Information AboutDigital8 |
| CATEGORIES ABOUT DIGITAL8 | |
| video storage | |
| 1999 introductions | |
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The Digital8 format is a combination of the older Hi8 tape transport with the DV Codec . Digital8 equipment uses the same videocassettes as Analog Hi8 equipment, but differs in that the audio/video signal is encoded ''digitally'' (using the industry-standard DV codec.) Since Digital8 uses the DV codec, it has identical audio and video specifications. To facilitate digital recording on existing Hi8 videocassettes the video head drum spins 2.5x faster. For both NTSC and PAL Digital8 equipment, a standard-length 120-minute Hi8 cassette will store 60 minutes of Digital8 video (Standard Play) or 90 minutes (Long Play). LP is model specific, such as the TRV-30, TRV-40, and others. Digital8 recordings can be made on standard-grade Video8 cassettes, but this practice is discouraged. Hi8 metal-particle cassettes are the recommended type for Digital8 recording, and most tapes currently sold are marked for both Hi8 and Digital8 usage. MINIDV/DVC VS. DIGITAL8 Contrary to popular perception, the Digital8 format is not technically inferior to MiniDV -- both are identical at the bitstream level. From a user standpoint, Digital8 ''is'' DV (or rather, equivalent to and compatible with consumer miniDV.) At an application level (for example, in a 1394/Firewire link), a Digital8 camcorder appears and behaves exactly like a Mini DV camcorder. Digital8 and Mini DV use different, non-interchangeable cassette media, with Digital8 cassettes being the physically larger of the two. The two formats may also use different media formulations: Digital8 can use metal-particle or metal-evaporated media, while miniDV is based solely on metal-evaporated media. The standard (SP) recording time for both formats, on standard length media, is 60 minutes. Special 80 minute cassettes are availble for Mini DV at over twice the price of the standard 60 minute one. There are no LP cassettes for Digital8. However, 160 meter 8mm data cassettes have been successfully used to give 50% more recording time than the standard 112 meter Hi8 cassettes. In addition, Digital8 uses tape at 29mm per second; more like the higher-end DVCAM (28mm/s) and DVCPRO (34mm/s). MiniDV uses tape at 19mm/s. According to SONY's press release of January 7, 1999, for the MiniDV format one frame is recorded onto 10.0 tracks, with the Digital8 format one frame's worth of information is recorded vertically onto 25 tracks. The use of this recording method enables digital images to be recorded on a Hi8 tape. Another area Digital8 cameras excelled over the MiniDV cameras is their optical zoom. Digital8 cameras range from 15x and 25x optical zoom while MiniDV cameras of the same year and market segment were between 10x and 12x, with some topping out at 15x. This makes them perfect for filming wildlife or other subjects that are distant and also gives beautiful separation of subject from foreground and the background; even without extreme zooming. MARKET SEGMENT While analog Hi8 video enjoyed widespread use by amateur home video, current affairs TV programs, and some professional news organizations, Digital8 seems to remain strictly a consumer (amateur) product. This is likely a reflection of Sony's design and market objectives for Digital8 format: to serve as a lower cost upgrade path for current customers (from analog 8 mm), by leveraging existing manufacturing infrastructure of 8 mm video equipment, and offering a familiar media format but with digital capabilities. Furthermore, Digital8 was released some time after miniDV, giving the rival DV format a lead in the professional market. While little or no Digital8 equipment has been produced for the professional market, there are no technical barriers opposing its development. In fact, Digital8 cameras have been used on the professional side of the film/TV business; example, Hall Of Mirrors, The Movie CAMERA MODEL VARIATIONS In the early years after Digital8's introduction, Sony sold a product line with coverage from entry level to high-end consumer ("prosumer.") Although Sony never marketed by entry level or prosumer, there is, in fact, such variation. NOTE: The following information is general. See the owner's manual for the most accurate information on a given model. The more consumer oriented line uses a 1/6" CCD and the more prosumer line uses a 1/4" one. Both