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Topic: Ultra Short Throw on an Angled Screen
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Joined: Nov 24, 2021
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It is time to replace our projector. Our screen is 96 inches wide, and mounted diagonally at the front of the church to one side. It is also tilted down since the projector is actually inside the communion table in the center front of the church. You can envision is as manually taking out the keystone effect of having the projector near the floor and the screen up high. See my picture of the front of the church.

I would like to use an ultra short throw projector below the screen. I can't move the top of the screen closer to the wall because of the angle of the cathedral ceiling. So having it tilted like we do actually means a better fit for the location. How much keystone can an UST projector do? Can I mount it at the bottom and angle it so that it will fit the screen? The projector being used in the picture is a Sony VPL-PWZ10 which we have as a loaner. The throw distance is too short for that location. I had to shrink the image using the menu commands. The screen is 8 ft wide and 16 ft away from the projector. That projector has a throw length of only 1.88. You can also see that in 16x9 orientation the screen is taller than it needs to be. So I could lower it some.

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Front of Church

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If using a UST projector, you need to get the projector at the proper height and you should angle the projector so it is exactly at a right angle to the screen. This will allow it to proper project the image without the need for any keystone adjustment at all. UST projectors not only have a problem induced by the severe angle of projection with any off-axis projection, but ANY flaws to the screen surface will be magnified exponentially due to the severe projection angle. Keep this in mind if your screen has any bend, waves, or flaws in the projection surface. A small bend in the screen is not something that can be corrected. That's just physics... light travels in a straight line, and if you are directly below a wave, you can't project to the opposite side of it.

Imagine standing on a nice wide open plain, and there are some VERY gentle rolling hills. No matter how hard you try, you can't see what is on the opposite side of the hill, no matter how small that hill is. Same with UST projection. You need a PERFECTLY flat screen.
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