The dynamic range slider is best left alone unless you dont mind messing up the white clipping point, it works pretty much like the contrast adjustment on most displays.. The SDR output will alow you to display a HDR movie on a display capable of 200nit/ 60fl or more, and look like it was intendet from 0 to around 70% IRE.So for maximum image fedelity HD blu ray is still the only thing that will work right on a projector, the UHD HDR needs pile of compromises to get a decent result on a low light display.Try measure the SMPTE 2084 gamma curve on your projector at different HDR converter settings, using UHD HDR patterns.
The slider is best left alone. But so far, 4K UHD BR's watched with HDR convered to SDR BT2020 looks better than standard Blu Ray. No question. HDR - not so much.
Not sure why max output is relevant. On the JVC RS600, the problem with HDR is that it disables the auto iris and raises black levels to a point that the blacks look grey. The excellent contrast of these projectors is their best feature. HDR doesn't bring enough to the table to offset the compromised black levels. it's pretty easy to see flipping back and forth with a Blu Ray. I don't think HDR really works on any projector, other than a Digital Projection light cannon ( and they don't have very good black levels to begin with ).
The max lightoutput is very relevant as the movie is mastered in SMPTE 2084, and thats a static HDR, and the SDR output you still need to follow the SMPTE 2084 up to around 60-70% IRE before the HDR converter compresses the highlight area. The SDR is not SDR like we normaly use it, thats why the image looks terribly dim and lifeless if you run it with 20fl on the screen, you need around 60fl to do the UHD SDR output, and track the 0-70% IRE.. So as long as we are working with a HDR format as it is today, its very very relevant how much light you can dump on the screen, and to give a bit of meaning to the format we have to have more light to create a bigger dynamic range.If you use the HDR convertion adjustment like on the UB900 you move the white clipping point, wich is never a good idea.
I asked another RS600 owner how much light he got on screen, and he told me 46fl, dont know what screen size he is running, but il think that would make it work pretty well for the UHD SDR.
The highest I measured on my screen was 44 foot lamberts. But who wants to watch in high lamp with the iris wide open? That negates the very best attribute of the JVC projector - contrast and black levels. Watching in HDR on many movies produces a picture that looks inferior to the Blu Ray ( due to gray blacks ). Converting HDR to SDR with the wide color gamut produces a visibly better picture with 4K Blu Rays. And it certainly doesn't need to be more than 16 or 18 foot lamberts.
I agree about the contrast and black level.. But not that 16 or 18fl works for UHD SDR.. It runs a way to high gamma out of black, making the image way more dim than a normal HD movie, unless you fiddle with the contrast or HDR converter, and add a serious amount of white clipping, or have a processor to change the shape of the gamma. The SDR output you get from the UB900 is not SDR, its a HDR with a brakpoint/ gamma roleoff to compress the highlights.. Its still mastered for 1000nit or more, and you compress that to 55-60nit.Sure we can like or dislike whatever we want, having a subjective opinion about it, but objectively, its a mess.The ilustration is a 30fl UHD SDR curve. it looks a bit like a 8-10fl HD image to me, as i see it its not that we need the huge amount of light output in the average movie content, so might work if the roleoff on the highlight was steaper, like the converter adjusted the 65% ire point up and down holding black and white reference, but it dont.What gamma do you run on your HD calibration.?
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