FS7: A million dumb basic questions about LUTs

L

LennyLevy

Veteran
I am finally doing some long overdue color correction of stuff I shot for a client whose editor will be working in Premiere Pro.
Right now I'm making the window dubs and using that task as an excuse to experiment with the overall color correction and I'm just getting my feet wet in both Premiere and Resolve and comparing the workflows.

I shot on the FS7 in Slog3 at EI's ranging from 800-1250 and labelled each scene and shot color charts.
I've got a ton of LUT's on my desktop by Alister Chapman and Art Adams for basic SLOG3 to 709 correction at different EI's and made some of my own in LUTCalc to do the same thing using a target gamma of both LC709A and also the Art Adams recommended Varicam 709.
I prefer to use the Varicam gamma LUT's in camera as they have a bit more punch and it all looked great on monitors while shooting.

When I look at the footage in Catalyst Browse with the LC709A LUT everything looks pretty great and exactly as I expect. I have to correct the exposure for EI 800 or 1250 but then the picture looks pretty nice right away without much additional fussing. .

However I'm not having the same luck with Premiere or Resolve. So here are my questions:

1 - In Premiere/Lumetri the Lut's I've made (or downloaded from Alister and Art) that are supposedly adjusted for 800 -1250 ISO look way too dark. The best looking ones out of the gate seem to be closer to EI 1500 or native 2000 LUT's.

Even when I get a LUT that looks correct for basic exposure it looks very flat, the whites are between 80 and 90 and the blacks are high also. I have to make major adjustments to get a decent contrast range and need to add saturation as well. I expected that my LUT should get me much closer. Just looks like a mismatch.

2 - When I try the same LUT's in Resolve ( the new 14) I have the same exposure issues. The adjusted LUT's for lower EI's ( higher exposures) look quite dark, but now the Luts are too punchy and contrasty and i need to tone them down the opposite way.

I seem to remember that you need to make different LUT's for Resolve and Lumetri but can't remember why. In the LUTCalc version I was using (3.1) the Resolve and Lumetri settings looked the same.

- Another Resolve question - what do the "Log color wheels do vs the standard ones?

3 - This is a side issue but when I imported directly from XAVC-I MXF camera files into Resolve i didn't get any audio. Do they need to be transcoded to roses or something else first or am I missing a setting?

I know I will have other questions, but this is a good start. Please don't be too harsh on me for waiting 2 years with this camera to work out the basics.
 
Len

First I recommend resolve if you can do a workflow that works with your clients.

The log wheel work on a tighter range of tonal range.. Ie the shadow wheel works just on the low values.

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I wonder if you should throw all your luts away apart from the standard lc-709 lut and just gain confidence throwing the image around - it sounds like you are in a bit of a tangle with so many luts

To some extent ei compensation luts are useful on set or if a client is grading to show them your intent - particularly to show clients you have not "over exposed everything"

The more competent you are the less you will need them. You can also store your looks by grabbing stills - even project to project.
 
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The audio should be fine in resolve.

You should also be able to..

Media pool
Select all clips
Clip attributes
Audio
Channels = 2

This will get rid of 6 empty tracks clogging your timeline
 
Thanks Morgan,

According to Alister Chapman the log adjusted LUT's were essential for grading to get the LUT matched to your exposure. I still don't get why they are so off & why they are different on Resolve vs Lumetri.

I think I will need to do a rough version in Lumetri/PP so the editor has good material to cut with. For the final I'll probably go to Resolve. I need to learn both anyway and this is my excuse. I never learn a damn thing without a job.

My impression was that in resolve you used the Log wheel o adjust your values before the LUT and then you could use the other wheels after LUT but I might be making that up altogether.
 
M and S on the time line - m = mute?

There are other icons near the Picture box you can mute the sound.

I find the audio iconography a little confusing.

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Resolve is 32 float so use of the diffenret wheels on diffenert modes may help but is not critical.

Gain confidence throwing everything around.

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I resolve nothing is "essential" but compensated luts may be handy in premier to get in the park for clients - working that workflow is an art.
 
fixed the audio , combination of the Mute on in the window and turning preferences IO to use system audio. Still confused about LUT's though.
 
A lut transposes some values to other values by Looking Up the the new values on a Table of values.

There is a lot of voodoo written and cra-ppy luts bogging the Internet

Id personally scrap them all but the one issued by Sony. Gain confidence at throwing the image around and maybe them revisit other luts and see if you find a use for them.
 
The only LUTs I have good results with in Resolve are those provided by Jacob Balazer, the proponent of his Logarist workflow (read about the workflow here: www.logarist.com). Other than that, I'm using RCM as this gives me straightforward path to HDR10 grading (BTW, Jacob has provided me with PQ output LUTs which also enable HDR10 rendering).

Piotr
 
Not quite to your question, but I've had fair success with the Film Convert plug-in. It has a camera profile specific to the FS7 and really seems to bring out the codec's potential. It has a decent color control panel, and of course, allows you to apply simulated film looks to your taste. The default KD 5207 Vis3 is a nice look to start with. If you shop around, you can usually find a 30% off coupon somewhere around NAB time and when Rode Reel has their annual. I agree that Logarist is a helpful tool for primary color correction.
 
