SIGMA FP with ProRes RAW and BRAW !

[Llaasseerr]

2 hours ago, kye said:

Are you talking about this one?

I figured that I'd have to learn the false colour standard at some point, but seeing that and realising there is no standard, and that some of these are really very unintuitive, maybe I'd just make my own false-colour LUT and get what I need from that!

Right, there is no standard and having not tested it, I'm not sure how the Atomos false color responds with all these different input log images. I just don't see how it could be reliable. The built-in fp false color is at least designed just for that camera though. 

[Llaasseerr]

On 5/31/2022 at 4:46 PM, OleB said:

For Rec709 and PQ it is true that ISO 800 = ISO 100 in terms of sensor clipping and the metering starts to change only from ISO 800 and upwards.

Native mode and now with the standard V-Log to Rec709 LUT the Ninja measures as from ISO 100 (both waveform and false colors change). However I do not know if this really showing something in regards to real sensor saturation or if it is just showing applied gain. Actually I think it is the later because of the Sigma ISO guide. ISO 100-800 is the same but with different distribution and gain levels.

Will take the measures tomorrow, at least for some key ISO values like 100, 800, 3200. Update to follow.

 

OK i think I know what you mean, you probably explained it before. So there's no difference in the display image between ISO 100 and 800 on the Atomos.

 

For DNGs, ISO 800 just has an increased signal (gain) vs the base ISO 100. So yes, the clipping point is a lot lower on ISO 100, 200, 400 images. It does sound like Native mode is more predictable on the Ninja.

 

Need to still look at your follow-up post with example images.

 

[Andrew Reid]

On 5/31/2022 at 4:50 PM, OleB said:

We are getting really close. The LUT seems to do the trick. There is a minimal difference in highlight brightness (monitor shows 78 IRE, FCPX shows 75 IRE) when imported into FCPX and applying the same LUT as in the monitor. Suppose this is due to the not 100% matching RAW to V-log conversion which is built into FCPX.

ISO values and middle grey seem to work as intended now. Interestingly the brightest part in the picture is only reaching red in the false colors when using ISO 400 and upwards. Seems the maximum steps from middle grey to white are increasing (that reacts as per Sigma ISO manual).

Will investigate further now.

Are you sure it is not just a broadcast safe range clipping problem in the NLE?

[Llaasseerr]

On 6/2/2022 at 8:24 PM, Andrew Reid said:

Are you sure it is not just a broadcast safe range clipping problem in the NLE?

Yes this is worth checking, I had previously mentioned video vs data levels and just needing to establish consistency. Probably easiest check is interpret the clip in the NLE as video levels and see if it then matches the Ninja V.

[OleB]

Any idea how to do that in FCPX? I have no idea how to do it. 😒

[mercer]

4 hours ago, OleB said:

Any idea how to do that in FCPX? I have no idea how to do it. 😒

A simple way to check would be to click on the View drop down menu next to the screen and go to the safe levels and select either Luma, Saturation or All. Then a Zebra-Like image will appear when you're beyond Rec709 safe levels.

[mercer]

With any footage I've ever worked on, it matches FCPX's waveform for 0 or 100 IRE. So it will only tell you if something is off if you compare.

Side note: it's a pretty nifty tool to use when practicing grading by hand/eye with FCPX's basic Color tools. 

[flo]

I love the sigma standard colors for my photos using the sigma lightroom color profile.

Is there a sigma standard color LUT to get a matching look on raw video in resolve ?

I did some looking around but couldnt find anything. This would be a nice starting point in resolve.

 

[OleB]

Have checked, the data itself is not clipping. So everything is there.

However the IRE value for the white patch was my fault. Middle grey is the forth patch, correct. What I did incorrectly is the exposure, it does not have to be green, it has to be grey. Which in fact is around 50 IRE in the Ninja V.

If you do that, the procedure with the LUT would be working. However I do not find the colors to be very pleasing. My way with the custom data to video curve seems to bring me better results. So I have decided that I will stick with the method of monitoring PQ and import it with my presets. Look of both is absolutely identical then. 

Let us see if Sigma will bring a future firmware update to make this a little more streamlined.

[OleB]

This topic seems to be endless the more I put my brain into. Have read through the white paper of ProRes RAW and studied a few more webpages.

