SIGMA FP with ProRes RAW and BRAW !

[Anaconda_]

Looks like Braw isn't far off as Blackmagic just updated their SDK:

Quote

 

https://www.blackmagicdesign.com/support/readme/75e7ddc4486e44579691ca11e6038f1f

What's new in Blackmagic RAW 1.8

Added support for Sigma fp Blackmagic RAW clips captured by Blackmagic Video Assist.

 

This is only the software side, so once you've recorded the clips. I guess in the next few days they'll release the Video Assist update to allow the recording.

[kuau]

FYI Blackmagic just released Blackmagic Video Assist 3.2 Update which now supports RAW recording from the SigmaFP 

[bjohn]

I am really looking forward to seeing some BRAW footage shot with the fp.  You can apply generation 5 color science to it now as well.

[Llaasseerr]

Just checking in on this thread because I'm still intrigued by this camera. There are two workflows of interest: shooting raw internally or externally. Obviously internally is preferable, but accurate monitoring is an issue. The Digital Bolex solved this so simply by just outputting a known log version over HDMI of the raw image recorded internally. That is all Sigma would have to do.

And when I say log, I also mean wide gamut - Rec2020 in this case. Digital Bolex supported this with a white paper in the same way that Arri, Fuji, Sony et al do. If the D16 was still getting firmware updates, then by this point we would probably see it outputting an even more accurate image over HDMI based on further spectral analysis of the CCD sensor, and it would be in Alexa LogC/AWG for further workflow compatibility.

Without any technical details, the "none" profile on this camera looks like it's just in the original wide gamut and maybe with no S-curve applied for highlight rolloff, and that's the only difference. Luminance-wise, it still clearly is gamma corrected to Rec709 and that means the highlights are clipped since a linear raw image holds a lot more range than Rec709, which is normalized to 0-1. That's why Rec709 custom display curves by individual camera companies have highlight rolloff baked in to hold the dynamic range. So it's pretty much useless for monitoring highlights, but you could at least use it for checking exposing middle grey with false color. Does it have false color in the new firmware update?

That's not to say people aren't getting great results anyway, but it just puts this camera more in the enthusiast category. We are now at the point where people are busting out rather arcane, complex color transform combos in Resolve but none of these are an actual simple, technically accurate workflow.

As for how to handle the DNG frames in Resolve, I personally just use ACES since the Resolve IDT does a decent job of interpreting the DNG matrix metadata and delivering a consistent result with what I saw monitoring on set. It's a decent solution when you don't have a specific IDT based on spectral analysis of the camera sensor. You just need to think of ACES on one level as being the biggest and most convenient bucket for capturing the dynamic range and wide gamut of the raw image. It maps it to RGB as linear floating point wide gamut at the correct exposure and displays it in a meaningful way. If you wanted, you could then transform ACES to AlexaLogC/AWG and render ProRes, then work in any Alexa log workflow.

The other option is to use an external raw recorder, either BRAW or ProRes raw. I don't know anything about these workflows. For example, how do you monitor ProRes Raw on a Ninja V? Is there a way of displaying it as a known log image then you can put your own LUT on top? Can you do that with BRAW and a BMD monitor? 

 

 

[Llaasseerr]

If Fuji released an XT-5 or XH-2 with ProRes raw recording that also allowed monitoring in F-log, then that would cover a lot of what the fp should do. But you would still need the external Ninja V recorder.

Does anyone know any more about recording with the director's viewfinder? I love the industrial design and the minimalism of the fp, as well as the internal raw option. Not sure if I've already stated it, but they should add true 24p and 2k DCI raw internal recording. The X-T3 has 2K DCI which is pretty neat, but of course it's crappy 4:2:0 chroma compressed. If you look at the U and V channels they are just garbage and it really affects even minor grading with qualifiers in Resolve.

It would be great if a future Sigma video camera uses a Foveon sensor and also sorts out some of these remaining workflow issues.

[rawshooter]

44 minutes ago, Llaasseerr said:

Without any technical details, the "none" profile on this camera looks like it's just in the original wide gamut and maybe with no S-curve applied for highlight rolloff, and that's the only difference. Luminance-wise, it still clearly is gamma corrected to Rec709 and that means the highlights are clipped since a linear raw image holds a lot more range than Rec709, which is normalized to 0-1. That's why Rec709 custom display curves by individual camera companies have highlight rolloff baked in to hold the dynamic range. So it's pretty much useless for monitoring highlights, but you could at least use it for checking exposing middle grey with false color. Does it have false color in the new firmware update?

Unfortunately not.

There's currently no way of getting correct exposure indication from the camera except when you shoot at ISO100 (the camera's first native ISO). There, the clipping indicators (zebras and waveform monitor) are reliable for RAW, too, even when using standard color profiles.

People are still looking into the question whether external RAW recording (BRAW with a BM Video Assist 12G HDR or ProRes RAW with an Atomos Ninja V) will yield correct external exposure metering as a welcome side-effect. (But then again, there's the problem of BRAW not really being an [undebayered] RAW signal, and ProRes RAW not being supported in Resolve and lacking standard RAW controls in all other programs except Assimilate Scratch.)

