GH5 GH5 to Alexa Conversion

[Sage]

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

EmotiveColor.com

PDF

Updated to V2 Reference Grade:

GHa Tungsten (Main) V2 - No other color alteration

 

[Sage]

Turn up the volume, choose 2K, and fullscreen it

(Edge/Explorer or Safari recommended for most accurate color; Chrome/Opera Ok; Avoid Firefox)



Vimeo

Youtube

 

[ryancglover]

Been playing around with some of my past GH5 footage and the GH5a transformations this morning, really liking it so far!

These were graded with the 'main' transformation then finished with a touch of a Kodak film print LUT and some grain:

Looking forward to trying them out some more on some upcoming shoots!

 

[AndrewTaran]

Been playing around with some of my past GH5 footage and the GH5a transformations this morning, really liking it so far!

These were graded with the 'main' transformation then finished with a touch of a Kodak film print LUT and some grain:

Looking forward to trying them out some more on some upcoming shoots!

Probably the best colour from GH5 I've seen so far. I was on the fence about buying this camera, but I think these shots just sealed the deal!

 

[joe12south]

The "Emotion II" color grade is pushed way beyond the breaking point. (I downloaded the source to make sure Vimeo wasn't introducing the artifacts.) Were those samples pushed beyond what the LUT does, or are they representative of the "out of the box" look of the LUT?

 

[Sage]

The "Emotion II" color grade is pushed way beyond the breaking point. (I downloaded the source to make sure Vimeo wasn't introducing the artifacts.) Were those samples pushed beyond what the LUT does, or are they representative of the "out of the box" look of the LUT?

You are quite right; I was looking at it this morning in the light of day, and came to the conclusion that on some shots I pushed the black levels especially way too far. I added a lot more 'punch' to the images on top of the conversion, in a raced grade going late into the night yesterday. All shots were 8-bit slow motion, and the 1080p 120fps shots in particular break down when underexposed with an extreme grade. *10-bit footage is notably free of artifacts/color blocking, no matter the grade on top of the conversion

 

[joe12south]

You are quite right; I was looking at it this morning in the light of day, and came to the conclusion that on some shots I pushed the black levels especially way too far. I added a lot more 'punch' to the images on top of the conversion, in a raced grade going late into the night yesterday. All shots were 8-bit slow motion, and the 1080p 120fps shots in particular break down when underexposed with an extreme grade. *10-bit footage is notably free of artifacts/color blocking, no matter the grade on top of the conversion

Cool. Thanks for the response. Yeah, 8-bit V-LOG is extremely fragile. A few questions if I may:

1. Your site mentions "8-Bit V-Log Preparation". What exactly is this?
2. How big (points) is the LUT?
3. Can you speak any to the creation process? Eyeballed or measured? Resolve or 3D LUT Creator or something else?
4. Is this a Rec709 LUT ready for finishing, or does it match V-LOG L to Arri LOG C?

 

[Sage]

Been playing around with some of my past GH5 footage and the GH5a transformations this morning, really liking it so far!

These were graded with the 'main' transformation then finished with a touch of a Kodak film print LUT and some grain:

Looking forward to trying them out some more on some upcoming shoots!

They look outstanding Ryan.

Probably the best colour from GH5 I've seen so far. I was on the fence about buying this camera, but I think these shots just sealed the deal!

From Bmc:
"Its wholly different from other color conversions.. I had to create a system that would allow me achieve the level of accuracy I was after, because what I needed was not commercially available." In particular, to achieve it I needed to track a considerable number of data points throughout the color spaces, accurately.

 

[joe12south]

One more question, do you include a version for in-camera monitoring (.vlt)?

 

[Sage]

Cool. Thanks for the response. Yeah, 8-bit V-LOG is extremely fragile. A few questions if I may:

1. Your site mentions "8-Bit V-Log Preparation". What exactly is this?

Its effectively a separate conversion from the color space of 8-bit V-Log to the color space of 10-bit V-Log. indeed, they are different enough to warrant a preparation conversion, and the result is considerably improved skintone (among others).

(Titled a [PRE] file, which is intended for use in line before the conversion is applied)

2. How big (points) is the LUT?

33x33. I can provide any size or format upon request. Though 33x33 is the best in terms of performance/quality/size tradeoff, and tetrahedral interpolation can be enabled in Resolve if desired.

