User:Camro7/Camcorder

Sony DV Handycam

A camcorder is a portable electronic device for recording video images and audio onto an internal storage device. The camcorder contains both a video camera and (traditionally) a videocassette recorder in one unit, hence its portmanteau name. This compares to previous technology where they would be separate.

The earliest camcorders, developed by companies such as JVC, Sony, and Kodak, used analog videotape, but since the mid-1990s (and even before that in professional markets), camcorders recording digital video have become the norm.

History edit

Before the camcorder. This separate portable Betamax recorder and camera arrangement slightly predates the first camcorders

Video cameras were originally designed for broadcasting television images — see television camera. Cameras found in television broadcast centres were extremely large, mounted on special trolleys, and wired to remote recorders located in separate rooms. As technology advanced, miniaturization eventually enabled the construction of portable video-cameras and portable video-recorders.

Prior to the introduction of the camcorder, portable video-recording required two separate devices: a video-camera and a VCR. Specialized models were introduced by both JVC (VHS) and Sony (Umatic & Betamax) to be used for mobile work. The portable VCR consisted of the cassette player/recorder unit, and a television tuner unit. The cassette unit could be detached and carried with the user for video recording. While the camera itself could be quite compact, the fact that a separate VCR had to be carried generally made on-location shooting a two-man job, however the advent of these portable VCRs helped to eliminate the phrase "film at eleven". Rather than wait for the lengthy process of film developing, portable VCRs and video cameras allowed video to be shown during the 6 o'clock news.

In 1982, two events happened that eventually led to the home camcorder boom: JVC introduced the VHS-C format, and Sony released the first professional camcorder named Betacam. VHS-C was essentially VHS with a reduced-size cassette that had been designed for portable VCRs. Sony's Betacam was a standard developed for professional camcorders, which used S-video (separated luminance & chroma signals) to provide a superior picture. At first, cameramen did not welcome Betacam, because before it, carrying and operating the VCR unit was a work of a video engineer; after Betacam they came to be required to operate both video camera and VCR. However the cable between cameramen and video engineers was eliminated, the freedom of cameramen improved dramatically and Betacam quickly became the standard for both news-gathering and in-studio video editing.

In 1983, Sony released the Betamax-based Betamovie, the first consumer camcorder. A novel technique was used to reduce the size of the spinning video head drum, which was then used for many subsequent camcorders. The unit was bulky by today's standards, and since it could not be held in one hand, was typically used resting on a shoulder. Some later camcorders were even larger, because the Betamovie models had only optical viewfinders and no playback or rewind capability. Most camcorders were and still are designed for right-handed operation, though a few possessed ambidextrous ergonomics.

Within a short time JVC released its own camcorder using its pre-existing VHS-C format. The VHS-C cassette held enough tape to record 40 or 120 minutes of VHS video, while a mechanical adapter enabled playback of VHS-C videocassettes in home VCRs. This first model can be seen in the movie Back to the Future.^[1] After seeing the popularity of the small VHS-C "palmcorders", Sony redesigned its Betamax system to create the Video8 standard. Video8 eliminated the problem of short running time, by using an all-new metal composition video cassette. 8 mm video used a tape whose width is 33% less than VHS/Betamax tape (~12.7 mm), allowing even further miniaturization in the recorder's tape-transport assembly and cassette media.

Both VHS-C and 8mm video represented a trade-off for the consumer. Although the Video8 and Hi8 camcorders produced quality equal to VHS-C and Super VHS-C camcorders (250/420 lines horizontal), the standard 8mm cassette had the advantage with up to two hours length (four hours in slow mode). On the down side, since the 8mm format was incompatible with VHS, 8mm recordings could not be played in VHS VCRs. Equally important entry-level VHS-C camcorders were priced less than 8 mm units, and thus neither "won" the war. It became a stalemate. (Side note - In 1986 companies like Panasonic began releasing full-sized VHS/S-VHS camcorders, which offered up to 3 or 9 hours record time, and thus found a niche with videophiles, industrial videographers, and college TV studios.)

