As Im very new to using HDR 4K films, I need some help with my NX9 please. ..... However Im not sure how to set the screen size for HDR, can someone help me please... Nigel
I have a Stewart Studio Tek 130 microperf curved scope screen of 145" diag. I use an Isco IIIL lens on a cineslide.
Is it just Picture Tone we move for a larger screen or do we also have to adjust dark/bright levels?
The manual also has settings for Tone, dark/bright levels for setting gamma when clipping point is 400, 1000, 2000, 4000nits, do I set for this or just leave it?
Your MP Screen has a bench-marked gain of 1.17 in the middle dropping to probably a little over 1.0 in the extreme corners due to the angle of view. However its a curved screen so you will have less drop off than a flat screen would. I would round that to 1.15 for the purpose of setting screen size. The lens also complicates things. so I would use your 16:9 size and assume that the scope size is much the same ballpark brightness (is it in SDR?) At the end of the day I would try +3 probably.
From my playing about, and this is not definitive yet, the adjuster is the same brightness changes as setting picture tone in manual. if you have a film that auto mapping has set to 0 and you use +3 then +3 picture tone seems to matches brightness. However I have found that the manual set tone map with the same settings as auto with picture tone = auto tone + adjustment has more contrast so this is not 100% the same thing.
Dark level seems to control the black clip point (I actually tried this with test patterns) 0 = 64.
White level seems to control the white clip point 0 = 2000. but I havn't had time to verify this.
Picture tone raises the gamma.
Setting the auto tone adjustment too high will result in a lose of saturation in the same way as using 2.2 vs 2.4 for SDR does; set this to the point where this does not happen. Note that it is currently fashionable for movies to be shot dark, even SDR version are dark and HDR could be a bit darker by intention. This makes setting this difficult, but do not immediately try to exactly match against the SDR version, the grading can be substantially different, but it should be ballpark in bright scenes.
most discs should be fine out of the box; and most titles that are missing metadata work ok with defaults for 1000nits. For a professional presentation I would be setting a manual tone map personally using the auto tone map values as a start point and setting at least the black clip point and picture tone to match brightness. White clip point is far less visible and very hard to set as there may only be a few seconds where it is hit if at all.
Remember, none of what I have said is definitive, this is my initial observations after 15 or so movies.
Edit: in HDR brightness levels in theory should all match from source and the tone mapping is just an optimization setting correct clip points from the media and using more or less compression above difduse white. However the reality is different. there are BADLY MASTERED discs out there where the brightest point is lower than the SDR version and aso discs which are super bright.
Most titles are OK; but you will be manually setting stuff from time to time even with auto mapping.
Same thing happens with SDR where some discs have raised black floor