 

[rawshooter]

35 minutes ago, Llaasseerr said:

If Fuji released an XT-5 or XH-2 with ProRes raw recording that also allowed monitoring in F-log, then that would cover a lot of what the fp should do.

That's unlikely to ever happen, since the Fuji cameras have X-Trans sensors, and no video software supports X-Trans debayering. As far as I know, ProRes Raw doesn't support X-Trans either.

[Llaasseerr]

10 minutes ago, rawshooter said:

That's unlikely to ever happen, since the Fuji cameras have X-Trans sensors, and no video software supports X-Trans debayering. As far as I know, ProRes Raw doesn't support X-Trans either.

Good point.

[Llaasseerr]

14 minutes ago, rawshooter said:

Unfortunately not.

There's currently no way of getting correct exposure indication from the camera except when you shoot at ISO100 (the camera's first native ISO). There, the clipping indicators (zebras and waveform monitor) are reliable for RAW, too, even when using standard color profiles.

People are still looking into the question whether external RAW recording (BRAW with a BM Video Assist 12G HDR or ProRes RAW with an Atomos Ninja V) will yield correct external exposure metering as a welcome side-effect. (But then again, there's the problem of BRAW not really being an [undebayered] RAW signal, and ProRes RAW not being supported in Resolve and lacking standard RAW controls in all other programs except Assimilate Scratch.)

 

Assuming you shoot with a grey card in your preroll, the easiest workaround is probably to shoot in the "none" mode and just add a cheap external monitor with false color, and adjust exposure to land on that. Which is annoying because it's more bulk, so hopefully Sigma will add false color in the next firmware update.  I mean I'm happy to shoot with a light meter, but if you're using a consumer level vari ND then it gets a bit more complex figuring out how many stops you're going down so it's easy to dial it in with false color mode pointed at a grey card.

I've accepted that the solution shooting external ProRes raw involves an ingest step through FCP before moving to your preferred editor. I'm not so concerned about lack of standard raw controls in some software, because these are just basic rgb multipliers that can be done in the grading environment as long as you are either in either linear or ACEScc log space. 

[Llaasseerr]

22 minutes ago, rawshooter said:

That's unlikely to ever happen, since the Fuji cameras have X-Trans sensors, and no video software supports X-Trans debayering. As far as I know, ProRes Raw doesn't support X-Trans either.

Well actually,  thinking about it again it should be trivial to just add an X-Trans debayer after the raw data has been saved as ProRes raw. It would just be a tweak to the display debayer on the Ninja V, I would imagine.  Something like a firmware update. Totally guessing, but if there's a flag in the raw stream, then it would tell the Ninja V to display with an alternative debayer method. Once it's on the computer there shouldn't be any constraints in software as to how bayered raw data is debayered. I just imagine they could add the X-Trans method the same way Lightroom does.

[Llaasseerr]

Decided to drill down a bit further on the Ninja V ProRes raw capabilities, and I found a video on setting it up for the ZCam. This link starts on a frame showing the raw display settings and it seems very comprehensive and flexible, offering choice with log/hdr, gamut, etc. At least I think so.

From 2:16.

If that's the case with the fp, that would be awesome. But it would be great to tighten up the internal raw options too.

As far as internal recording, I have an old Ikan VL35 3.5" monitor with 4k HDMI input that has false colour. This could be a great somewhat unobtrusive monitor to attach to the camera to do exposure checks, in I guess, the "none" mode, but probably any relatively neutral Rec709 mode would be okay. I'd be interested if current owners think this could be a good solution.

 

[rawshooter]

3 hours ago, Llaasseerr said:

Assuming you shoot with a grey card in your preroll, the easiest workaround is probably to shoot in the "none" mode and just add a cheap external monitor with false color, and adjust exposure to land on that. Which is annoying because it's more bulk, so hopefully Sigma will add false color in the next firmware update.  

This won't help because the video on the display (no matter whether internal or external) will be overexposed while the footage isn't. And a light meter and grey card are not really good for metering raw sensor exposure.  The only workaround I see at the moment is to use an external HDMI monitor with user-uploadable LUTs, build a LUT that pushes the Rec709 picture into two stops underexpose, and rely on the monitor's zebras. But this will only work in ISO 3200.

I think you're mistaken about the "none" mode. It is just a flatter Rec709 mode, with the same false exposure indication above ISO100 as all other color profiles of the camera.

[Llaasseerr]

28 minutes ago, rawshooter said:

This won't help because the video on the display (no matter whether internal or external) will be overexposed while the footage isn't. And a light meter and grey card are not really good for metering raw sensor exposure.  The only workaround I see at the moment is to use an external HDMI monitor with user-uploadable LUTs, build a LUT that pushes the Rec709 picture into two stops underexpose, and rely on the monitor's zebras. But this will only work in ISO 3200.

