                                  T H E

                               Z E P H Y R

                      __     M A G A Z I N E
                     {__]++++++++++++++++++++++++++[]
                     Issue #36                1-30-87

                A weekly electronic magazine for users of
                            THE ZEPHYR II BBS
                        (Mesa, AZ - 602-894-6526)
                    owned and operated by T. H. Smith

                        Editor - Gene B. Williams

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                                (c) 1987

    THIS ISSUE:

         It has long been known that light can cause chemical
    reactions to take place. In the last century this was put to use
    and the first photographs were made. Early in this century
    photography had advanced far enough so that anyone could own and
    operate a camera. This was made possible by putting the light
    senstive chemical coating on flexible celluloid - rolled film.
         That in turn made movies possible. Then came movies with
    sound. Then color movies with sound. Then home movies - color
    home movies - color home movies with sound -
         And now home video. No more waiting for a week while the
    drugstore processes your movie film. Make a mistake? No problem.
    Just back up and record over the top of the error.
         Too expensive? Not when you run a comparison. A 3 minute
    roll of silent 8mm (or super 8) movie film runs about $6, plus
    about $2 for processing. That comes to about $160 per hour of
    silence. Want sound? Now you're up to about $240 per hour.
         A single $5 video cassette can hold 6 hours. To duplicate
    that, someone with a film camera would end up spending over
    $1400.
         So you have convenience, speed, versatility and even cost.
    Is it any wonder that home video has become just about the
    biggest thing to ever hit the market?

                               Home Video

         When I was in high school the first home video decks came on
    the market. They weighed in at about 80 pounds, used expensive
    reel-to-reel tapes, were capable only of black & white, and
    carried a price tag of nearly $6000. To make matters worse, they
    had the unfortunate tendency to break down - and there were very
    few people anywhere in the country who knew how to fix them.
         The matching camera was just as limited, just as unreliable,
    and just as expensive.
         In other words, you'd end up spending some $12,000 (plus
    tax) for the ability to record rather low quality images in black
    & white on a $60 reel of tape that could hold maybe 15 minutes of
    movie.
         Things sure have changed in the past 20 or so years. It's
    not difficult at all to find a VCR for $250 or less that is
    capable of high quality reproduction, in color, and with as much
    as 8 hours squeezed onto a single $5 cassette.
         Video cameras have also come a long way. From that $6000
    black & white home camera, you can now get a smaller, lighter,
    better, color camera for as little as $400.
         It doesn't stop there. Earlier in this decade you had two
    choices. You could cable that camera to your home VCR deck and be
    limited to the length of the cable - or you could spend an extra
    $1200 or so to get a portable VCR that could be carried along and
    operated by battery power.
         In 1984 the industry brought out the first home camcorders.
    These are a camera and video recorder all built into the same
    case. That makes them smaller, lighter and generally less
    expensive. It also means that you can get by with less battery
    power.
         Taking it one more step, this coming spring Zenith will be
    making available a full stereo hi-fi camcorder.

