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Hey guys - a couple of us were working out some dimensions on rooms to take our Ruby's ;

can you help me with the formula/calculation for what the image size would be for a given throw distance; we are doing some room planning and mount positioning.... I thought I could find it , but it's escaping me in my searches for some reason;


thanks much-

ken
 

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Quote:
Originally Posted by kenliles
Hey guys - a couple of us were working out some dimensions on rooms to take our Ruby's ;

can you help me with the formula/calculation for what the image size would be for a given throw distance; we are doing some room planning and mount positioning.... I thought I could find it , but it's escaping me in my searches for some reason;


thanks much-

ken
I like the throw calculator offered at ProjectorCentral.com. Check out the one for the Ruby here: http://www.projectorcentral.com/Sony...ulator-pro.htm


Note that there's been different throw numbers circulating and some confusion over whether the numbers in the manual are correct. So, I'm not sure if the calculator at that location is using the correct forumla, but it may give you a good idea.


You can also try downloading the manual which lists the calculations to determine the min/max throw. The link to the manual can be found by searching the forums or sonystyle.com IIRC.
 

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Discussion Starter #4
excellent - got it; thanks very much lovingdad-


Ximori - thanks for the thread link -I knew I saw it somewhere in all my readings, just couldn't zero in on it-


thanks again-


ken
 

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Originally Posted by lovingdvd
I like the throw calculator offered at ProjectorCentral.com. Check out the one for the Ruby here: http://www.projectorcentral.com/Sony...ulator-pro.htm
As John Kotches mentioned already, the values given by Sony for the shortest possible distance are somewhat too high. I measured it and found that you can get 3.5% closer to the screen (with a given screen size) than calculated by the calculator. I didn't measure whether the largest possible distance is also incorrect.
 

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For a 110" diagonal 1.3 gain screen at minimum throw ProjectorCentral calculator shows 11fL. What are they using for lumens? I had figured about that level with an aged bulb. Wouldn't it start closer to 21fL and then decline to that level?
 

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Dave. ANSI lumers are I think based on a 100 IRE screen window. If you put an average brightness image up, let's say you get 1/2 that. Then lower by say 35% to 40% for bulb aging. The reult--about 11 ft laberts with a 36 square foot screen.



Ken Rick is indeed a loving dad but his handle is lovingdvd. It should be lovingsports.
 

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Originally Posted by DaveN
For a 110" diagonal 1.3 gain screen at minimum throw ProjectorCentral calculator shows 11fL. What are they using for lumens? I had figured about that level with an aged bulb. Wouldn't it start closer to 21fL and then decline to that level?
If I haven't mixed up my numbers, then according to the "Ruby and Brightness" thread and Greg R, with a new bulb there would be about 737 lumens, after D65 calibration. Then, depending on your throw distance you need to reduce that 737 by a certain percentage (detailed in that thread).


In my particular circumstance I'd be using a 106" diag Firehawk with a throw at about 14.9 feet. I've calculated this, based on all those formulas and numbers, to be about 550 lumens post calibration. This would yield about 21fL with a new bulb, and about 10fL after considerable bulb aging.


Considering my Sharp 10K started at about 10fL and went down to about 5fL after 800 some hours, I consider Ruby to be a huge step up in brightness for my particular tastes and screen size.
 

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Originally Posted by mark haflich
Ken Rick is indeed a loving dad but his handle is lovingdvd. It should be lovingsports.
loving... my most humble apologies; I'm sure both names apply equally well...


ken
 
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