# Projecting Backgrounds Wide Enough For The Stage



## gmff (Oct 28, 2012)

I got asked about projecting a background. The space, sizes and distances are not favoriable to this. Is there a wide angle adaptor that could give me the with 20'-24' from 10' projector distance. Any information would help


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## ruinexplorer (Oct 28, 2012)

What projector do you have available? If it has the option of different lenses, what do you have available? What are you projecting on, and will this be front or rear projection?


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## museav (Oct 28, 2012)

Also, is the 10' distance noted the total distance available or the distance available to the front of the lens or projector? If you have to account for the depth of the projector and lens as well as any required clearances, that could result in a less than 10' actual available throw distance.


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## ccm1495 (Oct 28, 2012)

Your also going to have to take into account the brightness of this projector. A stage has a lot of light on it. You are going to need a projector that is bright enough to over power any light that may spill on your screen.


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## MPowers (Oct 28, 2012)

You don't "adapt" a projector to change size of image, you change lenses. However, depending on what your image is, how sharp or accurate you need it to be, a method that has been used for years, indeed, it dates clear back to the "Magic Lantern" days of projection in the early 20th century, is simply to get a front surface mirror. The limit to this is of course the size of mirror you can obtain, as it needs to be relatively large to help very much. The method is simple, if you are rear projecting, you place the projector as close to the screen as possible, place the mirror as far from the screen as possible. Leaving the mirror stationary, move the projector closer as needed to get the image the size you want. The most common orientation is projector at center aimed straight upstage to the mirror and reflected back to the screen. This has the least amount of Key-stoning to account for. You can project form the side and turn the image 90 degrees sideways instead of 180 straight back, but this can present greater keystone issues. Note: as mentioned, brightness can be an issue with very large images and a mirror will absorb as much as 5% to 15% of your lumens.


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## metti (Oct 28, 2012)

The short answer is no. The shortest throw projector are roughly .48 or .5 throw ratio so you aren't going to be able to get a 24' wide image from 10'. You might be able to get a 20' image if you have 10' from the lens and not 10' total. The other issue is that the projectors that offer those sorts of throw ratios are generally between 2500 and 3500 lumens which is not going to be particularly bright once you get that wide, especially for a stage. Brighter projectors tend to start around .8 as the widest available throw ratio which would require a minimum of 20' or so to get a 24' image. The long answer is that you can definitely do this by edge blending multiple projectors. I did a show recently where we covered a 40x30 rear projection surface using only 7' of throw by using several edge blended 3000 lumen projectors that each has a .48 throw ratio. What are the actual dimensions you need for the screen? How many feet do you have total between the screen and whatever is preventing you from going back further? What sort of budget do you have for this?


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## gmff (Oct 28, 2012)

I have a 2000 lumens projector Epsom with 100' of vga cable, a platform to fasten the projector to and a clamp to fasten the platform to a batten. I front projected a movie in back of dancers who danced in silhouette. I adapt slide projectors with a fisheye lens from and old conversion kit from a rangefinder camera with a plumbing coupling it worked well but the projector had a lens barrel, we projected giant doughnuts on a police station as part of an experiment of police power. I did not know if someone had made something like that with success. This venue is tough, the stage is 18' wide (backwall to plaster line), refinished floor with a gloss poly finish, no barn doors for the stage washes and the syc needs to be moved and it was not installed properly to begin with. The director had seen a show that had projected backgrounds, he wants to do Beauty & the Beast with projected backgrounds. His grandaughter was in the recital that had the movie projected, he did the math and thinks that this should be simple. I like the blending idea, it should be simpler to find several projectors and laptops than one big one with a wide angle lens. I wish the police station was across the street from my studio I would experiment with more doughnuts.


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## metti (Oct 29, 2012)

gmff said:


> I like the blending idea, it should be simpler to find several projectors and laptops than one big one with a wide angle lens.


 That sounds like it is probably going to be your best option. Just keep in mind that getting all those projectors aligned and blended properly and keeping all those separate computers playing back in sync might be a little bit tricky. You will need to investigate software that will let you do what you need that is within your budget.


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