SL2 and SL2-S: Colour Grading & Correcting

[Aaron Daniel]

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Hi all, I've noticed there isn't a dedicated thread for editing L-Log footage, so I will begin one here. I realize that colouring and re-touching video is a very subjective field, but I wanted to see how others work within Leica's limited literature surrounding post-production in video.

I've just updated my Atomos Ninja V to the latest firmware, which now allows for L-Log recording from leica (the past year with the SL2 was a little tedious working with both internally and externally recorded video footage). Now, with this update, BT2020 seems a lot nicer.

I've just done my first video about this update here:

 

[Aaron Daniel]

I've just done another test with internal L-Log recording (without the Atomos Ninja V)

The biggest takeaway is that it seems better to expose for the highlights– it is cleaner to bring the shadows up rather than bringing the highlights down. So my thing to remember is to save your highlights!

 

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[hansvons]

Hi Aaron, thanks for sharing your thoughts. It’s heartwarming to see other people keeping hope alive amid the pandemic, the lockdown and all the hardships that follow in its wake. 
Hope this might answer your BT 2020 / Rec 709 question:

I haven’t had the chance to test drive the Leica SL2s yet. I cannot comment on how the camera specifically deals with colours, colour spaces and LUTs. But generally speaking, BT 2020 is a display-referred colour space, as is Rec 709. However, L-Log is a scene-referred colour space, similar to Arri Log C and other camera colour spaces. Since BT 2020 is a display-referred colour space, you need a BT 2020 Display to see the camera’s colours in their full glory and right tones. Watching BT 2020 footage on a laptop (Rec 709) or phone (Rec 709) or any other HD display will look different and somewhat wrong compared to a BT 2020 display. 

With an IDT (input transform), scene-referred footage such as Arri Log C can be fed into ACES (digital colour space, a tad larger than our eyes' colour space) and from there via an ODT (output transform, kind of specific ACES LUT) be displayed on numerous displays like HD screens (Rec 709), HDR screens (BT 2020), digital cinema screens and other not yet invented future displays. Leica’s L Log is said to be close/same as Arri Log C and thus makes it ACES compatible. When I get the chance to confirm that (probably at the beginning of March), I’ll let you know.

Edited February 18, 2021 by hansvons

[Aaron Daniel]

3 minutes ago, hansvons said:

Hi Aaron, thanks for sharing your thoughts. It’s heartwarming to see other people keeping hope alive amid the pandemic, the lockdown and all the hardships that follow in its wake. 
Hope this might answer your BT 2020 / Rec 709 question:

I haven’t had the chance to test drive the Leica SL2s yet. I cannot comment on how the camera specifically deals with colours, colour spaces and LUTs. But generally speaking, BT 2020 is a display-referred colour space, as is Rec 709. However, L-Log is a scene-referred colour space, similar to Arri Log C and other camera colour spaces. Since BT 2020 is a display-referred colour space, you need a BT 2020 Display to see the camera’s colours in their full glory and right tones. Watching BT 2020 footage on a laptop (Rec 709) or phone (Rec 709) or any other HD display will look different and somewhat wrong compared to a BT 2020 display. 

With an IDT (input transform), scene-referred footage such as Arri Log C can be fed into ACES (digital colour space, a tad larger that our eyes' colour space)  and from there via an ODT (output transform, kind of specific ACES LUT) be displayed on numerous displays like HD screens (Rec 709), HDR screens (BT 2020), digital cinema screens and other not yet invented future displays. Leica’s L Log is said to be close/same as Arri Log C and thus makes it ACES compatible. When I get the chance to confirm that (probably at the beginning of March), I’ll let you know.

Thank you so much for your detailed response, Hans! I really appreciate it  I will look forward to your added experience and insight next month as well

[hansvons]

Until then, I’m looking forward to seeing more clips. Perhaps, if you’ve got the time, it would be interesting to see a bit more what the camera can do in terms of skin tones, colour fidelity and  roll-offs in the whites. Your second clip has promising moments in that regard. Thanks for sharing!

[Mick H]

3 hours ago, Aaron Daniel said:

I've just done another test with internal L-Log recording (without the Atomos Ninja V)

The biggest takeaway is that it seems better to expose for the highlights– it is cleaner to bring the shadows up rather than bringing the highlights down. So my thing to remember is to save your highlights!

