How do I make an optical comparator?

Discussion in 'Archived Threads 2001-2004' started by RyanDinan, Jul 5, 2001.

  1. RyanDinan

    RyanDinan Stunt Coordinator

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    Hello everyone,
    I tried posting this a while back in the DIY section, and also over at the AVS forum with no replies. I also tried doing a search for this, and can up with little info. I'm hoping that maybe someone will see this here..
    Does anyone have details or instrucions on how to make these home-brew optical comparators? All I've really read about is using a VHS tape....But I'm not clear on how to construct it. Also, what type of bulb or flashlight should be used (a model number maybe?)
    Once constructed, what IRE windows do you use? 30 and 90?
    Any help would be greatly appreciated!
    Thanks,
    -Ryan Dinan
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  2. Gregg Loewen

    Gregg Loewen Video Standards Instructor, THX Ltd.
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  3. Jim Robbins

    Jim Robbins Stunt Coordinator

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    I seem to remember that you must use a small fluorescent lamp that puts out 6500K. The inside of the box is painted with a neutral grey to more or less match the brightness of the video source's screen. The idea is to view the two sources and match the color of light produced. I believe the article mentioned using a certain radio shack lamp. I would think you might need a light meter also to match the lumens. I'm sorry I can not remember more or the source. I believe the Image Science Foundation sells it already made for about $400.
     
  4. Michael TLV

    Michael TLV THX Video Instructor/Calibrator

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    Greetings
    That would be ... "Used to sell" Past tense. A new, more portable unit is now on the market called "a visual standard" ...
    The device looks suspiciously like a small black tricorder from ST-TOS. $895.
    Regards
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    Michael @ The Laser Video Experience
     

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