GH5 to Alexa Conversion

[Sage]

"GH5 V-Log and Hybid Log-Gamma are transformed to precisely match the color science of the Alexa, without compromise."

"The GH Alex conversion completely transforms the GH5 image, addressing every nuance of color reproduction (from shadows to highlights, low saturation to high saturation, for every possible hue). This includes an organic rolloff which fully eliminates channel clipping."

EmotiveColor.com

PDF

YouTube

[Jonesy Jones]

1 hour ago, Sage said:

"GH5 V-Log and Hybid Log-Gamma are transformed to precisely match the color science of the Alexa, without compromise."

"The GH Alex conversion completely transforms the GH5 image, addressing every nuance of color reproduction (from shadows to highlights, low saturation to high saturation, for every possible hue). This includes an organic rolloff which fully eliminates channel clipping."

EmotiveColor.com

PDF

This looks really great. Thanks for doing this Sage. 

The powers that be here have been pretty heavy handed lately, but I wish you all the best with this.

My 2 cents would be that it is pretty pricey. Not that $65 is crazy expensive, but it seems well above what the owner of this forum charges for his profiles. And most lut packages come in under what you are charging. 

I'm going to look at this again later, but to my eye it looked great. Thanks again for what I know was a lot of work. I hope it pays off.

[Sage]

36 minutes ago, Jonesy Jones said:

This looks really great. Thanks for doing this Sage.

Thank you Jonesy Jones, I really appreciate that.

I will take it into consideration. Just one light source conversion may still be used on other light sources to good effect. It is likely that it won't earn back what it cost to make, but it is something that I personally really wanted and was passionate about having (I was seriously considering used Alexas last December). Also, the research and development put into this may prove vital in my next, more costly, effort.

Currently available color solutions (FilmC) are far from accurate, and are best described as 'looks'. This is something different, and I intend to raise the standard for *conversions specifically (color transformations that should make one format look exactly like another)

[Jonesy Jones]

11 minutes ago, Sage said:

Thank you Jonesy Jones, I really appreciate that.

I will take it into consideration. Just one light source conversion may still be used on other light sources to good effect. It is likely that it won't earn back what it cost to make, but it is something that I personally really wanted and was passionate about having (I was seriously considering used Alexas last December). Also, the research and development put into this may prove vital in my next, more costly, effort.

Currently available color solutions (FilmC) are far from accurate, and are best described as 'looks'. This is something different, and I intend to raise the standard for *conversions specifically (color transformations that should make one format look exactly like another)

Sage, upon further review you have done an excellent job with the color matching. I assume this is where you spent most of your time, and again I think it is excellent. There is a slight tendency in your conversion toward magenta compared to the more green Alexa. But this the simplest slight adjustment on our end, but I thought it worth noting. 

The one thing that I do find odd though is the roll off. On my monitor your added roll off is too harsh. It removes too much of what was there. Question, would that be easy to mitigate on my end? Could I bring back some of the highlights lost with your lut?

[AaronChicago]

Great work! Looking fwd to trying it.

[Sage]

51 minutes ago, Jonesy Jones said:

Sage, upon further review you have done an excellent job with the color matching. I assume this is where you spent most of your time, and again I think it is excellent. There is a slight tendency in your conversion toward magenta compared to the more green Alexa. But this the simplest slight adjustment on our end, but I thought it worth noting. 

The one thing that I do find odd though is the roll off. On my monitor your added roll off is too harsh. It removes too much of what was there. Question, would that be easy to mitigate on my end? Could I bring back some of the highlights lost with your lut?

The rolloff is accelerated compared to the Alexa, due to the limited dynamic range of the GH5. All the data is there, albeit in a very subdued form. Clipping is left as desaturated detail just below full white. The one area that I revisited, because I felt the same, was when the Red channel clips. Red suddenly shifts to yellow, and this area of the color space is inseparable from actual yellow. There are times when it looks like real yellow/orange image data is too strongly being limited; however be assured, this is precisely where the red channel clips, and red objects unmistakably shift to looking like 'video'. You can resaturate the highlights - though in practice the rolloff is really quite ideal (one of my favorite parts)

18 minutes ago, AaronChicago said:

Great work! Looking fwd to trying it.

Thanks Aaron! You convinced me, I finally got around to posting! The Pdf Hlg update is coming soon

[kaylee]

a test video of people with different skin colors in daylight??? i love it lol great work @Sage

[mercer]

Looks pretty good. Checked out your Vimeo... what did you shoot Victim on?

[Sage]

1 hour ago, kaylee said:

a test video of people with different skin colors in daylight??? i love it lol great work @Sage

Thanks Kaylee! It is a legacy piece for me, that I'd been meaning to do since before the GH5. I wanted to upstage the early work, and do something spectacular

39 minutes ago, mercer said:

Looks pretty good. Checked out your Vimeo... what did you shoot Victim on?

Thanks Mercer - it was a hacked GH2, set to Smooth -2. I also used a Speedbooster with Nikkor Series E lenses.

[mercer]

3 minutes ago, Sage said:

Thanks Kaylee! It is a legacy piece for me, that I'd been meaning to do since before the GH5. I wanted to upstage the early work, and do something spectacular

Thanks Mercer - it was a hacked GH2, set to Smooth -2. I also used a Speedbooster with Nikkor Series E lenses.

