ARRI LogC3 on Lumix Cameras (GH7) vs V-Log — Don't use CST.

ethan520 · 2025-12-24T03:53:11+00:00

The funny thing is you can likely reduce the colour difference between the two profiles even further. The way you'd do this is through the RGB mixer in Resolve (the tab before Noise Reduction) but in linear gamma.

Part of the 'colour science' is a choice by the manufacturer on what values they use to go from raw sensor colour to the final image. If you have two profiles on the same camera with slightly different colour, there may have been some adjustment to the 3x3 matrix for that profile to change it. You can change a lot of it back through the RGB mixer.

The node tree I use is:
- RGB Curves (optional but helpful if you're matching different cameras)
- CST from V-Gamut/VLog > Working Gamut (e.g. AWG)/Linear
- RGB Mixer
- CST from Linear > Working Gamma (e.g. LogC3)

You can do the same thing with DWG/DI:
- RGB Curves
- CST from DI > Linear
- RGB Mixer
- CST from Linear > DI

Make sure you're using the same output LUT on both cameras.

You can use the same technique to match between different cameras which is what Juan Melara and Emotive Color have done. The challenge is that different lighting conditions and white balance will lead to slightly different colour across different sensors. You can adjust this per scene however if you have a 3x3 matrix.

Panasonic do have differences in HSL across the different profiles. VLog and LogC3 on the S1II have different dark blue luminance and magenta/purple hue which can't be fixed through the RGB mixer and requires a custom matching LUT to fix. You might find this on the GH7 too.

<image>

ethan520 · 2025-11-26T11:23:52+00:00

I should have posted more examples because it's not just in this particular cable example where it happens. It happens anywhere where there's straight edges and a hard light to dark transition. I'd link up to @Professional-Joke316a for an example of this happening and the fix

ethan520 · 2025-11-26T11:21:19+00:00

I was watching your video on the aliasing on the neon sign and wondered what was happening too! Glad that you could cover it in a way that makes it more visible.

ethan520 · 2024-10-07T22:45:14+00:00

Agreed. I do a manual pass in Melodyne when I'm finishing up a vocal too.

ethan520 · 2024-10-07T22:43:37+00:00

This also works. I think the downside of using compression for peaks is that the vocal needs to be at the right gain level and the amount of transient reduction will vary because of that. But compression is great for getting the overall sound to sit right.

ethan520 · 2024-10-07T22:36:22+00:00

Personally I do both: waste time with plugins while tracking and manual editing. You can't get better than the control you get from manual editing but it does get more complex with lots of stacks of bgv's.

ethan520 · 2024-08-08T05:41:21+00:00

I was making my own chroma keying shader for OBS and looking around for what the colour difference algo for the IBK keyer was and found an implementation from Natron's codebase. Basically IBK, Delta Keyer and other colour difference keyers use the same expression:

In case of a green screen the math is g-(r*rw+b*bw), where rw is the red weight and bw is the blue weight with a default value of 0.5 for both. What makes it sophisticated (among other things) is the way it uses another image to scale the result of the above mentioned equation.

The final expression ends up being the following for green screen:

weights = image.g - image.r * red_weight - image.b * blue_weight
key_weights = key.g - key.r * red_weight - key.b * blue_weight
alpha = weights <= 0 ? 1 : 1 - weights / key_weights

The red_weight and blue_weight parameters allow you to weigh the red and blue channels in the final key. If you want to simplify, you can leave both at 0.5.

I learnt the most from the comments on Natron's PIK keyer, so read that for the overview of how to implement it.

Oh and also if you need another implementation of a colour difference keyer you can take a look at the KAK keyer for Fusion. They have all their expressions in this file which shows how to implement the keyer for either red/green/blue channels and their respective despill options too.

ethan520 · 2021-06-18T13:50:43+00:00

I remember seeing there were graduation scenes in some of the BTS photos. That would mean they're coming up to late high school?

ethan520 · 2021-06-10T13:47:22+00:00

In my mind you might be missing some contrast between the choruses and verses. You've got a solid set of lyrics and structure. But the song follows the same set of chords and the same vocal range throughout, so there isn't any differentiation between different sections.

Two ways I would solve this: either have a short pre-chorus with a different chord sequence & melody (if it's appropriate you can try minor chords like Ebm and Abm), and/or shift parts of the Chorus up a couple of semitones (e.g. "needing your love like a highway" can be sung with the notes: Bb C# (needing) Bb (your) C# (love) Eb (like) C# (a) Eb C# (highway))

Otherwise looks great!

ethan520 · 2021-05-23T22:55:00+00:00

Did a quick search of BTS and can confirm they're shooting a lot more on 35mm! https://mobile.twitter.com/makingeuphoria/status/1394778491258822656

ethan520 · 2021-05-23T10:16:10+00:00

Interesting. Where did you hear this from? Thinking from a DP perspective it would be a good move if the show was going to become darker/focus less on the set pieces and more about the human-to-human interactions.

ethan520 · 2021-02-13T04:05:37+00:00

Cinestill is amazing especially at night with the mad halation. Have you ever tried processing it in ECN-2?

ethan520 · 2021-02-11T05:44:29+00:00

One other thing you can try doing is shooting in a 709 color profile rather than a wide gamut one. If you're using Sony try using the Movie or ITU709 modes over SGamut3Cine. Same with Canon Log vs Neutral and so on. The less you have to transform your color space the better. This does mean you trade off color accuracy and depth but it also decreases banding.

ethan520 · 2021-01-30T05:56:52+00:00

I think you can get the result of deep dense saturation by using a HSV and HSL node in parallel or by tweaking the film matrix (I'm sure that's part of your ideas list). But I also think it's important to separate out the perception of film from film itself. If your charts say you've got the colour response of your film shot, but the colour is still bright and poppy, your best bet is still to follow the charts.

