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Legal & Extended PSA

 

After a great experience working at SIM / Chainsaw / Bling in Hollywood, my last couple of jobs have really surprised me in that the Post / Dailies outfit had no idea about Legal vs Extended.  

I imagine many DIT’s have been frustrated by Post as they deal with this constantly. 
If its the other way around, Post houses should present guidelines on what type of LUTs they’d like… EL, EE… 

One dailies outfit confused it with Log/709, while right after on another job I used the Canon ME20 on a low-light shoot, and it only outputs Extended.  
I made Editor/Colorist aware and he kept jumping from 10-bit 8-bit, 4:2:2 to log… 

So I’ve been sending this link to clarify… 

Panasonic has recently done this right when they posted LUTs, and they labelled their 2 folders EE or EL, matching looks in each.  
One set are “grading LUTs” the other “monitoring LUTs” - and its up to us to misuse them.    :-) 

A DIT from a previous job (not mine) has already been blamed for handing in “useless LUTs” - and it did look that way when I saw them applied in a color bay, but they were so far off it seemed like a bigger problem.  After a little bit of homework its clear that nobody was managing legal / extended and only one Engineer in the equation is aware of what it is, but nobody talked to him.  

Obviously a lot of places handle this just fine, and just last night after wrap the Fotokem Dailies Tech came by and I asked him about it, he answered, “yeah 0-1023 but where’s top & bottom”   Ok that works.   

Finally, I need help figuring out a few LUTs (because the dailies outfit cannot tell me how they implement LUTs or how they export the one’s they send out)

It was recommended that they can be opened in Excel or Lattice to graph them and see if they’re bottom is a 4 or 64, and the top at 940 or 1019.  I’ve tried that but haven’t had success in seeing a plateau at top & bottom, or anything else that would indicated legal vs extended.  

Any help greatly appreciated, otherwise, I hope you enjoyed this PSA.   :-)

mdp

Mark Doering-Powell, ASC
LA based DP 





alister@...
 

LUTCalc by Ben Turley https://cameramanben.github.io/LUTCalc/ can analyse LUT’s, plot them against code values and then be used to produce new LUT’s in either legal or extended range.
Alister Chapman

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Alister writes:
LUTCalc by Ben Turley https://cameramanben.github.io/LUTCalc/ can analyse LUT’s, plot them against code values and then be used to produce new LUT’s in either legal or extended range.

This app seems particularly useful !
Great that its graphing with actual code values.
Thanks so much. 

The other thing making this tricky is I’m using Alexa Mini’s on my current project, and although they’re recording a codec that’s recognized as Extended / Full-Range (ProRes 444) its actually recording LEGAL values inside of that.  Its a bit of a mind-bender when you go through workflow… its technically Extended, but the values are legal, and you’ve made your LUT to legal values. 

I think ACES accounts for this, which is another reason it should be used… still a bit of resistance to that. 
Current project is not ACES compliant which is probably the main reason this homework is necessary.  :-)

Hope to learn more today.  

mdp 


Mark Doering-Powell, ASC
LA based DP 





Michael Most
 

Hi Mark,

Normally the output of these cameras is put through a legal to full LUT prior to any color grading. That allows you to do the grading in full range space, use an extended to extended LUT on output, and then put it through a full to legal transform for proper display on a monitor. That’s often done “automatically” in a number of software packages, so it’s not something you deal with directly. LiveGrade does not do that automatically, but has the transforms built in so you can just select them and stay with extended to extended LUTs.

Feel free to give me a shout if you want a better explanation……

Mike Most
On Location Services Director
Technicolor
Los Angeles, CA.

On Sep 5, 2018, at 7:13 AM, Mark Doering-Powell, ASC via Cml.News <markdp123=me.com@...> wrote:

Alister writes:
LUTCalc by Ben Turley https://cameramanben.github.io/LUTCalc/ can analyse LUT’s, plot them against code values and then be used to produce new LUT’s in either legal or extended range.

This app seems particularly useful !
Great that its graphing with actual code values.
Thanks so much. 

The other thing making this tricky is I’m using Alexa Mini’s on my current project, and although they’re recording a codec that’s recognized as Extended / Full-Range (ProRes 444) its actually recording LEGAL values inside of that.  Its a bit of a mind-bender when you go through workflow… its technically Extended, but the values are legal, and you’ve made your LUT to legal values. 

I think ACES accounts for this, which is another reason it should be used… still a bit of resistance to that. 
Current project is not ACES compliant which is probably the main reason this homework is necessary.  :-)

Hope to learn more today.  

mdp 


Mark Doering-Powell, ASC
LA based DP 





Nathan Armstrong
 

There is quite a few working folks who don't bother to understand video ranges, but luckily that does keep DIT's employed.  Here is a link - an article by Bennett Cain that covers the basic principles about as simply as can be done. 


I usually try to explain to folks that the post software is almost always working in the full (data) range, so EE LUTs is what post needs. Most LUT boxes on set imitate this process by scaling the video to full (data) range before applying the EE LUT. In this way you can use the same LUTs on set and post and you get the same final look. That's the goal, right?

Keep in mind that the video passing through your SDI cables is almost always Legal (video) Range, so your monitors are calibrated for Legal Range Display. Of course there are exceptions to this but the vast majority of video is monitored in the legal range, and broadcast video is delivered in the legal range. 

Also when we record in Arri Log-C Prores for example, the Log-C is in the Legal Range. So Davinci Resolve or whatever software you use will automatically scale this to full (data) range on input. You can change this manually using clip attributes in Davinci, telling the software if your video file is in the legal (video) range, and must be scaled, or if it is already in the full (data) range. 

