Screwed up planning now need advice

[Dan Smith]

Long story short, screwed up planning, didn't a count for image drop distance on ceiling mount. Now to get image desired hight the projector is tilted upward slightly.

This creates a subtle trapazoid. Top and bottom are straight but side to side measurement varies by 1" from top to bottom.

The width is 150.5 and 151" respectfully. So it's impossible to tell by eye when only projected on the wall. I assume it will be more apparent when trying to build a fram and screen. Of course I could build a trapazoid screen but that's a pain not sure I want.

Question is; I'm going to build a frame, am I better off framing to the larger width and the image will just be further inside the frame at the bottom, or should I frame the smaller with bleeder on to black frame at the top?

Thanks
DAN

 

[BoredSysAdmin]

Why just don't do trapezoid adjustment on the pj?

 

[Dan Smith]

It's a viewsonic pro8200 I don't see that adjustment... maybe I missed something all I saw was keystone.

 

[Dan Smith]

Any thoughts?

 

[BoredSysAdmin]

It's a viewsonic pro8200 I don't see that adjustment... maybe I missed something all I saw was keystone.

yea, keystone should adjust the the trapezoid issues you have, then use zoom to fix overall size. if you don't have zoom, you might have to move the PJ mount.
and yes it's tricky and more expensive PJs have more adjustments... c'est la vie

 

[Big Jake]

Auto Keystone
The ViewSonic Pro 8200 is capable of ±40 degrees of vertical keystone adjustment, allowing the projector to be arranged in places that are not aligned perpendicularly to the screen to a certain degree. This feature not only offers better placing flexibility, but also gives the image a perfect rectangular shape from any viewing angle.

http://ap.viewsonic.com/in/products/projectors/pro8200.php

 

[Dan Smith]

Yep i have auto keystone (+18) and this is how close it got me +/- half inch top to bottom. any deviation from that auto keystone set point makes it worse


Also, the real question i have is should i frame the screen to the small or larger of the widths? Light inside the frame or slightly bleed over onto flat black be less noticeable?

 

[KEW]

If your screen is 12.5 feet wide, I am guessing it is about 10 feet high.

You say it is off by 1", but the measurements you give indicate 1/2" deviation from top to bottom.

Assuming you get a square screen perfectly mounted, you would see 1/4" deviation over the 10 foot height on each of the two sides. 1/4" over 10 feet is not something to be too worried about, but I think your best solution is to build a square frame and shim out the top (so it tilts more perpendicular to the projector beam) until the image is square. I like the look of a screen that tilts down (more square to the viewer), so you might consider taking the keystone adjustment closer to neutral and putting more tilt into the screen.

But my main point is adjusting the tilt of the screen is the best way to precisely fine tune things.

 

[BMXTRIX]

If your keystone correction is maxed out, then that projector is not pointed up 'slightly'.

I would ditch whatever ceiling mount you are using completely, and get that projector slammed against the ceiling as tight as you can make it. Make your own mount, and put it so that projector is half an inch from the ceiling.

With a 150" screen width, you are looking at a 172" diagonal and a 84" screen height, which is well beyond what that projector is rated for, but that's your call if you are happy with it. Still, the center of the lens should be 29" above the top edge of the screen. That's about 2.5', and would require very tall ceilings to work properly.

You are giving up a huge amount of brightness with the keystone in use. You are giving up a ton of resolution with the keystone as well. Combine that with the medicore brightness, and lamp fade, and you are looking to have serious viewing issues over time.

I think I would bring the size down to something that projector is designed to handle, get it flush to the ceiling, get keystone down to zero, aim it right at the wall, and see what screen size realistically works. Or, if within any sort of return period, I would return it, pay the restocking fee, and get a projector which actually meets the needs of the situation I was trying to achieve.

The BenQ W1200, by example, is a very bright entry level model which can handle larger screen sizes in light controlled situations, and has only 2"-3" of offset with larger screen sizes.

 

[Dan Smith]

150.5"w(bottom+1 for top) by 80"h

 

[mtrycrafts]

Any thoughts?

The alternative is to just zoom in a bit so thewhite is covered where the image is shortest left to right/ You will get a slight over projection on the black, so what. Hardly noticeable.

 

[Dan Smith]

Thats what i was thinking... thank you!

One last thing... For some reason my ratio is off. With the pj set to 16:9 my measurements across the board from every direction leaves an aspect ratio of about 1.89... vs 16:9 would expect to see 1.77. Maybe i missed something but its really odd. Source material is ps4 set to 16:9 (menu showing) as is the pj.