LUT for P4P D-Log?

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Now the D-Log setting on the P4P seems to have been massively improved, does anyone have an accurate LUT for the new D-Log profile (or know what the accurate curve data is)?

fwiw I'm editing in Premiere CC 2017

Thanks!
 
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I don't tend to use LUTs and have nothing against the use of them, but I'd argue that unless you always fly under the same conditions how is a single LUT supposed to handle the variety of scenes and conditions of lighting etc.? Frankly, the technique to do color grading in PP or any of the major NLE's is not all that hard once you get the hang of it and being able to judge the scene and conditions and make the appropriate adjustments is part of the job. If I spend, say, 4 hours editing a video I'd wager I spend probably less than 30 minutes on average grading it and I'm fully manual with my grading. Yep, a LUT might get you closer quicker in some scenes and conditions but could wind up taking you longer in other settings.

Just my opinion...


Brian
 
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I don't tend to use LUTs and have nothing against the use of them, but I'd argue that unless you always fly under the same conditions how is a single LUT supposed to handle the variety of scenes and conditions of lighting etc.? Frankly, the technique to do color grading in PP or any of the major NLE's is not all that hard once you get the hang of it and being able to judge the scene and conditions and make the appropriate adjustments is part of the job. If I spend, say, 4 hours editing a video I'd wager I spend probably less than 30 minutes on average grading it and I'm fully manual with my grading. Yep, a LUT might get you closer quicker in some scenes and conditions but could wind up taking you longer in other settings.

Just my opinion...


Brian

Brian is (unfortunately) absolutely right. A lut will only help you as long as it is calibrated for your particular conditions during capture. The p4p has a 12+ stop dynamic range and making a global lut for correcting any capture in this range (mapped to 100 IRE) is not possible.

However, I have as an example added a calibrated curve that match one particular set of requirements:
* Capture must be exposed to-the-right (side of the histogram)
* 18 % grey must be about 2.5 stops below pure white (low contrast scene)

In these scenarios, you will end up with the table you find here (in the range middle 10-90 IRE):

Resolve 10 Waveform Values for the Unsure

below this, all shadows are present but crushed
above 90 IRE highlights are linear and present

For any other conditions (unless you compensate before applying lut) you will most likely end up with a very dark and "crushed" image.

I do plan to create a calibrated 10 and 12 stop lut as well (if for nothing else to get a quick preview of potential of a scene), but you should really do the necessary adjustments for each capture to get the full potential of the fantastic dynamic range of the sensor.

For interested parties, curve for attached lut:

upload_2017-1-16_22-2-3.png
 

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  • p4p_dlog_etr_5stop.zip
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Thomas this is working really well for me. Thanks for creating this.
I compared to my best effort matching with colorchecker and your's is even closer.

What contrast setting did you film this with? That would be a crucial info. I used -1 and it looks pretty identical..?

Also, I dont quite understand the point that this is not applicable for every scene. It s (trying to be) a mathematical method to bring the gamma frrom DLOG back to real world. That isnt dependent on a scene. It counters only what DLOG is doing to the footage.

If an image looks too dark all of a sudden, then cant you simply counter it by adding EV adjustment the same time you add the LUT? that should be non-destructive when done at the same time.

thanks
 
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Thomas this is working really well for me. Thanks for creating this.
I compared to my best effort matching with colorchecker and your's is even closer.

What contrast setting did you film this with? That would be a crucial info. I used -1 and it looks pretty identical..?

Also, I dont quite understand the point that this is not applicable for every scene. It s (trying to be) a mathematical method to bring the gamma frrom DLOG back to real world. That isnt dependent on a scene. It counters only what DLOG is doing to the footage.

If an image looks too dark all of a sudden, then cant you simply counter it by adding EV adjustment the same time you add the LUT? that should be non-destructive when done at the same time.

thanks
This is calibrated for contrast 0 (which I use exclusively) and 18% grey (mid-tone) 2.5 stops below white clipping.

I'm glad you find this profile useful as is, and in many cases it will give you a good result or at least starting point. However, as it severely squishes any shadows (which are still recoverable) I find that doing a manual toning (from base) of most scenes gives more freedom and in the end better results. This means more work, so starting with this or similar profile can be a good and time-saving compromise.