 

I assume you added grain to this...Is L Log this noisy when recording in camera?

[Aaron Daniel]

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1 hour ago, Mick H said:

I assume you added grain to this...Is L Log this noisy when recording in camera?

Haha yes, I forgot to mention that there was heavy 16mm grain added in to that clip! The first post in this thread has lowlight clips without the grain as well

[Slender]

If you like (beautiful) grain you should give a try to the 5K mode of the SL2 at 6400asa. It looks really really really good. I would actually urge people to try this mode (it's L-Log only, internal only too.... hmdi cannot funnel 5K weirdly) and ask Leica to get an ALL-I 422 version of it. It's in 4:3, intented for the maddest videographer who has anamorphic glass, but you can preview in camera and crop in post to whatever ratio you want, and that offers great margins for framing.

It is also, as we speak, the only Pixel-to-Pixel readout SL2 offers (none on SL2s as of today): so moire due to sensor fringing/lack of OLPF + binning OR Over/Down sampling is much less of an issue ---- as long as you can play the video close to its real size on monitors.

On the other hand, it is useful to know the SL2 5K mode is actually in HEVC h.265 .mov.... which is, interestingly "grosso modo" the recording flavours the SL2s is expected to get with a future update for more formats (UHD, DCI...etc).

Edited February 20, 2021 by Slender

[Aaron Daniel]

Aaah yes, I was a little confused why the SL2-S did not incorporate the 5K feature that the SL2 has. I'm sad I never got to test the 5K mode on the SL2 while working. The closest thing I probably have to that is a few wedding shots with the ASA around 6400 here actually (at the 4:44 mark):

Although there is a little additional grain applied, you can definitely still see the grain that the SL2 has. Perhaps you have a few uploaded shots we can see??

I am looking forward to h.265 update 🤞

[Aaron Daniel]

Another test with the Leica SL2-S here, this time trying out Leica's Natural LUT in both full-frame and aps-c mode. This was a very last-minute run-and-gun shoot, so not the most comparative and substantial (maybe tomorrow I will do a more methodical test), but I do think it helps show how the Natural LUT with L-log renders in changing lighting conditions

TL-DW, it's beautiful:

"

In this video, I test the way Leica's supplied Natural LUT renders on both full-frame and aps-c L-Log files. All shots were on the SL2-S with a voigtlander 35mm f1.2 lens (varying apertures throughout video). Similarly, the goal was also to see how the skin tones and whites take the Natural LUT.

An unintended test was the IBIS. I forgot I had turned off the IBIS before taking these shots, so the entire film is with in-body image stabilization turned off. Watching these clips makes me thankful for the L-mount and Leica team for producing such an effective IBIS system (when turned on 😅).

CONCLUSIONS:

As expected, there are not many colour-rendering differences between full-frame and aps-c footage. The reason this test was conducted was becaused the original Leica SL2 was known to have better video quality output in aps-c mode – undoubtedly due to its high megapixel count.

Edited February 21, 2021 by Aaron Daniel

[Mick H]

On 2/18/2021 at 5:29 PM, Aaron Daniel said:

 

The biggest takeaway is that it seems better to expose for the highlights– it is cleaner to bring the shadows up rather than bringing the highlights down. So my thing to remember is to save your highlights!

 

I followed this advice and my L Log results improved on the SL 601 recording in camera.   The Natural Rec709 LUT works well.  I use the histogram overlay to make sure my highlights are preserved.  I "expose to the center" so that the bulk of the data is in the middle of the histogram.  There is no waveform or built in L Log exposure tool (like the S1H has) on the SL.  The 4K24p files are 8 bit in camera but they look good.  L Log color with the Natural Rec709 LUT looks slightly better than Leica Rec709 SOOC, especially in the reds.  I need to experiment more with exposure to optimize L Log.  Leica gave SL 601 owners the improved L Log of the SL2 with the latest firmware.   

On a side note, Leica Natural Rec709 and Classic Rec709 LUTs work great on S1H V Log.

Does anyone know what the optimal, base ISO for L Log is?  For the SL, SL2 and SL2-S?  I can use ISO 50 with L Log with my SL with good results.  Suggested base for V Log is ISO 640 (S1H).  I can't seem to find this info.  

