Logarist Color Correction for DaVinci Resolve, Vegas Pro, Final Cut Pro X

B

balazer

Well-known member
Logarist now supports Adobe Premiere Pro and Premiere Elements with a free plugin.

Logarist brings color science to the art of color correction, enabling fast and accurate adjustment right inside your video editing application, without the need to shoot raw. Logarist reduces color correction to its fundamentals, with controls that work much like the controls built into a camera or a raw image processor like Lightroom. Logarist uses look-up tables (LUTs) to transform your camera's video into a color space optimized for exposure compensation, white balance correction, and contrast adjustment, and then renders it for viewing on a standard display. Logarist makes basic color correction easy and accurate, and enables advanced corrections that are otherwise difficult or impossible. Logarist is free, and you can download it from logarist.com.

Supported camera color spaces:
  • BT.709 (standard HD video)
  • Arri Alexa Log C
  • Canon EOS Neutral
  • Canon Log 1–3
  • Canon Wide DR gamma
  • Fujifilm F-Log
  • GoPro Protune
  • JVC J-Log1
  • Panasonic GH2 Standard
  • Panasonic GH4 Cinelike D
  • Panasonic GH4 V-Log L
  • Panasonic GH5 Cinelike D
  • Panasonic VariCam V-Log
  • Sony Cine1–2
  • Sony HyperGamma 2, 4, 7, and 8
  • Sony S-Log1–3


 
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I have to admit that I don't quite understand how a 3D LUT can change the working color space of an application? For example, I think FCPX processes everything internally as YUV with 16 bit precision, right?
 
Hi, joe12south. RGB and YUV are pixel formats, not color spaces exactly. I couldn't find any definitive info from Apple about the pixel format used by FCPX, but from my testing (at least with the Color Correction effect) it's using a high precision RGB pixel format, probably 32-bit floating point RGB.

Logarist isn't changing the pixel format. The pixel format is determined by the video app, and sometimes by the plugins you're using. The Logarist LUTs do color space transformation and display rendering. A LUT is just a way of encoding an arbitrary three-dimensional transformation, so it can be used to change colors or the color space. To the video app, it's all just numbers. The numbers only become colors when you assign a color space, which establishes the relationship between the colors and the numbers.
 
Thanks for sharing.
What about the Panasonic DVX200 with Scene 4 (i.e. natural)? What color space should be used?
 
Hi, diegocervo. I don't have a transform specifically for the Panasonic DVX200. I'd suggest using a custom scene with Gamma set to HD, Matrix set to Norm1, and Knee turned Off. That *should* correspond to BT.709, though it's anyone's guess what Panasonic has really done there. Then use the BT.709 to Logarist input transform. If you shoot in BT.709 with a normal exposure you may find that highlights are clipped too low, so you may want to underexpose by half a stop to a stop to extend your highlight range, and then compensate in Logarist. I would guess that Cinelike D on this camera does not match Cinelike D on the GH4. And I recommend against using V-Log L in 8-bit recordings.

Try it and let us know how it works.
 
Please forgive a layman question, but how is it different from grading with regular LUT's and tools available within each of the color grading programs?
 
balazer said:
Hi, joe12south. RGB and YUV are pixel formats, not color spaces exactly. I couldn't find any definitive info from Apple about the pixel format used by FCPX, but from my testing (at least with the Color Correction effect) it's using a high precision RGB pixel format, probably 32-bit floating point RGB.

Logarist isn't changing the pixel format. The pixel format is determined by the video app, and sometimes by the plugins you're using. The Logarist LUTs do color space transformation and display rendering. A LUT is just a way of encoding an arbitrary three-dimensional transformation, so it can be used to change colors or the color space. To the video app, it's all just numbers. The numbers only become colors when you assign a color space, which establishes the relationship between the colors and the numbers.
Click to expand...

Sorry, I should have said "color model."
So, I understand the benefit of being able to do transforms with more precision, or inside of a bigger gamut. I also understand how certain models allow for certain types of transformations that would be difficult or impossible in a different model. What I don't understand is what benefit is gained from going in and out of your LUT transformations?

I've got a bunch of questions:

- The NLE is working at high precision (at least 16bit) and a "wide" internal gamut. How do these LUT's make doing transforms "better"?
- If what you're doing is transforming to a different color space, then isn't knowing the input camera's color space important? For example, the GH4 can use either sRGB or aRGB. Picture profile settings like saturation don't change the color space...why does the latter matter but not the former?
- How is this easier? It's a minimum of 2 extra steps in FCPX for every single clip. For what gain?
- I don't understand how this would help rescue white balance any better than you can without it? Certainly not like Lightroom (or Premiere for that matter) does with a RAW file. The color error is baked into the non-raw file, and is going to be destructive no matter what.
- How is this different than the standardized LOG LUT's you released earlier?

Sorry if I sound skeptical, but the language around this "LUT system" is very opaque, and we've all been bitten by LUT's that promise to be miracle cures. I'm sincerely trying to understand why it's worth the extra work. If there are real, meaningful benefits, it would be great to know how to capitalize on them.
 
joe12south said:
Sorry if I sound skeptical, but the language around this "LUT system" is very opaque, and we've all been bitten by LUT's that promise to be miracle cures.
Click to expand...

