Zephyr Magazine - Issue 36

                              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.