[Slender]

5 hours ago, Aaron Daniel said:

CONCLUSIONS:

As expected, there are not many colour-rendering differences between full-frame and aps-c footage. The reason this test was conducted was becaused the original Leica SL2 was known to have better video quality output in aps-c mode – undoubtedly due to its high megapixel count.

Cheers for conducting theese. I should try to do the same for everyone with my SL2.

Also the reason I am curious to see about APS-C and FF for both cameras is that the SL2s has almost no difference in term of actual/rendered resolution on APS-C format.... since leica doesnt say clearly if there is any oversampling/downsampling/mixing/skipping on this mode, I am curious to see how it can affect the following:

- Luminance noise and its size (the look of the "grain").

On the SL2, people said its better in APS-C.... on the S5 some say it's better in FF = the interesting thing is that in both case the camera processes an area of 6K to produce a 4K image.

- Sensitivity to alliasing reduced or not = as I mentioned earlier, I have seen some still showing up its nose on SL2s sample footage, but as I suspect all of it was shot in FF, I was wondering if, as you select APS-C and allow the camera to work with a closer ratio of pixels to proccess / pixels to display.... the issue improves, like with the 5K mode on SL2.

Ultimately for dedicated, long running video work, a Lumix S1h with OLPF, great audio imputs, flip screen, more menu options, batterie grips, affordable cages  ----- thank you not Lockcircle 🙄 ---- specialist accessories = There even is a screwhole on the L lens mount of the S1H to secure third party adapters like PL....etc is a more sensible choice, but we can still dream to get the leica look in both still and motion from one camera.

Panasonic cameras allow you to make an informed decision about sensor scanning by offering you to select options clearly labelled as pixel-to-pixel readout. Leica sadly is still very obscure about the video characteristic of their new cameras and mainstream reviewers either get it wrong or dont do it at all 😭 so again, thanks for trying this out.

 

Edited February 21, 2021 by Slender

[Aaron Daniel]

9 hours ago, Mick H said:

I followed this advice and my L Log results improved on the SL 601 recording in camera.   The Natural Rec709 LUT works well.  I use the histogram overlay to make sure my highlights are preserved.  I "expose to the center" so that the bulk of the data is in the middle of the histogram. 

So glad it's working out for you too! It was a change coming from the Sony system (as I believe the shadows were more of the priority, exposing to the right). Agreed that the Natural LUT is very beautiful haha

 

9 hours ago, Mick H said:

Does anyone know what the optimal, base ISO for L Log is?  For the SL, SL2 and SL2-S?  I can use ISO 50 with L Log with my SL with good results.  Suggested base for V Log is ISO 640 (S1H).  I can't seem to find this info.  

In terms of base ISO, I am also curious about this. I just conducting another test and noticed that the ISO gets noticeably cleaner when moving from 1600 to 3200, so this may be a good clue to how the sensitivity works. I would love to see if you have any uploadable footage with your SL! I can also upload some ISO tests shortly

I'm jealous of all the add-ons and real benefits that the S1H has over the SL2/SL2-S haha, as much as I was really considering getting that camera for video work, I think every one here can attest to the fantasy-like aura of Leica haha

[Aaron Daniel]

7 hours ago, Slender said:

Ultimately for dedicated, long running video work, a Lumix S1h with OLPF, great audio imputs, flip screen, more menu options, batterie grips, affordable cages  ----- thank you not Lockcircle 🙄 ---- specialist accessories = There even is a screwhole on the L lens mount of the S1H to secure third party adapters like PL....etc is a more sensible choice, but we can still dream to get the leica look in both still and motion from one camera.

Panasonic cameras allow you to make an informed decision about sensor scanning by offering you to select options clearly labelled as pixel-to-pixel readout. Leica sadly is still very obscure about the video characteristic of their new cameras and mainstream reviewers either get it wrong or dont do it at all 😭 so again, thanks for trying this out.

 

Aaahh yes, the S1H was such a top contender when considering between other cameras and the SL2-S. The cage is a major drawback with the SL2's, as I'm dreamily hoping that SmallRig or Tilta will take the SL2-S a little more seriously as a video camera and produce their own *manageably attainable* cage. It may help if Atomos and Leica finally come out with their ProRes RAW update 🤞 but who knows!

