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Z3 and 16:9 not uniformly filling the screen 16:9 screen

Discussion in 'Projectors, Screens & Video Processors' started by mrm3, Mar 20, 2005.

  1. mrm3

    mrm3
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    Just moved my projector to a new position and I am using the zoom and lens shift to fill the screen. But when I zoom to fill the vertical, the sides are not filled in and if I zoom a bit further, the vertical is too high.
    I am just trying to perfectly fill the 16:9 beamax projector screen (up to the black surround).

    What is this problem called if it has a name and how do I fix it ? Any suggestion are welcome !

    My PC is set to 1280 x 720. The Sanyo Z3 projector is also set up for this. I am using VGA out from PC. I am sure it is something simple. Hopefully it is nothing to do with the fact that the projector is off center, to the left and above the screen and I am using adjustments with lens shift.

    Thanks.
     
  2. mrm3

    mrm3
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    oops the projector was tilted lightly forward... now fixed
     
  3. KraGorn

    KraGorn
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    The effect you saw is known as 'keystone', where the projected image isn't rectangular but trapezoidal, ie. one side is shorter than its' opposite so that the adjacent sides don't meet at right-angles .. the same shape as the key-stone of a bridge.

    There, you really wanted to know that, didn't you. ;)
     
  4. mrm3

    mrm3
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    Thanks i have had keystone too in my short experience but this time the width and the top and bottom were the same so not a trapeze.

    Just me being a fool.
     
  5. KraGorn

    KraGorn
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    In that case I don't understand how the effect you saw was caused by an uptilted projector .. non-perpendicular alignment causes keystoning. :confused:

    Oh well, as long as it's fixed.
     
  6. mrm3

    mrm3
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    well having put a spirit level on it and adjusting left and right, up and down then making it square to the screen fixed the problem of filling the screen

    having my projector not very central (high and to the left) am I compromising the PQ ? ... does not seem as good as it was very center center before though head height ! But I now know all the bad things to look for thanks to you other sticky thread showing me what are bad things to look out for :)

    Lastly can I tilt it forward or should it be sqaure to the ground ... as focus at the top and bottom could be slightly out?

    thanks for your help and advice KraGorn !
     
  7. Neelix

    Neelix
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    I had a bitch of a job to setup my HS50 as I was getting some really odd shaped trapezoidal images. If the projector hits the screen at any angle that isn't central on both axis then it goes funny... the lens shift works to get rid of this. That said I still can't seem to get a perfectly square image as it is about 3 pixels out on the bottom left. How do others square up the image and is 3 pixels nothing to worry about as it doesn't effect the movie when running as you just can't see it!
     
  8. KraGorn

    KraGorn
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    mrm3: I had a Z2 and used lens shift in both directions, from a 'high/left' position similar to you, and what I found was that if I tried to use to much then I got a very slight focus problem, which I put down to imperfections in the optics.

    Ultimately it's a compromise, as ever, between perfection and practicality. The ideal position is dead centre to the screen, which with projectors with this sort of throw is exactly where *you* want to be.
     

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