@Tjabo

Depending on your preferred workflows, PrPro has several ways of incorporating LUT's ... in the Effects panel tab in the lower left quadrant, in the search type in lut and see what pops up ... also, in 2015, the new color workspace ... there's an "Input LUT" on the basic tab that is there to "place" non-Rec709 footage into the Rec709 space that Lumetri panel is built around.

I'd suggest first putting a Fast or Three-Way effect on a clip, THEN going to the Basic & loading the LUT you want, THEN going back to the color control effect you'd chosen to tweak the image there for WB/exposure/contrast (think L/G/G or O/G/G if you understand colorist lingo) and then go back into the Lumetri panel for doing your colorist work.

Neil

ZEBRAS!!

Hello everyone. Today I received my 100% legit unlock code and installed VLog-L on my GH4 with firmware V2.4. Unless I am totally messing something up, neither of the zebras function at any percentage above 80%. Not at all, no matter how blown out something is... I'm planning to do some testing to see if I can really work with the zebras at 80%, but in the mean time I figured I would just check in here.

I have seen others, such as @crowbar mention using the zebras at higher than 80% settings, but I just wasn't sure if that was the covert version still being used from before, or the legit version on V2.3 firmware, or what.

Some really slapdash test footage I shot using only the exposure meter and the histogram provided results as expected, and so far I am happy with VLog. I think I'm going to shoot a little bit of slightly more important footage with it tonight and see how that goes. I'll try to gain more understanding of how the histogram relates to the 80% zebras.

@balazer, thank you! I haven't used SpeedGrade because I've always been happy enough with what I was able to do manually (3-way color corrector and RGB curves mainly), and I'm still learning -- a LOT, Lol. I really never felt like I should use a LUT before because I wanted to learn about color science. I've gotten pretty good results with VLog samples so far from my manual efforts, so is it a real benefit to use LUTs? If so, I will see about trying SpeedGrade or Reslove.

@rNeil, thank you also! I have to study your post a bit more to make sure I'm understanding you well. I will try what you said first for PrPro and see how that goes.

There is a very nice analysis of VLogL here -- suggest everyone give it a read: http://www.provideocoalition.com/v-log-l-on-the-gh4-don-t-panic

@balazar ...

PrPro's Lumetri color workspace "panel" is designed to "smooth" things, so they've built new controls not just brought Sg's ones over ... it's an effort to simplify things for the Masses. So depending on the footage, the controls are designed to induce knee & shoulder roll-offs to "protect" the upper/lower values. And remember ... that Color workspace is total Rec709.

I can understand the choice for the "main market" they're expecting to use that part of the program, but ... it ain't ideal for people with specific "power use" needs. Hence my comments, if one uses the Color workspace, about putting another color-control effect on the clip PRIOR to making ANY changes on the Color controls panel, and putting out-put film/print emulation LUT's on say LUT Buddy effect AFTER the Lumetri panel controls in the Effects Panel.

The Color Workspace panel's "Basic" tab, that Input LUT option ... that is designed to convert whatever footage you've got into Rec709 workable media. Which is why, again, you MUST have a color effect control loaded onto the clip & in the Effects panel BEFORE doing anything in the color workspace. Load Fast or Three-Way, got to Basic tab & load your LUT, then go back to the Fast or Three-way "above" that in the Effects panel, and work the controls ... does that get you what you need?

For the stuff you're doing, SpeedGrade would get you the better results ... and be easier to "control". And I'd note ... for a lot of people (though not everyone) ... PrPro & Sg in Direct Link workflows are not as smooth a combo with the 2015 build ... the 2014 pairing is more stable & robust, very little if any lag issues & so on. Now, some people are working in 2015 just fine without lag & such. Some days, & smaller projects, I can do it fine. Other days, it is a bit cranky. Your mileage will vary ...

But I'd love to have you try the above workflow and see if by using a Fast or Three-way prior to the Basic Tab intro of your LUT's into the 'chain', you can get the proper action of things ...

Neil

@rNeil,

Load Fast or Three-Way, got to Basic tab & load your LUT, then go back to the Fast or Three-way "above" that in the Effects panel, and work the controls ... does that get you what you need?

