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Re: HDR question

Re: HDR question

Kevin Shaw

Hi Jean Marc

>I have shot a doc on a FS7 in XAVC-I / Slog. It is now being sold to NHK Japan and they are asking if it was shot in HDR.

James gave a great answer and i agree with everything he says. 
I have some additional thoughts on what they may be asking, but just guessing - I have no experience with NHK. (I am a colorist)

First - yes FS7 is HDR compatible, it has enough dynamic range for decent HDR, but as James says there is not much latitude at 1000 nits or higher
Yes - Slog is a valid HDR source. In fact Sony demo a very viable color managed workflow where everything stays slog until the final export

Now the less clear areas. 
Working on HDR and having worked with broadcasters and post houses that work with broadcasters, it is generally agreed that lighting ratios and creative decision in production would ideally be different for HDR planned productions. This is especially true for example if you like to rely on the limits of BT709 and shoot blown out windows, or have practical lights in shot. Even shooting into the sun (way more than 1000 nits!) is a problem. All these things require a lot more work in the grade. So whilst the source media is technically HDR ready, creatively it may need a lot of tweaking. Unless you were asked to deliver HDR it is unlikely that you metered or monitored the extended range or allowed for the changed perception increased brightness and highlight detail might bring.

As James said they may just be asking if there is any clipping in the source media - clipping is hard to sell in HDR deliverables. It usually involves tricky color  grading. Dont think just about bright whites either. Neon lights and bright colors in sunlight may clip in a single color channel. In BT709 we expect them to desaturate, but in HDR we do not.

If the program was post produced in ACES or another color managed workflow, your camera dynamic range has been protected. But if it was just graded and finished as straight BT709, a trim to get HDR might produce disappointing results. They would have to re-conform and re-grade. Or they might ask for the colorist project to work from. Given they only asked if it was shot HDR this seems less likely to be the case but it is worth bearing in mind. 

Finishing HDR and delivering SDR does not have the same limitations, and may actually give a better BT709 version

I dont think they are asking if it was shot HLG. 


Kevin Shaw, CSI :
colorist, instructor and consultant
t +44 7921. 677  369 

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