Originally Posted by R Harkness
The contrast numbers jump usually associated with DIs sounds really impressive - JVC's numbers have their DI gaining a tenfold increase in contrast - but I'm wondering how this works out in practice.
(Since ultimately there is a limit put on by a projector's native contrast).
Thinking about it, the higher your native contrast is, the more you can push a DI probably. Think about it, our eyes have an enormous dynamic range, I think I figured by looking at a NASA report that you'd need about a range of 1 (or was it 10) million:1 to achieve impreceptible black, with a white point on the order of 10ftL. But at the same time within any given frame one can's see nearly that much dynamic range. I've seen it listed around 10-14 stops
which works out to be between 1000-4000:1 in ratio terms. Of course our eyes move around the seen, adapt, and fuse the scene together so the mental range is a good bit larger than that.
But even so, when you start getting to really dark average levels, it takes a while to adjust. So JVC could probably have a very "aggressive" (large multiplier) DI, but if they operate very slowly over that range, they could probably reduce/minimize gamma boosting since they've got a large native dynamic range, and avoid pumping and white crushing.
I mean if you think about it (and I'm going from what I've heard here), in any one scene JVCs probably have plenty of contrast, I'd think 150k:1 is plenty. What's been missing is during the darkest scenes, with little bright content, as ones eyes adjust you begin to see the black floor.
If JVC can figure out how to run their DI rather slowly (maybe even more slowly than the good DI implementations out there today) but over a wider range, maybe it will be great. I'm certainly interested. Part of the reason I haven't looked more seriously at a JVC so far is because even they really couldn't do "black", but these may finally be able to do that.
By the way, anyone ever actually measure the "total" dynamic range of a good JVC? I mean blackest black with iris clamped down vs brightest white with it wide open?
Looking at Cine4Home for the X95 I see:
Low Lamp, open iris 790 Lumens
Low Lamp, closed iris 210 Lumens with 111,000:1 contrast, so that would make the black level 0.00189ftL.
So the dynamic range would be 790/0.00189 = 417000:1 even if they just had a DI that operated over the normal iris range.
Originally Posted by Ericglo
I would be interested in if you could change the multiple factor or if it is set at 10x. One thing is for sure is that JVC is now close to if not better than CRT on/off cr. How many people are going to jump ship this year?
I keep seeing "adjustable" when they talk about it which implies there are settings beyond just on and off.