Wow, that looks so good. Sorry for OT but I love seeing good videos from old forgotten cameras. I spent an hour this afternoon watching old hacked GH1 videos.

[Sage]

18 minutes ago, mercer said:

Wow, that looks so good. Sorry for OT but I love seeing good videos from old forgotten cameras. I spent an hour this afternoon watching old hacked GH1 videos.

Those two hacked cams were exceptional. I was quite resolute in sticking with the GH2vk, because I concluded it was all that was needed. Indeed, it remained in use until this year! I'm still keeping it for good.

[Hene1]

Does this work with both 150 Mbps and 400 Mbps modes? I bought the daylight version and it seems nice!

[Fritz Pierre]

@Sage...your conversion luts look fantastic....great work...in a film the two cameras would be a good match...have you tried to push both cameras for say a colder look...or a blown out desert look for example...or does that push the GH5 codec too far in combination with the Alexa LUT?...also read your spot on comment about LED colors being much more inconsistent in color than daylight or tungsten on DVX...this is an interesting project and speaks volumes too of the capability of the GH5

[Don Kotlos]

Looks good but I agree with @Jonesy Jones it needs less magenta. 

Even though colors are well matched, the weak codec compared to the Alexa gives you these ugly green-magenta blotches:

Recording externally and baking-in your LUTs should give much better results:

 

[Sage]

6 hours ago, Don Kotlos said:

Looks good but I agree with @Jonesy Jones it needs less magenta. 

Even though colors are well matched, the weak codec compared to the Alexa gives you these ugly green-magenta blotches:

Recording externally and baking-in your LUTs should give much better results

Thanks Don. I did see your bake-in post early on.

That rolloff shot in particular is the 1080p 120fps Vlog shot without conversion. Attached is the full converted shot. I found that grading 120fps Vlog results in a tussle between red and green macroblocks, especially when underexposed. If possible, baking in here would be a very wise move.

With regards to 10 bit footage, if you choose to bake-in, make sure to accurately white balance in camera. If you know you are the type of person who will not forget to WB, then this will work. If you know you may forget to WB, or want to use presets instead of custom WB, you will likely want to apply the conversion in post. This will leave you the freedom to correct or fine tune the WB should you miss it on set.

The conversion is dependent on an accurate white balance, unlike generalized look luts etc.

[Sage]

7 hours ago, Hene1 said:

Does this work with both 150 Mbps and 400 Mbps modes? I bought the daylight version and it seems nice!

Yes, both modes are supported. Its the 8-bit V-log modes which are different. For an accurate conversion with 8-bit V-log, there is an 8-bit [PRE] file for use in-line before the conversion.

7 hours ago, Fritz Pierre said:

@Sage...your conversion luts look fantastic....great work...in a film the two cameras would be a good match...have you tried to push both cameras for say a colder look...or a blown out desert look for example...or does that push the GH5 codec too far in combination with the Alexa LUT?...also read your spot on comment about LED colors being much more inconsistent in color than daylight or tungsten on DVX...this is an interesting project and speaks volumes too of the capability of the GH5

Thanks Fritz. Applying further color cast grades is perfectly acceptable and intended. The GHa conversion itself was carefully put together to ensure absolutely no artifacts. Indeed, the conversion appears to improve the appearance of macroblocking on some 8 bit footage, because of the placement of color and skintone in the Alexa color science.

The conversion is completely neutral, with no 'look' or color cast. The 'Soft' variation places contrast and saturation for further color cast grading.

[Attila Bakos]

Hi Sage, may I ask what software you use to build your conversions?

[austinchimp]

This looks great and your demo footage is beautiful. I would be sending you my money right now but it's WAAAAAYYY too expensive for a lut.

I think many of us have been burned before with Luts promising to transform this, or fix this, or make our lives easier, and the truth is I've never found any of them to completely live up to their promise, so it's hard to splurge this much money. If it were 50% cheaper I would try it out and reward you for what has obviously been a lot of work, but this is just too much right now without any way to test it myself on any footage.

If there were more demonstrations on other people's footage in a variety of different circumstances then I might be persuaded.

Your results do look fantastic though.

[Sage]

4 hours ago, Attila Bakos said:

Hi Sage, may I ask what software you use to build your conversions?

I can say, several pieces of software in chain. However, I will be coding something that will fine tune the process, and simplify it to one.

1 hour ago, austinchimp said:

This looks great and your demo footage is beautiful.

Thank you austinchimp.

I hear you about the luts; I bought many of the Alexa-like luts in my quest. Support for Hybrid Log-Gamma was just added, and something *may be released next year that will be more budget and hobbyist oriented.

No one will pay more for the conversion to be a reality than me. It was a huge savings for me though, because the used Alexa package that I almost bought last year was over $20K for everything that I needed to get it to work (and the GH5 moves a lot better)

I am preparing a series of Gif comparisons to demonstrate the difference between native GH5 color and the unmodified main GHa conversions. If you would like to see the conversion in action, send me stills from raw footage

[majoraxis]

@sage Great work!  When not recording in RAW, there are many choices/compromises that have to be made in post to make the footage look as good as possible considering the limitations for the recording format etc.  I have stopped looking for perfect and have been hoping to find good enough.  I think we are there with your LUT.  Please take good enough as big complement.  I have also found that the Logarist input and output LUTs combination significantly help the footage hold together better with color correcting.  Any advice on using your LUTs with Resolve and Logarist?  Thanks!