                                 Formats

         Essentially you have 3 choices, with a 4th soon to come.
    These are Beta, VHS, 8mm and the soon to be released (by Samsung)
    4mm.
         Beta came first. It was developed by Sony, and Sony still
    holds proprietorship on Beta. Anything Beta has to go through
    Sony's approval - and they are sticklers! Beta is well known for
    having a superior reproduction, particularly in the video.
         JVC (Japan Victor Corporation) jumped into the game and
    developed a new system. They called it VHS, for video home
    system. It didn't quite match Beta for picture quality, but the
    system was easier on the tapes. That longer tape life caused the
    VHS to be more popular with both owners and rental stores, which
    in turn influenced owners to go VHS because of the wider
    selection of tapes, which brought out more tapes, which . . . and
    so on. (It also didn't hurt that the extra playing time allowed
    by VHS tapes is better suited to movies.)
         The battle between Beta and VHS continues. Beta came out
    with Beta Hi-Fi, then stereo, and various other improvements. VHS
    introduced HQ (for high quality) an even more reliable transport
    and now its own version of hi-fi and stereo.
         When camcorders became available, the buying public went on
    a buying craze. The market for VCRs had been unmatched by
    anything before. Camcorder sales have knocked the socks off even
    those sales figures.
         JVC developed something they call VHS-C. This is a scaled
    down version of the standard VHS transport system. The miniature
    cassette holds only 20 minutes of recording or playing time, but
    it's fairly rare that more than this is needed for the average
    home movie. If more IS needed, it's a simple matter to pop in a
    new cassette. They can later be dubbed to a full-sized VHS
    cassette, again allowing as much as 8 total hours of playback
    time. And nicely enough, since the VHS-C is still the VHS format
    (it's just smaller) it's easy to build (and to get) and adapter
    that allows you to plug that smaller cassette into a standard
    home deck.
         This new format made it possible to build even smaller video
    camcorders. But that wasn't enough. An 8mm format was developed.
    This one is even smaller, which makes the camcorder smaller and
    lighter. The problem came in that the smaller size made decent
    recording and reproduction difficult. The solution was to come up
    with a new way to manufacture the tape.
         A standard video tape is made by depositing a layer of tiny
    magnetic particles on a base of Mylar. (Interesting side note -
    Mylar is the brand name for the stuff, owned by DuPont, and only
    DuPont or a licensee of DuPont can make Mylar. The generic name
    is polyethylene terephthalate. Anyone can make that.)
         8mm tape is manufactured in a vacuum. Instead of being glued
    to the plastic, the magnetic particles literally boil off the
    source and are deposited directly. The result is a tape that has
    a much wider range of response. Enough so that the image from a
    8mm video recording is at least tolerable. It can't quite match
    the quality of VHS or Beta, but is good enough so that many
    people, if not most, couldn't really see much of a difference.
    And new techniques are being studied at this time to make the
    8mm tape even better.
         Now Samsung has gone that one better. Later in the spring
    they intend to release a tape (and the camcorder that uses it)
    that is about half the size of 8mm. It's commonly - but
    inaccurately - referred to as 4mm. The only real information
    available about it at this time is that the cassette will look
    similar to a standard audio cassette.
         An even newer format and type is also scheduled for release
    this spring. This is SVHS - super VHS. If the news releases are
    accurate, this format will put everything previous to shame.
    Refinements have been made to the video heads and also to the
    special tape used by the format. It's still a standard VHS
    transport pattern, which means that you could technically load a
    VHS cartridge into a SVHS machine (and it will play it) or a SVHS
    cartridge into a VHS machine (but it WON'T play it).

         Which of the formats you choose depends a lot on your needs,
    and on your prejudices. At the moment, Beta still produces the
    best video and audio. It also tears the tapes up faster. VHS is
    such a close second in quality reproduction that most people
    wouldn't be able to see the difference, especially if VHS-HQ is
    being used.
         With the smaller formats, the VHS-C has superior character-
    istics over the others. For now. It's also a little more
    convenient, and a little less expensive. The 8mm is smaller,
    which makes the camera smaller and lighter. This can become
    important if you're going to be lugging the camcorder around for
    a number of hours. (The 8mm tape also records for a slightly
    longer time than VHS-C.)