Since the fp does not provide a Sigma RAW to Log conversion and no LUT which is fitting that Log back into Rec709, FCPX uses its standard settings. That means it is importing the file without any sort of adjustment (tone mapping) into the color space of the project. In my case usually Rec709. 

Because the Rec709 color space has way less stops of DR (about 6 if I am not mistaken) only the first 6 will be shown, rest will cause the picture to be looking overexposed as they do not fit in there in a linear way. Should be about 6 stops more available out of the fp totaling 12 stops of DR.

This is how FCPX was designed, so that is something we cannot blame Apple for. The correct mapping should have been provided by Sigma.

Seems what I did with my curves is basically a reverse engineered tone mapping. That curve fits the linear DR data of the ProRes RAW file back into Rec709. Additionally taking into consideration a middle grey and the false color steps of the fp in PQ mode.

According to the white paper (we already knew that) RAW is HDR, so it absolutely makes sense to monitor the 10 stops we can see in this setting on the Ninja V to get an as close as possible preview of what the sensor captures.

In regards to ISO, usually ISO is completely irrelevant for the exposure of a RAW file. Only iris opening and shutter angle have an impact. The ISO value in the metadata is just an information telling the NLE what (digital) amplification to apply. But that seems to be true for complete iso invariant sensors only. The fp however seems to apply some analog gain on some ISO settings making it only partly ISO invariant. This is what the Ninja V shows in the false color mode when you turn up the ISO settings.

All in all we are missing that tone mapping stage from Sigma. If I knew how to create a LUT out of these settings there would be possibly the solution to take that LUT onto the Ninja V to grab the RAW data and show a near to final image in Rec709 as well...

 

 

[Llaasseerr]

9 hours ago, OleB said:

This topic seems to be endless the more I put my brain into. Have read through the white paper of ProRes RAW and studied a few more webpages.

Since the fp does not provide a Sigma RAW to Log conversion and no LUT which is fitting that Log back into Rec709, FCPX uses its standard settings. That means it is importing the file without any sort of adjustment (tone mapping) into the color space of the project. In my case usually Rec709. 

Because the Rec709 color space has way less stops of DR (about 6 if I am not mistaken) only the first 6 will be shown, rest will cause the picture to be looking overexposed as they do not fit in there in a linear way. Should be about 6 stops more available out of the fp totaling 12 stops of DR.

This is how FCPX was designed, so that is something we cannot blame Apple for. The correct mapping should have been provided by Sigma.

Seems what I did with my curves is basically a reverse engineered tone mapping. That curve fits the linear DR data of the ProRes RAW file back into Rec709. Additionally taking into consideration a middle grey and the false color steps of the fp in PQ mode.

According to the white paper (we already knew that) RAW is HDR, so it absolutely makes sense to monitor the 10 stops we can see in this setting on the Ninja V to get an as close as possible preview of what the sensor captures.

In regards to ISO, usually ISO is completely irrelevant for the exposure of a RAW file. Only iris opening and shutter angle have an impact. The ISO value in the metadata is just an information telling the NLE what (digital) amplification to apply. But that seems to be true for complete iso invariant sensors only. The fp however seems to apply some analog gain on some ISO settings making it only partly ISO invariant. This is what the Ninja V shows in the false color mode when you turn up the ISO settings.

All in all we are missing that tone mapping stage from Sigma. If I knew how to create a LUT out of these settings there would be possibly the solution to take that LUT onto the Ninja V to grab the RAW data and show a near to final image in Rec709 as well...

 

 

It's worth keeping in mind that ProRes Raw is essentially identical to DNG, but in this case the workflow is confusing because of the apparent unknowns around the Ninja V, and possibly FCPX which is limited in how much you can control the image.

The only real variable between PRR and DNG is that you appear to be having exposure issues with PRR. If I get hold of the camera in the coming weeks I'll see if I can do a test myself.

To be clear, every linear RAW format and every log format is an HDR format. All PQ does is offer a Rec709-like display-referred image, but where the highlights are sent into the brighter part of the high-nit display so they pop more. So it's not any different to a "log to rec709" LUT on an SDR display, except the highlight rolloff is not as aggressive.

If you look at the K1S1 Arri LogC to Rec709 1D s-curve, you can see how aggressively the entire linear raw range of the Alev III sensor (encoded as LogC as an intermediary) is rolled off on the shoulder. If it was LogC to PQ, it would be a less aggressive rolloff with a more steep slope due to the additional headroom of the HDR display.

