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Horizontal shift

post #1 of 3
Thread Starter 
Hi - I'm in process of mounting my projector screen an realized I'm about .75-1" off center in my room (room is 15Wx17L); this drives me nuts since it was preventable. My screen is a Stewart 133" cine-w.

At any rate - I have my projector mounted essentially dead center on the other side of the room @ 14'2" therow (which will probably be more like 14" now that the screen is mounted on the wall).

I also have a Schneider 1.33x M lens that will be installed. However, I've read that horizontal shift should be more/less avoided when using lenses as they exacerbate these geometry issues (not sure if this is specific to prism vs cylindrical lenses or not...).

So I forseeably will need to shift my image accordingly (horizontally) about 1" (maybe 1.5" to account for some fluff). Do you guys see this as insignificant when paired with my lens? Or do you think I should bite the bullet and reposition everything (by shifting over both mounts .5")?
post #2 of 3
I see nobody responded. The most important fact is to keep the project square with the screen and use lens shift to center the picture and keep from moving the projector from square. Next you will need to adjust the angle of the lens both horizontally and vertically to account for the projector being not in exactly the center of the screen. The big mistake is to turn the projector off square to align the picture to the center of the screen. Yes it is better to have everything square but you should obtain acceptable results if you follow these instructions. If you use the Schneider lens mount it does have both vertical and horizontal adjustment. Mark at CAVX had a test pattern that is excellent to setting this alignment. Perhaps he can email it to you or check out his website.
post #3 of 3
Thread Starter 
Thanks CRGINC! My OCD kicked in and I ended up re-centering the screen in the room which I'm glad I did! I have to hand it to you guys that can get proper angles with all this stuff - I've spent a 3-4 hours over the past couple of weeks just trying to get things "just right" with angling my PJ to the screen and getting the a-lens correct.

I'll check out CAVX website for test patterns - it seems that the top line of the projected image is straight with the top of the screen, but the bottom right corner seems to curve upwards more than the left. Still some more trial and error to go!
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