In the mid-1990s, the camcorder reached the digital era with the introduction of DV and miniDV. Its cassette media was even smaller than 8 mm media, allowing another size reduction of the tape transport assembly. The digital nature of miniDV also improved audio and video quality over the best of the analog consumer camcorders (SVHS-C, Hi8), although some users still prefer the analog nature of Hi8 and Super VHS-C, since neither of these produce the "background blur" or "mosquito noise" of Digital compression. Variations on the DV camcorder include the Digital8 camcorder and the MPEG2-based DVD camcorder.

The evolution of the camcorder has seen the growth of the camcorder market as price reductions and size reductions make the technology more accessible to a wider audience. When camcorders were first introduced, they were bulky shoulder-operated luggables that cost over $1,500 US dollars^{[citation needed]}. As of 2007, an entry-level VHS-C, S-VHS-C, or Hi8 camcorder fits in the palm of a person's hand and is sold at a retail price of just over $150 US dollars (http://cameras.pricegrabber.com/camcorders/m/17729872).

Overview edit

Major components edit

Camcorders contain 3 major components: lens, imager, and recorder. The lens gathers and focuses light on the imager. The imager (usually a CCD or CMOS sensor on modern camcorders; earlier examples often used vidicon tubes) converts incident light into an electrical (video) signal. Finally, the recorder encodes the video signal into a storable form. More commonly, the optics and imager are referred to as the camera section.

The lens is the first component in the camera-section's "light-path". The camcorder's optics generally have one or more of the following adjustments: aperture (to control the amount of light), zoom (to control the field-of-view), and shutter speed (to capture continuous motion.) In consumer units, these adjustments are automatically controlled by the camcorder's electronics, generally to maintain constant exposure onto the imager. Professional units offer direct user control of all major optical functions (aperture, shutter-speed, focus, etc.)

The imager section is the eye of the camcorder, housing a photosensitive device(s). The imager converts light into an electronic video-signal through an elaborate electronic process. The camera lens projects an image onto the imager surface, exposing the photosensitive array to light. The light exposure is converted into electrical charge. At the end of the timed exposure, the imager converts the accumulated charge into a continuous analog voltage at the imager's output terminals. After scan-out is complete, the photosites are reset to start the exposure-process for the next video frame. In modern (digital) camcorders, an analog-to-digital (ADC) converter digitizes the imager (analog) waveform output into a discrete digital-video signal.

The third section, the recorder, is responsible for writing the video-signal onto a recording medium (such as magnetic videotape.) The record function involves many signal-processing steps, and historically, the recording-process introduced some distortion and noise into the stored video, such that playback of the stored-signal may not retain the same characteristics/detail as the live video feed.

All but the most primitive camcorders imaginable also need to have a recorder-controlling section which allows the user to control the camcorder, switch the recorder into playback mode for reviewing the recorded footage and an image control section which controls exposure, focus and white-balance.

The image recorded need not be limited to what appeared in the viewfinder. For documentation of events, such as used by police, the field of view overlays such things as the time and date of the recording along the top and bottom of the image. Such things as the police car or constable to which the recorder has been allotted may also appear; also the speed of the car at the time of recording. Compass direction at time of recording and geographical coordinates may also be possible. These are not kept to world-standard fields; "month/day/year" may be seen, as well as "day/month/year", besides the ISO standard "year-month-day". And the Danish police have the speed of the police car in the units "Km/t" sic (time being Danish for "hour").

Consumer camcorders edit

Analog vs. digital edit

Camcorders are often classified by their storage device: VHS, Betamax, Video8 are examples of older, videotape-based camcorders which record video in analog form. Newer camcorders include Digital8, miniDV, DVD, Hard drive and solid-state (flash) semiconductor memory, which all record video in digital form. (Please see the digital video page for details.) The imager-chip is considered an analog component, so the digital namesake is in reference to the camcorder's processing and recording of the video.