8 hours ago, Slender said:

I am curious to see how it can affect the following:

- Luminance noise and its size (the look of the "grain").

On the SL2, people said its better in APS-C.... on the S5 some say it's better in FF = the interesting thing is that in both case the camera processes an area of 6K to produce a 4K image.
 

Now in terms of grain, I have just done an ASA test in both Full-frame and APS-C mode.

Spoiler: APS-C mode has more/coarser grain in terms of luminance and color noise– specifically in the shadows. So I believe SL2-S is the opposite of the SL2 when it comes to noise between APS-C and FF.

[Aaron Daniel]

Newest test belowwwww:

"

In this video, I test the ISO/ASA noise of the Leica SL2-S in two main comparisons:

1) Full-Frame VS APS-C

2) Internal VS External L-Log

 

TIMESTAMPS:

0:16 - Title

0:21 - Full-frame

0:54 - APS-C

1:34 - Full-Frame + APS-C

1:47 - Full-Frame + APS-C: Highlights

2:23 - Full-Frame + APS-C: Shadows

3:00 - Highlights VS Shadows: Full-Frame

3:20 - Highlights VS Shadows: APS-C

3:41 - Conclusions of Full-Frame VS APS-C

4:40 - Internal + External: SOOC

5:28 - Internal + External: Natural LUT

6:11 - Conclusions of Internal + External L-Log

6:50 - Thank You

 

Let me know if you have any questions or suggestions for future videos

[hansvons]

Hi Aaron, nice clip! (I mean especially the wedding video) What I like most in terms of picture fidelity is the filmic interpretation of skin tones and the handling of overexposed whites. When it comes to ISO and video, it's probably wise to start with ISO 800 as most sensors with pixel pitch in a similar ballpark show at ISO 800 their widest latitude. 

It seems logical that at 6K (FF), the texture/grain looks less pronounced than at APS resolution, which is a centre crop and could perhaps be a pixel to pixel readout at UHD/4K. I've read somewhere that at FF resolution, the SL2s samples down straight to UHD/4K and doesn't skip pixels or anything other undesirable. That way, the texture is only affected by the codec and internal denoising.

I have no clue how the SL2s handles denoising. Hopefully, denoising can be dialled down to 0, meaning the sensor shows texture as less manipulated as possible.
In my experience, apart from colour science and a codec that leaves things as untouched as possible, it is a pure representation of the sensor's pixel on the image, which is the secret of high-end film cameras such as the Alexa or Red's offerings. 

[Aaron Daniel]

Thanks so much Hans, I really appreciate all the detailed info you have on this subject!

[Ashkanani1985]

Hi Aron 

I have question since your using SL2S for video, I’ve been using the camera now for 3 months.... did you figure out a way to record only to external recorder? The prob that if you press record in Ninja without recording in camera the AF will stop after 2-3 min so you have to engage recording from SL2S, I try to figure away around but couldn’t ?! 
By the way I did a test high ISO with A7S and R5 and SL2-S did shine in ISO performance if you interested you can see it in my youtube channel

  

[Ashkanani1985]

This is another video with some tests i’ve done with SL2S 

 

Edited March 14, 2021 by Ashkanani1985

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[Aaron Daniel]

13 hours ago, Ashkanani1985 said:

Hi Aron 

I have question since your using SL2S for video, I’ve been using the camera now for 3 months.... did you figure out a way to record only to external recorder? The prob that if you press record in Ninja without recording in camera the AF will stop after 2-3 min so you have to engage recording from SL2S, I try to figure away around but couldn’t ?! 
By the way I did a test high ISO with A7S and R5 and SL2-S did shine in ISO performance if you interested you can see it in my youtube channel

Hi Mohammad,

Wonderful videos! I remember stumbling upon your machine shop video a few weeks  I also really appreciate the ISO tests you've done, as I've yet to see a direct comparison with the A7Siii (I just sent your video to a friend who is using the A7Siii, to rub it in his face how much nicer the Leica is  )

In terms of your question and external recording, I unfortunately don't have experience with this. My lenses are all manual so I've been naive to this issue. I completely understand what you're saying about the autofocusing going to sleep while recording externally. The only solution I can think of is turning off the sleep option of the body. Perhaps this will keep the continuous autofocus of your lens activated.I understand this may hinder your overall battery life, so I'm curious to see if this is a plausible solution.