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Sony A7riii - HDR HLG - Yay or Nay?


Robert Collins
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So help me out here.

I am really interested in the HDR HLG profile(s) on the A7riii. I am not really looking to make HDR footage for oled TVs - what I am looking to do is a 'picture profile' that lets me get good dynamic range and colors in a format that suits me.

I do know of the advantages of s-log2 and s-log3 but I am a still shooter primarily (that is getting into video) and the whole minimum iso800 (+1.5 EV exposure) isnt exactly conducive to switching between stills and video. a big (potential advantage) for me of HDR HLG is that you can shoot at iso100 and expose normally.

Now as I understand it Sony's HDR HLG mode shoots a very flat gamma curve and then applies a lut in camera. While this sounds a bit like 'smoke and mirrors' to me - if it actually means that I can get good dynamic range video while shooting at iso100 it does sound very attractive.

From what I can determine it does shoot a flat profile. Here is a still shot shot in PP10 (HLG2) that I took in raw + jpeg. The raw shouldnt be affected by the picture profile and looks like this in adobe lightroom at default...

5a75467f0ba97_ClipboardImage(63).thumb.jpg.e541513f98b35e7376eb7dca09eebae7.jpg

Note the histogram....

And this is the jpeg (which includes the affect of the picture profile)

5a754732a0c8d_ClipboardImage(64).thumb.jpg.c9f7f6c70f6a14dddedd1a193a19f0d2.jpg

And again note the histogram and how flat the profile is.... 

So, in principle this picture profile sounds attractive. BUT on the internet, there appears very little interest in it which presumably means that most people think it isnt of much use. Some have suggested that 8 bit hdr hlg is a joke or an oxymoron (although I note that Andrew Reid is mildly enthusiastic.) So is it something I should just ignore or is it worth digging deeper into?

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9 hours ago, Robert Collins said:

 

"Now as I understand it Sony's HDR HLG mode shoots a very flat gamma curve and then applies a lut in camera. While this sounds a bit like 'smoke and mirrors' to me - if it actually means that I can get good dynamic range video while shooting at iso100 it does sound very attractive."

I do not get what you are trying to do, but I can correct this.

There is no LUT applied when shooting Profile 10 - it is the HLG gamma and the REC2020 color space. There is a *viewing* LUT that transforms to REC709 that you can use when shooting or turn off. It is NOT baked into the recorded image whether you use it for viewing or not.

The HLG gamma does give you more room in highlights. And you can muck around with it in post. The real issue is that you are shooting in the REC2020 color space and if you are delivering REC709 video then you must transform that color space to conform to the more limited REC709 space. If you do not do that the colors are odd, and the transformation is not simple. There are LUTs available for that though.

My view is that HLG is best used to produce HDR video. When delivered in HDR to YouTube you get both the HDR and a nice SDR translation made by YouTube. So everyone can watch the video at its best depending on the capability of the viewing devices.

 

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  • 2 weeks later...
On 2/3/2018 at 5:04 PM, Andrew Reid said:

It's a superb grading format and similar to Canon LOG, with a wide colour gamut.

Definitely good for more than just TV compatibility.

Where might one find good normalization (technical) LUTs for HLG-1, HLG-2, and HLG-3 that can be used in, say, Resolve or another editing platform?

Not really interested in Catalyst Browse or Catalyst Prepare.

Thanks

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Here is an HLG HDR (Sony) video. By this I mean the video was shot in HLG REC2020 color gamut and the rendered video (from Resolve Studio) is also HLG HDR, REC2020. It will thus play as an HDR video on a suitable viewing device if you watch within the YouTube app or on the YouTube web site.

If you cannot view in HDR, the video will play in SDR - the SDR version is made by YouTube using the HDR version - it is a conversion to REC709, not HLG viewed in SDR.

The HDR version nicely captures the glowing, golden sun reflecting off fauna and other objects. The SDR version has the correct colors.

The difference between the SDR and HDR versions is large, because the golden light highlights are the centerpiece of the video..

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7 hours ago, blafarm said:

Where might one find good normalization (technical) LUTs for HLG-1, HLG-2, and HLG-3 that can be used in, say, Resolve or another editing platform?

Not really interested in Catalyst Browse or Catalyst Prepare.

Thanks

I have looked but couldn’t find anything so I have just made my own...

I have been shooting hlg2 and rec709 because I don’t understand BT2020 properly (again not a lot of info around).

I just happen to like hlg because I can shoot at iso100.

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  • 11 months later...


