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Maximum angle for a projector

36209 Views 15 Replies 6 Participants Last post by  coderguy
My apartment is in an old building with high ceilings. The room I want to use for my home theater is rather small and I can only put the projector on the ceiling, but it will have to project at an angle. (See attached picture.)

I'm not very knowledgeable about projectors yet. I would like to know if keystone correction in sub $3000 projectors can go as far as I would need it to.

I'll appreciate any help.

PS: Just in case you can't see the numbers: room width=3.30m (10.83ft), room height: 2.90m (9.51ft)

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If you are going to use a mount to hang the projector from the ceiling anyway, why can't you just put a 1 or 2 foot down tube on the mount? That will at least get the projector low enough that you can use lens shift on the projector and not need the keystone feature?
Just going by the drawings, that looks extreme and is probably well beyond the limits of the projector and practicality. I would either use a downtube as Davecraze suggested or hang it on the wall. The ideal (and recommended by the manufacturer) vertical location for the projector is close to the top of the screen, if hung upside down.

You haven't indicated a make/model but I would strongly advise that you pick one and download the owners manual so you can see what the mounting requirements are.
That much keystone, if even possible, would destroy the image quality. Are you not able to wall mount? Or are you worried about people walking in front of the projector?

Lens shift is probably a better way to go about it, but even that has tradeoffs. How big of a screen are you wanting?

You might be better placing it on top of a large bookshelf to the left or right of your couch (even though this isn't ideal).
Thanks everyone.

A shelf is against our current decoration design. We just can't do that.

I might check the tube solution, but is probably going to ruin the design as well. (There wasn't a projector in our minds when we did it some years ago.)

How about putting the projector below the table and projecting upwards?

The screen size will be around 100" diagonal (16/9)
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DLP projectors generally have a natural offset that makes them ideal for sitting level on a table and projecting the screen square and higher up.
Thanks for the replies.

After reading your advice, we have researched the price of an 85" plasma... and we have decided we must find a way to put a shelf and change our decoration aspirations.

Do you guys think most projectors will produce an 85" 16/9 diagonal from 3 meters (10 feet) away? Or do we need a special lens for that?

Thanks again.
Use the following website. It will give you a list of projectors that meet your criteria.


Originally Posted by comomolo /forum/post/20767415

Thanks for the replies.

Do you guys think most projectors will produce an 85" 16/9 diagonal from 3 meters (10 feet) away? Or do we need a special lens for that?

Thanks again.

Most projectors can do right at about 85" from 10 feet away as long as they have some zoom on the lens. The Mits hc4000 can do it. Some LCD's can do an even larger screen from that distance.

If you want DLP instead of LCD, the hc4000 seems to fit your purposes. There is also the Epson 8700ub or Epson 8350 if you want to keep your original mounting plan.

If you want to shelf mount, then the Benq w6000 would also work. It depends on your budget, those are the main sub-$2000 projectors.
This would also affect image quality, but you could always look in to ways of mounting the projector so a mirror would reflect the image back to where you want. I did this a few times in small rooms where I wanted a larger image.

Not a conventional way of doing things but might fit your design a bit better.
Thanks for all the replies.

We have considered the mirror but it takes special care to keep it clean, affects image quality as you said and, all in all, we'll take the plunge and redecorate the room.

Now I'll investigate the best choice of projector. Lots of reading ahead.

Thanks again.
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Originally Posted by coderguy /forum/post/20767640

There is also the Epson 8700ub or Epson 8350 if you want to keep your original mounting plan.

What do you mean? Do these projectors support such a big angle of projection? How do they do it?

See the diagram below:

These numbers are available in the user's manual or the calculator:

User's Manual = http://files.support.epson.com/pdf/p.../plhc87uug.pdf

Calculator = http://www.epson.com/alf_upload/land...ce-calculator/


It has lens shift, so it's done by a little knob that you manually move so that the lens inside the projector is actually displaced, it's essentually an OFFSET-ON-DEMAND feature.

The 8700ub can do a 100" screen from slightly less than 10 feet back, but given the size of the projector's DEPTH from the back of its case to the lens, you might only get away with a 92" screen from your placement distance.

Since it will do a 92" screen from about 9 feet back, then that leaves you about 20 inches of space for the projector's case itself, this is based on the 10 feet 8 inch measurement of the room you gave. The projector's case is 16" long/deep, so that leaves you 4 inches of room behind it which should be enough for the AIR intake to get enough air to cool. The cooling exhaust is on the front, so no worries there.

So I would shoot for at least a 92" screen if you can, the bigger the better, I personally wouldn't go smaller than 92" in your setup, but you could do an 84" if you really want it smaller I suppose.

Buy the projector first, then the screen last. You can project onto the wall ahead of time to make sure you have the placements correct and to ensure you can get the screen size you want/need.

A 92" 16:9 screen is 45" high and 80" wide. So if you mount the screen 30" from the floor, then that means the top of the screen's projection area is 75" off the ground, or 6 feet 3 inches. Assuming you mount the projector nearly flush to the ceiling, the center of the lens will be about 9 feet from the ground, give or take a couple inches.
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According to the Epson screen size calculator, you should be fine to mount the projector flush to the ceiling.


This shelf is unobtrusive. You can also paint the metal part the same color as your room and it will blend in to the room since it will be monochromatic and the glass shelf is not all that noticeable.
Also it should be noted that there is no exact STANDARD height for mounting the screen from the floor.

I personally prefer it lower than most people becuase I lay down on the couch sometimes, in my case my screen is mounted about 25" off the floor.

Most people would want to mount the screen somewhere between 30" to 36" off the floor from the bottom of the screen, I would personally recommend about 30" depending on your seating type, but you can go up to about 3.5 feet if you really want it higher.

It is a personal preference sort of thing in combination with how you sit more than anything else. Going too low makes it so that if you are in a recliner, your feet can get in the way of the VIEW from the bottom of the screen, but that's generally only if you go below 30" or so.

That is why you should buy the projector first, and use a ladder or something to temporarily place the projector near the ceiling as if you mounted it, decide what you want, then buy the mount and screen and finalize the setup after you spend some time watching the screen at different sizes and messing with the projector's placement.
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