ahalpert
Major Contributor
I'd love to, as I'm sure many others would. Please drop a link!
Other: Is Your Sony FX6 Soft?
- Thread starter Joshua Milligan
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I'd love to, as I'm sure many others would. Please drop a link!
Doug Jensen
Veteran
I'd like to get your input first before making them public. What if they suck? I'll try to send you a link to tomorrow after I export a final version.
drboffa
Well-known member
I basically use one of two LUTs for everything. Alister Chapman's LUTs or the Phantom LUTs. Those links should take you directly to each.
In Resolve it's easy to make different versions of a grade within the same timeline, so generally I'll try out both of these and decide which gives me a better starting point (toggling back and forth to compare). I'll then grade underneath the LUT (as you do with your exposure pull before the LUT in FCP) to get the look I want.
The really nice thing about Alister's LUTs is the inclusion of exposure offsets, which I find does a better job bringing up exposure than just doing a straightforward exposure lift.
To my memory, I've never used the Sony LUT in a project.
ahalpert
Major Contributor
ahalpert
Major Contributor
I'll check those out. Does that mean you don't like the Sony LUT or that you've never played with it?
Also I remember someone, maybe Doug, saying that slog3 is designed so that you can make exposure changes to it before using the LUT and that Alister's exposure shift LUTs are a little unnecessary. Maybe they work even better than using an exposure shift + a LUT, but that's what I always do.
And out of curiosity, are you saying that you only grade before the LUT and not after? I would assume that you would do at least your secondary corrections after the LUT, but I was a little confused by the wording you used.
drboffa
Well-known member
I've played with the Sony LUTs a bit, but I wasn't wild about the results. I think there are several, if I'm not mistaken. They were fine, but once I got the Alister Chapman LUTs (back when I was using the Fs5) I basically settled on them. The Fs5 really needed 1 to 1.5 stops of overexposure (compared to Sony's "correct" exposure) so having the offset LUTs for monitoring and grading was key. It's only recently that I've started to use the Phantom LUTs more and more.
As for exposure shifts: yes, I've definitely found that exposure shifts pre LUT are generally fine with slog3. That's my normal workflow. But in my experience Alister's LUTs really shine when you're doing a dramatic exposure shift: e.g., you need to pull something back from 2 stops under, or similar. Those use cases are rare, but they do happen. E.g., recently I was filming a super 8 projector and wanted to keep the detail in the projected image, which meant exposing for that (which meant the rest of the scene was heavily underexposed). With Alister's LUT I got a better result pulling the underexposed areas up to make them visible and then I could use a power window to keep the projected image viewable (if that makes sense). I tried doing it manually a variety of ways and nothing working quite as well as Alister's LUT.
In general, my secondaries are also pre-LUT. I don't know if that's better or worse that doing them after the LUT but I find it works for what I do in most scenarios. I'll occasionally just use a LUT across the whole timeline (in Resolve you can apply corrections at the clip level or the timeline level) if everything was shot on the same camera. In those instances you're always working under the LUT, since the timeline nodes are applied after the clip nodes.
Doug Jensen
Veteran
Yes, that was me. I do not think it is necessary to have different LUTs for different exposures. If that was the case, everyone who makes LUTs would also provide several variations of every LUT they make. But they don't. I'm not saying Alister's approach is wrong, just unnecessary in Resolve. Perhaps it is helpful if you're trying to grade in an NLE that doesn't have the same controls as Resolve. In Resolve, Node 1 is for exposure adjust only. Node 2 is the LUT. And all subsequent nodes are where all the creative stuff happens. I don't do anything pre-LUT except to fine-tine the exposure, which hopefully is pretty darn close already if I have been doing my job correctly while shooting.
Did Alister ever post any split-screen examples that demonstrate using his off-set LUTs versus using Node 1 for exposure adjustment? If so, I'd love to see it. If not, why?
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ahalpert
Major Contributor
Sony does have several LUTs, or that least they did or they do somewhere. But when you go to the main LUT page, they just have 1 for slog2 and 1 for slog3
https://pro.sony/ue_US/support-resources/software/00263050
in terms of correcting hues before the LUT, i would have thought this made more sense after the LUT because of working with the colors after the gamut correction. But if it works, it works.
In FCP, I can do something similar to a timeline correction by using an adjustment layer across the entire project. Not as elegant a solution, but useful for a 1-pass grade and I can tweak clips underneath as you do, or cut it off a shot where it just doesn't work
drboffa
Well-known member
Conversely, I was under the impression that you want to work in the largest color space possible—i.e., sgamut3 or sgamut3.cine, assuming you shot slog3 in the normal way—when doing corrections, rather than in the smaller Rec.709 color space.
But, I am not a full-time professional colorist, even if I do a fair amount of color work.
