# Projector Positioning. Please check my thoughts..



## grinthock (Dec 17, 2010)

8700UB Epson is what I am going to go with I think....

using the calculator here is what I have...

13FT viewing distance, 94" wide / 109" Diagonal (16:9) 

Mounting at 15FT -- 1.51x Zoom 

This sound good? Anything I should consider? I need to make these predictions so I can do the ceiling and conduit.


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## Prof. (Oct 20, 2006)

When considering the mounting position for the projector..make you distance calculation based on zero or minimal zoom..


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## grinthock (Dec 17, 2010)

Ok.... Well... 

If I set the ZOOM to 1.0 - it tells me that to get 94" Wide - i'd have to be out of the room..

At a zoom of 1.3 -- I can put it at 17" (back of the room) and shoot the same size screen but it says

"Recommend higher brightness - Reduce image size or increase screen gain" 

Screen is going to be a BlackWidow... 

Do I need a more powerful projector?


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## Mark Techer (Jan 17, 2008)

You also have to consider CR vs Brightness. Yes using more zoom can give a brighter image, however using less zoom increases the CR. My preference is for the 2nd.


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## grinthock (Dec 17, 2010)

CR?


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## Mark Techer (Jan 17, 2008)

grinthock said:


> CR?


CR = Contrast Range. Basically, the whites may dim, however you get much better blacks.


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## grinthock (Dec 17, 2010)

I would also err on the side of Contrast Range over brightness as well.

The room is 100% light controlled. 

For the 8700UB - the best I can do for my screen size is 16.5FT Back, gives me 95" wide, at a zoom of 1.37

It's right on the edge of "Recommended higher brightness" if I change the screen gain to 1.1 from 1.0 then it says "recommended for low ambient light" 

I was considering BW DIY - which has a stated gain of .89 however. 

Calculator gives me a "Image Brightness of 10FL"

I wish I knew - subjectively what that means. 

If there is another projector that can give me a 95" wide image, at a lower zoom at 10-16FT -- i'm listening if anyone has a suggestion.


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## Tooley (Jan 2, 2011)

The last 3 Epson's we installed were 14' from screen to front of lens 2 8700UB and 1 8500UB we had 2 112" screens and a 121" screen they look awesome plenty bright and the white's are white and the blacks are black.


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## grinthock (Dec 17, 2010)

As cost is a factory (a bit) unless there is a better idea than something has to give.

I suppose i'm not sure how many FL I should be shooting for... 

If I was willing to give up some contrast (and the 8700uB is rated for good contrast so I suppose I could afford to lose some)

Then at 12' with 1.8X Zoom, I get 18FL.


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## lsiberian (Mar 24, 2009)

I would not use minimal zoom because it gives no tolerances. Always give yourself flexibility.


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## tcarcio (Jun 27, 2007)

Remember PJ calculators are made to show you pretty much a perfect scenario but it is not written in stone that you need to do exactly what it say's.Especially if you have a light controlled room you can tweak some to make it work.


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## Prof. (Oct 20, 2006)

Personally, I would be looking for a projector with a shorter throw lens..The Epson appears to have quite a long throw lens..
A shorter throw lens will give you more flexibility in your mounting position and probably give you more fL at the screen..


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## Mark Techer (Jan 17, 2008)

grinthock said:


> I suppose i'm not sure how many FL I should be shooting for...


SMPTE standards for 35mm Film Projection is 16FL +/-4FL or 12~20FL
SMPTE standards for Digital projection is 12FL +/-4FL or 8~16FL

Given we use digital projectors in our home, should we not also chasing the 12FL ~ 16FL range?


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## grinthock (Dec 17, 2010)

Mark;

I suppose that's what my question is on the matter.. Don't know what to really look for. I think I have decided on what to do.. The question moves now to getting some of the infrastructure in place (conduit/electrical/ceiling/mount)


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## Mark Techer (Jan 17, 2008)

So you asking about the TR? My recommendation is to place the projector back as far as you can. Others seem to disagree with this.


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## grinthock (Dec 17, 2010)

Well I think I need to put it as far back as I can while still maintaining the right # of FL... So really the question is - how many FL do I need. 12? 14? What should i aim for.

I also agree that mounting location should be somewhere WITHIN the zoom range -- while 1.0 is ideal, the amount of CR lost at 1.1 zoom is probably difficult for me to detect - and it would make sense to put mount it so that it's adjustable


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## Mark Techer (Jan 17, 2008)

grinthock said:


> Well I think I need to put it as far back as I can while still maintaining the right # of FL... So really the question is - how many FL do I need. 12? 14? What should i aim for.


You want 12FL and there is +/-4FL allowed, so if you got 16, that would still be OK (and very bright).


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## grinthock (Dec 17, 2010)

Mark, ok that answers my question.. Is there a negative to having 14 or 16FL? Other than a bright image? Could it be corrected via the projector? I guess i'd just rather have a slightly bright image than a dull image. I am also sitting here considering future considerations for a cinemascope setup.


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## Mark Techer (Jan 17, 2008)

grinthock said:


> Mark, ok that answers my question.. Is there a negative to having 14 or 16FL? Other than a bright image? Could it be corrected via the projector? I guess i'd just rather have a slightly bright image than a dull image. I am also sitting here considering future considerations for a cinemascope setup.


The overall brightness comes from what the projector is rated to do. You can turn it down, not up. In the case of CinemaScope, you want the longest throw to minimize pincushion.


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## KelvinS1965 (Feb 6, 2011)

Also bare in mind that after the first couple of hundred hours you may well lose 30% of that figure anyway as lamps tend to dim quickest when new, then stabilise to a slower decay once the initial drop has occured. What you don't want is to start out barely bright enough, then find that you have to replace the lamp early as it's become too dim...


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