It should be noted that the take up of digital video storage in camcorders was an enormous milestone. MiniDV storage allows full resolution video (720x576 for PAL,720x480 for NTSC), unlike previous analogue video standards. Digital video doesn't experience colour bleeding, jitter, or fade, although some users still prefer the analog nature of Hi8 and Super VHS-C, since neither of these produce the "background blur" or "mosquito noise" of Digital compression. In many cases, a high-quality analog recording shows more detail (such as rough textures on a wall) than a compressed digital recording (which would show the same wall as flat and featureless).

The highest-quality digital formats, such as MiniDV and Digital Betacam, have the advantage over analog of suffering little generation loss in recording, dubbing, and editing (MPEG-2 and MPEG-4 do suffer from generation loss in the editing process only). Whereas noise and bandwidth issues relating to cables, amplifiers, and mixers can greatly affect analog recordings, such problems are minimal in digital formats using digital connections (generally IEEE 1394, SDI/SDTI, or HDMI).

Both analog and digital can suffer from archival problems. Theoretically digital information can be stored indefinitely with zero deterioration on a digital storage device (such as a hard drive), but other types of media can have problems. Both analog and digital tape formats are prone to deterioration over time, and since digital often squeezes tracks only ~10 micrometers apart (versus ~500 ?m for VHS), a digital recording is more vulnerable to wrinkles or stretches in the tape that could permanently erase several scenes worth of digital data, but barely register as "noise" on an analog tape. Even digital recordings on DVD are known to suffer from DVD rot that permanently erase huge chunks of data. Thus the one advantage analog seems to have in this respect is that an analog recording may be "usable" even after the media it is stored on has suffered severe deterioration whereas it has been noticed[1] that even slight media degradation in digital recordings may cause them to suffer from an "all or nothing" failure, i.e. the digital recording will end up being totally un-playable without very expensive restoration work.

Modern recording media edit

For more information, see tapeless camcorder.

Some recent camcorders record video on flash memory devices (in MPEG-1, MPEG-2 or MPEG-4), Microdrives, small hard disks or size-reduced DVD-RAM or DVD-Rs in MPEG-2 format - but due to the limited size of the recording medium, their uninterrupted recording time is limited, and editing is difficult due to limitations of the data formats.

Most other digital consumer camcorders record in DV or HDV format on tape and transfer content over FireWire (some also use USB 2.0) to a computer, where the huge files (for DV, 1GB for 4 to 4.6 minutes in PAL/NTSC resolutions) can be edited, converted, and (with many camcorders) also played back to tape. The transfer is done in real time, so the complete transfer of a 60 minute tape needs one hour to transfer and about 14GB disk space for the raw footage only - excluding any space needed for render files, and other media. Time spent in post-production (editing) to select and cut the best shots varies from instantaneous "magic" movies to hours of tedious selection, arrangement and rendering.

Consumer market edit

As the mainstream consumer market favors ease of use, portability, and price, consumer camcorders emphasize these features more than raw technical performance. For example, good low-light capabilities require large capturing chips, which affects price and size. Thus, consumer camcorders are often unable to shoot useful footage in dim light (though some units, particularly single-chip units by Sony, offer night vision capability). Manual controls need space, either in menus or as buttons and make the use more complicated, which goes against the requirement of ease of use. Consumer units offer a plethora of I/O options (IEEE 1394/Firewire, USB 2.0, Composite and S-Video), but lack many manual settings, often excluding video exposure, gain control, or sound level management. For the beginner, entry-level camcorders offer basic recording and playback capability.

For the sophisticated hobbyist (prosumer), high-end units offer improved optical and video performance through multi-CCD components and name-brand optics, manual control of camera exposure, and more, but even consumer camcorders which are sold for $1000 such as the Panasonic GS250 are not well-suited for recording in dim light. When dimly-lit areas are brightened in-camera or in post-production, considerable noise distracts the viewer.

