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Mad BenQ PB6100 Iris mod :)

Discussion in 'Projectors, Screens & Video Processors' started by cyberheater, Jun 29, 2005.

  1. cyberheater

    cyberheater
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    After being inspired by a thread on the US avsforum from a bloke that modded his X1 I decided to attempt a similar mod on my BenQ PB6100!

    I had the machine apart for my monthly dust blob check and clean so had the ideal opportunity to attempt the mod.

    Using black cardboard and gaffer tape. I constructed a small diamond shaped aperture that was around 75% smaller then the lens at the rear of the projector lens assembly and attached it to the rear of the assembly lens housing.

    Quite simple really. Took a couple of goes to get the size right but no too difficult.

    I then (with trepidation) sparked up the PJ.

    The results.

    Amazing.

    Deep inky blacks. Much more contrast. More snap. Somehow a deeper image. It looks brilliant. It's like getting a new projector.
    Now even dark bits in films look right. The LOTRs cave scene were transformed. It really is incredible.

    Obviously there is a fair amount of lumens lost due to the diaphragm but as the BenQ is a bit of a light cannon and I project in a fully light controlled environment it's not a problem.

    Well worth it in terms of time and effort.

    Will post piccies later.
     
  2. Peter Parker

    Peter Parker
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    Great stuff Cyber. :)

    The new Benq 8720 has two irises which give it an advertised figure of around 6200:1! Positioning is probably critical for performance though. Of course that figure will drop for video but anything over 4000:1 is pretty good for a digital. Have you got a light meter? I'd love to see what kind of readings you're getting now.

    Gary.
     
  3. PJTX100

    PJTX100
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    Fascinating stuff. Is this simply a case of making the iris aperture smaller = darker blacks / better contrast but less lumens?

    Or is there something more complex going on here?

    ...PJ :)
     
  4. Fordy

    Fordy
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    is this a fire risk?
     
  5. cyberheater

    cyberheater
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    Piccies of the mod :)

    [​IMG]

    [​IMG]
     
  6. PJTX100

    PJTX100
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    Wish the TX was as easy to take apart as this!

    Why diamond shaped as opposed to circular?

    I do echo the concern about fire risk...PJ :)

    PS is that your anamorphic lens?
     
  7. cyberheater

    cyberheater
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    No. The anamorphic lens looks like this. It's a bit of a beast.


    [​IMG][/URL]

    I used the diamond shape as it's the one the guy used in the US.

    (I don't think it gets that hot at that point. Time will tell...)
     
  8. PJTX100

    PJTX100
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    Nice one! :smashin:

    ...PJ

    PS are you going to mod your sig to include "with DIY iris & anamorphic lens" ;)
     
  9. cyberheater

    cyberheater
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    LOL. I might do that :)
     
  10. Peter Parker

    Peter Parker
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    Does the iris go inside the lens or before it? You could try one inside if you can get it apart and have two irises like the 8720. :)

    You really must get a light meter and take some measurements because I really need to know how much you've improved the CR!!

    Gary.
     
  11. PJTX100

    PJTX100
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    Just noticed your classified ad Cybes. Must admit if I was in the market for buying this I'd be slightly wary to see such experimentation going on while you are in the process of selling it!

    ...PJ :)
     
  12. cyberheater

    cyberheater
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    I'm being very careful and everythings reversible. I'm starting to think about just keeping it now. I don't think i'm going to get a buyer anyway.

    The iris goes before the lens. Actually, it's attached to the end of the lens.

    I haven't got a light meter but I did go out today and get a couple of LDR's (light dependant resistors) which i'll attach to my meter.

    I should be able to get a good reading from that.
     

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