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Discussion Starter · #1 ·
Is there a difference between perceived screen brightness for a PJ with a short throw vs one that is a long throw?? In other words, some PJ's have an option for long or short throw lens, if you place a short throw lens on a long throw PJ will the screen appear to be brighter give the same screen size (since the PJ then will be physically closer to the screen)??
 

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No. As long as the image (screen) size is the same, the brightness will be the same for the given projector, regardless of throw distance and lens focal length.


The image brightness is determined by (1) lumen output of the projector; (2) screen gain; (3) diagonal screen size. The brightness is propotional to:


(1) x (2) / (3)^2
 

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Brightness can however decrease with distance, but only if the air is not clean and has dust or other particles in it in quantities sufficient to degrade the light.
 

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Yeah, but I would never use a front projector in such abysmal air conditions in the first place. Bad for the projector, bad for the screen!
 

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Quote:
Originally posted by sushi
Yeah, but I would never use a front projector in such abysmal air conditions in the first place. Bad for the projector, bad for the screen!
Not real good for the viewer either:)


mds
 
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