Author Topic: ML-Log: new log profile for Magic Lantern  (Read 1471 times)

hyalinejim

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ML-Log: new log profile for Magic Lantern
« on: October 16, 2017, 10:55:46 PM »
(5D3 only for now)

It gives me great pleasure to announce the imminent arrival of ML-Log, a DCP log profile for Magic Lantern DNGs. Those of you who enjoy the benefits of using Adobe Camera Raw over other methods (superior debayering, colour rendition and noise control) might like to give this profile a whirl.

DOWNLOAD:
https://bitbucket.org/hyalinejim/ml-log/downloads/

Key features:
1. Maps RAW linear to a logarithmic curve with blacks at 9.3 IRE, 18% grey at 46 IRE and 90% white at 72.6. This gamma is very close to Cineon or RedLogFilm

2. The profile is fairly colorimetrically accurate. All you need to do is apply a curve to restore proper contrast and colours should look good. In this screengrab the outer area of the patches is a CR2 shot of a ColorChecker with ML-Log applied, followed by a curve to match the gamma to that of the chart values. The inner squares are an RGB visualisation of a typical ColorChecker. You can see it's not a perfect match, but it's close.



3.  I've included two options for de-logging footage based on an old paper on the relationship between Cineon and film. One of these curves has a colour cast, and the other is clean. They are included as Adobe curves, and as .cube luts. That paper is here, and it is interesting http://www.digital-intermediate.co.uk/film/pdf/Cineon.pdf You should get some nice results with this, but do try other luts as well.

How the profile was constructed:
With Danne's help, I used LutCalc to generate a linear to log curve. I then incorporated this into Lumariver Profile Designer, which is a GUI for DCamProf - a DCP designer. The matrix and HSV tables were derived from a CR2 shot of an X-Rite Colorchecker using Lumariver's inbuilt colour calibration function. If you are interested in seeing what's going on inside you can use DCPTool to peek at the contents.

What's next?
I'd like ML users to test this profile for usability. Any comments, questions and criticisms are very welcome. If it proves useful, we should be able to generate similar profiles for other Canon cams. Not only that, but there's no particular reason why we need to be locked into this particular curve. It should be possible to generate curves to match, for example, Sony's S-Log, Canon's C-Log, Panasonic's V-Log or Arri's Log-C

So will this turn my camera into Alexa / C300 / Varicam / etc.?
That would be nice but, no. This profile does two things: it changes the gamma of the RAW output so that it matches a particular curve (in this case Cineon / RedLogFilm) and it slightly tweaks the colours so that they are more accurate. The advantage of this is that you can apply this profile to your DNGs, render to a lossless intermediate codec, save on hard drive space, make editing smoother and defer decisions on colour correction until after editing. But it won't make your Canon look like an Arri.

Are there any disadvantages to using ML-Log?
If colours are very saturated, there is a chance that one channel will clip at the lower end of the scale. I can avoid this by globally lowering saturation across the profile, but this hurts overall colour accuracy so I decided not to do that. It's probably not a big deal.

How do I install the profile for Adobe Camera Raw?
Put the DCP file here:

MAC
User Library>Application Support>Adobe>CameraRaw>CameraProfiles

PC
C:\Users\YourUsername\AppData\Roaming\Adobe\CameraRaw\CameraProfiles

What's the best workflow?
Bring in your DNG sequences to After Effects.
Set white balance in Adobe Camera Raw if necessary. It will behave a little differently to Adobe Standard. So Daylight will look different, for example. Choose either "As Shot" if you set it close to correct in camera, or tweak manually and trust your eyes.
Leave everything else at the default, including exposure. You might also like to turn off noise reduction if you will do it later with Neat Video.
Export to an intermediate codec. At the minimum 10bit 422, and preferably 444. Cineform, ProRes and DnXHD are your choices here.
When grading, simply add one of the included curves or luts. Before this curve or lut, tweak exposure. Try using a curves effect here, using only the midtones. The curve is likely to make things a little dark but it shouldn't clip too much in the shadows and highlights. If you need more or less contrast play with the white and black points as well.

Finally, I'd like to thank Danne for his support, encouragement and advice in making this. I hope it's useful to you. Here are some pics with the film curve:








Lars Steenhoff

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Re: ML-Log: new log profile for Magic Lantern
« Reply #1 on: October 16, 2017, 11:05:15 PM »
Wow love this!!!

