Digital camcorders have all these same elements, but have an added component that takes the analog information the camera gathers and translates it to bytes of data. Instead of storing the video signal as a continuous track of magnetic patterns, it records the picture and sound as ones and zeros. Digital camcorders are so popular because you can copy ones and zeros very easily without losing any of the information you've recorded. Analog information, on the other hand, "fades" with each copy -- the copying process doesn't reproduce the original signal exactly. Video information in digital form can also be loaded onto computers, where you can edit it, copy it, e-mail it and manipulate it (editing digital video is discussed in detail on this page).
Let's take a look at the how the camera component of a camcorder works. [For a full explanation on how a camcorder actually takes an analog signal from the camera and records on tape, check out How VCRs Work.]
Each photosite measures the amount of light (photons) that hit a particular point, and translates this information into electrons (electrical charges): A brighter image is represented by a higher electrical charge and a darker image is represented by a lower electrical charge. Just as an artist sketches a scene by contrasting dark areas with light areas, a CCD creates a video picture by recording light intensity. During playback, this information directs the intensity of a television's electron beam as it passes over the screen.
Of course, measuring light intensity only gives us a black-and-white image. To create a color image, a camcorder has to detect not only the total light levels, but also the levels of each color of light. Since you can produce the full spectrum of colors by combining the three colors red, green and blue, a camcorder actually only needs to measure the levels of these three colors to be able to reproduce a full-color picture.
This simple method produces a rich, high-resolution picture. CCDs are expensive and eat lots of power, however, so using three of them adds considerably to manufacturing costs of a camcorder. Most camcorders get by with only one CCD by fitting permanent color filters to individual photosites. A certain percentage of photosites only measure levels of red light, another percentage measures only green light and the rest measure only blue light. The color designations are spread out in a sort of grid (the Bayer filter below is a common configuration), so that the video camera computer can get a sense of the color levels in all parts of the screen. This method requires the computer to interpolate the true color of light arriving at each photosite by analyzing the information received by the other photosites in the vicinity. For a full explanation of this process, check out this page.
A digital camcorder works in basically the same way, except at this last stage an analog-to-digital converter samples the analog signal and turns the information into bytes of data (ones and zeros). The camcorder records these bytes on a storage medium, which could be, among other things, a tape, a hard disk or a DVD. Most of the digital camcorders on the market today actually use tapes (because they are less expensive), so they have a VCR component much like an analog camcorder's VCR. Instead of recording analog magnetic patterns, however, the tape head records binary code. Interlaced digital camcorders record each frame as two fields, just as analog camcorders do. Progressive digital camcorders record video as an entire still frame, which they then break up into two fields when you output the video as an analog signal. To learn more about analog-to-digital picture conversion, check out this page from How Digital Cameras Work or this article about the difference between analog and digital recording.
This is why all camcorders come with an auto focus device, usually an infrared beam that bounces off objects in the center of the frame and comes back to a sensor on the camcorder. To find the distance to the object, the processor calculates how long it took the beam to bounce and return, multiplies this time by the speed of light, and divides the product by two (because it traveled the distance twice -- to the object and back again). The camcorder has a small motor that moves the lens, focusing it on objects at this distance. This works pretty well most of the time, but sometimes you have to override it -- you may want to focus on something in the side of the frame, for example, but the auto focus will pick up what's right in front of the camcorder. To learn more about auto focus mechanisms, check out How Autofocus Cameras Work.
Camcorders are also equipped with a zoom lens. In any sort of camera, you can magnify a scene by increasing the focal length of the lens (the distance between the lens and the film or CCD). An optical zoom lens is a single lens unit that lets you change this focal length, so you can move from one magnification to a closer magnification. A zoom range tells you the maximum and minimum magnification. To make the zoom function easier to use, most camcorders have an attached motor that adjusts the zoom lens in response to a simple toggle control on the grip. One advantage of this is that you can operate the zoom easily, without using your free hand. The other advantage is that the motor adjusts the lens at a steady speed, making zooms more fluid. The disadvantage of using the grip control is that the motor drains battery power.
One of the great things about a camcorder is that it can adjust automatically for different levels of light. It's very obvious to the CCD when an image is over- or under-exposed because there won't be much variation in the charges collected on each photosite. The camcorder monitors the photosite charges and adjusts the camera's iris to let more or less light through the lenses. The camcorder computer always works to maintain a good contrast between dark and light, so that images don't appear too dark or too washed out.
