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Discussion Starter · #1 ·
I will have an ISCO II and want to have a 110 to 120 inch screen.

I am guessing the GreyHawk but....

I have complete light control and I will be sitting roughly 16.5 ft away. I might be talked into a microperf but the one I have seen, the holes were visable at 13 ft.


Thanks anyone


Greg
 

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Discussion Starter · #6 ·
Thanks!


From what I have read you want 17+ lamberts but I guess 14 will do....


The microperf idea is growing on me and I know it is a must for one of your HT beauties.


Dennis, if had the $$ you would be the first man I'd call.:cool:


Greg
 

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Aggie,


I have seen the Dwin at trade shows but I have not made actual measurements. Does anyone in LA want to bring down their projector so we can take a good look?


Dennis's (one of my favorite HT designers) FL numbers are correct. These numbers will vary downwards when color temp is adjusted to 6500K.


Don
 

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Discussion Starter · #12 ·
Well let me know if get to test one out. At this point I know three things about my screen:


1. I will buy it from Jason @AVScience

2. It will be a Stewart

3. I have some time before I have to make that critical decision(Dec/early Jan)


Thanks for the response Don and Dennis. Don if you get more info on the Transvision, please post it.


Thanks

Grace and Peace

Greg
 

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"A 54x96 (110") GrayHawk MicroPerf will provide just over 17 ft. lamberts. The same material in a 60x107 (123") screen will provide just over 14 ft lamberts. If you don't use MicroPerf, the image will be slightly brighter."


Dennis,


Are you reporting these numbers based on actual measurements of these two combinations?

Or are you just plugging in the manufacturers claim of a 1000 lumen output into a formula?


I ask because others are reporting digital projectors with grossly inflated brightness ratings. Not to mention the decrease in bulb brightness over time.


Aggie might be in for a big surprise if he buys a 60" X 107" Greyhawk and ends up with less than 8 ft Lamberts on screen.


Joe
 

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Discussion Starter · #14 ·
I have read on here before that the DWIN as roughly 700 lumens as apposed to the listed 1000.


Maybe Don will have exact measurements before I have to make that critical decision:D


I think the equation looks like this:


Lumens(1000)*Gain(.95) divided by Sq ft of screen(44.58) = 21.30 fl


I would assume he used the real lumens in this case.


Thanks,

Greg
 

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Measured output. (Without calibration.)


The published specs from DWIN are not entirely useful. They specify 1000 lumens but do not specify if that is Peak or ANSI nor the parameters of the test or ASTM method used. I suspect they are peak and tweaked.
 

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:)

I guess I would only be happy with actual measurements on fully calibrated PJ with bulb use of say 100/300/900 hours.In room to be used.How about "worst case scenario"-every time.

:) :)
 

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I'd guess, you'll have a real long wait for a projector. :) I'd suspect any manufacturer would not be forth coming with a projector if one of the requirements was to put 300 hours on it. It's tough enough to get one, much less long enough to turn it on.


OTH, my own suspicions would lead me to believe the decline in Ft.Lamberts over 300 hours would not be significant, and, if you're starting out fresh but just barely on the upside of minimums, you should not be flying that airplane anyway (I mean, using that screen material). Understand, we have been speaking of Ft.Lamberts in the range of 14-17. I've seen many where the picture was hovering at 8 very nicely (typically from a CRT).


Actually, to become "Design Cinema Certified" (now that carries about as much weight as a flea), I'd like to see the following specs listed at 50% of the rated bulb life:


Lumens at 6500K at 30%, 50%, and 100% white levels (or 70%, 50% and 0% gray).
 

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The DWIN is a 4:3 ratio projector. The correct area for a 4:3 107" wide screen is 107 X 80.25/144 = 59.6 sq ft.


The screen brightness equation - assuming a "real" 700 lumen output is


lumens (700) * gain (.95) / sft (59.6) = 11.1


As the bulb ages, you could very easily drop below 8 ft Lamb with this setup.


Dennis. I don't understand your last post


"Measured output. (Without calibration.)"


Are you saying you actually measured over 14 ft Lamberts with a 107 X 60 Grayhawk? That would mean the DWin is putting out very close to it's 1000 lumen spec.
 

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Uncalibrated, white, lumens, center lens, measured at 1 meter (ie, no uniformity test and at 1 meter that would not be useful).


BTW, the original criteria specified an ISCOII lens, as I recall so effectively 100% of the panel would be used on a 1.78:1 screen.
 
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