Looks like a giant plasma but its not.

[stanger89]

I always forget, but how much contrast is in a single f-stop?

In photography, talking about exposure, a "stop" is a factor of 2.  So 10 stops is 2^10, a factor of 1024, so, 1024:1.

[Dylan Seeger]

I'd really love to see some sort of technical explanation on how stacking two "low" dynamic range machines on the same screen creates a "high" dynamic range image.

I remember the description from CEDIA talking about how one projector is for the bright content and one for the darker content.  I found this thread that goes into a bit more detail...
http://dci-forum.com/sim2-product-support-forum/16/hdr-projection-sim2-solution/1623/

However the fundamental problem remains, that the light adds between the two projectors, so if the "bright" projector is showing "nothing" (black) it will still be washing out the black level of the "dark" projector.  Or are they putting a shutter or something in the bright projector so that it's output is completely blocked?

FWIW, from the above article, it seems dynamic range is pretty much in line with a standard Lumis as you might expect:
Results
Screen Area 73,6 sqft Screen Gain 1
Illuminance Measurement
Peak White 1020 lx
Black Level 0,045 lx

1020/0.045 = 22,667:1.

So is there really more to this than just a stacked Lumis pair to achieve really high brightness levels?

That is native contrast or is that with a dynamic iris? That seems to be in line with my last Lumis I had here. I measured right around 25000:1 dynamic contrast.

[AVSMike]

I saw that demo at Cedia ! 

Yes we did. It looked good. I was surprised at how many FL they were putting on the screen.

[AVSMike]

I'd really love to see some sort of technical explanation on how stacking two "low" dynamic range machines on the same screen creates a "high" dynamic range image.

I remember the description from CEDIA talking about how one projector is for the bright content and one for the darker content.  I found this thread that goes into a bit more detail...
http://dci-forum.com/sim2-product-support-forum/16/hdr-projection-sim2-solution/1623/

However the fundamental problem remains, that the light adds between the two projectors, so if the "bright" projector is showing "nothing" (black) it will still be washing out the black level of the "dark" projector.  Or are they putting a shutter or something in the bright projector so that it's output is completely blocked?

FWIW, from the above article, it seems dynamic range is pretty much in line with a standard Lumis as you might expect:
Results
Screen Area 73,6 sqft Screen Gain 1
Illuminance Measurement
Peak White 1020 lx
Black Level 0,045 lx

1020/0.045 = 22,667:1.

So is there really more to this than just a stacked Lumis pair to achieve really high brightness levels?

I do not remember the details, but yes, there is a lot more to this.

[AVSCraig]

Yes we did. It looked good. I was surprised at how many FL they were putting on the screen.

It was pretty bright.

Looks like a giant plasma but its not.

[stanger89]

That is native contrast or is that with a dynamic iris? That seems to be in line with my last Lumis I had here. I measured right around 25000:1 dynamic contrast.

I assume dynamic, but the thread didn't have a lot of details.

[Kris Deering]

I've seen this demo twice now. The only way it would truly "work" is if the DMD's could shut off, and use a processor as essentially a digital crossover for video. But that is not the case. So they have one projector optimized for the dark content and one for the bright. The combination gives you more light output on the top end and a bit more bit depth on the bottom end, but the black levels will still be worse than a single DLP projector, and that was already bad. But highlight info will look good. The question is at this price is it worth it? How much of P3 does it cover? How does it handle the tone mapping? There is more to an image than just adding brightness at exponentially more cost.

[stanger89]

Thanks for the update Kris.  That's what I was wondering.  It would make sense that you could use the second, dimmer projector to fill in some detail, resolution (bits) on on the dark side, but of course your black level is still limited to the sum of the minimum light output of the two.