SIGMA FP with ProRes RAW and BRAW !

[Ryan Earl]

6 hours ago, Owlgreen said:

Thank you OleB and Ryan. 

I'm curious why it is not advisable to use a similar workflow but to substitute Blackmagic Design colorspace instead of P30 D60. 

What I understand is that the Blackmagic Design Color Space and Blackmagic Film Gamma was specific to Blackmagic's cameras like the original Blackmagic Cinema Camera and URSA 4.6K.  The conversion will be inaccurate but some users have found it pleasing or workable.  I personally compared the DNGs as P3 D60 and Linear to the URSA 4.6K in Blackmagic and found the colors to be more accurate with a transform to REC709 and with the tone mapping tool better access to the highlights from the Sigma. 

I think as the Sigma happened to use DNG people just started using the Blackmagic gamma because it gave you an instant log to grade but since Sigma had not given a log profile for it, it's linear, then it's most appropriate to transform from linear. 

[TomTheDP]

2 minutes ago, Ryan Earl said:

What I understand is that the Blackmagic Design Color Space and Blackmagic Film Gamma was specific to Blackmagic's cameras like the original Blackmagic Cinema Camera and URSA 4.6K.  The conversion will be inaccurate but some users have found it pleasing or workable.  I personally compared the DNGs as P3 D60 and Linear to the URSA 4.6K in Blackmagic and found the colors to be more accurate with a transform to REC709 and with the tone mapping tool better access to the highlights from the Sigma. 

I think as the Sigma happened to use DNG people just started using the Blackmagic gamma because it gave you an instant log to grade but since Sigma had not given a log profile for it, it's linear, then it's most appropriate to transform from linear. 

Yeah it seems pointless to use BM colorspace and ruin the great color the sigma has.

[Owlgreen]

2 hours ago, Ryan Earl said:

What I understand is that the Blackmagic Design Color Space and Blackmagic Film Gamma was specific to Blackmagic's cameras like the original Blackmagic Cinema Camera and URSA 4.6K.  The conversion will be inaccurate but some users have found it pleasing or workable.  I personally compared the DNGs as P3 D60 and Linear to the URSA 4.6K in Blackmagic and found the colors to be more accurate with a transform to REC709 and with the tone mapping tool better access to the highlights from the Sigma. 

I think as the Sigma happened to use DNG people just started using the Blackmagic gamma because it gave you an instant log to grade but since Sigma had not given a log profile for it, it's linear, then it's most appropriate to transform from linear. 

That makes sense, thanks Ryan.

[OleB]

Hi all,

have uploaded a small video file to YouTube for you to check. It was recorded the way which I have described above. Think the dynamic range of the fp is great. 🙂 

 

[kye]

8 hours ago, OleB said:

Hi all,

have uploaded a small video file to YouTube for you to check. It was recorded the way which I have described above. Think the dynamic range of the fp is great. 🙂 

 

I saw another FP video yesterday, and even though I think the person didn't do a great job on the grade, you could see immediately from the footage that the camera isn't overpowered by high-contrast scenes, but seems to render them quite neutrally without it being a "stretch".

This is perfect as it gives a really solid base for your grade and if you are wanting to really push/pull the footage then it gives you extra leeway to push/pull it further from neutral before the image starts to suffer.

The more I see images from this the more I like what I see.

I wish CineD would revise their DR tests, as the one they did was on the first firmware version and had some odd qualities to it that I think might have been improved upon in subsequent updates.

Can anyone comment on the DR and image quality in V4 vs V1 firmware??

[OleB]

4 hours ago, kye said:

I saw another FP video yesterday, and even though I think the person didn't do a great job on the grade, you could see immediately from the footage that the camera isn't overpowered by high-contrast scenes, but seems to render them quite neutrally without it being a "stretch".

This is perfect as it gives a really solid base for your grade and if you are wanting to really push/pull the footage then it gives you extra leeway to push/pull it further from neutral before the image starts to suffer.

The more I see images from this the more I like what I see.

I wish CineD would revise their DR tests, as the one they did was on the first firmware version and had some odd qualities to it that I think might have been improved upon in subsequent updates.

Can anyone comment on the DR and image quality in V4 vs V1 firmware??

Agree! Unfortunately I came in too late for the V1 party. Bought the camera very well with V2 on it. Took me well over a year to figure out the correct settings, because of this misleading ISO behavior and combination with the Ninja V. But now I am extremely happy and even in direct sunlight find the DR not lacking at all. Most of the times I will even add more contrast back in the grade.

