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PJ Mounting Advice Req'd Please..

Discussion in 'Projectors, Screens & Video Processors' started by LDR, Aug 25, 2004.

  1. LDR

    LDR
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    OK just got a Infocus 4805 and a LMP close ceiling mount..already fitted my 92" diag DRH screen, now according to projcentral's distance calc I can get a 92" diag at 14.1 ft with no zoom at all, or using a little zoom anywhere from 13 ft up. Is it critical to get the fixing of the mount spot on or is it ok to bang it somewhere in the middle of these calcs and use the zoom to compensate ? Ive tried..somewhat foolishly..to hold the PJ and mount roughly in place but of course the pic is bouncing all over the place and Im just getting hot and bothered.. any advice in simple terms welcome..

    TA :suicide:

    LDR
     
  2. pgre

    pgre
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    I had the same dilema with the TX100 I celing mounted. I put it in somewhere between the capabilities of the zoom..

    I actually put a table underneath and then several boxes ontop and sat the PJ on top of that to give me an idea of where to mount it.. this means you lose the bounce a little giving you chance to make some adjustments.
     
  3. LDR

    LDR
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    Anyone else mounted using this method of "roughly there should do"?
     
  4. zoolap

    zoolap
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    I would also be interested to know. What would be really nice is if someone could do a step-by-step with pictures.
     
  5. Gary Lightfoot

    Gary Lightfoot
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    You could try using a good steel tap from the top corners of the screen, and marking a point on the ceiling where they converge for your prefered mounting position - 14.1ft in this case - or you can use a 14.1ft piece of string with a pencil in the end, and draw some light curves on the ceiling roughly where the pj should go - they will make a cross central to the screen at the correct place provided the string was kept tight).

    Where they cross, is where the center of the pj lens should go.

    That's the theory - I used a little trial and error with mine, but I'd fitted a largish flat piece of mdf above the ceiling so all I had to do was screw through the ceiling plasterboard and into the wood. If it needed moving, it was easy to unscrew it and move it. I didn't think of the string or tape idea at the time. Both methods would probably only work well with someone helping though.

    Gary.
     
  6. LDR

    LDR
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    Gary, So your saying its got to go at exactly 14'1" and use no zoom at all.. ?
     
  7. Gary Lightfoot

    Gary Lightfoot
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    No, I just chose that figure because I thought that's where you wanted to put it.

    In theory, you get slightly better contrast from a pj by having it zoomed smallest, and then move it back until the image is the right size, but that isn't always practical.

    Quite often it's useful to have the pj roughly central within it's zoom range so that it allows some flexibility in mounting it. Then you just zoom to fit the image to the screen. The thing to watch there is that quite often the projected image height varies as you zoom in or out, so that may affect screen height an inch or two and depends on the pjs ability to move the image up and down opticaly or digitaly...

    Gary.
     
  8. LDR

    LDR
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    And I thought this was gonna be easy.. :rolleyes:
     
  9. theritz

    theritz
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    ........... Gary, for one awful minute I thought we were back to a "water-cooling" solution to projector placement !! :D

    The idea of using a piece of string to locate a point which is dead-centre to the screen is a very good one......... Agree that finding a location allowing some scope for zoom in and out provides the best flexibility.

    Using the Search facility is a good idea - the following threads from "the Vaults" about projector mounting.... Click Here and Here, for example.


    Sean G.
     
  10. Gary Lightfoot

    Gary Lightfoot
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    I was going to correct it to 'tape' but forgot as I was typing my other reply. Now you've gone and quoted me I can't do anything to save face!! :)

    Gary.
     
  11. LDR

    LDR
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    Oh **** it, my head hurts..I have absolutely no clue what Im doing..Ive just tried to work out the correct distance using the PJ on top of a box, and I cant get a non distorted picture..the keystone wont give me a completely square image no matter what I try..so god help me if I eventually work out how to mount it upside down...anyone wanna buy a 4805 with 10 hours on it.. ? :suicide: :laugh:
     
  12. theritz

    theritz
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    LDR,

    Forget using the keystone..... set it to zero. Place the pj LEVEL on the box and project the image low down on the wall - just concentrate on getting the image the right width on the wall with the zoom at half point - then you'll have the projector the right distance from the wall with flexibility to zoom in and out a little................... mark this distance from the wall on the cieling, follow Gary's instruction for finding a point which is centered on the screen that distance from the wall in question and you'll have the correct position for the lens....


    Sean.
     
  13. LDR

    LDR
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    On a side note...has anyone noticed that according to the PJcentral distance calculator, there are no longer 12" in a foot... :nono:
     
  14. LDR

    LDR
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    Well, I certainly owe a great deal of thanks to Gary & Sean for helping me through this task, it wasnt really that bad after all, once I'd sat down and thought about it logically. Even more of a bonus was the point I'd picked to install the mount I found that the first 2 screws were directly into the centre of a joist, so added another bit of 2x2 noggin and away to go. Now just need to sort the cables out and tidy the ceiling up. Thanks again guys :clap:
     
  15. Gary Lightfoot

    Gary Lightfoot
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    Glad to hear it all turned out OK. :)

    Gary.
     
  16. theritz

    theritz
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    Good news............... glad you got it sorted out...... Gary and I will waive our usual "advice fee" on account of you came back and said thanks !!!!!! :smashin:


    Sean.
     

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