Can someone explain to me why does this happen?

Discussion in 'Amateur Video Production' started by Paiasoloco, Aug 14, 2006.

  1. Paiasoloco

    Paiasoloco Guest

    Paiasoloco, Aug 14, 2006
    #1
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  2. Paiasoloco

    David McCall Guest

    Flaws in the camera. I did a lot of playing around with feedback
    and other analog distortions back in the mid 70s (we built an exhibit
    for Boston's Museum of Science). One of the things we learned
    was that a crummy camera made much more interesting feedback
    than a broadcast camera.

    David
     
    David McCall, Aug 14, 2006
    #2
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  3. Paiasoloco

    Paiasoloco Guest

    Hi David, do you have anything that I can see online? I guess if it was
    back in the 70s but have you digitized comething?
     
    Paiasoloco, Aug 14, 2006
    #3
  4. Remember that single-chip color cameras (such as your
    "webcam") form colors by dividing up the light-sensitive
    chip surface between the different primary colors (or some
    equivalent). A slight shift in position will slightly change the
    color which will be quickly multiplied into saturation by the
    video feedback into one of the primary (red, green, blue)
    or secondary (magenta, cyan, yellow) colors. Note that
    those six colors (along with hard black and white) are the
    colors you recorded (and not coincidentally, also the colors
    in the SMPTE color bar test pattern).
     
    Richard Crowley, Aug 14, 2006
    #4
  5. Paiasoloco

    David McCall Guest

    Sorry no. Almost none of it made it to tape, and I don't know if I even
    still have any of it.

    It was mostly just experimentation to decide how we wanted to build the
    exhibit.
    The exhibit was called "Vision and Television". The first half attempted to
    explain
    how vision works in humans and various other animals, and the rest was what
    they called a video synthesizer. It was a round room with mirrored walls and
    a
    lot of video monitors (modified TVs). Some of the TVs could have their scans
    distorted by feeding signals into coils around the neck of the CRTs, there
    was
    also adjustable quantization, and other effects. The part you would have
    liked
    was the camera mounted in the center of the room on a motorized pan and
    tilt,
    plus another rotator that moved the camera on the X axis You could point the
    camera at monitors and mix it with other effects to create some weird stuff.
    This was before the microprocessor was common, so just about everything
    was totally analog. There were some logic chips involved but that was it for
    digital.

    David
     
    David McCall, Aug 14, 2006
    #5
  6. Paiasoloco

    Paiasoloco Guest

    Very Cool Thanks for sharing, it sounds like quite a complicated settup
    you got back then, now you can do it with a $30 cam and a computer.

    Fede
     
    Paiasoloco, Aug 17, 2006
    #6
  7. Paiasoloco

    David McCall Guest

    One of the tricks was that it had to be usable by several visitors at the
    same time and be interactive. Plus it had to hold up to inner-city kids.
    They tell a story about a guy that built a modified bicycle that was
    hooked up to a generator that would light a light bulb when you
    pedaled the bike. He built it at home and had all of the neighborhood
    kids over to test it. As far as he could tell it was robust enough for
    kids to play with without breaking it. So, he delivered it and set it
    up, watched the children playing with it, then went up stairs to
    collect his final payment. On his way out he dropped by his exhibit
    to see how it was doing, and the kids had disassembled it and
    stolen some parts. He was in tears.

    David
     
    David McCall, Aug 17, 2006
    #7
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