The problem with Premiere's Fast Color Corrector is that it operates in YUV space instead of RGB space. The Three-Way Color Corrector has that problem too, plus it's just not the kind of operation that's needed for a pure log space. What's needed for basic color correction in a pure log space are offset operations: filters that will shift the R, G, and B values up or down uniformly. And for contrast, you want a linear slope with a 0.5 pivot. Premiere's Brightness & Contrast effect, and the Channel Mixer's Red-Const, Green-Const, and Blue-Const are actually the right idea, except they are only 8-bit and the adjustments are too coarse for an HDR wide-gamut log space. If you want to have a try, here's a little test file that lets you see how operating in YUV space is not equivalent to operating in RGB space: https://www.dropbox.com/s/3aq70zap8tucehm/Gradients.mp4?dl=0 Watch the RGB Parade scope while performing some adjustments to that file.

I'll give SpeedGrade a try and see if it has the right tools.

@balazer

What's needed for basic color correction in a pure log space are offset operations: filters that will shift the R, G, and B values up or down uniformly.

Can After Effects' Color Finesse plug-in do this for you? One trick I use is lowering RGB pedestals in the Highlight band to recover superbright channel data without altering shadow and midtone color balance. I've remained an After Effects fan as I never warmed up to Speedgrade's UI and share rNeil's distrust of Lumetri.

Yes, it's supposed to be a measurable improvement of nearly 2 stops in dynamic range, according to Ilya From HotRod Cameras

@ mrbill, I did a quick comparison and saw about 1 extra stop of DR. 11 to 12. Still awesome.

@LPowell ...

Personally, I love working in Sg ... once I understood what the OFFSET/Gamma/Gain controls of the color wheels there do, and when I like to cut to sliders instead of wheels ... and since my Kensington 2" trackball w/surround ring and four paddles works so nicely with the wheels ... click in a wheel, the ball handles chroma & slider the luma without re-clicking on anything. There's a few things I'd want changed ... AHEM! ... but in all, it's a great start ... and I'm MUCH faster and capable of so much more there than in PrPro or Ae. With any of their tools.

I don't distrust the Lumetri panel/workspace in PrPro at all ... just as always, wanted to know precisely how and in what order it 'works' ... as those things DO matter. So I'm a bit of a techie-type as far as needing to KNOW how things work, but I think in all not nearly so far out as @balazar ... but I'm very grateful to have him here as he tests stuff even out farther than I'm willing to spend time on! Which is way cool ... we all learn from his work.

Yours too, by the by.

@rNeil Thanks for the props, and your info on Lumetri. I respect Speedgrade for those who like its workflow, but despise Adobe's attempts to consumerize its formerly professional tools. (Don't get me started on "Process 2012").

For an Apply LUT plug-in you might find Red Giant's free LUT Buddy useful. I use it in AE to crunch entire adjustment layers into a quick lookup conversion:

https://www.redgiant.com/products/magic-bullet-lut-buddy/

@rNeil That's funny, it seems to work fine in PrPro CS5.5... ;)

@Tjabo, just to clarify that you are correct - zebras can be set up to 100% but they do not function passed 80. I think I confused myself when shooting - thought I was using zebra 1 at 100 but in fact zebra 2 was selected, set at 80 and that does yield good results even though Camera meter may be over exposed a stop or two. I am wondering now where to set the spare zebra for average caucasian Skin Tones? Perhaps around 45 to 50%

I finally had a chance to experiment a little with Vlog, and it seems like a tradeoff of ability to me. The gain is that we get an extra stop of sensitivity at the upper end, which means that if we overexpose by a stop or two, we gain a wider range of sensitivity.

But the loss is that this wider range is compressed into a smaller range of values, and stretching those values across the full range of output means there's a risk of banding-- less so if we're shooting in 10-bit, but I can't afford a 10-bit recorder just yet. So, I didn't see a huge improvement in the Vlog footage, but that may be due to my shooting a basic street scene. I'm not sure if I'll be using the Vlog unless I'm certain I know it's getting me good skin tones.

The LUTs I played with in Premiere Pro were the Alexa LUT that came with PP (Alexa Default Log c2Rec709) and the two Vlog LUTs that Panasonic makes available (Vlog to 709 for v35 and Vlog to 709 Varicam). The Alexa LUT seemed to bring the Vlog footage very close to the footage I shot in Standard mode: the Panasonic LUTs were similar, but didn't bring the darkest areas to black.

Any recommendations for good, clean, basic LUTs to use as a basis for color correction?