Projector distance

Discussion in 'Displays' started by Chris Stock, Jul 21, 2004.

  1. Chris Stock

    Chris Stock Extra

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    The following question is dependant on a few things:

    1) The screen is a fixed 16:9 ratio of 90 inches.
    2) The material viewed is always widescreen, be it from 1.78 to 2.35.

    Knowing this...

    Do you mount a projector the minimum distance (read: closest) to the screen to improve picture quality? Or do you mount it as far away as possible?

    I recently acquired a SP 5700 which has a massive manual zoom of 1.4:1. I've yet to mount it as I still don't have a "real" screen. So I've been playing around with the positioning of it from the painted wall and trying to decide what is the best placement.

    I don't remember my physics to well, but I would figure that the further a source is from its object, the more loss is obtained. (HUH!?) That is, light diminishes over distance. Also, the screen door effect is not very noticeable but can be if...? Who knows. Can't decide.

    A little help thanks.
    :b
     
  2. Chris Stock

    Chris Stock Extra

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    Also, the optics might play a part in the answer. You could say the optical distortion is greatest at high zoom depths, versus, minimal at the low end.

    Your thoughts,

    Chris V [​IMG]
     
  3. Parker Clack

    Parker Clack Schizophrenic Man
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    Chris:

    Projector Central as a throw distance calculator on their site for that projector and the screen size that you are wanting to use.

    According to their information a 90 inch diagonal screen will reguire you to have the projector from 12.4 to 17.2 feet back from your screen wall. You also need to take into account that you want to be setting back away from the screen about twice the width of the screen or about 156 inches.

    I also recommend that someone that has a new projector just shoot it on to a blank wall and figure out the best picture from where they are setting at for optimum viewing. Then go get the screen to go with it or make your own.

    Parker
     
  4. Chris Stock

    Chris Stock Extra

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    Thanks Parker Clack

    I'm currently shooting on to my wall, but what what I need to know though is, do you put a projector as close as possible to the screen, or furtherist away? The noise issue isn't a problem thus far, although I haven't watched a romatic flick on it yet. Just the big block busters (read: spearker busters). Still have good relations with the neighbours.

    Thanks again though.


    Chris V
     
  5. RomanSohor

    RomanSohor Second Unit

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    Here's the physics behind it... it's called the "inverse square" rule, meaning that you the brightness you lose is proportional to the square of the change in distance, so if your projector is 1 foot away and then you move it another foot away (double the distance) your brightness is cut in half. (I think, I need to grab my old lighting design handbook!!!) But I do know that there is more light lost the further away you are.

    I would say put it as close as possible (unless it causes distortion). Just keep in mind that you might want it placed behind your seating so it isn't in your field of view while you are watching movies.
     
  6. Chris Stock

    Chris Stock Extra

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    Perfect! That was the answer I was looking for. The projector will eventually be mounted to the roof, so that won't bother me RE seeing the projector.

    I knew Physics 101 would come into play some how! Now, all I need to do is grab video essentials and see if there is any distortion.


    Thanks again,
     

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