"The proof is in the pudding"

It's free, so I would try it out and see what you think of it after using it.

I was not expecting much from this, but then I tried it with a few different 8-bit cameras ( and one 10-bit camera ) and was quite surprised at how good the default color was and how much more I could modify my footage before it fell apart.

Since I mainly edit with MAGIX Vegas Pro 14, I can apply the Logarist controls to any clip in two mouse clicks, or apply it to an entire track in two mouse clicks.

It took me about 5 minutes to install and set up Logarist default settings in Vegas Pro.
 
So far I'm really impressed with how this handles V-log from the GH4. Cine-D seems to clip much easier than it does with manual grading or when using Leeming LUT. I know the shots are not clipped because I can recover them and other luts do not show this.

Are there recommended exposure levels you suggest for Cine-D to avoid this?

Same but opposite issue with V-log. When using these luts my shots get a lot darker than they do with the Leeming lut, Panasonic lut or my own manual grading. Are their recorded exposure levels that are different from normal V-log luts to shoot with or is it natural to be that much darker and I grade in between?

Finally why do you suggest only adjusting the global exposure setting in the FCPX color board and not the highs and shadows? I find this to be very limiting in grading by not tweaking the highs and shadows.

By the way this lut is extremely slow on my 2012 i7 iMac with 24GB ram and a 2GB GTX680m GPU. Not slow in terms of playback but FCPX really locks up for a good 20 seconds when I apply the first lut. I assume there is a lot going on in the background vs other luts to make it run that slow.
 
Here is a quick test I did last night with some GH4 V-log 4k to HD captured via HDMI to a Ninja Blade.

Version using Leeming LUT.
V-log-leeming.jpg

Version using Logarist with some exposure adjustment in between the two luts using the FCPX color board. No other color grading.
V-log-logarist.jpg
 
Thomas Smet said:
Version using Logarist with some exposure adjustment in between the two luts using the FCPX color board. No other color grading.
Click to expand...

Which looks more accurate to you ?

I have no idea, but I like the Logarist color better.
( not a fan of yellow-green plant life )
 
TheDingo said:
Which looks more accurate to you ?

I have no idea, but I like the Logarist color better.
( not a fan of yellow-green plant life )
Click to expand...

Shot this during the summer in Colorado but I'm pretty sure the plants were more green than yellow. Also pretty sure the Leeming LUT wouldn't be that much off either so I'm not entirely sure which is more accurate. The Logarist version does seem more accurate to my memory however.

This thing sure is slow however and I'm finding it to be rather painful to use in FCPX.
 
TheDingo said:
"The proof is in the pudding"

It's free, so I would try it out and see what you think of it after using it.

I was not expecting much from this, but then I tried it with a few different 8-bit cameras ( and one 10-bit camera ) and was quite surprised at how good the default color was and how much more I could modify my footage before it fell apart.

Since I mainly edit with MAGIX Vegas Pro 14, I can apply the Logarist controls to any clip in two mouse clicks, or apply it to an entire track in two mouse clicks.

It took me about 5 minutes to install and set up Logarist default settings in Vegas Pro.
Click to expand...

I did try it, and I tried the LUT's released some months ago. From a surface view it seems to move the footage to a log-based camera-independent "ideal" for processing, and then to REC.709 for output. I'm struggling to find scenarios where it is materially "easier" or "better" to work with, though. What can I do in this space that I can't do with Resolve's plethora of tools without transforming first? I seem to be able to push the footage roughly the same amount.
 
Thomas Smet said:
This thing sure is slow however and I'm finding it to be rather painful to use in FCPX.
Click to expand...

Using my 6 year old first generation i7 desktop at home with 16 GB of RAM, it takes MAGIX Vegas Pro 14 about 3 seconds to display the Logarist image for the very first time, and then I can adjust things in what appears to be real-time. I did upgrade the graphics card about 18 months ago to an AMD R9 280 card and Vegas Pro does make good use of the video card. ( my rendering times were cut in half just by adding the new video card )

At work I'm using a 5th generation i7 desktop with the same AMD video card and the Logarist image pops up in about 1 second for the very first time, and everything is real-time after that.
 
TheDingo said:
Which looks more accurate to you ?

I have no idea, but I like the Logarist color better.
( not a fan of yellow-green plant life )
Click to expand...

If it's a more accurate input LUT than Panasonic's or Paul's, that I can see a use for.

But how does this LUT make my NLE perform white balance adjustment on an 8-bit baked image like a 14-bit RAW image in Lightroom?
 
joe12south said:
But how does this LUT make my NLE perform white balance adjustment on an 8-bit baked image like a 14-bit RAW image in Lightroom?
Click to expand...

I suspect that it's not the same as a 14-bit RAW image, but the Logarist color space does seem a lot better with 8-bit and 10-bit footage than anything else I've worked with.

I'm guessing that higher precision math is part of why Logarist works better, and maybe why it's slower on some computers.
 
TheDingo said:
What about the default color when you're working with well shot footage ?

I saw better default color with Logarist right away.
Click to expand...

I built an input LUT with 3D LUT creator around the same time Paul Leeming made his. Color and exposure near dead on, and I don't have to apply any clunky workarounds.
 
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