Nathan Armstrong
DIT, Minneapolis
801.362.1741

Geoff Boyle
 

This is why the CML ACES LUT’s are available in both LL & EE.

 

Nick Shaw and I had terrible problems finding out from manufacturers of cameras, LUT boxes & Monitors what levels they required, often each of us getting different answers from the same manufacturer!

 

So, we ended up making both and advising people to suck it and see.

 

cheers
Geoff Boyle NSC
EU based cinematographer
+31 637155076

www.gboyle.nl

www.cinematography.net

 

._,_

Argyris_Theos_cml
 


 we ended up making both and advising people to suck it and see


How do you choose?
Is it just what you like or something more technical?
Best 

Argyris Theos, gsc 
DoP, Athens Greece,
+306944725315
Skype Argyris.Theos
via iPhone

9 Σεπ 2018, 10:26 π.μ., ο/η "Geoff Boyle" <geoff.cml@...> έγραψε:

This is why the CML ACES LUT’s are available in both LL & EE.

 

Nick Shaw and I had terrible problems finding out from manufacturers of cameras, LUT boxes & Monitors what levels they required, often each of us getting different answers from the same manufacturer!

 

So, we ended up making both and advising people to suck it and see

Geoff Boyle
 

It is explained on the ACES LUT page on the website.

 

cheers
Geoff Boyle NSC
EU based cinematographer
+31 637155076

www.gboyle.nl

www.cinematography.net

 

 

From: cml-raw-log-hdr@... <cml-raw-log-hdr@...> On Behalf Of Argyris_Theos_cml
Sent: 11 September 2018 07:11
To: cml-raw-log-hdr@...
Subject: Re: [cml-raw-log-hdr] Legal & Extended PSA

 

 

 we ended up making both and advising people to suck it and see

 

How do you choose?

Is it just what you like or something more technical?

Best 

Argyris Theos, gsc 

DoP, Athens Greece,

+306944725315

Skype Argyris.Theos

via iPhone


9 Σεπ 2018, 10:26 π.μ., ο/η "Geoff Boyle" <geoff.cml@...> έγραψε:

This is why the CML ACES LUT’s are available in both LL & EE.

 

Nick Shaw and I had terrible problems finding out from manufacturers of cameras, LUT boxes & Monitors what levels they required, often each of us getting different answers from the same manufacturer!

 

So, we ended up making both and advising people to suck it and see

Nick Shaw
 

And here is the list I made of which version  of the LUTs is appropriate for some devices which I have tested:


On 11 Sep 2018, at 06:16, Geoff Boyle <geoff.cml@...> wrote:

It is explained on the ACES LUT page on the website.

Nick Shaw
Workflow Consultant
Antler Post
Suite 87
30 Red Lion Street
Richmond
Surrey TW9 1RB
UK

+44 (0)7778 217 555

 

Argyrs writes: 
How do you choose?
Is it just what you like or something more technical?

In well thought out post pipelines, those 2 flavors will work (LL & EE). 
Once in a blue moon you might need EL and that might be because some software or LUT box is doing something under the hood, or a peculiarity of that post route. 

The good news is, if it’s wrong you’ll often know. 
Checking to see where highlights roll off, and where blacks block up is where you’ll see it. 

Also, make sure monitor gammas are all 2.4. 
I’ve chased the legal extended thing once and after half hour found one monitor gamma was off. Then everything fell in place. 

mdp


Mark Doering-Powell, ASC 
Los Angeles, California

Steve Shaw
 

There is a fair bit of info here too: 

https://www.lightillusion.com/data_tv_levels.html

But, there are more than two forms of LUTs required, as while Extended and Legal are the main requirement, some susyems require Legal range data in an Extended LUT format, while others need the LUT data rescaled to 16/64-235/940, and some need 16/64-1023, while others need to take into account the protected bits in the signal range...

Steve

Geoff Boyle
 

Don’t ya just love standards 😊

 

cheers
Geoff Boyle NSC
EU based cinematographer
+31 637155076

www.gboyle.nl

www.cinematography.net

 

 

From: cml-raw-log-hdr@... <cml-raw-log-hdr@...> On Behalf Of Steve Shaw
Sent: 12 September 2018 08:43
To: cml-raw-log-hdr@...
Subject: Re: [cml-raw-log-hdr] Legal & Extended PSA

 

There is a fair bit of info here too: 

https://www.lightillusion.com/data_tv_levels.html

But, there are more than two forms of LUTs required, as while Extended and Legal are the main requirement, some susyems require Legal range data in an Extended LUT format, while others need the LUT data rescaled to 16/64-235/940, and some need 16/64-1023, while others need to take into account the protected bits in the signal range...

Steve

Mark Weingartner, ASC
 

Standards are GREAT!  That’s why there are so many of them!

Weingartner
LA DP ETC

On 11Sep, 2018, at 23:46 48, Geoff Boyle <geoff.cml@...> wrote:

Don’t ya just love standards 😊

Video Assist Hungary
 

"of course my standards are outdated. That's what makes them standards" Douglas Adams


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On 2018. Sep 12., at 8:50, Mark Weingartner, ASC via Cml.News <vfxmark=me.com@...> wrote:

Standards are GREAT!  That’s why there are so many of them!

Weingartner
LA DP ETC
On 11Sep, 2018, at 23:46 48, Geoff Boyle <geoff.cml@...> wrote:

Don’t ya just love standards 😊