Let's explore the difference between analog and digital cameras, and see what you can do with the two formats. We'll explain what computers have to do with digital cameras and learn about the capabilities of consumer movie-editing software. If you've been wondering why everybody's so excited about digital camcorders these days, we'll help get you up to speed.
You can do all sorts of things with video that you can't do with film because the two media work in completely different ways. Film is a very physical medium: When you film a movie, you are simply capturing a series of pictures on specially treated strips of material. You develop this film to produce another strip of still images that you can run through a projector. Video, on the other hand, is an electronic signal. Once you have that analog signal recorded, it's very easy to transmit video between different electronic devices, whether to make copies or simply play your movie on a television.
Another impressive quality of video is that you can shoot in a wide range of lighting conditions. Everybody knows that you need a good amount of light to take a good picture with a film camera. This is why you usually need a flash for indoor photography. The CCD in a camcorder, on the other hand, allows you to record good-looking video by the light of one candle. In most lighting conditions, a camcorder can also automatically adjust its aperture so that it doesn't over- or under-expose the picture. Even if the lighting conditions around you are changing rapidly, you don't have to do anything but point and shoot. This quality helps make camcorders remarkably easy-to-use.
The chief advantages of video, then, are that it is a versatile, easily transmitted medium and that it adapts very well to different lighting conditions. These qualities let camcorder manufacturers automate and simplify many of the tasks involved in shooting and recording video, making camcorders extremely user-friendly devices. In the next section, we'll look at some of those standard features manufacturers include with their camcorders.
The other problem with editing and copying this way is that every time you make an analog copy, you "lose a generation," meaning the quality of the image and sound deteriorates. There is a noticeable difference between an original and a direct copy, and if you were to make a copy of a copy, you'd really be able to see the effect. This is because when you make an analog video copy, you're not making a direct reproduction of the magnetic patterns on the video tape, but actually decoding those patterns into a video signal, sending the signal to another VCR that then re-records the signals as magnetic patterns. Every time a device reinterprets the video signal, the signal changes a little bit, and so the picture quality degrades.
Even with a simple setup using two VCRs, your second-generation copy will still look pretty good. Very few people bother to edit their home movies this way, however, because the process is so cumbersome and the results usually look fairly messy. Up until recently, quality video-editing equipment was too big an investment for the casual video-maker, and most units could easily fill a small room. Consequently, most people with analog camcorders have boxes of tapes with hours of choppy, unedited footage, which they rarely watch. This is too bad because it means the typical camcorder-owner has been missing out on one of the most rewarding elements of making home-movies -- assembling footage into a finished work.
In recent years, however, manufacturers have changed all this with the advent of affordable digital camcorders. With digital camcorders, you can download video footage to your computer, edit it with easy-to-use, inexpensive software (some camcorders and home computers actually include basic editing programs as part of their software package) and copy it back to tape with virtually no loss in image quality.
With editing capabilities, camcorder owners can create polished home movies, ones that they'll actually feel like watching from time to time. This expands the functionality of the camcorder a great deal, allowing consumers to make impressive school presentations, documentaries, training videos, concert movies and many other interesting projects.
No matter what kind of connection you use, you'll need a software application that can receive digital video. Most digital camcorders are packaged with this software, but you need to make sure the program is compatible with your operating system (Windows, Mac OS, etc.). You'll also need a computer program that will let you edit digital video. There are all sorts of software applications available, and even the simplest ones will let you cut scenes, rearrange sequences and add titles. Your camcorder may come with a simple program, and many new computers now have an editing application included in their introductory software package. Higher-end applications let you apply special effects to your video, such as interesting filters or distortions. Digital video is fairly easy to manipulate, in the same way that digital photographs are easily modified in a computer. All this requires a pretty fast computer with a lot of memory and hard drive space, so you may not be able to use your camcorder this way if you have an older computer. A digital camcorder is still a good investment, however, because there's a good chance that the next time you buy a computer, it will already be configured to receive digital video.
If you've already been recording analog video for years and years, a digital camcorder can help you finally edit it into something you'll want to watch. Your original camcorder and a digital camcorder with audio-video input jacks gives you everything you need to convert analog footage to digital. All you need to do is connect a VCR or your old camcorder to your new camcorder, using standard audio-video cables (commonly called RCA cables). Hit Play on the analog VCR and Record on the digital camcorder, and you'll have a digital copy in no time. You'll lose one generation in the conversion process, of course, but after that the footage is in digital form and so won't degrade any further. You can then edit it just as you would any other digital footage.
