# Help with projection!!!



## jaredwooden921 (Sep 29, 2008)

My director decided 2 weeks before the run of our show that he wants to use rear projection instead of a number of cloth drops. Sounds great, except he put me in charge of it! I have not the slightest clue what I'm doing so I turn to you all for help. Heres my list of questions..answer as many or as few as you care to. But first a little background about the venue/scenario.

*20x30 Screen
*15 foot throw (yikes)
*No existing projector (At least not that will do what we need it to.)
*Size of screen can be "shuttered" with borders and traveler if need be.


Ok, now questions:

*If the screen is 20x30, what aspect ratio is that? 

*I am hoping to have a 16:9 aspect ratio in the end so what dimensions do I need to make the screen in order to accomplish that?

*Can anyone reccomend a good projector and lens that will suit my needs? I've used several different lens calculators but it is just confusing me more.

*Would you suggest using a slideshow program (PowerPoint) or a program such as Sound Cue System 10 with built in video cues (Here)?

*Does anyone have any experience with the program Keystroke from Rosco(Here)? 



I'm sure I will have more and more questions as we get closer to the show. Thanks so much for your help, CB never lets me down!!


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## museav (Sep 29, 2008)

jaredwooden921 said:


> My director decided 2 weeks before the run of our show that he wants to use rear projection instead of a number of cloth drops. Sounds great, except he put me in charge of it! I have not the slightest clue what I'm doing so I turn to you all for help. Heres my list of questions..answer as many or as few as you care to. But first a little background about the venue/scenario.
> 
> *20x30 Screen
> *15 foot throw (yikes)
> ...


2:3 or 1:1.5, which would be a vertical 35mm slide format. 30x20 would be horizontal 35mm slide 1.5:1 format.


> *I am hoping to have a 16:9 aspect ratio in the end so what dimensions do I need to make the screen in order to accomplish that?


Anything that is 16X wide by 9X high, e.g. 16'x9' or 32'x18' or 30' wide x 16'-10 1/2" high or 35'-6 2/3" wide by 20' high.


> *Can anyone recommend a good projector and lens that will suit my needs? I've used several different lens calculators but it is just confusing me more.


You mentioned a 15' throw but is that in addition to any depth for the projector and ventilation or would the actual throw distance available be shorter? Even with a 0.8:1 on-axis short throw lens and a 15' distance, you won't be able to fill a 30' wide screen, so either mirrors to fold the projection path or a smaller image would probably be required. Until you nail down the image size and have some idea of the screen material and lighting conditions, it is difficult to address what projector might be appropriate.


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## BillESC (Sep 29, 2008)

BenQ offers the MP771 short throw projector. Considering it will product a 78" diagonal image at one meter, it should be just the thing you're looking for for your screen size and throw distance.

3300 ANSI lumens and available under 2k


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## museav (Sep 30, 2008)

BillESC said:


> BenQ offers the MP771 short throw projector. Considering it will product a 78" diagonal image at one meter, it should be just the thing you're looking for for your screen size and throw distance.
> 
> 3300 ANSI lumens and available under 2k


According to BenQ, the MP771 is a 3,000 lumen, XGA projector. The largest 16:9 image it supports is 239.76" (19'-11.76") wide x 134.87" (11'-2.87") high, which is much smaller in both dimensions than the 30'x20' screen size noted. In addition, at that maximum 239.76" x 134.87" screen size the 3,000 lumen output and native XGA format yield only 10ftL, a virtually unusable screen luminance (well below the 17ftL recommended for dark cinemas and a fraction of that commonly used for applications with any ambient light levels). For something like a 10.67' wide x 6' high image the MP771 might be a practical solution, but it does not seem a reasonable option for this application. 

Jared, if you really want a 30' wide image, think more along the lines of two stacked 10,000 lumen projectors with short throw lenses and 25' to 30' of throw. Even then, you are going to want a decent screen surface and if you have to have a shorter throw you may need to consider a mirror system. All that is going to be a serious cost. I don't know your complete situation, but you may need to sit down with the Director and discuss what is realistic and practical, especially if there is a budget you have to meet. For example, what image size do you really need? Could you maybe work with multiple smaller images? What budget do you have?


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## SHARYNF (Sep 30, 2008)

my suggestion would be unless you have a HUGE budget, look at multiple projectors and design the images that it works with the design. If you make the design accomodate the spacing between projectors, avoid having hard edges of anything near the end of the images, it can work, and you can do it
Remember you are looking at greating an effect, as suspension of disbelief not necessarilly a 30 foot photo grade panaroma

Sharyn


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## jaredwooden921 (Sep 30, 2008)

Thanks for your input everyone..

Ok so I'm getting more of an idea how this might work. Since we are a high school, we obviously have a relatively limited budget. We are most likely looking to rent a projector for this project, not purchase, so that broadens our horizon a bit. Now lets say for instance I want...a picture of a desert with mountains in the background to be project about, 15x25 (about as small as the director is willing to go), what image size and aspect ratio would that be? I wish we had the budget to do stacking projectors but as I mentioned we are limited by money. 

*Would the iPro be bright enough to be vivid under typical stage lighting? I know that that isnt specific at all but I dont know how else to describe it.

*How far does the luminarie need to be from the screen for the iPro to look best? What size barrel? We will be using a S4.

*Would the mirror option be a relatively simple operation where you can just adjust the mirrors until they work or is there more to it than that?

*I like the idea of multiple images set on different projectors, but how will I synchronize all the images. ie fades?

*Powerpoint or SCS 10?

You guys rock!! Thanks again.


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## derekleffew (Sep 30, 2008)

A 15x25 screen would have a ratio of 5:3, not a standard.

See the glossary entry: http://www.controlbooth.com/forums/glossarys/9221-ratio-projection-image.html.

You'd be much better off with multiple projectors than mirrors, but here's a link: http://www.stewartfilmscreen.com/mirrorproducts.html.


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## Pip (Oct 6, 2008)

jaredwooden921 said:


> Thanks for your input everyone..
> 
> Ok so I'm getting more of an idea how this might work. Since we are a high school, we obviously have a relatively limited budget. We are most likely looking to rent a projector for this project, not purchase, so that broadens our horizon a bit. Now lets say for instance I want...a picture of a desert with mountains in the background to be project about, 15x25 (about as small as the director is willing to go), what image size and aspect ratio would that be? I wish we had the budget to do stacking projectors but as I mentioned we are limited by money.
> 
> ...



As far as the iPro goes - 
It's definitely bright enough using (as is intended) it in a S4. We shot ours (rear proj) onto the back of our white scrim, i believe, and we had our black scrim in front of it and it looked great. You have to have their little slide things though, so if you have specific pictures you want to use, you have to have them custom made by Rosco.
We hit our surface from about 10 - 15 feet, I don't remember what barrel we had in it, but it depends on how big you want the image to be. Sounds like this would definitely be your cheapest option that has so far been suggested, even though the ipro is fairly expensive.

As long as you don't have to change images REALLY fast, it's easy to switch them in and out if you're staffed enough to have someone back there to swap out the slides.

Good luck!


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