Before the 21st century, consumer video editing was a difficult task requiring a minimum of two recorders. Now, however, a contemporary Personal Computer of even modest power can perform digital video editing with low-cost editing software. Many consumer camcorders bundle a light (feature-limited) version of such software, as do some computers, and more advanced software is widely available at a variety of price points.

As of 2007, analog camcorders are still available but not widely marketed anymore; those that are still available are often less than US$250, but require special capture hardware for non-linear editing. In terms of sales, miniDV camcorders (and to a much lesser extent, Digital8) dominate most first world markets. Camcorders which record directly on DVD media are also on the rise, primarily among users with no plans to edit their footage. Nonetheless, software for editing video files created by DVD camcorders is available, including Womble DVD and VideoRedo.

Hard disk based camcorders are appearing as well; JVC and Sony are the primary manufacturers of these units. Increased storage capacity over other types of media is the main advantage with these models; however, with this follows a slightly reduced image quality and loss of flexibility when compared to other formats such as MiniDV, making the ease of transferring the footage to a PC for quick editing the main attraction of Hard disk camcorders.

Uses edit

Media edit

Camcorders have found use in nearly all corners of electronic media, from electronic news organizations to TV/current-affairs productions. In locations away from a distribution infrastructure, camcorders are invaluable for initial video acquisition. Subsequently, the video is transmitted electronically to a studio/production center for broadcast. Scheduled events such as official press conferences, where a video infrastructure is readily available or can be feasibly deployed in advance, are still covered by studio-type video cameras (tethered to "production trucks.")

Taping the San Francisco bay from Coit tower using a JVC recorder

Home video edit

For casual use, camcorders often cover weddings, birthdays, graduation ceremonies, and other personal events. The rise of the consumer camcorder in the mid to late '80s led to the creation of shows such as the long-running America's Funniest Home Videos, where people could showcase homemade video footage.

Politics edit

Political protestors who have capitalized on the value of media coverage use camcorders to film things they believe to be unjust. Animal rights protesters who break into factory farms and animal testing labs use camcorders to film the conditions the animals are living in. Anti-hunting protesters film fox hunts. Tax protesters provide live coverage of anti-tax demonstrations and protests. Anti-globalization protesters film the police to deter police brutality. If the police do use violence there will be evidence on video. Activist videos often appear on Indymedia.

The police use camcorders to film riots, protests and the crowds at sporting events. The film can be used to spot and pick out troublemakers, who can then be prosecuted in court.

Entertainment and movies edit

Camcorders are often used in the production of low-budget TV shows where the production crew does not have access to more professional equipment. There are even examples of movies shot entirely on consumer camcorder equipment (see Blair Witch Project and 28 Days Later). In addition, many academic filmmaking programs have switched from 16mm film to digital video, due to the vastly reduced expense and ease of editing of the digital medium as well as the increasing scarcity of film stock and equipment. Some camcorder manufacturers cater to this market, particularly Canon and Panasonic, who both support "24p" (24 fps, progressive scan; same frame rate as standard cinema film) video in some of their high-end models for easy film conversion.

Even high-budget cinema is done using camcorders in some cases; George Lucas used Sony CineAlta camcorders in two of his three Star Wars prequel movies. This process is referred to as digital cinematography.

Formats edit

The following list covers consumer equipment only. (For other formats see Videotape)

Analog edit

8 mm Camcorder

Lo-Band: Approximately 3 megahertz bandwidth (250 lines EIA resolution or ~333x480 edge-to-edge)

Betamax (1975): Only used on very old Sony and Sanyo camcorders and portables; obsolete by the mid/late-80s in the consumer market.
VHS (1976): Compatible with standard VCRs, though VHS camcorders are no longer made. Obsolete.
VHS-C (1982): Originally designed for portable VCRs, this standard was later adapted for use in compact consumer camcorders; identical in quality to VHS; plays in standard home VCRs. Still available in the low-end consumer market (JVC model GR-AXM18 is VHS-C; see page 19 of the owner's manual}.
Video8 (1985): Small-format tape developed by Sony to combat VHS-C's compact palm-sized design; equivalent to VHS or Betamax in quality, but not compatible. Obsolete.

