Originally Posted by coderguy
I don't think the Lumis vs. RS 20 comparison is valid at all, the on/off ratios with two projectors in a room are affected by not only the gamma response and level of the proejctor opposing (which then causes an uneven light distribution for on/off pollution). He has introduced a lot of variables that shouldn't be there.
It's completely valid, if you understand what it's trying to compare and what it isn't.
Starting with what's not
valid, the measured
contrast ratios of either machine in this comparison are not valid for anything other than comparison in this test. As noted each machine will pollute the other, thus the black levels for both will be inaccurate (higher) than either machine alone. Now that said...
What is valid is the relative comparison of their performance to each other. As you noted later, the projector with the higher on/off would be polluted more. This would cause the two machines to appear closer
in performance than either on their own. Now what this would not do, nor explain, is why the black floor of the JVC, with it's higher on/off (and matched peak white levels) would appear higher than that of the Lumis. No matter how much more light pollution a given projector A may be producing, it can not make the black level of a projector B higher than itself, a given projector will always
pollute itself more than it's neighbor since pollution drops as you move away from the image.
Originally Posted by coderguy
The projector with the higher native on/off would receive more pollution,not less, especially as it appeared to the eye. This is not debatable. The Lumis is close enough in on/off to the JVC that it could beat the JVC with the ANSI boost, but it wouldn't be as profound as shown by that test.
But that doesn't explain how the Lumis would have lower black level in that very low APL scene. Unless ANSI is more important than some want to believe.
This is very easy for me to test, if I turn my Benq and JVC on at the same time in split-screen on my screen, even without overlapping the images, the BENQ starts quickly catching up to the JVC in blacks.
But I'm sure the JVC is always better. The BenQ, no matter how much worse than the JVC simply can not increase the JVC's black level more than it's own.
You can measure the peak white fL with 100 IRE on both projectors, but the Benq will still be brighter and outputting more light, and therefore when you increase additive light over the Benq, you are making the whites brighter while raising the black floor without even re-compensating the black floor calibration of the projectors in doing so (test doesn't make sense).
I don't understand this comment at all. If you put a 100IRE screen on both projectors and calibrate them both (via IRIS/lamp/ND filters/etc) to be the same ftL, they are the same ftL and are putting the same maximum amount of light on the screen*.
Well, one small exception, JVCs reflect light back into their lamp assembly so a small 100 IRE patch is actually brighter on a JVC than a full-screen 100 IRE field (the "recycled" light from the black area boosts the white a bit).