 

[Llaasseerr]

I should say that even thought DNG and PRR are essentially the same thing except for compression and highlight recovery, the display of the raw images while shooting is what differs. Also, based on your tests, maybe there's some funny business with the ISO interpretation on the Ninja, but nothing that can't be accounted for.

I'd say the only advantage of using PQ on the Ninja V is that it's a quick and easy way to bring the FP raw image into viewable range if you want to check highlights. Or if you wanted to use the same PQ display in FCPX.

But if my V-log theory turns out to be true, where Atomos made the executive decision to encode the raw as V-log for display, then a display LUT can be added on top of that on the Ninja so that a more defined color pipeline can be set up so that the image appears consistent to the look design when monitoring and later when bought into the NLE. That means there would be two levels of non-baked display transforms on the Ninja: raw to V-log, and then a user-applied V-log to display LUT.

 

[OleB]

1 hour ago, Llaasseerr said:

That means there would be two levels of non-baked display transforms on the Ninja: raw to V-log, and then a user-applied V-log to display LUT.

Yes, that should do it. Within my tests with the V-log LUT the biggest pain point was that the highlights cannot be monitored unless you select ISO 800 and upwards. Despite that it looked promising.

Interestingly the very same issue with the PRR files is happening for all cameras which do not have a manufacturer LUT and log conversion available. Like Z Cam for instance.

Atomos has a video on YouTube how to deal with the Z Cam PRR footage and their official way is the same I have used, but with the color wheels for exposure adjustments.

Final Cut is not applying any sort of highlight rolloff, they leave it to the manufacturer of the camera to provide for the camera, or for the user to create it themselves.

2 hours ago, Llaasseerr said:

It's worth keeping in mind that ProRes Raw is essentially identical to DNG

From what I have seen I think they are not in terms of how they handle ISO. cDNG seems to use as well digital applied gain. That is why in the camera all looks good in the newly created internal false colors, but in ISO 800 you can pull back lots of highlights over middle grey. That can only be the case if the camera is still using ISO 100 and after that is underexposing 3 stops to reach ISO 800 and adjust the preview accordingly.

PRR in that respect seems to be 'more' RAW. It only takes the ISO analog gain levels and that ISO setting of the camera per se is only a metadata entry. 

Remember that article you have shared weeks ago from DPreview? The fp seems to have partly ISO variant settings and is pushing and pulling them to reach 'real' ISO values. Would fit the behavior I have noticed perfectly.

Anyway, looking forward to your own results. Agree it is quite complicated to follow up without the camera and possibly the Atomos in hands.

[Llaasseerr]

13 hours ago, OleB said:

Yes, that should do it. Within my tests with the V-log LUT the biggest pain point was that the highlights cannot be monitored unless you select ISO 800 and upwards. Despite that it looked promising.

 

Yeah, I still won't understand this until I see it. Of course I'm operating under the assumption that the naked image might be V-log, but that might be wrong. Originally I thought the Ninja was showing the "OFF" image from the camera, but now I'm not so sure.

So if you don't have the V-log LUT switched on (I assume you mean V-log to Rec709), then the log image, if it is in fact V-log, should show all highlight detail. But maybe the naked image directly into the recorder just is not being displayed as V-log at all and is just the "OFF" profile, meaning "flat-ish", and the display is still clipping the highlights somewhat. Then the PQ preview is the only solution that is readily available.

 

13 hours ago, OleB said:

Interestingly the very same issue with the PRR files is happening for all cameras which do not have a manufacturer LUT and log conversion available. Like Z Cam for instance.

For sure, it makes sense that for some cams that Atomos just decided on adding a default V-log tag to the metadata. Although Z cam does have its own log format so that's surprising.

13 hours ago, OleB said:

Final Cut is not applying any sort of highlight rolloff, they leave it to the manufacturer of the camera to provide for the camera, or for the user to create it themselves.

That sounds correct in that there should not be a decision forced on the user about a generalised way to interpret a raw file. The issue is that most people don't know how to handle the data, so they just start playing with the controls to bring the image in range. However the inspector does seem to offer a number of viable options as to how to transform the raw image to make it instantly usable for most people. The basic thing you have to do with raw data is apply a log transform and then apply a log-to-display transform.