I think you're mistaken about the "none" mode. It is just a flatter Rec709 mode, with the same false exposure indication above ISO100 as all other color profiles of the camera.

For sure, I can't say without having the camera to mess around with. But I just did a quick test in Nuke with a few frames of the  "none" mode.  Unfortunately it's displaying very dark in the browser, but in Nuke it's displaying correctly.

EDIT: I forgot to apply the sRGB output transform to the two darker images which is why they look too dark, I'll upload the corrected versions. But the image of the girl is correct.

Basically what they seem to have done is mapped the raw gamma 1.0 footage to Rec.709 gamma and called it a day, which is what I suspected. So anything outside of a nominal 0-1 range is getting clipped. They also left it in the native Rec2020-ish gamut which is fine. But that doesn't mean it can't be used with false color because most false color is I believe set up for rec709, and often you can adjust false color bands based on IRE levels. So if it doesn't work, you just need to do some tests and set it up. Without the camera, I can't say though.

For example, I monitor F-log by applying an F-log to ACES Rec709 LUT and then I can use false color to confirm that I'm hitting 18% grey exposure, and it matches a light meter reading as an additional sanity check.

Whether that would work for this camera and a particular monitor with false color would need to be checked. But I also monitor DNG raw from a Digital Bolex by monitoring the Bolex log signal in the same way, and that matches the DNG to ACES image in Resolve later. Again, with the lightmeter sanity check. As long as you know the colour transform path, this should be totally doable.

 

 

[rawshooter]

I think we're talking past each other. I'm referring to something else: The camera, in RAW, is ISO-invariant between ISO 100 and 2500, and from 3200 and above (the two native ISOs). So, clipping indicators for everything below ISO 3200 shouldn't change  - but they do, because they meter Rec709 exposure with software gain applied instead of raw sensor exposure.

Same happens at ISO 3200 - it's metering Rec709 gain, not the native ISO. And if you switch to ISO 6400, the camera will say that you're clipping one stop over ISO 3200 although this is factually not the case. This on top of ISO 3200 metering being incorrect re: raw sensor exposure.

"Profile off" doesn't change any of that behavior.

[Llaasseerr]

I see, so you're using the clipping indicators with the attendant issues you describe.

What I'm saying and I've mentioned a few months ago is don't use them, IMO they are useless and you're saying they are misleading you anyway. It's a DSLR thing. Use false color to expose 15% grey. Have faith (and do some tests) there is enough range in the raw image to check clipping. I mean babysitting highlight clipping is admittedly always a battle unless you are shooting on Alexa or film. 

Yes it would be good if there was a better indicator of the sensor clipping point. I mentioned the D16 has a raw b+w display mode that is just the bayer sensor and you can easily see if it's clipping if you need to protect your highlights. 

Another way of doing this with log, is on the monitor you have your log to rec709 dailies LUT and you can quite easily see whether the image is clipping vs nicely rolling off. But that's not possible with this camera unfortunately.

 

[Chris Whitten]

Another thread was created a while ago for a deep dive into FP colour management and codecs:

I think it was felt (not me by the way) that the Sigma FP thread was descending into microscopic detail rather than a general discussion of the camera in this thread.

I'm not a professional cinematographer or delivering content to a public broadcaster other than Instagram and Youtube, however I've shot a lot of CDNG on the FP inside and out and have yet to find a problem with the exposure. I've tried several different processes in Resolve and they mostly end up with pleasing looking footage, without any obvious colour shift, artefacts or issues. You can process this CDNG very quickly and get fantastic results.

That's not to say those with a technical eye or who are doing this full time shouldn't look for best practices. just the tone this thread is again taking is that the FP has serious issues that are at the moment not solvable. 

personally I think it's very forgiving and pretty easy to use.

 

 

[TiiPii]

This is what we know about the effect of color mode None from the firmware 2.0 video:

 

Also the following is good info to keep in the back of ones head:

 

[TiiPii]

It is interesting to see from the ISO dynamic range chart that Sigma decided to rate this camera as ISO 100, which I feel is very much a "photography" thing to do rather than cinema approach where the more appropriate rating, perhaps, would've been ISO 800 or even higher like ISO 1000, to get that 18% grey into the middle range. But it's great they released that chart so we have this info now.

 

[rawshooter]

9 hours ago, Llaasseerr said:

I see, so you're using the clipping indicators with the attendant issues you describe.

What I'm saying and I've mentioned a few months ago is don't use them, IMO they are useless and you're saying they are misleading you anyway. It's a DSLR thing. Use false color to expose 15% grey.

 

The problem is that at no ISO except 100, the camera will correctly meter 15% grey... There is no internal false color, but even the external false color of a field monitor will be wrong because the camera sends out an HDMI signal with gain baked in on all ISOs except ISO 100. So the only workaround would be a monitor LUT that reverses that baked-in gain...

[Chris Whitten]

3 hours ago, rawshooter said:

The problem is that at no ISO except 100, the camera will correctly meter 15% grey... 

What about 3200?