Choosing a Camcorder Format
During the past few years, the two most popular formats for amateur underwater videographers have been standard 8mm and Hi-8. However, there are some new kids on the block. Digital camcorders have arrived with a bang.
What’s the difference? All non-digital camcorders and VCRs use an analog format. The video signal is a stream of fluctuating voltages that magnetically records the picture on videotape. When you shoot or dub (copy) video, the recording VCR can’t perfectly duplicate the varied voltages of the video signal. Each copy degrades picture quality.
Digital camcorders send a digital signal—a series of Is and Os—from the image sensor to the videotape. Thus, the image is recorded more accurately. If you dub digital to digital, generation loss is virtually nonexistent because the digits (either a 1 or a 0) can be copied exactly.
Who should use standard 8mm? If you want a low budget personal hobby, 8mm is the way to go. Dozens of standard 8mm camcorders are available at prices lower than $500. You can easily record images that will please your family and friends. However, 8mm has some limitations. First, 8mm images will not be as sharp as Hi-8 or digital images. Second, if you make dubs of 8mm tapes, image quality declines quickly. Standard 8mm camcorders
record less than 300 lines of resolution (a measurement of image sharpness).
Who should use Hi-8? Hi-8 is an enhanced version of 8mm video and is still probably the most popular choice for underwater videography. If you want sharper images than 8mm but don’t want the added cost of a digital camcorder, Hi-8 is your best choice. Many of the underwater videos you’ve seen on commercial TV were shot on Hi-8 camcorders such as the SonyTR81 and Sony CCD VX3. Hi-8 camcorders record up to about 400 lines of resolution and cost more than 8mm camcorders.
Who should use digital? If you want high quality acquisition footage for commercial use, digital is the way to go. Digital camcorders record about 500 fines of resolution, are expensive and can be copied to any other format for editing and duplication. Even if the end product will be a VHS copy, the better the image quality on the acquisition tape, the better the image quality of the edited copy. Digital is for professionals, aspiring professionals and rich amateurs.
For computer editing, digital images can be downloaded directly into a computer. The editing can be computerized rather than from tape to tape. Thus, the edit master is of the highest possible quality.
You won’t see all the increased picture quality if you connect your digital camera to a TV set with an RCA cord for playback. This is because the RCA cord only passes about 240 lines of resolution to a TV set. If you use an S-video cord and TV input, you’ll see about 400 lines of resolution. You would need a digital connection and a TV set that could show 500 lines of resolution.
Don’t let the limitations of your present VCR or TV keep you from switching from analog to digital. Your next VCR may be digital and your next TV may have a digital input.
Three chips or one? Unless the manufacturer states otherwise, camcorders have one CCD chip, which must handle all the colors in the video image. Some camcorders have three chips; one for each of the primary colors.
Any camcorder needs a minimum amount of light to record pleasing images. In bright conditions, a three chip camcorder (either digital or analog) records images and colors more accurately than a one chip camcorder. In dim light, however, one chip camcorders often record better images because the single chip sees all the light passing through the lens. (A three chip camcorder has a prism that divides the light among the three chips. Each chip may see only one-third of the total light. Thus, in dim light, picture quality suffers.) Lastly, I’ve seen dropouts (those little white glitches) in 8mm and Hi-8 playback but I’ve never seen a dropout on digital tape.