Originally Posted by audioguy
I am planning on using an anamorphic lens and the 120 inches is width (so that would be 130 diagonal I think). I don't remember the output of my CRT.... it was OK but there were some dark films were extra brightness would have been very helpful.
I have a similar setup. My screen is slightly different as it is an Ultramatte 1.5 gain that is microperfed. It is 1.35 theoretical actual gain so it should be similar. It is 120" wide and I use a Panamorph lens with it.
Right now I can't make measurements, but I will post ft lamberts as soon as I can. I had to move my risers and recliners (9 of them) into my test area while I paint the new HT.
I have calculated what the theoretical FT lamberts would be for my screen and it would be quite close.
First of all I use the RS2 on high lamp mode. Using Greg's measurements, with my throw distance, I calculated that my lumens would be: 567
OK so first with this screen in 16:9 mode, CIH the height is 51" the width would be about 91" making a 104" diagonal image. This would be the default mode sans panamorph. The calculated Ft Lamberts would be 23.8.
Now taking that and using VStretch (or actually my radiance to do the stretch) and putting the panamorph in place, the ft lamberts are going to drop about 32% due to stretching the image across the extra square feet. Add another theoretical 3% loss for adding the panamorph. The final calculated ft Lamberts would be about 15.5.
So I recall reading recently that a good bright 9" CRT would be around 300 lumens. (I could be wrong on this so take this calculation worth a grain of salt). If this is the case with your 1.3 gain 54x96 screen, you would be getting 10.8 ft Lamberts.
Anyone please feel free to correct me if any of my numbers are off.