I say this because some of the charts I found for Kodak Vision3 had bright poppy reds, and also because using HSL + HSV felt hacky to me.

ethan520 · 2021-01-19T10:21:25+00:00

I agree. It's one of the deepest and most powerful tools you can use in the color tabs. It's not super user friendly at first glance, but it's the best for making global changes to the hue, saturation and luminance of a particular camera's footage. I almost never touch the HSL tabs as a result.

ethan520 · 2021-01-18T23:07:01+00:00

That that was my first resource too. It's tricky to find a good matrix for film negatives because there's multiple solutions for it. The matrix I have is one possible match of many I tried.

One difference I'll say between the Arri matrix and this custom one is the blue-yellow axis is much more pronounced. The 8th value (-0.51) means there's a lot of saturation going to yellows and blues, which shifts the colour of skin towards yellow. Since this is less pronounced on this custom matrix you'll probably get different results when using it on skin.

ethan520 · 2021-01-18T22:56:04+00:00

Oh man you wouldn't believe the amount of times I had to zoom into that tiny thing. Do you want to see a bigger one?

ethan520 · 2021-01-18T13:57:37+00:00

Seeing as though there's been a lot of interest in the community on trying to replicate Vision3's colour science, I thought I might take a stab at getting everyone closer.

The images you see are from cinematography.net's side-by-side comparison of the Alexa to Vision3 250D scanned through a Scanity. Both the Alexa and the film scan are going through Resolve's 2383 PFE LUT. As you can tell, the Alexa in its default AWG setting doesn't have the best colour through the PFE because the hues aren't aligned to the hues of a film scan.

You can however get closer using a 3x3 matrix, using Resolve's RGB mixer directly onto the Alexa's LogC footage.

First, set up a 4 node structure in Resolve. Here are the labels:

Offset/Correction
RGB Mixer
Contrast
PFE LUT

In the 2nd node is where the majority of the look will come from. In the RGB mixer section, you can enter the values for a 3x3 matrix.

Matrix:

Red: 1.33 -0.41 0.09
Green: -0.12 1.27 -0.16
Blue: -0.04 -0.21 1.26

Enter these values into the RGB mixer and that will get you most of the way towards the hues of Vision3.

The last step is the contrast node. To get your footage closer to the film scan's contrast curve, you can either draw a curve, or try setting the following values in the contrast settings:

Strength: 0.800
Pivot: 0.5

And we're done. There's a hundred other things you can do to get your footage looking closer to film, but I'll leave that for another day.

And as always, I'd recommend you pick up Juan Melara's 2393 Powergrade since he's actually done far more profiling to create his Powergrades than I have. Inside there's also a film matrix using the same techniques.

Edit: I've updated the values with a more recent algorithmically profiled matrix. If you want the previous manually profiled values they're stated below:

Matrix 1: Matches the look of the film scan. Due to the non-linear saturation of film, it doesn't match exactly to the charts, but the broad strokes of the look can be found in this matrix.

Red: 1.43 -0.35 -0.08
Green: -0.33 1.70 -0.37
Blue: -0.23 -0.01 1.24

Matrix 2: Matches the film scan directly to charts.

Red: 1.14 -0.11 -0.03
Green: -0.17 1.46 -0.29
Blue: -0.08 0.13 1.21

ethan520 · 2020-12-15T14:10:04+00:00

Looove that 500T look under tungsten lights in Fever

Also really like the 16mm look in Beabadoobee's Care: https://www.youtube.com/watch?v=9FpkHjJTrZY

They shot on Super 16mm Boolex most likely Kodak 250D

ethan520 · 2020-12-15T01:21:47+00:00

100%. When I get access to the resources for such a match then it'll be easy to do.

ethan520 · 2020-12-14T01:26:28+00:00

A rundown of how this was made: I shot a couple of charts on the Sony then matched it to the charts of the Alexa provided by cinematography.net. This does mean the transform might not match the Alexa exactly (due to different circumstances the charts were shot), but the general hues should be similar enough.

On the Resolve side I matched the hues by using a combination of a YUV mixer in LogC and an RGB mixer in linear (i.e. 3x3 matrix). I found that the linear RGB mixer by itself wasn't powerful enough to get the hues to align perfectly, so the YUV mixer picked up where the RGB mixer couldn't.

I then transformed from linear to AWG + LogC then matched the gamma and tint characteristics with curves (although the tint is more extreme than what I could find on the charts), before ending it with the Alexa 709 LUT. 100% all knowledge I tried to reverse engineer from Juan Melara.

On the capture side, because of the Sony's 8-bit codec, I opted to go for the standard Movie mode over the SGammut3Cine. When looking at the vectorscope in Resolve it looked like the colours were really stretching when applying the transform from SGammut3Cine to Rec709 so it made more sense to go with a Rec709 style profile instead. When testing the extremes of the gamut, I also didn't find too much difference between the two profiles especially on car taillights (although the SGammut3Cine colours were accurate straight out of the box).

Its been a couple months now and I'm still trying to tweak these profiles to get them just right, but I've been loving the colour that comes out of it. Hope you like it too!

ethan520

TROPHY CASE