[Owlgreen]

I'm feeling very frustrated by this camera. I might be spoiled by the BMPCC 6K, but I'm finding it very hard to get anything other than ugly highlight rolloff. This is a matter of taste, I know, but it seems my tastes aren't aligning with this aspect of the camera. Half of the time, in addition to the ugly rolloff, I get a weird pink grid just below the clipping point. This is all in Resolve, however. In Capture One, processing a single frame, it looks better. Even then, the highlights blowout sooner than I'd like. I've tried all the possible Camera Raw options with and without CSTs. So far I like using the BMD colorspace the best. It seems to be the only way I can avoid having a yellow ring around my blown highlights. The noise floor is impressively low, I'll give it that. I guess the only way I'll be happy is to underexpose everything, and never let anything clip. I'm not sure how practical this is. I watched a video comparing the stills capabilities of the FP with a Sony A7something. The FP blew out the highlights earlier and more abruptly, but was less noisy when underexposed. So, I guess you could say they had similar DR, but the FP was kind of shifted to favor the shadows. Maybe by underexposing I can shift it the other way.  Until the highlights blow, the camera does look pretty damn good. 

[TomTheDP]

4 minutes ago, Owlgreen said:

I'm feeling very frustrated by this camera. I might be spoiled by the BMPCC 6K, but I'm finding it very hard to get anything other than ugly highlight rolloff. This is a matter of taste, I know, but it seems my tastes aren't aligning with this aspect of the camera. Half of the time, in addition to the ugly rolloff, I get a weird pink grid just below the clipping point. This is all in Resolve, however. In Capture One, processing a single frame, it looks better. Even then, the highlights blowout sooner than I'd like. I've tried all the possible Camera Raw options with and without CSTs. So far I like using the BMD colorspace the best. It seems to be the only way I can avoid having a yellow ring around my blown highlights. The noise floor is impressively low, I'll give it that. I guess the only way I'll be happy is to underexpose everything, and never let anything clip. I'm not sure how practical this is. I watched a video comparing the stills capabilities of the FP with a Sony A7something. The FP blew out the highlights earlier and more abruptly, but was less noisy when underexposed. So, I guess you could say they had similar DR, but the FP was kind of shifted to favor the shadows. Maybe by underexposing I can shift it the other way.  Until the highlights blow, the camera does look pretty damn good. 

Yeah it keeps the information in the shadows rather than highlights. Still you'll inevitably run into situations where you have to clips highlights and that sounds problematic.

[OleB]

31 minutes ago, Owlgreen said:

I'm feeling very frustrated by this camera. I might be spoiled by the BMPCC 6K, but I'm finding it very hard to get anything other than ugly highlight rolloff. This is a matter of taste, I know, but it seems my tastes aren't aligning with this aspect of the camera. Half of the time, in addition to the ugly rolloff, I get a weird pink grid just below the clipping point. This is all in Resolve, however. In Capture One, processing a single frame, it looks better. Even then, the highlights blowout sooner than I'd like. I've tried all the possible Camera Raw options with and without CSTs. So far I like using the BMD colorspace the best. It seems to be the only way I can avoid having a yellow ring around my blown highlights. The noise floor is impressively low, I'll give it that. I guess the only way I'll be happy is to underexpose everything, and never let anything clip. I'm not sure how practical this is. I watched a video comparing the stills capabilities of the FP with a Sony A7something. The FP blew out the highlights earlier and more abruptly, but was less noisy when underexposed. So, I guess you could say they had similar DR, but the FP was kind of shifted to favor the shadows. Maybe by underexposing I can shift it the other way.  Until the highlights blow, the camera does look pretty damn good. 

May I ask how you determine the correct exposure? Because as stated earlier, all regular tools, including in camera metering, are only working for ISO 100. That ISO value tends to clip highlights indeed very quickly. 

[Owlgreen]

7 minutes ago, OleB said:

May I ask how you determine the correct exposure? Because as stated earlier, all regular tools, including in camera metering, are only working for ISO 100. That ISO value tends to clip highlights indeed very quickly. 

I just have the histogram. I saw a video where a guy showed you can pull back around two and half stops of highlights relative to the clip point on the histogram. So if the histogram is unclipped I can increase the exposure by about two stops knowing I can pull it back later. I'm still finding my way around this thing.

Given that chart you posted a few days back, would it make sense for me to shoot ISO 800 most of the time, given that I would like to protect the highlights at all costs? I think the noise characteristics of this camera look great, so I don't mind trading noise for more highlight latititude. 

Should I be using false color? 