13 hours ago, OleB said:

From what I have seen I think they are not in terms of how they handle ISO.

Right, that's what I meant when I said exposure, but it may be more accurate to say ISO or gain.

13 hours ago, OleB said:

PRR in that respect seems to be 'more' RAW. It only takes the ISO analog gain levels and that ISO setting of the camera per se is only a metadata entry. 

That's not inherent in the PRR file format. Really, we are just talking about choices by Atomos and Sigma as to how much gain to add or not add to an ISO invariant image and there seems to be some difference here for internal DNG vs external PRR. Tbh in this case, neither is ideal. Yes ISO 800 internally is just ISO 100 with +3 stops of gain. Then the Ninja V is doing something as well that is more ISO invariant. But if the underlying ISO is known when you account for the weird "interpretations" and the image is exposed correctly, then at least at a glance the image is pretty much the same. With the caveat of factors like shadow noise levels and highlight clipping point.

13 hours ago, OleB said:

The fp seems to have partly ISO variant settings and is pushing and pulling them to reach 'real' ISO values.

Yes the fp is baking the gain transform in as opposed to an EI approach, which is more what the Ninja is doing. If you look at cameras that shoot with an exposure index mode (EI) like a Sony cine cam, they are just shooting at the base ISO and are not baking in the extra gain, and the exposure difference is just metadata. So that does make more sense professionally.

What is idiosyncratic is that just shooting at the base ISO 100 internally and cranking by +3 stops is not as good as shooting at ISO 800 when accounting for noise floor and highlight clipping point. There is some internal processing beyond just a +3 stop gain increase. So I think I can understand why Atomos decided to start at ISO 800 instead.

I can't remember my findings from 1600+, except that they have diminishing returns with the exception of a slight noise floor advantage for 3200 in some situations because it's the higher base ISO.

 

 

 

 

[OleB]

For those of you who would like to play around a little with my method. I have uploaded my sample PRR file with the sun as ultimate highlight and the preset I have created for exposure correction, highlight rolloff etc. into the following folder. 🙂 

https://www.dropbox.com/sh/cgm80q9w682oc19/AADWHieOS-Wka9JuD-GnXerca?dl=0

All you need is FCPX (trial is available for free). Am very satisfied with the results.

[Llaasseerr]

8 hours ago, OleB said:

For those of you who would like to play around a little with my method. I have uploaded my sample PRR file with the sun as ultimate highlight and the preset I have created for exposure correction, highlight rolloff etc. into the following folder. 🙂 

https://www.dropbox.com/sh/cgm80q9w682oc19/AADWHieOS-Wka9JuD-GnXerca?dl=0

All you need is FCPX (trial is available for free). Am very satisfied with the results.

Thanks for the clip, by way of comparison I rendered it within a basic color managed setup. In this case I decided to ingest the PRR file in Play Pro to V-log/Vgamut based on the included metadata tags. This is assuming that maybe the Ninja V image is just V-log (unconfirmed), so that would create monitoring consistency with the Ninja V.

Since I took this into an ACES-managed imaging pipeline, it would not have really mattered if I exported as Alexa LogC, since I would just use the appropriate input transform for the log/gamut encoding into the common ACES space.

First I have the ACES default rendering for sRGB (good for web viewing). This is just a film print-like transform that is parametrically generated as opposed to being fixed like a LUT, so it's able to account for the output device. Basically, it's similar to an Arri to Rec709 LUT except it's adjustable on the fly for the output device.

If the Ninja V is really showing a V-log image, then you could apply a "V-log to ACES to Rec709" LUT to get the same appearance while shooting.

 

Next I pulled down the exposure by -2 stops so you can see how the output transform handles the rolloff when there are more distinct transitions visible. The underlying exposure transform is on the linear floating point file, and the final look is just a view transform:

 

Now I disabled the output transform so you can see the linear file. This is probably the sort of thing people see in FCPX with no transform applied when they first import their PRR footage, with all the info clipped:

 

This is the same image with -2 stops exposure change so you can see that the highlight detail is in fact there, but it was not in viewing range and with no rolloff to look the way we want:

[OleB]

2 hours ago, Llaasseerr said:

If the Ninja V is really showing a V-log image, then you could apply a "V-log to ACES to Rec709" LUT to get the same appearance while shooting.