Well so far I've been having better luck with Premiere/Lumetri. I experimented with LUTCalc and made LUT's at different exposures each with different versions of Data and Legal In/out. it seemed that if I set the LUT for Data In (109%) Legal Out (100%) I got the best range out of the LUT's and have been having good luck using exposure adjusted LUT's whose ISO (as made by LUTCalc) is a little higher than the way I shot it. Sometimes I still need to adjust range and the levels but its a lot better than where i started which was Data In Data Out. I don't quite understand what that all means but its working OK and color only needs slight correction if at all. I'll try Resolve next but I suspect I'll need to use a different blend of the LUT Calc adjustments.
CameramanBen actually suggested that you should experiment with those parameters for Lumetri, as he wasn't sure what worked best.
 
To me all my pipeline is organised around PP (don't want resolve in the pipeline time saver) and i didn't see any différences beetween catalyst or PP in image quality or colors, i use Kojicolor luts with lumetri color to affect lut. My sequence in PP is setup to quality and resolution maximum in vidéo preview tab (very important to have maxi bits depth, the three boxes must be checked). In lumetri color i use creative tab to apply lut, like that i can choose how many % the lut is applied on my rushes. I would like to see image exemple to show me quality differance between PP and resolve, i still very curious. I work on Fs7 4k 50P slog3 CineEI@800iso.
 
I'd highly recommend renting Doug Jensen's piece on grading with Davinci Resolve:

https://vimeo.com/ondemand/resolve/186323074

I did, and it was very very useful with regard to answering your questions.

Also, if you can afford it on the right upcoming project, I would highly recommend finding a good colorist, paying him/her for your time, and going the extra mile with your footage. I just did that after attempting to grade my own footage and boy was I wowwed by the work this gentleman did for me. The guy I worked with has been doing color work for decades and he just made my footage look beautiful! He pulled ever bit of wonderfulness that he could out of it and I'm so grateful for his skills and talents.

A final note...I've noticed that different software handles the way footage looks differently. For example, I do all of my editing in Avid Media Composer, but have done some grading in Resolve on my own. I've noticed that Resolve does a much better job of displaying color and contrast range even on my computer monitors than the Avid does. And...this is when the same video is displayed on the same Dell Ultrasharp monitors from Resolve vs. Avid. So...something is going on under the hood that I haven't taken the time to figure out yet. So...when you say that it looks different from one tool to the next, it makes me wonder what might be going on underneath the hood. Just a thought!
 
Yea Dougs got some great stuff out. I'm wanting to buy his FS7 Masterclass but $70 is still steep for me. I might do his course on Davinci soon thoigh
 
I do encourage you to try Logarist. It's made for exactly this problem. You can do all of the color correction right inside Premiere with the Logarist plugin and Lumetri.

 
Thanks for all the input folks.
Re Logarist, I just looked at the video and am not sure why this would be any better than using the far more precise controls in Lumetri which I'm quite comfortable with. Perhaps you like its LUt's more than the other available LUT's ?
 
Lenny,

If I didn't know better I would say that the discrepancy you're experiencing is somehow linked to how lumetri is seeing the levels of your file, or the LUTs you downloaded were not made properly for full range signals like slog3.

For testing you can just use the Sony slog3 3D LUTS built into DaVinci Resolve and it should look like your image did in Catalyst. You can also download Sony's 3D LUTS (exact same ones in Catalyst) directly from Sony's website. I have a copy of the slog3.sgamut 3D LUTs on my server here. In DaVinci when you add a clip to your media pool, right click on it and select clip attributes, and set it to DATA LEVELS. If you set it to VIDEO LEVELS you will see the image gain lots of contrast, that is fine if you want to grade manually like that, but VIDEO LEVELS will not work for most 3D LUTS so be sure to switch to DATA LEVELS. Give it a try, I'm curious.


Regarding logarist, without being able to adjust black, mid, and white points for R G B channels you can't really even begin to color correct an image. You'd be far better off adding curves filter and fast color corrector. For basic color correction those are the only 2 filters you really need if you want to keep it in Premiere.
 
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Logarist mimics the basic controls that you get inside your camera or in a raw processor. You start with exposure, white balance, and contrast. I know that sounds simple and ordinary, but in Logarist these controls work better than anything built into Premiere. So you won't often need to resort to adjustment of the black, mid, or white points of the red, green, and blue channels. But if you want to do that after primary color correction, you absolutely can. If you've spent a lot of time working with raw images, you'll appreciate how this helps you get colors that look right with less effort. The more correction your video needs, the bigger the difference it makes. Not all of us are DPs who can get things almost perfect in the camera.
 
Dennis, i hope to get to Resolve later in the week, but I did just check out the Sony made Slog3>709A plus Alister Chapman's and I definitely got better results with the ones I made in LUTCalc Date > Legal and with very little tweaking to just up the contrast a bit they looked very good. The odd thing was that I needed 1250 ISO Luts for stuff I exposed at 800ISO. I would first question whether my exposures were correct but in Catalyst Browse my ISO numbers were right on the button.. I have read somewhere that Lumetri and Resolve seem to need LUTs with different outputs but why is beyond me.

Been quite happy with preliminary results so far in Lumetri and with the range of tools available . Once i got my LUT's straight 5 days of shooting required very little basic correction . Of course I tweak the hell out of every detail anyway.

Here's a question though:

Do you guys commonly add a touch of sharpening after shooting with Slog?

Thanks again for all the input. I will give Logarist a try
 
I certainly sharpen.

It would be considered "normal" to do this when there is no sharpening in camera.

You should sharpen at the delivery resolution.
 
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