Shooting in HLG (I prefer HLG3) is great for creation of HLG videos but as already mentioned on SDR TV it looks dull. I was searching for a LUT too that transforms bt.2020 back to bt.709 keeping highlights/color as good as possible.
If you are searching for a technical LUT I suppose this is what you mean?
As I was not successful I created LUTs myself. On my website http://www.famoss.de you can download and test it. It should work for every HLG capable camera. The test LUT is free for use.
I created it based on footage of my Alpha 7mk3.

Good luck!

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On 1/17/2019 at 2:41 AM, famoss said:


Shooting in HLG (I prefer HLG3) is great for creation of HLG videos but as already mentioned on SDR TV it looks dull. I was searching for a LUT too that transforms bt.2020 back to bt.709 keeping highlights/color as good as possible.
If you are searching for a technical LUT I suppose this is what you mean?
As I was not successful I created LUTs myself. On my website http://www.famoss.de you can download and test it. It should work for every HLG capable camera. The test LUT is free for use.
I created it based on footage of my Alpha 7mk3.

Good luck!

any examples on the tube

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On 2/12/2018 at 10:52 AM, blafarm said:

Where might one find good normalization (technical) LUTs for HLG-1, HLG-2, and HLG-3 that can be used in, say, Resolve or another editing platform?

You could - instead of using a lut in resolve - use the Resolve color management feature, which is something I highly recommend. You can set it up to effectively transform the gamma and gamut.

Avery peck has a good video on youtube on how to use resolve color management.

 

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 No, I did not create a video yet but it is a good idea. I will upload when it is created. 
Meanwhile on my website http://www.famoss.de/samples.htm there is a gallery of some images. There you can compare different pictures taken as screenshots from graded videos using different Luts including the original nongraded picture.
Bt.2020 has a wider gamma and gammut as Bt.709. As each footage has its own gamma/gammut characteristic I realized that there is no universal Lut to do a good transformation. Some Luts are good for low light some for bright pictures. In addition mid tones are treated differently.
So watch yourself.

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  • 2 weeks later...
On 1/19/2019 at 4:15 AM, Mark Romero 2 said:

You could - instead of using a lut in resolve - use the Resolve color management feature, which is something I highly recommend. You can set it up to effectively transform the gamma and gamut.

Avery peck has a good video on youtube on how to use resolve color management.

+1 - Just use Resolve's integrated conversions.

@blafarm @famoss

In fact, there's a big difference between using the conversions in Resolve and a LUT:

  • If you use a LUT and the conversion clips any parts of the signal (highlights or shadows) then they're clipped forever and nothing you do after the LUT can get them back.
  • If you use Resolves conversions (either in the Clip properties or via the Colour Space Transform plugin) the clipped values are retained within Resolve (as super-whites or super-blacks) and if you adjust the image after the conversion then you can get them back into the normal range without damaging them.

The internet talks a lot about LUTs but that's mainly because the people doing all the talking are selling......  LUTs.

I don't know how the other NLEs work, but I'd imagine they work similarly.

If you have to use a LUT then you can lower the contrast before the LUT to get the output from the LUT within range, but this defeats the purpose of using a LUT in the first place (because your inputs to the LUT now don't match how the camera encoded them) and you may as well just apply contrast or curves to get the look you want and ignore the LUT.

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As I was working first time on HLG I was disappointed watching the result on a usual TV. I tried to use Resolve but it was to complex for me (I am no professional) and also did not want to change editing software. So I tried to go another way using LUTs to get colours back. I did not found HLG (!) LUTs in the internet at that time.

I am pretty sure that Resolve offers many possibilities to work on HLG. What I want to show is an easy way to grade HLG footage getting a good result. HDR will be a rising feature and will be implemented in more public editing software in future. I am sure about this. Just drag and drop the LUT on your clip, finished.

I offer a LUT for free. So you do not have to pay anything. The other LUTs differ in tone/colour mapping. Depended on your footage you can chose the suitable solution yourself.

So for me Resolve or taking LUTs are both feasible solutions.

Bye!

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Just to build off of @kye post above...

It is important to go into the settings and adjust the monitor's NIT values as well, which default to 100 NITs (which is kind of low and will display clipped highlights even when they aren't clipped).

I don't know what the "average" brightness is for monitors and smartphone screens. When editing, I set my NIT value to 350 and it seems that is kind of conservative. Most newer iphones have a display brightness of over 600 nits for rec.709

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17 hours ago, famoss said:

As I was working first time on HLG I was disappointed watching the result on a usual TV. I tried to use Resolve but it was to complex for me (I am no professional) and also did not want to change editing software. So I tried to go another way using LUTs to get colours back. I did not found HLG (!) LUTs in the internet at that time.

I am pretty sure that Resolve offers many possibilities to work on HLG. What I want to show is an easy way to grade HLG footage getting a good result. HDR will be a rising feature and will be implemented in more public editing software in future. I am sure about this. Just drag and drop the LUT on your clip, finished.