[OleB]

18 minutes ago, Owlgreen said:

I just have the histogram. I saw a video where a guy showed you can pull back around two and half stops of highlights relative to the clip point on the histogram. So if the histogram is unclipped I can increase the exposure by about two stops knowing I can pull it back later. I'm still finding my way around this thing.

Given that chart you posted a few days back, would it make sense for me to shoot ISO 800 most of the time, given that I would like to protect the highlights at all costs? I think the noise characteristics of this camera look great, so I don't mind trading noise for more highlight latititude. 

Should I be using false color? 

Understand that you do not have a Ninja V available. So yes, I would try to use ISO 800 like Sigma intended. For the scenario you described, easily and ugly highlight clipping, they will recommend using ISO 800. Internal false color screen should help on setting exposure correctly.

Have attached the additional fp manual from the developer, which tells you what ISO to use and when, including the chart.

Keep in mind this is only true when you are using the in camera options including record to an external SSD. When recording ProRes RAW or most likely as well BRAW with an external recorder, you have to choose the approach which I have posted earlier to get the best quality.

Hope that helps 🙂

[Ryan Earl]

37 minutes ago, Owlgreen said:

I just have the histogram. I saw a video where a guy showed you can pull back around two and half stops of highlights relative to the clip point on the histogram. So if the histogram is unclipped I can increase the exposure by about two stops knowing I can pull it back later. I'm still finding my way around this thing.

Given that chart you posted a few days back, would it make sense for me to shoot ISO 800 most of the time, given that I would like to protect the highlights at all costs? I think the noise characteristics of this camera look great, so I don't mind trading noise for more highlight latititude. 

Should I be using false color? 

I agree ISO 800 will protect the highlights better.  You can also post a DNG frame or two to compare developing methods. 

[Owlgreen]

42 minutes ago, OleB said:

Understand that you do not have a Ninja V available. So yes, I would try to use ISO 800 like Sigma intended. For the scenario you described, easily and ugly highlight clipping, they will recommend using ISO 800. Internal false color screen should help on setting exposure correctly.

Have attached the additional fp manual from the developer, which tells you what ISO to use and when, including the chart.

Keep in mind this is only true when you are using the in camera options including record to an external SSD. When recording ProRes RAW or most likely as well BRAW with an external recorder, you have to choose the approach which I have posted earlier to get the best quality.

Hope that helps 🙂

Thanks, Ole! I wish I'd seen this paper sooner. 

[Llaasseerr]

Just chiming in after doing a few tests with random DNGs I've found online. I decided to revisit the camera since it's having a bit of a moment on Youtube and it's had a number of firmware updates, but I don't own one.

I'm converting the DNGs to ACES open exrs, generally in Resolve. The reason for this is that Resolve builds an IDT on the fly based on looking at the DNG metadata, and then it dumps a linear RGB image to disk that is similar to the raw file. It takes the native sensor gamut and dumps that into the larger bucket of the ACES container.

From what I gather, for DNGs the camera is mostly ISO invariant, based on looking at the ISO diagram in the manual. In absolute terms, for an ISO 800 image the sensor seems to be clipping at around 3.0-5.0 in the RGB channels - it varies per channel if unclipped. In the small number of test images I have, for ISO 100 I'm adding +2.5-3 stops because the images are underexposed, and it holds up well. Not sure if they were intentionally underexposed, so I should really do my own tests.

The clipping point isn't great, but considering the images are so noise free in the shadows it does suggest that the camera could be underexposed 3-5 stops to bring it more in line with other cameras. This also assumes you don't mind a bit of noise. So I would be interested to shoot at say ISO 800 with an ND and push the highlights as far as possible.

For reference, Sony cine cams clip at about 11.7 when shooting S-log3 (~1.5-2 stops), or a tad higher in ProRes Raw for the alpha cine cams, and the Alexa clips at about 55-ish (~4 stops). Amazingly, the BM Pocket 6k Pro clips around the same as an Alexa when highlight recovery works. I did not believe it when other people mentioned it, until I tested it out for myself.

Re: monitoring, there was a test I did a few years back where I inverted the "none" profile through the ACES Rec709 inverse IDT and the result is similar to the raw DNGs imported into ACES, but without the full highlight range. It was probably close enough for general monitoring if you want to check grey card exposure but are not too worried about checking highlight clipping, and also if you don't mind adding an external monitor. With the new false color feature, this might be less important if you just want to get the exposure in the right place without needing an accurate monitoring image.

Overall, the low highlight clipping point and the mediocre rolling shutter are a turn-off, along with the difficulty of monitoring a raw image accurately. But there's still something really compelling about this camera.