The other main advantage of digital video is that once you download it to your computer, it is stored as a basic computer file. This means you can e-mail your movies, post them on the Internet or simply store them on your hard drive. Keep in mind that digital video files are quite large, and that you'll probably need to upload small portions of your footage at a time and then upload your finished movies back to tape for permanent storage.
Many digital camcorders will also let you select still pictures out of your footage, effectively making them a camcorder and digital still camera in one. In fact, some camcorders have an option for taking digital pictures and storing them on a flash memory device, just as a digital camera does. Digital camcorders have a fairly high picture resolution, so these pictures will come out well, but they will not have as high a resolution as pictures taken with a high-end digital camera.
This is really amazing when you consider what movie-making equipment was available to the average consumer even 25 years ago. Very few amateurs had access to video equipment, and film was expensive and relatively difficult to manage. You could edit it, with a simple splicer machine, but this required a lot of skill and patience. It wasn't something you could take up casually.
These days, you can get a digital camcorder for $700 and pick up some tapes for under $10. Digital video editing programs simplify the editing process to the point where you can master it in an afternoon. Camcorders have so many helpful features that anybody can get decent footage with a little practice and you can create quality movies with more in-depth studying. The technology that was once the exclusive domain of television professionals is now available as hobby equipment. Whether you simply want to record birthday parties and recitals, or you hope to produce ambitious video projects, the newest camcorders have a lot to offer.
||VHS cams use regular VCR tapes, which are a lot less expensive than the tapes used in other formats; they also give you a longer recording time, two to four hours. But the size of the tapes necessitates a more cumbersome camcorder design. They have a resolution of about 230 to 250 horizontal lines, the low end of what's now available.
||VHS-C cams use standard VHS tapes housed in more compact cassettes -- you need an adaptor to play them on a regular VCR. The smaller tape size allows for more portable designs, but they have a much shorter recording time than standard VHS -- 30 to 90 minutes.
||Super VHS cameras are about the same size as standard VHS cameras, because they use the same size tapes, also with two to four hours of recording time. But a super VHS tape records an image with 380 to 400 horizontal lines, a much higher resolution image. To watch a super VHS tape on your TV, you have to use your camcorder as the VCR or purchase a super-VHS VCR.
||Basically, super VHS-C is a more compact version of super VHS, using a smaller size cassette, with 30 to 90 minutes of recording time and 380 to 400 resolution.
||These cameras use 8-mm tapes (about the size of an audio cassette), allowing for extremely compact design. 8 mm offers about the same resolution as standard VHS, with slightly better sound quality. Like standard VHS tapes, 8-mm tapes hold two to four hours of footage, but they are more expensive. To watch 8-mm tapes on your television, you have to use your camcorder as the VCR.
||Hi-8 cameras are very similar to 8 mm, but they have a much higher resolution (about 400 lines). Hi-8 tapes are more expensive than ordinary 8-mm tapes and they hold about two to four hours of footage.
||Digital Video (DV)
||DV cameras record on compact mini-DV cassettes, which are fairly expensive and only record 60 to 90 minutes. DV has 500 lines of resolution, and can be transferred easily to a PC. They're extremely lightweight and compact, and have the ability to capture still pictures.
||Digital 8-cameras (Sony exclusive) are similar to regular DV cameras, but they use standard 8 mm tapes, which are a less expensive, and hold up to 60 minutes of footage that can be copied without any loss in quality. Digital 8 cameras connect easily to your computer with a firewire connection. They are a bit larger than DV camcorders.
||This provides a very small black-and-white screen, viewed through a portal, where you can see exactly what you are taping.
||The only difference between this and the black-and-white eyepiece is the color, which provides a more accurate depiction of what you are recording. If you plan on using any special effects, you'll probably want to go for the color.
||With this feature, you can watch the color LCD screen instead of viewing through the eyepiece (some models provide both). The screen can usually swivel, to adjust your viewing angle. But LCDs do use more power than a simple eyepiece, so it could decrease your battery life.
||Optical zoom changes the size of the object in view without moving the camcorder. Usually limited to 24x, the larger the optical zoom number the more flexibility you have when shooting. A high number is especially important if your cam's lens is not detachable and you want some control over your shooting.
||Digital zoom uses the cam's processor to expand an image beyond optical zoom capabilities (up to 300x). But using this feature can degrade image quality, so for clear images you'll want to turn this feature off (note: the higher the optical zoom number, the clearer the digital zoom image).
||Nickel-cadmium batteries are pretty standard, and allow for one to two hours of recording time before they need to be recharged. Smaller or higher-end cameras may use proprietary batteries specific to the manufacturer, and this can make extra or replacement batteries expensive. Check the battery technology and prices before you buy a camera.
