SL2-S L-log Grading

[luke burgess]

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just to clarify.... 800 ISO has a larger DR than 100 ISO on the SL2S? I'm new to video and shoot (when conditions permit) all my jobs at 100 ISO (BASE)

Is base ISO for video different or 800 ISO the preferable ISO for video?

 

[Photoworks]

1 hour ago, luke burgess said:

just to clarify.... 800 ISO has a larger DR than 100 ISO on the SL2S? I'm new to video and shoot (when conditions permit) all my jobs at 100 ISO (BASE)

Is base ISO for video different or 800 ISO the preferable ISO for video?

 

base iso in L-Log is ASA 400

in regular video recording it is ASA 100, but if you wand to improve your image quality and editing control you would shoot in L-Log

[luke burgess]

@Photoworks thank you this super handy to know! I've not used L-Log for a project as yet. i'm hesitant to attempt it until i understand it a bit more.

Any tips for shooting an interview in L-log?

[Photoworks]

If I shoot video on the SL everything is done in L-Log.

I have assigned on of the buttons in the front to "LUT Profile "selection.

If you are new to it you can pick Leica's "NATURAL" LUT. that should give you an idea of color and exposure.

In post you can do the same if you are new, apply the same LUT in the editor.

If you are more advanced there are many more way to deal with it .

[BernardC]

12 hours ago, luke burgess said:

just to clarify.... 800 ISO has a larger DR than 100 ISO on the SL2S? I'm new to video and shoot (when conditions permit) all my jobs at 100 ISO (BASE)

Is base ISO for video different or 800 ISO the preferable ISO for video?

They will have the same DR, however ISO 800 has an even spread between highlights and shadows. Here's an image from Sony's latest video camera that explains this:

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I couldn't find the same chart for the SL2S's sensor, but most modern cameras work this way, at least until you get to "dual ISO" range.

This also explains the popularity of "expose to the right (ETTR)" for stills shooters: it's a technique where you set the exposure at the lowest ISO, and then shorten the exposure until highlights aren't blocked.

The reason why video shooters use a higher "base ISO" is that it provides consistent results. You don't want to tweak exposure for every shot with ETTR, and then tweak it again in editing because the exposure changes on every edit. It's also less likely that you'll shoot something where the highlights can't be recovered.

[luke burgess]

@photoworks - this is great info. I'll  be using a 5" small HD OC monitor for an interview. I'm planning on not applying a viewing LUT and working off the waveform.  It's being compiled and edited in post with other interviews shot in C-Log3.

i've read a little about the LOG settings and was wondering what sharpness is the optimum for Log?

[luke burgess]

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@BernardC  This chart is fantastic. I'll be hovering btw 400 ISO & 800 ISO and this helps visualise what i'm working with.

cheers!

[OleBe]

The above chart is only correct if the camera is using Cine EI instead of ISO (it reads EI on the bottom left) ...Meaning it depends. For the SL2-S I have not read anything yet which states it working in Cine EI mode. Would assume that it is using analog to apply different exposure levels and thus regular ISO behavior, meaning no matter which ISO setting you apply the DR distribution is always the same.

Some real cinema cameras, like the ARRI Alexa, are using the Cine EI mode. Sony sometimes gives you the option, like with the FX series (even the 3 got it lately). And also the Kinefinity Mavo Edge cameras give you the choice to use it in either ISO or Cine EI mode. 

I do not have my SL2-S available for testing as it is currently under repairs. Will do some tests anyway, however one more interesting fact is that I have heard from some insiders that L-Log and ARRI LogC are about 99% identical, only that the Alexa has more DR available. So you could start using the Rec709 Classic LUT from ARRI (which can be downloaded from their website) for testing purposes as well and see where it will bring you to.

 

 

[hansvons]

1 hour ago, OleBe said:

Will do some tests anyway, however one more interesting fact is that I have heard from some insiders that L-Log and ARRI LogC are about 99% identical, only that the Alexa has more DR available.

It’s 100% Rec2020-based with a proprietary log curve for 10 bit. For a hybrid camera it renders pleasing colours, not far from the Alexa. Much nicer than Sony hybrids, for instance. 
Log-C kinda works in ACES but renders yellow-ish skin tones. Definitely not what I‘m after.

While the current workflow is designed around the future HDR video space Rec2020 and does well in what it‘s supposed to do, it needs some more profound understanding of colour management when your deliverables are standard HD/UHD in Rec 709, which is the case for probably 99% of the SL2/S users.

I’d like very much what I get from L-Log but for a classic Rec709 workflow you need a Rec2020 to Rec709 transform LUT to get the colours right. Leica’s Rec709 Natural LUT does that but, unfortunately, has a video gamma curve that reduces the DR terribly if applied at the beginning of the pipeline instead of used at the end. 
 

All of that is, of course, the nature of log-based workflows, but Leica doesn't provide a proper manual for that. However, there is/was somewhere buried in their website a white paper that explains what L-log is about.

 

[OleBe]

vor 7 Minuten schrieb hansvons:

I’d like very much what I get from L-Log but for a classic Rec709 workflow you need a Rec2020 to Rec709 transform LUT to get the colours right. Leica’s Rec709 Natural LUT does that but, unfortunately, has a video gamma curve that reduces the DR terribly if applied at the beginning of the pipeline instead of used at the end. 

 

Great info, thank you! I will investigate this once I have the camera back...

[Photoworks]

Keep in mind that middle gray of the L-Log in 10 bit is 445. 
In Arri LogC3 it is 400

[rgerst]

not sure if I saw new link above or not:

https://leica-camera.com/en-US/search?query=LUT