I offer a LUT for free. So you do not have to pay anything. The other LUTs differ in tone/colour mapping. Depended on your footage you can chose the suitable solution yourself.

So for me Resolve or taking LUTs are both feasible solutions.

Bye!

There's some confusion online around HLG and conversions.

  • HLG is actually a delivery format, so if you shoot in HLG and are going to display it as HLG, you just hook it up to a HLG monitor and grade the way you want, no LUTs required
  • HLG isn't the technical term - it's more of a non-specific marketing term, and there's conflicting information online about whether HLG is Rec.2020 or Rec.2100, but if you're looking for conversion LUTs then those are what to look for
  • I did some experiments with my GH5 and I don't believe that HLG on the GH5 is either Rec.2020 or Rec.2100, but in the end I concluded that it's close enough to Rec.2100 that I don't care about the slight differences

It's complicated stuff.  I tell people that using Resolve is like flying the space shuttle, and to extend that analogy, navigating different colour spaces and gammas is like knowing how to be a pilot.  To get to where you want to go you must know how and where to fly and know what controls to adjust to do so.  Resolve, HLG capable cameras, and HLG capable TVs are all cheap now and available to the general public, but it's like making the space shuttle cheap and available, being able to afford it doesn't mean you will know how to fly it :)

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I think I belong to a majority of people: Shoot, Cut, Export. I have three children and two cats and don’t want to waste time on complicated editing software. ?

I don’t know for Panasonic but Sony doesn’t give useful information shooting HLG videos. At the beginning Robert asked using HLG for shooting photos. I use it shooting photos in difficult exposure situations too but I also don’t know if it is ok or not. Related to S-Log you can find information on Sony Professional including LUTs. HLG is mentioned as a HDR processing without doing grading. But everybody who watch a HLG video on a conventional television gets a bad surprise.

Almost every Sony camera gets this new feature but there is no easy guideline how to use it in real live. I would be happy that all I have written and many blogs in internet would be needless but it isn’t.

Anyway HLG is a technical term. It describes the transfer characteristic of a video. Another characteristic is PQ used by HDR10 and Dolby Vision. Using the tool MediaInfo I get the following header information (short extraction) from my Sony HLG video:

Color range                              : Limited
Color primaries                          : BT.2020
Transfer characteristics                 : HLG
Matrix coefficients                      : BT.2020 non-constant
Codec configuration box                  : avcC

So it is important how your HDR television has to work on the stream. I suppose it looks the same on your GH5.

My video editing software (Magix Video Pro X) is only able to export PQ and the exported video looks horrible colourful. So it is not well supported on public software, unfortunately.

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21 minutes ago, famoss said:

I think I belong to a majority of people: Shoot, Cut, Export. I have three children and two cats and don’t want to waste time on complicated editing software. ?

I don’t know for Panasonic but Sony doesn’t give useful information shooting HLG videos. At the beginning Robert asked using HLG for shooting photos. I use it shooting photos in difficult exposure situations too but I also don’t know if it is ok or not. Related to S-Log you can find information on Sony Professional including LUTs. HLG is mentioned as a HDR processing without doing grading. But everybody who watch a HLG video on a conventional television gets a bad surprise.

Almost every Sony camera gets this new feature but there is no easy guideline how to use it in real live. I would be happy that all I have written and many blogs in internet would be needless but it isn’t.

Anyway HLG is a technical term. It describes the transfer characteristic of a video. Another characteristic is PQ used by HDR10 and Dolby Vision. Using the tool MediaInfo I get the following header information (short extraction) from my Sony HLG video:

Color range                              : Limited
Color primaries                          : BT.2020
Transfer characteristics                 : HLG
Matrix coefficients                      : BT.2020 non-constant
Codec configuration box                  : avcC

So it is important how your HDR television has to work on the stream. I suppose it looks the same on your GH5.

My video editing software (Magix Video Pro X) is only able to export PQ and the exported video looks horrible colourful. So it is not well supported on public software, unfortunately.

The best way to shoot HLG is connect the camera to a true HDR display that supports HLG.

Also, Sony's 8bit HLG implementation can't be called official HLG. As BT.2100 HLG spec stipulates either 10bit or 12bit.

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20 minutes ago, famoss said:

As far as I know the usage of 10 or 12 bit is only a recommendation of Bt.2020/2100.

It's a requirement in the standards: http://www.arib.or.jp/english/html/overview/doc/2-STD-B67v2_0.pdf

Of course it's not enforced like everything else and it's the end-users that get all the trouble, Sony's 8bit H.264 HLG files are not directly compatible with most HDR TVs, or YouTube HDR.

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