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placing a dlp projector off centre

Discussion in 'Projectors, Screens & Video Processors' started by scouse258, May 29, 2005.

  1. scouse258

    scouse258
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    hello

    im currently building a cinema in my loft :clap:

    i have a hitachi 5200 42" plasma in my living room but thought - hell lets do out the loft.

    MY PROBLEM... :confused:

    the centre pillar keeping up the loft is in the way of projecting an image dead centre and so i was considering placing the projector slightly off straight - just behind and to the right of the column

    The projector is a BENQ PE8700 bought from Ebay

    It is a wonderful lifelike presentation when viewing without zoom but loses something when you use the zoom, the picture becomes a tad more blurry.

    projecting from 3.2m gives me a relitively small image whilst from 3.5 (off centre) it is far more respectible - its amazing how a few more inches can improve your life :)

    So - what i have is digital keystone correction but i am guessing is that i need a projector with lense shift ?

    i am keeping the projector so with this in mind - does this mean i am knackered and will simply have to use the lense zoom to fill the screen??

    cheers for your time

    PS - is the best colour for the walls of the cinema matt black and the carbet a dark colour too?
     
  2. cyberheater

    cyberheater
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    Have you thought about mounting a mirror on the center support.

    You could have the projector mounted nearer to the screen but pointing to the support and the mirrow would bounce the light back to the screen so you'd get a full centered screen.

    Worth a look.

    And in terms of colour. It doesn't have to be black. You could use a dark midnight blue ;)
     
  3. scouse258

    scouse258
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    cheers for your thoughts, however, i think the mirror idea is a horrible one :eek:

    the difference from centre to off centre is about 6 inches so i may simply point it straight and have the screen off centre

    any more comments guys?

    Chris
     
  4. PJTX100

    PJTX100
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    This is where optical lens shift comes into its own.

    If you haven't got that, or horizontal keystone correction (not many PJs do I think) then an offcentre screen seems to be the only solution (other than Cyber's mirror idea, which can work effectively if set up correctly)...PJ :)
     
  5. cyberheater

    cyberheater
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    Just out of curiosity. Why is it a horrible idea? Lot's of folks have used the technique to resolve set up issues.
     
  6. scouse258

    scouse258
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    simple - ignorance on how to do do it - how big a mirror do you need - etc

    i thought a knew a lot then i visited the forum and found out i know bugga all!!!

    at least sky are now gonna do HD via component from day1 making my plasma not so outdated after all!!
     
  7. Gordon @ Convergent AV

    Gordon @ Convergent AV
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    scouse: Cyberheaters idea is excellent and is how rear projection TV's work.

    Using electronic keystone correction or electronic zoom is a no no for good image quality. Both will substantially reduce resolution.

    First rule of FRONT PROJECTION: PUT THE PROJECTOR IN THE CORRECT PLACE.

    Of course the pj position is relative to the screen to moving the screen, if you can do it, is also a good solution. Moving the screen is the cheapest and best solution for image quality.

    Gordon
     
  8. Joe Fernand

    Joe Fernand
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    scouse258

    You could take the mirror idea a stage further and build a false wall incorporating a rear projection screen and then sit the projector behind the screen.

    You can purchase custom rigs for the projector which incorporate adjustable mirrors and projector mount (costly) or build your own.

    See http://www.draperinc.com/RearProjectionScreenSystems/RPXLite.htm

    Best regards

    Joe
     

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