3. Can you speak any to the creation process? Eyeballed or measured? Resolve or 3D LUT Creator or something else?

Measured, all the way. This was considerably more involved than a Colorchecker match The process took about six/seven months.

4. Is this a Rec709 LUT ready for finishing, or does it match V-LOG L to Arri LOG C?

Both; included are 'Main' and 'Soft' full contrast/saturation conversions, and a V-Log to LogC color science conversion (not simply a shift in known format parameters, ala Lattice/LutCalc). They are detailed in the included PDF.

And yes, a .vlt is included with each light source set. These are considerably better than the standard 709 profile in camera.

 

[roxics]

Have you tested this at all with a 10 bit output from a GH4?

 

[joe12south]

Have you tested this at all with a 10 bit output from a GH4?

GH4 color science is very different from GH5. (Different sensors sampled in a very different manner.) If this LUT is accurately transforming color mapping, it's not gonna work on another camera. I mean, who knows, you might find it pleasing, but it won't be a match.

 

[Sage]

Have you tested this at all with a 10 bit output from a GH4?

Not yet. That's on the roadmap, after HLG support.

GH4 color science is very different from GH5. (Different sensors sampled in a very different manner.) If this LUT is accurately transforming color mapping, it's not gonna work on another camera. I mean, who knows, you might find it pleasing, but it won't be a match.

That's exactly right.

 

[joe12south]

In case anyone is wondering how this LUT fares on GH4 footage, you can see significant problems with colors, most notably skin tones. This is to be expected, as the GH5 treats them quite differently.

 

[joe12south]

Sage, I've been playing with the LUT and find it nice and pleasing. Especially like how it handles highlights. Any plans to make a version for non V-LOG L profiles? I guess I could reverse engineer the gamma curve out of it, but I'm lazy.

 

[Sage]

Sage, I've been playing with the LUT and find it nice and pleasing. Especially like how it handles highlights. Any plans to make a version for non V-LOG L profiles? I guess I could reverse engineer the gamma curve out of it, but I'm lazy.

Yes, the rolloff continues to astound me.

My intention is to support Hybrid Log Gamma next (which is the other profile that allows the full dynamic range of the sensor). This will require an entirely new [PRE] conversion

 

[c3hammer]

Really like the look. Not interested in V-log anything. Curious if you might ever have a version for the Neutral profile in Vegas?

 

[Sage]

Really like the look. Not interested in V-log anything. Curious if you might ever have a version for the Neutral profile in Vegas?

Thank you c3hammer;
I understand. I intend to support Hybrid Log Gamma, because it is the only other profile that records the full sensor range

 

[fboonzaier]

The footage looks really good...so the conversion LUT is designed to be dropped on your log footage, whether you're shooting in daylight WB or Tungsten respectively....can you clarify a bit what is in the PDF?...for example is it a how to manual with settings....recommended exposure ETC....I'm interested but at this time the information is a bit thin....can you please clarify as much as you can without compromising your product?

 

[Sage]

The footage looks really good...so the conversion LUT is designed to be dropped on your log footage, whether you're shooting in daylight WB or Tungsten respectively....can you clarify a bit what is in the PDF?...for example is it a how to manual with settings....recommended exposure ETC....I'm interested but at this time the information is a bit thin....can you please clarify as much as you can without compromising your product?

Thank you fboonzaier; the PDF is now listed in the original post -

Here is the download

The color science conversion is independent of exposure; each stop corresponds to the Alexa's handling of that stop (except the top three stops, which only the Alexa has - GHa features an accelerated rolloff). You may expose the shot as you see fit. The 'Main' and 'Soft' variations do have a slight advantage to being exposed well, to achieve ideal saturation. Place middle gray around 40IRE; it does not need to be exact, but avoid excessive underexposure. If underexposed, 'Soft' may be used in place of 'Main'.

A neutral white balance is important for the accuracy of the conversions. Ideally this is done in camera, but may also be done in post using the dedicated white balance correction tools of your editing software (temperature, tint, eyedropper). Avoid correcting white balance with RGB curves or levels.