I might have some test footage of under/overexposure that I can dig up. If so, I'll see if I can do a quick comparison of Alister's offset LUTs versus a straightforward exposure adjustment.
Doug Jensen
Veteran
I suggest using the "offset" control for the exposure adjustment as it affects lift/gain/gamma fairly equally across the board.
drboffa
Well-known member
Okay, here are some stills showing Alister's offset LUT vs various exposure corrections. There are four stills in all: one is the exposure offset LUT (+2.5 to correct for "underexposure"); the other three are the neutral LUT with different manual exposure corrections. The only other correction is a WB node underneath the LUT.
The images, in order:
1) Alister +2.5 LUT
2) OFFSET only (raising offset until the white card IRE values match those in the correction LUT image)
3) CURVE only (dragging the top of the curve until the white card IRE values match those in the correction LUT image; essentially a "gain" correction)
4) CUSTOM CURVE (trying to match the white card and the rest of the image via a custom curve)
I think my custom curve gets pretty close, but the extra effort (when I have the correction LUT) doesn't seem worth it.
Also Alister's LUTs seem to perform even better as the underexposure gets worse. These are *not* ideal scenarios, nor is it what he likely intended them for. But sometimes we have footage that needs to be rescued. So here is severely underexposed footage with his +3 correction LUT and then my effort at a custom exposure recovery (with his neutral LUT). To my eye, Alister's LUT does a much better job, and with less effort.
The images, in order:
1) Alister +2.5 LUT
2) OFFSET only (raising offset until the white card IRE values match those in the correction LUT image)
3) CURVE only (dragging the top of the curve until the white card IRE values match those in the correction LUT image; essentially a "gain" correction)
4) CUSTOM CURVE (trying to match the white card and the rest of the image via a custom curve)
I think my custom curve gets pretty close, but the extra effort (when I have the correction LUT) doesn't seem worth it.
Also Alister's LUTs seem to perform even better as the underexposure gets worse. These are *not* ideal scenarios, nor is it what he likely intended them for. But sometimes we have footage that needs to be rescued. So here is severely underexposed footage with his +3 correction LUT and then my effort at a custom exposure recovery (with his neutral LUT). To my eye, Alister's LUT does a much better job, and with less effort.
Doug Jensen
Veteran
I agree with this statement. And that makes total sense, I would never expect any LUT to do all the work. It just gets you in the ballpark and then you have to finish from there -- which is what you did. Although 1 looks a little better than 2 and 3, I remain skeptical that offset LUTs are necessary.
Thanks for doing the tests.
ahalpert
Major Contributor
Drboffa, could I trouble you to post a still from the uncorrected footage? I agree that the Alister offset LUT looks best there.
I was going to raise a question about manipulating color values on the 1st node that don't represent the final color (because they're going to be subjected to a 3D LUT). But actually, it looks like sgamut3.cine is supposed to give us "natural color reproduction with minimum grading needed in comparison to SGamut3." So, I guess that if you're grading beneath the LUT and you take the reds and push them in the green direction, you're actually taking the reds and pushing them towards green. (Rather than pushing the magentas towards cyan or something like that.) So it makes sense that your approach would work and I can see the merit of making those manipulations before the LUT has been applied. I'll have to try it.
https:/us.community.sony.com/s/question/0D50B00004YTYIdSAP/sgamut3-vs-sgamut3cine?language=en_US
I was going to raise a question about manipulating color values on the 1st node that don't represent the final color (because they're going to be subjected to a 3D LUT). But actually, it looks like sgamut3.cine is supposed to give us "natural color reproduction with minimum grading needed in comparison to SGamut3." So, I guess that if you're grading beneath the LUT and you take the reds and push them in the green direction, you're actually taking the reds and pushing them towards green. (Rather than pushing the magentas towards cyan or something like that.) So it makes sense that your approach would work and I can see the merit of making those manipulations before the LUT has been applied. I'll have to try it.
https:/us.community.sony.com/s/question/0D50B00004YTYIdSAP/sgamut3-vs-sgamut3cine?language=en_US
drboffa
Well-known member
Happy to do so.
Here is the uncorrected footage from the first four stills:
And here is the uncorrected footage from the latter two stills (significantly more underexposed):
And yes, Doug, I'm not sure offset LUTs are entirely necessary either. I think this is even more true with the better images coming out of the latest generation of Sony cameras. But I find they're a nice tool to have, and generally I'll take whatever works to make my footage look better or my workflow easier.
I did 14 bit raw and 16 bit tiff and 8 bit jpeg files in photoshop before. 8 bit jpeg is seriously limited comparing to the first two, although jpeg itself can change color a lot with many layers. I got the impression that raw and tiff are miles better than jpeg, by pure hands on experience and feeling.