Thanks, would try that. Where do I get such a LUT file? 🙂

 

[webrunner5]

1 hour ago, OleB said:

Thanks, would try that. Where do I get such a LUT file? 🙂

 

 

[Llaasseerr]

19 hours ago, OleB said:

Thanks, would try that. Where do I get such a LUT file? 🙂

 

https://community.acescentral.com/t/luts-that-emulate-the-aces-workflow/1334

These were conveniently made available to download, so you would select the V-log LUT. They offer both full (data) range and legal (video) range versions depending on your device. I have a feeling the Ninja V is legal range, so if you use a full range LUT it will look too crunchy and contrasty.

There are "normal" contrast versions which is the default look, which is what I would use if wanting to match the default image when importing into an ACES project in Resolve. There is also a more low contrast version, but I would ignore that since to me, the aim it to get a matching image to Resolve.

You could also throw this LUT on PRR footage transformed to V-log in FCPX and although it would not be a true ACES project, you could see if the footage matches on the Ninja and on your Mac. Also, you have the option of trying the legal vs extended versions of the LUT in case there's a mismatch in how FCPX and the Ninja work. What I mean is, I don't know if internally FCPX works "full" range or "legal" range, or if there's the option to change that like there is on a per-clip basis in Resolve.

It might actually be worth just exporting your timeline to Resolve to grade there 😉

 

[OleB]

On 6/12/2022 at 4:50 PM, Llaasseerr said:

https://community.acescentral.com/t/luts-that-emulate-the-aces-workflow/1334

These were conveniently made available to download, so you would select the V-log LUT. They offer both full (data) range and legal (video) range versions depending on your device. I have a feeling the Ninja V is legal range, so if you use a full range LUT it will look too crunchy and contrasty.

There are "normal" contrast versions which is the default look, which is what I would use if wanting to match the default image when importing into an ACES project in Resolve. There is also a more low contrast version, but I would ignore that since to me, the aim it to get a matching image to Resolve.

You could also throw this LUT on PRR footage transformed to V-log in FCPX and although it would not be a true ACES project, you could see if the footage matches on the Ninja and on your Mac. Also, you have the option of trying the legal vs extended versions of the LUT in case there's a mismatch in how FCPX and the Ninja work. What I mean is, I don't know if internally FCPX works "full" range or "legal" range, or if there's the option to change that like there is on a per-clip basis in Resolve.

It might actually be worth just exporting your timeline to Resolve to grade there 😉

 

Have investigated this further.

Look what I have found in regards to the fp behavior in RAW on the Atomos.

Monitoring of RAW input in:

- Native – Linear to VLog for use with 3D LUTs – can use any existing VLog LOOK LUTs
- Rec709 – to view RAW input in SDR up to 6.7 stops of dynamic range
- HLG – to view RAW in HLG with up 10.5 stops of dynamic range
- PQ – to view RAW in PQ/HDR10 with up to 10.5 stops of dynamic range, for scenes with extended spectral highlights.

Am about 99% sure that the camera is showing Vlog when switched to native.

As far as I understand from the Vlog white paper 90% reflection is located at about 60 IRE, on ISO 100 the fp clips at about 62 IRE. The higher you go with the ISO (up to ISO 800). The more headroom on top is available.

That seems to match the design of Vlog. Panasonic itself writes that Vlog was build to capture the DR of the Varicam, cameras like the GH5 can use the same Vlog but will clip below 100 IRE because of the less DR available.

That means you can use the cameras in one shoot and mix them with the same Vlog look. Have also read that Blackmagic took another approach and always create a log for each camera to use the best DR available.

So yes, it seems that you can get a quite good match with the Vlog and the official Panasonic Vlog Rec709 as LUT on the monitor.

However I am not too sure if this is at least for me a good way of working since I do not know if the next step would be now to figure out the native ISO of the camera for maximum DR in Vlog? S1 or S5 seem to have dual ISO as well with possibly the same sensor, but min ISO would be 640...Cannot imagine that with the fp you can set it to ISO 100 and get good results with Vlog? Or am I getting something wrong now?

For now I prefer the manual colorspace matching in FCPX directly from the untouched linear RAW, which gives me great results. And with the PQ view in the monitor I can get a really good idea on how the picture will look like.