Hi-Band: Approximately 5 megahertz bandwidth (420 lines EIA resolution or ~550x480 edge-to-edge)

S-VHS (1987): Largely used in high-end consumer and professional equipment; rare among mainstream consumer equipment, and obsoleted by digital gear like DigiBetacam and DV.
S-VHS-C (1987): An upgrade to provide near-laserdisc quality. Now limited to the low-end consumer market (example: JVC SXM38).
Hi8 (1988): Enhanced-quality Video8; roughly equivalent to Super VHS in quality, but not compatible. Now limited to low-end consumer market (example: Sony TRV138)

Digital edit

MICROMV camcorder and tape (top) compared to miniDV and Hi8 tapes

Digital Tapeless: Low-end digital tapeless systems often use an MPEG-4 codec and flash memory; high-end versions, on the other hand, store video data to hard disk or optical disc.

H.264 codec based AVCHD format, which records MPEG-4 AVC (H.264) compressed video to various kinds of tapeless media (recordable optical discs, flash memory, hard disks, etc).

DV codec based:

MiniDV (1994) and several derivatives, including DVCPRO from Panasonic and DVCAM from Sony. DV records the highest quality pictures (generally agreed to be at or near broadcast-quality) on DV tapes that are easily transferable via Firewire or USB to personal computers. Though designed as a consumer standard, there is extensive use of MiniDV in low-budget film and television production.
Digital8 (1999), that uses Hi8 tapes (Sony is the only company currently producing D8 camcorders, though Hitachi used to). Some models of Digital 8 cameras have the ability to read older Hi8 analog format tapes. The format's technical specifications are of the same quality as MiniDV (both use the same DV codec), and although no professional-level Digital8 equipment exists, D8 has been used to make TV and movie productions (example: Hall of Mirrors).

MPEG-2 codec based:

MICROMV: Uses a matchbox-sized cassette. Sony was the only electronics manufacturer for this format, and editing software was proprietary to Sony and only available on Microsoft Windows; however, open source programmers did manage to create capture software for Linux[2]. The hardware is no longer in production, though tapes are still available through Sony.
DVD (with the biggest market increases): Uses either Mini DVD-R or DVD-RAM. This is a multi-manufacturer standard that uses 8 cm DVD discs for 30 minutes of video. DVD-R can be played on consumer DVD players but cannot be added to or recorded over once finalized for viewing. DVD-RAM can be added to and/or recorded over, but cannot be played on many consumer DVD players, and costs a lot more than other types of DVD recordable media. The DVD-RW is another option allowing the user to re-record, but only records sequentially and must be finalized for viewing. The discs do cost more than the DVD-R format, which only records once. DVD discs are also very vulnerable to scratches. DVD camcorders are generally not designed to connect to computers for editing purposes, though some high-end DVD units do record surround sound, a feature not standard with DV equipment.

HDV: Records up to an hour of HDTV MPEG-2 signal roughly equal to broadcast quality HD on a standard MiniDV cassette.

Digital camcorders and operating systems edit

Since most manufacturers focus their support on Windows and Mac users, users of other operating systems often are unable to receive support for these devices. However, open source products such as Cinelerra and Kino (written for the Linux operating system) do allow full editing of some digital formats on alternative operating systems, and software to edit DV streams in particular is available on most platforms.

Many low-end tapeless camcorders, however, do not support any operating system but Windows, requiring either third-party software or a switch to a more standardized format such as DV.

External links edit

History of Camcorders by Mark Shapiro
How Camcorders Work from HowStuffWorks
Guide Making Videos with your Camcorder from Internet Video Magazine

^ "First VHS-C camcorder". 2007-09-14. Retrieved 2007-09-14.

[1] "First VHS-C camcorder". 2007-09-14. Retrieved 2007-09-14.

[1]