAM - EasyLook System |
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