[Llaasseerr]

Also I recently got a Ninja V, so it would be interesting to try out ProRes Raw and seeing if a more accurate monitoring LUT can be applied, despite the fact that it somewhat negates the size advantage of the camera. It could be cool to mount the Ninja V underneath the camera instead.

[OleB]

4 minutes ago, Llaasseerr said:

Also I recently got a Ninja V, so it would be interesting to try out ProRes Raw and seeing if a more accurate monitoring LUT can be applied, despite the fact that it somewhat negates the size advantage of the camera. It could be cool to mount the Ninja V underneath the camera instead.

Yeah, give it a shot. It is working already nicely if you consider ISO 800 as ISO 100 and upwards and select monitoring: PQ. False colors from the Ninja V are accurate then. Giving you exactly the clipping point of the sensor. 🙂 

[Llaasseerr]

6 minutes ago, OleB said:

Yeah, give it a shot. It is working already nicely if you consider ISO 800 as ISO 100 and upwards and select monitoring: PQ. False colors from the Ninja V are accurate then. Giving you exactly the clipping point of the sensor. 🙂 

Gotcha. I appreciate your work translating the scaled ISO values. It does seem crazy the inconsistency with internal vs external recording, and I would need to try both to fully get it.

My first impulse is that I would probably not apply PQ personally, but instead choose Native and create a custom LUT. But that is based on the assumption that the linear image as displayed by the Ninja V appeared to be the similar to the "None" profile on the camera, ie, flat-ish but not log. So in other words, they've scaled the linear image for display, because an actual linear image is super contrasty and clipped on a Rec709 monitor.

I'm basing that on watching the Atomos Sigma fp setup video on youtube. The LUT approach may not be a good idea if the highlights are getting clipped in the default Ninja V display, whereas with PQ they will be fully present and rolling off according to the PQ spec. But the overall appearance of PQ would not match my intended final image, so it's a trade-off.

[Llaasseerr]

17 minutes ago, OleB said:

Yeah, give it a shot. It is working already nicely if you consider ISO 800 as ISO 100 and upwards and select monitoring: PQ. False colors from the Ninja V are accurate then. Giving you exactly the clipping point of the sensor. 🙂 

On the subject of false colors, I was making my own LUT to conform to the El Zone standard but I have to get around to finishing it.

Did you say that the new false colors are usable on the camera itself while recording out the Ninja?

[Ryan Earl]

The monitoring situation is tricky.  With the following image recorded in 1080 12bit DNG the whites of the window sill were considered clipping on the camera's monitor and the waveform. 

The ISO is 160 and it pretty much looked this way on the camera's monitor.

I think you will struggle to pull them back down while working directly in REC709 - GAMMA 2.4 or SRGB.

Then below is a transform to Blackmagic Wide Gamut and Blackmagic Film Gen 5 with the CST tool from P3-D60 and Linear.  Then from BMD GEN 5 a 2nd transform to REC709.  You can also try transforming to the RED or ARRI spaces if you have luts for those already.  I just added a bit of saturation on top without exposure adjustment, but you can see that I'm underexposing the flowers to hopefully pull them back up. 

[Llaasseerr]

6 minutes ago, Ryan Earl said:

The monitoring situation is tricky.  With the following image recorded in 1080 12bit DNG the whites of the window sill were considered clipping on the camera's monitor and the waveform. 

The ISO is 160 and it pretty much looked this way on the camera's monitor.

 

I think you will struggle to pull them back down while working directly in REC709 - GAMMA 2.4 or SRGB.

 

 

Right. The issue is being unable to see clipping like you describe while monitoring, with the default profiles on the camera. It would be a good reason to consider underexposing at a fixed level with an ND, and having the ability to toggle a LUT on and off that included an exposure boost. Again, this is where a published Sigma log curve would be useful - for monitoring.

As for working with the image, just to be clear I'm not advocating working in Rec709. Personally I would work in either linear ACES or then convert the linear image to Arri logC. the DNG IDT is the most accurate DNG raw import available in Resolve since it's generated on the fly.

In the case of transforming to LogC, the ACES inverse Alexa IDT will do a pretty accurate transform from the linear image to Alexa. Arri's log color space is well documented and not confusing compared to BMD. Basically, I could round trip the image from LogC back to linear ACES and it would match the original imported DNG (via the ACES IDT), so then I know the image integrity has been maintained. My assumptions are based on sound DNG metadata though, as this is what Resolve relies on for accurate ACES input transform.