Originally Posted by SirMaster
I don't understand why people keep saying this like you can't do it with the NX5.
You can certainly clamp down the single iris on the NX5 and still engage Auto DI.
At -15 you are already clamping the one iris down almost to max, leaving you almost no dynamic iris.
You don't have the same range of iris control in the single iris nx5 as you do in the nx7. You have the same *setting*, but not the same range. On the nx7, -15 means one iris is at -15 (mostly closed) and the other at -7 (about half closed), and you still have a lot of dynamic range left for the DI, so you start darker on the NX7 than on the NX5 at -15, and go go even darker still in dark scenes to achiever a lower black floor.
No, it will be nowhere near 60fL.
See this review of the NX5:
It was measured on a 110" screen and with iris at -15, in low bulb, it was 15fL. This is 538.63 lumens. If you convert this to an 80" screen, at 538.63 lumens you will get 28.37 fL.
Assuming that 538 lumens is accurate at the absolute lowest setting on the NX5, that is actually 36 fL
on his 1.3 gain screen (assuming mid throw, in a shorter throw it would be even brighter). Your SDR target is ~16fL, with 20-25 being about the highest you would ever want to go. 36 is just too bright for SDR.
The key here is you can't go dimmer, so when you are trying to watch a movie with bright scenes, you either suffer the pain or turn on the lights in the room and completely destroy what little contrast you had. You can't turn it to a lower lamp or clamp the iris down further, you're just stuck with it. It's a no win situation.
The NX7 could take that same situation and with the dual iris and the color filter, drop that lowest figure well into the low 20's which is perfectly acceptable for SDR, improve on contrast and black floor by double, and have a wider color gamut.
Together they can get a little darker than the NX5 though, but it's not drastically darker.
It's enough of a difference to get twice the contrast, and if you then add in the color filter that drops it another 15-20%, you indeed would get "drastically darker".
I'm far from an expert here, I have just followed the new JVC projectors closely and there was a LOT of discussion on this topic where someone with a 120" 2.8 gain screen was told by the pros that it would be way too bright with an NX5, and that screen translates to slightly dimmer than an 80" 1.3 gain screen with the same lumens. So throw everything I have said out and just go by that. It's too bright for that screen and SDR is not going to be good to watch on it.
My recommendation stands, either go with an NX7, change out to a low gain screen and stick with the NX5, or just do an OLED and call it a day.