I use it myself combined with a fitting offset/ev adjustment for a quick preview of a scene, and often this is very close to acceptable.
 
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i ve tried it on some other DLOG footage and for me this really works well. Footage looks just as natural and balanced as what I was able to do manually. Exactly what i was looking for, so thanks a bunch.

Coming back to the point of LUTs arent universally usable.
AFAIK your LUT is simply a gamma adjustment that "undoes" to any footage what LOG profile did to it in the first place (which is distort the gamma values). It s not an artistic LUT.
That being said, when using such a LUT, no matter what the footage is you will first get back the real world undistorted gamma map. It doesnt matter if DLOG footage is underexposed.. then you will simply end up with real world underexposed footage. what better starting point in editing could there be?

Or what am i misunderstanding :) ?
 
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i ve tried it on some other DLOG footage and for me this really works well. Footage looks just as natural and balanced as what I was able to do manually. Exactly what i was looking for, so thanks a bunch.

Coming back to the point of LUTs arent universally usable.
AFAIK your LUT is simply a gamma adjustment that "undoes" to any footage what LOG profile did to it in the first place (which is distort the gamma values). It s not an artistic LUT.
That being said, when using such a LUT, no matter what the footage is you will first get back the real world undistorted gamma map. It doesnt matter if DLOG footage is underexposed.. then you will simply end up with real world underexposed footage. what better starting point in editing could there be?

Or what am i misunderstanding :) ?

First, let me say that I am happy the lut can be used by others than me, as it was a bit of work to create. :)

If we assume I have a perfectly calibrated curve, you are right in your assumption. However, as I mostly work in challenging light, I find myself doing another curve-adjustment on top of this curve-adjustment and in these cases starting with the baseline is actually easier from a workflow perspective (and also forces you to position the tones giving more creative potential).

But for a result that more or less matches none (but with more recoverable shadows) the lut should get you most of the way.
 
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Hi Tomas,

are you busy this weekend? ;)

FW 1.03.0418 Update Notes:
- Upgraded D-Log color mode to extend dynamic range.

you planning to update your LUT?

Thanks,
Sebastian
 
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I'm a beginner regarding color correction but thank you for creating the LUT, Tomas! I've downloaded your LUT and put it in Filmora. The next time I fly, I'll use D-Log and apply your LUT, thanks!
 
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I spent what seems like forever making a D-Log LUT that I use. It took about 20 revisions because the highlight saturation in D-log can become a bit oversaturated during sunsets, so the LUT can fix that.

Sham-less plug, but I do love it. It's a super easy refund if you don't like. Just message me on here or hit the contact on the site and I'll take care of you.
Phantom 4 Pro D-Log LUT - Film Poets Education
 
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Brian is (unfortunately) absolutely right. A lut will only help you as long as it is calibrated for your particular conditions during capture. The p4p has a 12+ stop dynamic range and making a global lut for correcting any capture in this range (mapped to 100 IRE) is not possible.

However, I have as an example added a calibrated curve that match one particular set of requirements:
* Capture must be exposed to-the-right (side of the histogram)
* 18 % grey must be about 2.5 stops below pure white (low contrast scene)

In these scenarios, you will end up with the table you find here (in the range middle 10-90 IRE):

Resolve 10 Waveform Values for the Unsure

below this, all shadows are present but crushed
above 90 IRE highlights are linear and present

For any other conditions (unless you compensate before applying lut) you will most likely end up with a very dark and "crushed" image.

I do plan to create a calibrated 10 and 12 stop lut as well (if for nothing else to get a quick preview of potential of a scene), but you should really do the necessary adjustments for each capture to get the full potential of the fantastic dynamic range of the sensor.

For interested parties, curve for attached lut:

View attachment 73631
This is 100% wrong. The purpose of a LUT is to restore what things looked like upon capture, and specifically to convert back to REC.709 color space. A clue as to how this is reliable, is the fact that DJI at some point revised the methodology to lock down ISO at 500, thereby stabilizing the conversion process from a fixed dynamic range.

Unlike literally any other camera manufacturer, DJI weirdly refuses to provide a free LUT for converting their D-Log to REC.709. That's dumb. And any third-party LUT converter is suspect, especially since D-Log itself has undergone revisions as noted earlier in this thread.
 

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