Originally Posted by tk123
posted this in post #4
. I'm just not sure how he got the distances he posted. I've seen other posts with the same kind of information and was wondering how it's calculated.
The 5040 has a lens to screen distance that you can adjust with the zoom lens. With the EXTENSIVE range, you may put the lens to screen distance (throw distance) anywhere between 14'8" to 30"11". So, basically 15' to 30' lens to screen with a 150" diagonal screen
I use the calculator over at Projector Central as my default. It gives a good insight on the throw range for any specific image size easily.
Lens shift has minimal impact on brightness typically, so shouldn't be considered.
Zoom range is going to have some impact, and should be considered from reviews.
Be VERY aware, that there are TONS of settings on a projector which significantly impact brightness. So, you may get anywhere from 500 lumens to 3,000 lumens out of the same projector depending on what settings you use. The end deal is that the closer you are, with a model like the 5040UB, the brighter the potential image will be. So, if you are running at 150" diagonal with a 16:9 screen, you will want it 16 or 17 feet away (or so) to get the brightest image possible.
If you have a specific question, please ask.
The Epson 5040UB has brightness ranging from 3,500 lumens down to 825 lumens - https://www.projectorcentral.com/eps...0ub-review.htm
The zoom lens will decrease light output by 33% from one end of the range to the other. So, at the furthest point, light drops from 3,500 lumens down to about 2,400 lumens (brightest) and from 825 lumens to about 580 lumens (dimmest).
With a 150" diagonal 16:9 screen, you will have a surface area of 66.4 square feet. (131"x73"/144")
Take your brightness and divide it by the square footage of the screen to determine the brightness in lumens per square foot at either extent. If your screen has gain, include that in the math.
BRIGHTNESS / SQUARE FOOTAGE * GAIN = LUMENS PER SQUARE FOOT
3,500 / 66.4 * 1.0 = 52 lumens per square foot
825 / 66.4 * 1.0 = 12.4 lumens per square foot
A more realistic setting, is using lower lamp modes, to reduce noise and increase lamp life, and to have the projector backed off from closest by a little bit, then use a good setting like 'Bright Cinema' which has good color quality and go from there...
That makes it 1,800 lumens, but backed off a bit, so maybe a real world 1,500 lumens...
1,500 / 66.4 * 1.0 = 22.6 lumens per square foot.
A commercial movie theater often operates at 15 lumens per square foot and a good goal for home movies is 18 lumens per square foot for a very enjoyable image.
So, the math supports using this projector.
If you want even more brightness, then you can get a screen with a bit of gain. Getting a 1.1 gain screen doesn't add much, but it does a bit. 1,500 / 66.4 * 1.1 = 24.8 lumens per square foot. A very real 10% jump in brightness. A 1.3 gain screen will take you up to nearly 30 lumens per square foot, which may be overly bright for typical viewing, but will be great for 3D or some 4K viewing.