Re: [Avid-L2] HDR vs SDR in production?

Anything can be pretty much turned into HDR. As other mentioned, HDR is just the way video signal is transmitted and displayed, including existing video. You need newer displays because old monitors do not understand the new signal format and cannot get bright enough to display a signal beyond SDR. 

HDR is about placing actual nit values to the video signal and assigning a newer gamma curve. Wider color gamut is something added as part of the new standards but technically not required to achieve HDR. You can do HDR in 709. 

Of course modern cameras with wide dynamic range and color gamut will create more pleasing HDR images, especially if you compose for it. But 8 stops or 13 stops can be turned to HDR. Log video is not necessary.

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DQS

On Nov 27, 2019, at 9:00 PM, John Moore <bigfish@pacbell.net> wrote:

So is it correct to say that anything shot in log can be transformed into either SDR or HDR.  That's the jest I'm getting.  So what would be at a 100 nits and 100%/700 mV using say an Arri Log C to Rec 709 would get transformed to a level of approx 48%/340 mV on the scope.  IIRC with Arri LogC a value of 18% screen grey but I've never quite understood how 18% screen grey is determined.  Here's what I found on their site. 
"Log C actually is a set of curves for different EI values/ASA ratings. Each curve maps the sensor signal, corresponding to 18% gray scene luminance, to a code value of 400 in a 10 bit signal. A 10 bit signal offers a total code value range of 0 to 1023. The maximum value of the Log C curve depends on the set EI value. The reason is quite simple: When the lens is stopped down, by one stop for example and the EI setting is increased from, say, 800 to 1600, the sensor will capture one stop more highlight information. Since the Log C output represents scene exposure values, the maximum value increases."

My brain begins to start hurting about now.  Thanks for the clarification.


On Wed, Nov 27, 2019 at 01:49 PM, Pat Horridge wrote:

John camera have had wide dynamic range for some years now. The limitations of SDR required we manage that dynamic range in camera. 
The new log based LUTs allow us to retain that dynamic range in a high bit depth sacrificing bit depth at the top end for more useful bit depth at the lower end. 
HDR is just a delivery and display technogy. 
So you are capturing wide dynamic range using a LUT or Raw to transport it. 
I'm the grade you then limit that to SDR or reformat it into HDR.