Uneven screen image from projector - AVS Forum
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post #1 of 14 Old 10-30-2010, 06:26 PM - Thread Starter
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Hey I don't know if there is a post about this already but I couldn't seem to find it. I am new here and was wondering if someone could help me out. I just built a projector home theater type setup in my college dorm but the image on the bottom left corner of the screen is uneven. The distance from the screen to the projector is 12ft. Does anyone know how to fix this? Thanks!

Sorry if I posted this in the wrong thread or if there was one already. If I did can someone please redirect me to the correct one? Thanks!
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post #2 of 14 Old 10-30-2010, 06:36 PM
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Try turning the projector to the left and right, and then use the lens shift to bring it back to center.
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post #3 of 14 Old 10-30-2010, 06:47 PM - Thread Starter
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I did try turning it but that just shifts the screen left and right and its still uneven Here are a couple of images I have a hunch that it might be uneven or something but I'm not sure which part is uneven or how to fix it.
LL
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LL
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post #4 of 14 Old 10-30-2010, 06:58 PM
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If that is an LCD projector with lens shift, the projector should be pointed directly at the opposing wall so that it directly perpendicular to the wall. Don't point it at the screen, point it at the wall! The resulting image should be a perfect rectangle. The lens shift controls should be at their middle positions.

Then and only then, use the lens shift to move the image onto the screen.

If the projector is not pointed directly perpendicular to the screen, then when you use the lens shift, the resulting image will be more of a trapezoid.
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post #5 of 14 Old 10-30-2010, 07:07 PM - Thread Starter
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Thanks a lot! I'm going to try that out. It might be a little hard because the room is actually uneven. It concaves in towards the window so maybe thats why its uneven. I'll see what happens.
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post #6 of 14 Old 10-30-2010, 11:17 PM
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Also check that the keystone controls, if any are neutral. If they are, it looks like the right hand side of the projector is slightly closer to the screen than the left. You should again try pivoting the projector about the y-axis (vertical), and bring the right hand side of the projector fractionally away from the screen
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post #7 of 14 Old 10-31-2010, 09:41 AM - Thread Starter
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I think I realized the issue. I tried tilting the projector up and down to make it even but the screen is still uneven on the bottom left corner. The projector is not directly perpendicular to the wall because our walls are uneven (cheap dorm construction...) I think the only way to remedy this is to put the screen at an angle as well and not perfectly straight. I think I have to either move the right corner closer to the projector or move the left corner back so the screen is on an angle.

Btw if you guys want to see more pics of my setup here it is. (I think its pretty good for a college dorm setup )
http://min.us/mvbDojc
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post #8 of 14 Old 10-31-2010, 09:53 AM
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I have seen cases where images coming out of the lens were not in fact rectangular...even though the installation was perfect. It is rare, but it can happen.
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post #9 of 14 Old 10-31-2010, 12:17 PM
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My epson 8350 seems to project a trapezoidal image to the screen no matter what adjustment I make. More obvious when I watch espn , you can see the left side ticker slanted. Is this a defect on the projector?
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post #10 of 14 Old 10-31-2010, 12:29 PM
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I'm having a similar problem with my 8500UB. The screen and projector are both perfectly perpendicular. However, the image is still trapezoidal, slightly larger at the bottom. Only slightly, but I do notice. I was wondering if my lens shift might be defective (out of alignment?)
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post #11 of 14 Old 11-01-2010, 07:40 AM
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There are some variations...if the image is slightly larger at the bottom you might try tilting the backside of the projector down, and then lowering the lens shift. This in theory should help...
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post #12 of 14 Old 11-01-2010, 07:53 AM
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Quote:
Originally Posted by mj75 View Post

My epson 8350 seems to project a trapezoidal image to the screen no matter what adjustment I make. More obvious when I watch espn , you can see the left side ticker slanted. Is this a defect on the projector?

Try rotating your projector left and right. This sounds like your projector isn't actually facing 100% directly forward. If the left side of your image is taller, then rotate the projector a little to the right. Then center the image using lens shift. Check it again, and repeat as necessary. It might take a few iterations but you should be able to fix the image.
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post #13 of 14 Old 11-01-2010, 10:31 AM
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Quote:
Originally Posted by SaxCatz View Post

I'm having a similar problem with my 8500UB. The screen and projector are both perfectly perpendicular. However, the image is still trapezoidal, slightly larger at the bottom. Only slightly, but I do notice. I was wondering if my lens shift might be defective (out of alignment?)

Jason and DrewK are right.
To get a perfect focus and a square image, the PJ's lens must be perpendicular (Horizontally and Vertically) to the screen. This in not always the center of the screen. If the bottom is larger than the top, tilt de PJ up (or viceversa). And/or if the left side is larger than the right side, turn the PJ clockwise (or viceversa). Then use the lens zoom and/or shift to fill and/or center the image.
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post #14 of 14 Old 11-06-2010, 03:01 AM
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..... Kids these days.. what kind of dorm room is this? I didn't even have space for a TV in my dorm room, how did you fit a projector. This looks more like a common room. Nice set up btw. Wish I had a roomate like you.

Btw did you do all the wiring yourself cause I looked at the rest of your pictures... pretty impressive wiring setup!

I Love Apple, BenQ, Samsung, and Acer Products = )
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