Lumix G9, V-Log L, and color grading

mistergarth Posts: 32 Just Starting Out*

I'm about to take the plunge and buy a grown-up video camera which produces gradable footage, a Lumix G9. I shoot nature and hiking videos, so many of my scenes are in very contrasty light with bright skies and deep dark shadows. I'm looking forward to having some control over dynamic range.

The G9 ships with a variety of color profiles, including flatter ones like HLG and Cinelike-D which give one some control of dynamic range. For an extra $100, one can add V-Log L capabilities. One disadvantage of V-Log L is that the footage looks like mud straight out of the camera; it must be graded.

I'm trying to figure out if it's worth the extra hundred bucks to just get the upgrade when I buy the camera. Does anyone here grade V-Log L footage with Hitfilm? I have the Pro version. Are there specific LUTs you'd recommend as a starting point? Am I likely to be so dazzled by the wonderfulness of HLG that I won't want the bother of V-Log L?

thanks in advance



  • laconstantedeplanck
    laconstantedeplanck Posts: 99 Enthusiast

    Hi @mistergarth, I'm a Sony user, so I work with S-Log instead of V-Log but it's pretty much the same thing. Log formats shoot everything in a low contrast profile. That means the raw footage directly from the camera will seem quite dirty and unusable, that's true. Although it may not seem right at first, those are good news. Recording with the contrast this low allows you to enhance the video later in a better way because -as you mentioned- you get greater dynamic range for both shadows and highlights. If you shoot with a regular profile, you might end having a scene with some areas that are pitch black or full bright, which makes almost impossible to grade the video properly.

    I wouldn't be worried because you'll surely be able to choose if you want to shoot in V-log or any other non-neutral profile, so it's always a safe bet to have at least the ability to shoot at V-Log than not having it at all. In my last trip to Manchester I specifically configured one of the custom buttons of my Sony camera to switch between a neutral profile (log) and a more vivid one. This way I was able to shoot some of my vacation footage with log profile with the idea of grading it later and then with a single click, change the profile straight away to a vivid color one, as I didn't plan to grade all the clips.

    Regarding the LUTs, I have a bunch of them that I can share with you if you want (all were free, hopefully no copyright issues here :)). In case you don't know, there are 2 dimensional LUTs and 3 dimensional LUTs. A LUT is a lookup table with some pre-defined values for hue, saturation and contrast. A 2D LUT will only change two of those parameters (most likely hue and saturation), and a 3D one will change brightness as well. If you shoot log, you'll need 3D LUTs or just adjust the contrast first with a Curves effect then apply the 2D LUT. Nonetheless, always consider a LUT as an starting point to grade your footage, it usually don't look as great as people tend to think, but as a one click solution to start the grading they're quite useful.

    Hope this helps!

  • Triem23
    Triem23 Posts: 20,529 Ambassador

    More on LUTs

    As @laconstantedeplanck mentioned, LUT stands for "Look Up Table," and what they DO is pretty simple in concept.

    Digital color can, and are, of course, be represented by numbers. All a LUT does is repeat something like 128, 128, 128=115, 115, 128 (this would take a pure 50% Gray and make it a little darker and a little blue), millions of times across the entire spectrum (which is why the only control for LUTs is "Strength," which "fades" the LUT from full effect to no effect).

    There are two purposes for LUTs - correction and grading. Correction is the stage where you take all your raw footage, make sure it's well exposed, color neutral, and that all the different takes and angles of a scene match each other. These LUTs should have descriptive names like "V-log to Rec 709,"which would take V-log footage and expand it to the full Rec 709 - broadcast HD - color/contrast range. These are the LUTs you apply FIRST.

    Since you can stack multiple LUTs you can then get into other LUTs.

    Here's where you can get into "emulation" LUTs. These are designed to mimic the color/contrast of specific film stocks, and they might have names like "Rec 709 - Kodachrome 400." Mapping the HD broadcast range to look like Kodachrome 400 film. Technically this isn't a grading LUT because this is still trying to take a "neutral" image and give it the color response of the particular film being emulated.

    Grading is when you recolor your footage for style and creative looks. These will have vague and descriptive names. A LUT named "Desert," will most likely push everything to that stupid yellow everyone uses to represent the Middle East now. Something called "Matrix" is going to push a lot of green.

    Again, LUTs come earlier in the coloring process. You might have as many as three LUTs going - a correction LUT to neutralize/correct your footage, an emulation LUT to emulate a film stock (although an emulation LUT CAN be considered a grading LUT as well), then a creative LUT to first - stage a look. You might have color effects between the correction and emulation LUTs - say I've shot a scene near sunset and the last shots are darker and more yellow. Correcting brightness and color so all the shots match comes after a correction LUT, before everything else. Then Emulation (if used) LUTs, then the creative LUT, THEN you do your manual tweaks to dial in the final look.

  • mistergarth
    mistergarth Posts: 32 Just Starting Out*

    Thanks to both of you. I've been doing lots of reading, watching lots of videos, and trying harder to do contrast-control grading with my existing cameras to get a baseline to work from. But ultimately, I'm just gonna have to buy the V-Log L upgrade and fiddle with it. One reason I haven't been shooting many nature/hiking videos the last few years is contrast. I've had to restrict my shooting to a narrow range of Goldilocks subjects: not too contrasty, not too flat, just right. This camera and its color profiles should expand the good zone quite a ways. But there's a steep learning curve to climb.

  • miliniwe
    miliniwe Posts: 3 Just Starting Out*
    There are some tutorial on lumix experience

    The topic has still a level of mystery but is not hard to comprehend if you are technically minded

    Basically a log profile takes a logarithm of reflectance so it compresses the signal therefore you need higher level of gain to make it work (min ISO is 400)

    You then decompress this using a Look Up Table and goes back to a standard gamma curve theoretically having retained the full dynamic range

    Vlog in the varicam implementation has 14 stops DR.

    In the consumer cameras with a 12 stop sensor the level of compression you need is minimal so a square root type of operation like gamma compression achieves same results with less sweat