||AC adapters can be used to supply power to the camcorder whenever you are near an electrical outlet. This saves the battery for times when you are without an external power source.
||If you plan on using your camcorder in or near your vehicle, you might want to buy a car adapter to save some battery power on those occasions.
||Most camcorders do quite well in low-light conditions without help from additional lights. As long as you don't plan on filming primarily in indoor or low-light conditions, you do not necessarily need supplementary light.
||Some cameras come with a built-in light source, and many can be programmed to turn on automatically when conditions require additional light.
||Some cameras allow you to connect an external light source to the unit, for greater control over lighting conditions.
||This feature electronically stabilizes the image being filmed, but can decrease its clarity.
||This feature does the same kind of stabilization, only it uses digital technology, and can also correct for tilting and panning movement -- again, this feature can decrease image quality.
||Uses a series a lenses to reduce shake, optical stabilization decreases the effects of camera movement and vibration on the image being filmed -- very important with handheld cameras and when filming a moving object. Not common on inexpensie camcorders.
||Most cameras use a single CCD chip to capture and transmit image information. Look for size and pixel specifications, the higher the better.
||Some high-end cameras use three chips to enhance colors and provide better resolution. Three-chip cameras capture more information than one-chip cameras, and can capture and transmit colors with greater accuracy. This is an expensive feature found only on high-end and professional cameras.
||Most cameras will set the proper exposure mode for the conditions you are filming in. If you are strictly amateur and don't feel the need to alter the exposure, automatic settings will suit you just fine.
||Some cameras allow you to adjust the exposure for certain conditions, such as low light, backlight or motion.
||If you want to be able to control all aspects of exposure and focus to fit your creative vision, look for a camera that allows you to adjust these settings freely.
||Most camcorders come with a built-in microphone to record sound. Unless you plan on professional use, this standard feature will suit your needs very well.
||If you need professional sound quality, look for a camera that allows you to attach an external microphone.
||Some camcorders automatically adjust everything -- for amateur movie makers, these settings will be more than satisfactory.
|| For professional use, or if you just want greater control over the look of your video, you probably want a camcorder that allows you to adjust the various settings on your own. Look for manual exposure control, manual focus, manual zoom, manual white balance and so on.
|Still Image Capability
||Digital camcorders let you pick still images out of your video. Camcorders with a built-in or removable memory device let you take still pictures as you would with a digital still camera.
|Detachable Lens Adapter
||If you want to be able to switch the lens on your camcorder depending on conditions, look for one with a detachable lens adapter. For example, A wide-angle lens attachment is a common accessory to buy if you shoot lots of video indoors in small rooms.
||Camcorders come with specifications regarding the minimum recommended level of light during recording. The higher this LUX number, the more light you need. If a camcorder specifies 0 LUX, it can see images in complete darkness.
||Only available in digital formats, progressive scan records an image with a single scan pass instead of as odd and even fields, increasing the quality of the image. This technology is especially important if you plan to use your camcorder to take still pictures.
|Analog Video Input
||If you want to be able to convert your existing VHS format tapes to digital format, for editing or viewing purposes, look for a digital camcorder that allows for analog input.
|16x9 Recording Mode
||This is "wide-screen" recording mode -- if you plan on viewing your handiwork on a widescreen TV, look for a camcorder that supports 16x9 format (such a camera will also support regular mode).
|Audio Recording Formats
||Most digital camcorders can support both 32 kHz 12 bit and 48 kHz 16 bit audio formats. 48 kHz 16 bit audio is better than CD quality, so if you need REALLY amazing sound to go with your video, this is the format for you.
|IEEE 1394 (FireWire, i.Link) Compatibility
||Most of the newer digital camcorders come with IEEE 1394 compatibility, which is basically a way of connecting the camcorder to your computer for extremely fast downloading. Not all computers are FireWire compatible, and not all camcorders use the exact same FireWire technology, so be sure to check out specifications in both areas before choosing a model.
||Almost all camcorders come with VCR-type features like rewind, play and pause -- just make sure to find a camcorder with the playback features you're looking for, because they do vary.
||Some of the higher-end camcorders come with special effects features, such as fade-in/fade-out, and special recording modes like sepia or negative.
||Some camcorders have special sensors that turn the camera on in the presence of movement or sound. This is generally only useful for security purposes.
The feature comparison chart is available to you as a PDF. You will need the free Adobe Acrobat Reader to view it.
To give you an example of some typical camcorders, here are several popular models: