D-Log to HDR (Rec.2020) workflow

[WorkHardFlyHarder]

As the title says.

I can only find D-Log to Rec.709 workflows online. The way I always thought about it, was that 'log'-profiles in general store the most dynamic range, even compared to the HLG format.

This video suggests it's possible, but I can't replicate the result in DaVinci. Highlights clip off at 768 (using the same settings suggested under the video).

What is the correct way to do this? Or was (D-)Log never meant to be used for HDR in the first place?

 

[SmilingOgre]

I don't think I understand what you are asking. D-log or any "log" for that matter compresses the dynamic range allowing more headroom for an extended dynamic range. In the NLE one decompresses the log footage (often thought of as increasing contrast). Color space relates to the number of color divisions available. The more color divisions available the finer the graduations and the more latitude in color manipulation. The end results of both of these perimeters are the ability of the monitor to reproduce luma and gamma. I like to use Davinci wide gambit intermediary color space as the controls in Davinci work the best for me with this setting. I also use Davinci managed color space and tell Davinci the file is D-log. With this approach I am trusting Davinci to "decode" the log files for me. This is obviously not the only to approach grading in DR but so far from my experience it produces results I like and a reasonable compromise in complexity. Most of my work is done with raw files and they are my bench mark as I can do the most with them both in dynamic range and gamma. Using this approach I can get convincing results mixing log and raw. I'm finding that even D-log M from the Pocket 3 can produce great results although Davinci offers no option to decode D-log M as they do with d-log.

At the end of the day I believe experimentation with different approaches will best reveal the approach that works best for you. All of my monitors are rec-709 so the only benefit I get from extended color spaces are the responses of the controls within Davinci. The final image is confined to Rec 709.

 

[Filmarik]

As the title says.

I can only find D-Log to Rec.709 workflows online. The way I always thought about it, was that 'log'-profiles in general store the most dynamic range, even compared to the HLG format.

This video suggests it's possible, but I can't replicate the result in DaVinci. Highlights clip off at 768 (using the same settings suggested under the video).

What is the correct way to do this? Or was (D-)Log never meant to be used for HDR in the first place?

I am not an expert in video colour grading by any stretch of imagination but I am not sure what you are asking or what you are trying to demonstrate with that video. It is nice with a good dynamic range but other than that? I edit my videos in DR and simply apply the DJI LUT to either D-log or D-log M footage and tweak further in DR parameters such as highlights, shadows, saturation etc to my liking and am able to achieve good results with sunset shots, similar to yours in that video. My monitor is only capable of covering Adobe RGB colour space and I only view my videos on normal TV Rec.709 capable so to me the HDR Rec.2020 is an enigma I am yet to uncover benefits of

 

[smbishop]

I am not an expert in video colour grading by any stretch of imagination but I am not sure what you are asking or what you are trying to demonstrate with that video. It is nice with a good dynamic range but other than that? I edit my videos in DR and simply apply the DJI LUT to either D-log or D-log M footage and tweak further in DR parameters such as highlights, shadows, saturation etc to my liking and am able to achieve good results with sunset shots, similar to yours in that video. My monitor is only capable of covering Adobe RGB colour space and I only view my videos on normal TV Rec.709 capable so to me the HDR Rec.2020 is an enigma I am yet to uncover benefits of

Yep, I am still trying to figure out when it is worth filming in D-log M, vs. normal. D-log M when the light is flat? Pretty sure there is no reason for me to record in HDR/HLG...

 

[Filmarik]

Yep, I am still trying to figure out when it is worth filming in D-log M, vs. normal. D-log M when the light is flat? Pretty sure there is no reason for me...

The bebefit from shooting in D-log as I understand it is to maximise the dynamic range. So when shooting high contrast scene it is a good idea to shoot in D-log as the footage preserves more information in highlights and shadows. The highlights and shadows are compressed by D-log and that information is then utilised in editing software. By applying LUT to D-log footage in essence decompresses the info. It is a bit like unscrambling the eggs so to speak. The final video will have greater dynamic range than if it was shot in Normal mode.
That is at least my understanding of benefit shooting in D-log

 

[smbishop]

The bebefit of shooting in D-log as I understand it is to maximise the dynamic range. So when shooting high contrast scene it is a good idea to shoot in D-log as the footage preserves more information in highlights and shadows. The highlights and shadows are compressed by D-log and that information is then utilised in editing software. By applying LUT to D-log footage in essence decompresses the info. It is a bit like unscrambling the eggs so to speak. The final footage than has high (-er) dynamic range.
That is at least my understanding of log

Thank you!

 

[Filmarik]

Thank you!

You are welcome. I edited my original post, refresh in your browser if you'd like to read it..

 

[SmilingOgre]

Yep, I am still trying to figure out when it is worth filming in D-log M, vs. normal. D-log M when the light is flat? Pretty sure there is no reason for me to record in HDR/HLG...

If you are shooting something with a large dynamic range e.g. bright sky and deep shadows, log will help you get more of that dynamic range to work with. The other consideration is that "normal" has a "look" baked in. Many cameras will give you some choices of look like "vivid", "flat", "standard", etc. It is meant to be a finished product out of the camera, no color grading necessary. Log will need color grading to achieve a "look" in post. From my understanding of HDR/HLG, you will get more dynamic range than "normal" but not as much as "log". I've tried the format and don't care for it. Like "normal" it has a baked in look. I like the extra control over the look in post that "log" offers.