have existed from the beginning, but the 1/4" CCD models were quietly dropped at some point in time. Some models allow an LP recording mode, thus giving 90 minutes on a standard Hi8 tape. Examples are the 2003 TRV-150, 250, 350, and 351 models. Interestingly, the owner's manual is the same for all of these models AND the TRV-118, 318, and 418 Hi8 versions! Both general variants use a tiny 3mm CCD, although the pixel count varies between the Digital8 (460K) and the Hi8 (320K) models. Although the 1/4" CCD models are fully capable of taking a still photo, that is a secondary function and they lack the Sony Memory Stick feature to off load the jpeg images. Most of the entry level and later models focused on features like better quality still pictures (see below,) off loading the same via Sony Memory Sticks, and more programing selections. (The combining of still and video seems to be one of the marketing trends still going amongst the camcorder manufacturers. However, a good still image CCD has different qualities from a good video CCD. One can clip stills from video in many video editing programs, although it will not have the - still low - quality of a still/video CCD. Alternatively, carry a digital still camera! Many now take short video clips of Video8 or Hi8 quality.) The cameras generally lost features appealing to a prosumer level customer. The 1999 TRV-310, for instance, has the 1/4" CCD,a full 3.5" LCD screen, now only found on the very professional Sony miniDV models, an f1.4 lens, variable shutter speed settings, manual focus, and other professional controls. The lens on a typical 1/6" CCD is f1.8, about 60% as fast as an f1.4. Thus, some of the low light level capabilities between models. Sony's Digital8 product line released only two Digital8 camcorders in 2005, the DCR-TRV480 (capable of playing back Hi8 and 8mm tapes) and the DCR-TRV280 (plays back only Digital8 tapes). Only the entry level DCR-TRV280 with a 1/6" CCD is officially available as of Q3, 2007, although the TRV480 is still available new. As of 2005 and later, Digital8 product line caters purely to the entry-level consumer. This is most likely because the larger, bulkier Digital8 cassette is perceived as an inferior technology, even though the Digital8 and DV formats offer indistinguishable A/V performance. In fact, the larger 8mm format is more robust, laying down wider tracks. Sony, the format's original backer, is the only company still producing Digital8 equipment. Hitachi marketed a few Digital8 camcorders for a while but no longer does so. 1/4" VS 1/6" CCD'S The TRV-310, has a 1/4" CCD with a pixel count of 460K and "effective count" of 290K. The larger CCD with fewer pixels allows a smaller depth of field for intentional blurred backgrounds in some situations unattainable with the 1/6" CCD. It also has greater light sensitivity, 1 lux vs. 7 lux for the 1/6" CCD (without Night Shot), and less sensor noise in low light conditions. Another example of these capabilites changing with pixel count may be seen in the TRV-150, 250, 350, and 351 Digital8 models and their TRV-118, 318, and 418 Hi8 cousins. Despite having the same size CCD and the same f1.6 lens, the lower pixel count Hi8 models permist a 1 lux low light rating as compared to the 4 lux of the Digital8 models. Higher pixel counts without corresponding increase in CCD size has a price tag! The Sony DCR-TRV730/828/830 (and the later DCR-TRV740/840), were the only Digital8 camcorders to be built with a 1/6" (4.5mm) with advanced HAD ( Hole Accumulation Diode )CCD. HAD is useful on smaller, high megapixel count CCD's and CMOS's. The pixel count for the TRV-730 is 1,070,000 pixels (690,000 in camera mode.) ANALOG RECORDINGS Digital8 equipment cannot record in analog Video8/Hi8 format, but some equipment offers playback compatibility with 8 mm analog recordings. Even so, there are limitations, audio playback is limited to the Video8/Hi8 analog FM soundtrack and there is no inherent timestamping to edit with. Most Digital8 camcorders with analog playback also can simultaneously digitize the analog footage, sending the converted signal through the camcorder's FireWire interface to a computer with video capturing HW and SW. Such a conversion will have the same Video8/Hi8 audio and video quality as the original, but being digitized can be edited and used as video files or converted to DVD's. SEE ALSO |
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