Originally Posted by elmalloc
I'm looking at 2.35 AR, at least 12ft wide. It looks like silver ticket stops around there. I had a sim2 with A-lens doing 14ft from the same location and it "worked" but it was nowhere near as bright as this Epson, so I think I can get the Epson to do so with the right lens.
From what I understand the lens won't have a major affect on the lumens output, it probably has plenty to spare. I currently use the standard lens which can only get 10ft wide from current location, will have to spend about $1800 for Epson's shorter throw lens to get a 14ft wide image from 15ft away.
The project image will be 16:10 with the epson, when using outside it worked very well because it just projected into pitch darkness. Inside, it will be hitting a white wall for the "black bars".
The largest silver ticket 2.35 is their 153" wide, which is roughly 100 square feet on 16x10. Do you mean lumens / square foot (instead of other way?). 6500 / 100 = 650.
I am using Carl's FlexiWhite outside and I see no moire, but I'm sitting 30ft away from it. The image looked perfect, better than anything I had ever set up inside, which was st range, but I think it has to do with outdoors being the perfect pitch black environment. My home gym in the basement used to be my small theater room and I painted the ceiling black, used black velvet on the front wall, and the image was very nice.
I think no projector really wants to deal with any ambient light, unfortunately.
You are not any type of noob that I have met.
Yes, divide the lumens by the square footage.
It does not matter the format of the screen, the square footage calculated is that of the projected image (16:10 or otherwise).
Then adjust for fabric gain.
If a fabric has 0.59 gain for example, and the resulted fL is 110, 110x0.59=64.9fL
15fL is recommended for SDR, 30+fL for HDR.
A zoom lens is different from a lens that changes the format of the image (i.e. from 16:10 to 2.35:1).
The brightness with a zoom lens will decrease because the projected image is larger. Or at least that's how it works with regular zoom on projectors. If the projector remains in the same position and the zoom is used to create a larger image the brightness decreases.
had some insight about this subject on another thread.
One issue here is determining what the lumens is for that projector.
This what the actual lumens are for a Epson 3LCD (HC3700) rated at 3000lm are:
Lamps dim with time.
The G7500U is rated at 6500lm.
If you have a luxmeter or colorimenter, or a luxmeter app on a phone, the lumens can be measured with that, although I have not done it.
For example, a 16"10 projected image with a width of 144" (12ft) has 90 ft².
With Cinema on Eco lamp (lowest lumens output) plus whatever age the lamp has could result could be~3000lm. 3000/90=33.33fL
With a 1.0 gain screen. With a 0.59 gain screen that would be 19.66fL.
An ND filter could be used to lower the lumens.
As in the thread linked above regarding projector use in ambient light, a grey screen would also reflect less light around the room which will improve black levels and contrast.
An ND filter reduces the brightness at the lens.
Options would be:
White screen with ND filter.
Grey screen. With ND filter?.
Paints. The wall could be painted, or some other surface that does not have to be a screen. Paints are also cheaper, can have ALR properties that will help with the white walls, and can be darker than the ST options above (even the 0.59 fabric).
The subforum where this is discussed.
I'm not too familiar with screen brands of this size, but there a cinema hall screen manufacturer that could accommodate whatever screen is required: Harkness Screens (UK) (link
). You have to send them an email to get an update list of fabrics, but when I got it a few years ago they had a 0.2 and 0.3 gain screens.
There seems to be a US outlet as well. They do send samples.
You may also want to make a separate thread on the screens subforum:
So depending on what size screen is possible, the fabric/paint would have to be chosen. The brightness is an important factor. An ND filter can be used if the fabric has too much gain (i.e. 1.0 or 0.59). With a gain of 0.3 an ND filter might not be required.
LE: A grey fabric would help with wall reflections, but a 0.2 might be too dim. So a combination of a 0.7 gain and a ND filter could work. It really depends on the brightness of the projector.