This fits my workflow perfectly

Danne

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Re: ML-Log: new log profile for Magic Lantern
« Reply #2 on: October 16, 2017, 11:13:02 PM »
Yes. It is badass. Great work on calibrating curves and colors. My crude start was only working the tone curve points so color accuracy was heavily needed. Testing and feedback welcome.

hyalinejim

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Re: ML-Log: new log profile for Magic Lantern
« Reply #3 on: October 16, 2017, 11:47:26 PM »
In brief, this is the workflow:

ACR defaults:




Apply ML-Log DCP profile:




In After Effects (or Premiere, or Resolve) add curve or lut and tweak exposure


Lars Steenhoff

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Re: ML-Log: new log profile for Magic Lantern
« Reply #4 on: October 17, 2017, 12:11:52 AM »
Do you advice picking the white balance after or before selecting the curve in ACR?
Or it does not matter

bpv5P

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Re: ML-Log: new log profile for Magic Lantern
« Reply #5 on: October 17, 2017, 12:15:59 AM »
Finally something like this. Thank you very much to everyone that put effort on it.

hyalinejim

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Re: ML-Log: new log profile for Magic Lantern
« Reply #6 on: October 17, 2017, 12:16:12 AM »
Ideally, it's best to do it first, Lars. But you can also change it afterwards if you have a good white balance tool. The Lumetri color panel is available in AE and will work.

But I wouldn't agonise over getting it exactly perfect - you'll be able to push the white balance quite hard in post. Sometimes you're not sure what exactly the final WB should be until you're ready to grade and that's fine.

hyalinejim

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Re: ML-Log: new log profile for Magic Lantern
« Reply #7 on: October 17, 2017, 12:18:50 AM »
@bpv5P I hope you find it useful.

Everybody who tries this, please let us know if it works out well for you. We're going to use this v1.0 5D3 profile to fine tune anything that might need fine tuning before attempting to create similar profiles for the other cams.

Lars Steenhoff

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Re: ML-Log: new log profile for Magic Lantern
« Reply #8 on: October 17, 2017, 12:51:50 AM »
Yes it works well, I compared it to cinelog and its even flatter it seems.
same workflow that I'm used to with cinelog so that is nice

Now I will try to source some LUTS that work directly with this.

hyalinejim

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Re: ML-Log: new log profile for Magic Lantern
« Reply #9 on: October 17, 2017, 01:05:35 AM »
Try Juan Melara:

http://juanmelara.com.au/print-film-emulation-luts-for-download/

Or anything designed for Cineon or RedLogFilm will hopefully work well.

bpv5P

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Re: ML-Log: new log profile for Magic Lantern
« Reply #10 on: October 20, 2017, 11:46:26 PM »
Hey hyalinejim and Danne, what do you need to port it to 50D and 600D? I have both cameras, maybe I could help with some data. I don't have a color checker, though. I see you're already working on 100D release.
Also, GPL license only applies if the code is open, but I can't find the code. Wouldn't be better to use github instead of bitbucket, btw?

Danne

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Re: ML-Log: new log profile for Magic Lantern
« Reply #11 on: October 21, 2017, 06:38:32 AM »
Hyalinejim knows the steps to build the profiles with lumariver. Steps to learn and build them are decribed in first post.
You can also view and alter the content in the dcp profile with dcptool. Also mentioned in the first post.
It's conversion work which Is created in lumariver, there is no programming code.
I only know dcptool and a little about tone curve building. The rest is hyalinejims stuff.

bpv5P

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Re: ML-Log: new log profile for Magic Lantern
« Reply #12 on: October 21, 2017, 08:03:35 AM »
Ok, but them it's not code and GPL is not the proper license to use. Maybe CC0 would be better applied...

hyalinejim

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Re: ML-Log: new log profile for Magic Lantern
« Reply #13 on: October 21, 2017, 11:40:03 AM »
I confess I know as little about GPL licensing as I do about code! As Danne mentioned, there was no coding involved in making this profile just the use of some free and paid tools as outlined in the opening post. I'll remove the reference to GPL in the first post for now.

Has anybody been stress testing the profile? Danne and I have noticed some colour artifacting under certain conditions. Look at the colour fringing around patch 4E:

Digital Colorchecker SG CR2 downloaded from Imaging Resource. Temp and tint sliders at the extremes in ACR. ML-Log v1.0



This can be prevented by choosing a different Tone Reproduction Operator (TRO) in Lumariver (ML-Log v1.0 uses "ACR" TRO and v1.3 uses "Simple")

ML-Log v1.3


All well and good, but the colour accuracy of this profile is slightly affected.

ML-Log v1.0 - the inner square is the correct colour the outer square shows the result of the profile


ML-Log v1.3


With v1.2 reds, yellows and purples are brighter but it might hurt colour accuracy. Can you guys try to stress test this new version versus v1.0? If v1.2 still has good colour for real world images it's the obvious choice as there are little to no colour artifacts with it.

v1.0
https://bitbucket.org/hyalinejim/ml-log/downloads/5D3%20ML-Log%20v1.0.dcp

v1.3
https://bitbucket.org/hyalinejim/ml-log/downloads/5D3%20ML-Log%20v1.3%20Simple.dcp

hjfilmspeed

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Re: ML-Log: new log profile for Magic Lantern
« Reply #14 on: October 21, 2017, 03:21:33 PM »
This looks awesome! I'll have to try these later! And stress test them too!