The issue I always had with the X-H1 is that you cannot easily convert the gamma and color space to anything else. I had come up with a rudimentary solution using LutCalc to convert the F-Log into something like Arri Log-C or a flavor of rec709 and then editing with that. That is not to say that the Fujifilm default rec709 conversion LUTs are not great. I love them, but they give me more of a modern and video-y look.
I will be going over LutCalc in a later blog post and YouTube video but for now I will leave it here.
With the X-T4 I recently bought I can now shoot HLG. I did not know really anything about it but vaguely that it is a hybrid of log and rec709 that makes editing easier without sacrificing quality or dynamic range. My first experience with it was with a Sony A7 when I was in college and it had just come out. I could not tell you which camera it was. At the time I thought it was a cool idea but I was still sold on using S-Log.
I found this really well thought out site that explains HLG and editing very very well. It is called Xtremestuff.net. I highly recommend reading his full tutorial for a better understanding.
Basically the idea is that HLG is an alternative to log that is more standard than log. HLG is HLG whether you are on a Sony or Fujifilm camera. The only difference is if the HLG is BT2100 or BT2408 compliant.
Fuji themselves say that the HLG in the X-T3 is BT2100 compliant(Fuji's X-T3 Brochure) I am assuming it is the same, which makes sense since they share sensors and processors. It is sometimes hard to find specifics on some of their models while others will have a litany of information and documents describing their specs.
The BT2100 standard is for both gamma and color space, which means that with shooting HLG on Fuji we can fully utilize Color Space Transform(CST) in Davinci. Which is something I have been missing with shooting Fuji.
In my experimentation I have found that if you set your input color space to rec.2100 and your input gamma to rec.2100 (scene) you will get a correct image out. The difference between the rec.2100 and rec.2100 ST2048 is where middle grey is meant to be exposed. It is very hard to find any technical recommendations straight from Fuji but I believe that you are meant to expose based off of the rec.2100(Scene).
The great thing about shooting in HLG with a Fuji camera is that we can now more accurately convert our footage to any other standard we would like in Davinci. For instance in the screenshot above I have transformed it to rec.709 color space and Cineon Film Log for the gamma. Those are the color space and gamma for using the Kodak 2383 film emulation LUT included in Davinci. Before I would have to use a LUT from LutCalc to convert the footage but that is never a good solution.
Now I feel very comfortable transforming the footage to anything I want without fearing loosing any quality in the image. For example, if I want to transform it to Arri Log-C and use the Arri classic rec.709 conversion LUT that Arri provides for free on their site.
I have experimented with using different manufacturers versions of log and then to their rec.709 LUT, but for the most part they all come out the same. So if you are going to convert to rec.709 you might as well just use the CST to go straight to it.
Here is a link to download one of my raw HLG shots from that video above.
If you do not own a Fuji camera that can shoot HLG or you just want to get something that looks good already to play with, here you go. Enjoy.
I will be making more of these in the future to explore more possibilities with HLG, and continuing the series on editing F-Log. Thank you for reading. Have a blessed day.
Will.
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