                                 Pickups

         Call them pickups, imagers, or whatever else. It's the same
    thing. The pickup device reacts to the incoming light and
    generates the electrical signals that can then be recorded
    magnetically on tape. They are somewhat like film, but not
    really.
         Most of you know what pixels are. They are picture elements,
    which is a fancy way to say that they are dots of light sensitive
    something-or-another. The more dots (pixels) you have, the better
    the resolution.
         In a sense, film has pixels. In actuality, those are tiny
    particles that change chemically when light strikes them. The
    particles are too tiny to see with your eye, so when you look at
    the picture you see the composite image made by all those tiny
    bits together.
         A video pickup works somewhat the same way. Light strikes
    the pickup device, effecting thousands of tiny light sensitive
    spots. The brighter the light, the more charge is held by a
    particular pixel. The device "fills" and then dumps the entire
    image into a memory section - and you have an electronic picture
    (of sorts). This happens every 1/30th of a second (which is the
    effective "shutter speed" of the video camera) after which the
    pickup device is erased and it starts over again.
         Professional video cameras usually use video tubes to pickup
    the image. Almost always there are three of them - one for each
    of the primary colors. (In video, the primaries are red, green
    and blue - RGB - with the combination of them making white.)
         Home video cameras have a single pickup designed and
    adjusted to pick up all colors in the proper proportions.
    Filtering the color of the incoming light is handled with a
    single stripe filter (while professional cameras can filter the
    light on each of the three pickups).
         The light sensitive material is usually either Saticon or
    Newvicon. (Coming into use is a new material, the lead-based
    Plumbicon, developed by North American Phillips, if memory
    serves.) Of Saticon and Newvicon, both are about equal. The real
    difference is basically chemical. There remain many myths and
    prejudices, however.
         Originally, Saticon was used in studio cameras because of
    its ability to render color accurately. Newvicon was used more in
    surveillance cameras because it was more light sensitive and
    worked better in low-light conditions.
         Over the past years, Saticon has been made to be more
    sensitive to low-light, while Newvicon has been made to have a
    better response to color. Today, as I just said, the two are
    about equal.
         What makes more of a difference is the KIND of pickup. Tube
    pickups are still used in most professional cameras. These are
    sort of like miniature TVs in reverse. Instead of the electron
    guns painting a picture on a television screen, the electron guns
    of a tube camera scan the pickup. The result is a constant
    freshing of the image, better light sensitivity, and considerably
    higher quality. Another result is a very high cost. You won't be
    able to find a professional, 3-tube camcorder for less than about
    $20,000. Also, the 3-tube cameras require regular checks on
    registration - the making sure that all three tubes are "hitting"
    the same spot.
         The first home video cameras used a tube. To lighten the
    weight, reduce power requirements and to lower the cost, a new
    system has been developed. It's called CCD, for charge coupled
    device. It works as I explained above. The device gets hit with
    the light, gets charged, and dumps that charge as a whole image
    over to a memory section. The images can then be handled by the
    circuitry and eventually get put onto the tape.
         Even newer is MOS CCD, with the MOS describing the circuitry
    in general, and with MOS being a kind of extremely low-draw (in
    power) circuit. The idea was to come up with a way to make it
    possible to use smaller batteries, or to be able to use the same
    batteries for longer periods of time.

                             Video Problems

         There are two main problems with video. Both concern the
    color of the final image.
         Red is a "high energy" color. The present video cameras have
    a very hard time with it. Watch television for a while and you'll
    notice something. There are no reds. (If there are, you're
    probably watching the broadcast of a film.) "Video red" is more
    of a red-orange. In home cameras this becomes even more apparent.
    Also, any color with red in it can be "off" a bit.
         More important is the way the pickup and the circuitry
    handle color in general. In actuality and as far as chemical
    stimulation is concerned, red is a "low energy" color. As the
    amount of light coming into the camera decreases, the reds and
    blues start to disappear. Shoot in dim light and everything is
    going to have a greenish cast. And because half to two-thirds of
    the pixels are less active, the image will be more grainy in
    appearance - less sharp.
         There's not much you can do about either condition other
    than to provide the correct type and amount of light. Sunlight is
    generally best. (My own camera also works extremely well under
    flourescent lights, although this isn't true of most cameras.)
         Of prime importance here is for you to know up-front what to
    expect. Quite a few go out and spend $1500 or so on a high
    quality camcorder, and are then disappointed when their tapes
    aren't as good as what they see on television.
         That just isn't going to happen! The home video camera
    simply isn't capable of reproducing the same quality as a
    $50,000+ studio camera, and you shouldn't expect it to.
         However, it should produce acceptable images. The only way
    to know for sure is to test the camera yourself before buying it.
    Test it under a variety of lighting conditions. Most will do fine
    outside in the sunlight, but how well does the camera handle the
    shadows? How about incandescent and flourescent lighting? How
    does it handle low-light conditions?

    CAUTION:  When shooting outside, never, never, NEVER aim the
    camera at the sun. That will burn or destroy the pickup
    permanently! Don't even aim it at a very bright subject for long
    periods.

    Until Next Time

         Geez, I could write a book about this. In fact, I am.
    "Chilton's Guide to Home Video Movies" is my ninth book in that
    series for Chilton. At this point, release is scheduled for the
    upcoming fall. (Don't forget to run on down to the local
    bookstore and pickup copies of my other 8 books in that series -
    or at least one of the 5 that deal with computers!)

    Next Time:  The article continues with more information. What is
    lux? How does the image and the sound get onto - and off of - the
    tape? What simple steps can you take to make your home video
    movies more professional in appearance? How about signal
    enhancers and other accessory devices?
         There's lots more to come, so stay tuned. Meanwhile, feel
    free to ask any questions you might have on cameras, camcorders,
    VCRs, tapes, lighting, special effects, or whatever else is
    appropriate to the topic.

Zephyr Magazine is © Gene Williams. All rights reserved.