Originally Posted by batpig
Curious to get some feedback from fellow owners who’ve been down this road on the pros/cons of the two approaches? Seems like either way Gamma D is resolved, but is there anything I’m not considering which could tip the scales either way?
Holy smokes, its batpig! First let me say I've followed your Denon work for over a decade. In fact, you were probably the reason I joined this forum. Thank you very much for your contributions. I'm glad to have the opportunity to give back, if in only a small way.
Short version: Buy the UB820. Calibrated Gamma D is basically a super shiny turd. Your only regret will be wondering why you waited so long (the only caveat being possibly getting the UB9000 if you plan to get a NX5/NX7 projector as apparently there is an UB9000 HDR mode designed to communicate with the NX projectors but that function hasn't been reviewed or tested yet and that specific function doesn't work with the older RSxxx projectors). Also keep in mind, you are still getting the benefits of the color and gamma points calibration, you are not throwing out the entire calibration.
Originally Posted by batpig
This makes me wonder if the UB820 outputting SDR.2020 would be preferable since I wouldn’t have to use high lamp mode... but would the HDR content then look too dull?
With the UB820 & SDR2020 your projector is already using the full range and isn't leaving any brightness or color "on the table." For example, "100% white" is the exact same thing whether you are in HDR or SDR, HD or 4K. I used to always use high lamp with HDR and now almost always just stay in low lamp mode for everything except 3D.
I cried foul on "HDR" with these projectors a long time ago and grew increasingly frustrated at varying levels of brightness based on title, looking at darkness and everybody else pretending it looked good. On some titles, the projector would make 99% of the movie half brightness just to make once scene brilliantly bright (How do you make a flash twice as bright than the rest of the move? Make the rest of the move half as bright).
The loaded premade Gamma curves (directions in my guide below) made things significantly better but occasionally I'd still hit an unpleasantly dark title. The UB820 normalizes everything and almost completely removes this issue. Basically, the UB820 will make your 4K Blu-ray discs behave exactly like HD Blu-ray discs, just with more color and resolution. You will be very happy, I promise.
I made a JVC 4K QuickStart Guide
for newcomers, I suggest you take a look as it will be a good refresher and I talk about loading premade gamma curves, which you'll want if you are streaming HDR content. It needs a bit of updating specifically for the UB820, but all you'll need to do is turn on SDR2020 in the UB820 settings. This change means the projector will not see a "HDR" signal so it will not switch to Gamma D. You will need to set projector to Gamma 2.4 and will still use the BT2020 Color Profile. I set my user modes up for quick switching: User1-HD, User2-4K, User3-3D.
I've heard some people having trouble with HDR content on the ATV as it would resend some signal to the projector frequently retripping the Gamma D switch and this would happen several times during regular playback. The only work around I've heard for this is the HD Fury products. If you are just watching HD you probably haven't noticed this and if you watch HDR on the ATV, you must be one of the lucky ones.
The long sync times are just something you have to live with. It seems very basic, but pressing pause until you see picture is the only way to keep the frustration at bay.
Once you see what a 4K disc looks like on a UB820 in SDR2020 with Gamma 2.4 & BT2020 Color Profile, you'll be blown away and will never ever return to Gamma D. You will seriously think you bought a new projector.