100" TVs

Discussion in 'Archived Threads 2001-2004' started by Carlo, Jan 21, 2002.

  1. Carlo

    Carlo Extra

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    Just out of curiousity, has anyone encountered these things? I'm seeing a lot of these on Ebay latelty. I know they are no good, but I would like to see some reviews and an explanation on the basic setup.

    From the limited info I obtained, these use some sort of magnifying sheet. Nevertheless, I would like to find out about its image quality.
     
  2. Allan Jayne

    Allan Jayne Cinematographer

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    You use an existing TV set together with the lens provided in the kit. A lens with characteristics comparable to a magnifying glass and reasonably suitable for the "100 inch TV" can be fabricated as a thin sheet of plastic with ridges, that is called a Fresnel lens.
    I haven't seen exactly what you get with the kit but most likely all you get is the lens and an instruction sheet. You must obtain or construct a box to put around the TV and hold the lens in front of the picture tube. The box is to prevent light from the picture tube missing the lens from hitting the projection screen or other areas in the room and washing out the picture.
    The picture is likely quite dim therefore you need a dark room. Also a single lens (probably all they give you) is and not able to be focused for both at the edges and the center of the picture. The bigger the lens, the brighter but also less sharp the picture will be. Good cameras, projectors and FPTV's have lens systems with several lenses to achieve good focus all the way across the screen or film.
    What is a fresnel lens?
    http://members.aol.com/ajaynejr/vidfres.htm
     
  3. Carlo

    Carlo Extra

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    Thanks for the very informative info! :)
     

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