GH5 to Alexa Conversion

[kye]

In Resolve I had this issue with my sunset time lapses and I found that the Hue vs Hue curve really helped.

Obviously fixing it in-camera is better, but fixing it in post isn't that hard.

[Jonesy Jones]

10 minutes ago, kye said:

In Resolve I had this issue with my sunset time lapses and I found that the Hue vs Hue curve really helped.

Obviously fixing it in-camera is better, but fixing it in post isn't that hard.

Are you referring to the red clipping?

[kye]

2 hours ago, Jonesy Jones said:

Are you referring to the red clipping?

Yep.  You use the Hue vs Hue to shift the yellows into the reds.

[Sage]

22 hours ago, Grimor said:

Thank you very much, Sage, for your support.

Now i'm rethinking my workflow in premiere.

Sure, glad I could help!

On 3/9/2019 at 3:29 AM, Slothorp said:

No, they haven't. 

(this is grabbed from a braw file)

That's unfortunate. @CaptainHook It really needs fixin

I have an idea for an in-cam ProRes fix once in hand, but it depends on how things are implemented therein

[Sage]

Stunning piece from Keith Hammond:

 

 

[thebrothersthre3]

that was lovely

[RCV]

On 3/10/2019 at 1:20 PM, Sage said:

Stunning piece from Keith Hammond:

 

 

Wow! Nice...this is the reason why this lut excels...we can make our gh5 practically indistinguishable from other quality tvcs out there

I have 4 commercials lined up and am using this ghalex lut on all 4

[Sage]

On 3/11/2019 at 11:10 PM, RCV said:

Wow! Nice...this is the reason why this lut excels...we can make our gh5 practically indistinguishable from other quality tvcs out there

I have 4 commercials lined up and am using this ghalex lut on all 4

Very cool, they will be very pleased. Do you have any work online?

Jamy Hang just shared these, one still from his film, and the others from fashion:

[RCV]

wow...those look brilliant

I dont have any using the lut but the next 4 projects will be shot using the GH5 so I'll definitely post

 

[Sage]

9 minutes ago, RCV said:

wow...those look brilliant

I dont have any using the lut but the next 4 projects will be shot using the GH5 so I'll definitely post

Ah very cool. Looking forward to it!

[kabuto1138]

On 3/6/2019 at 6:46 AM, Sage said:

Methinks it would largely work, given what I've seen from other VLog cameras (much more so than, say, NLog). That said, I'd like to do a version for the S1, as that would be fully accurate and tailored to its image. 

Yes!!!  I am not joking when I say this, but a big incentive for me in probably buying the S1 would be emotive @Sage

Can't wait.

[kye]

8 hours ago, Sage said:

Very cool, they will be very pleased. Do you have any work online?

Jamy Hang just shared these, one still from his film, and the others from fashion:

These are very nice.

One of the main challenges I see with this LUT pack is in the variation of skin tones.  Many images posted have skin tones where there are areas of skin that are obviously yellow and others that are obviously pink, or where the skin tone is completely pink and there is nothing towards the orange side of that spectrum.

I will be the first to admit that I'm not a keen judge of colour, but to me good skin tones seem to sit in the ambiguous area between the "why is that person yellow? are they sick?" and "why is that person pink? are they sick?" tonal ranges.  Some examples show colour in both of these areas and I suspect that its to do with excessive saturation in the final grade.

I've messed around with these LUTs on my own footage across a number of different shoots and it does push the skin tones quite far towards the magenta, but when I look at Alexa footage it doesn't seem to be graded with that level of push, so I think controlling that aspect of the colour is an important part of grading this material (and I suspect also when grading Alexa files, simple because of how well the LUT pack matches the Alexa, unfortunately I haven't had the pleasure of playing with Alexa footage myself).

To this end I find a lot of benefit in using hue adjustments to ensure that the hues in skin tones are contained within that sweet spot between yellow and pink.

I'm curious to hear what other people's views on this are, maybe it's a personal taste thing?

[Sage]

There are several variables that combine in skintone; color separation, saturation model, skin color, light color spectrum, white balance, lens coloration.

Color Separation: Good cameras have color separation. Less ideal color science will have 'accordioned' hues, compressing and expanding arbitrarily throughout the hue circle. For skintone - under quality light, the Alexa will have great separation between the pink aspects of the face (lips, blush) and skintone, which rides the line between too green and too magenta under flat spectrum light

Saturation Model: Photometric saturation models (like Alexa LogC+R709 or EC LogC+R709) have less saturation (the video model). Saturation amplifies hue difference, and photometric models can make skin tones seem more alike. The EC variations emphasize saturation (film backend), which foregrounds skin hue

Skin Color: The skin of the talent may be slightly more olive (dark and yellow in hue) or pale with pink as the primary hue accent (all vary towards magenta with emotion). Here is a recent still from the film I've been shooting, with two people in the same frame that had divergent skin hues:

Light Color Spectrum: On the Alexa (and cameras generally), filming under light that has a spikey color spectum (Leds, Flos, Sodium Vapor, etc.) can cast skintone distinctly to green or magenta, even with correct -

White Balance: A fully neutral WB is vital for EC, not only in skintone, but the whole of color space accuracy. Skintone is one of the reliable indicators that WB might be off on the green/magenta axis when under reference light without a white card reference (should anchor on the skintone line of the Vectorscope under sunlight and halogen). A common occurrence is that WB will be set for direct sun on the GH5 (possibly with the WB sun preset), and then the shoot will move into the shade, which will shift the WB towards blue/magenta (needs a new WB, or correction in post ahead of the conversion)

Lens Coloration: Interrelated with WB is lens coloration, which is like a WB that variably shifts throughout the grayscale [For EC: it is optimal to WB around middle gray, or a little brighter for the most salient part of the image]. This can vary from minimal coloration (Sigma 18-35) to heavy coloration (for example, Xeens). For NDs - the reference EC ND is the Firecrest FSND, which evenly cuts the full spectrum (visible/invisible). Non FSNDs (even IRNDs) will have a varying ratio between IR/UV and visible, which can unpredictably shift sensor response to a given light (interacting with the camera sensor's native cut). Variable IR ratio particularly acts on the green/magenta axis

Notably, EC Tungsten does have a slight magenta bias in the skintone region towards magenta compared to the Alexa. I've figured out what in the data was causing this problem (IR leak every third exposure slice), and this will be solved for the next release.

[Sage]

10 hours ago, kabuto1138 said:

Yes!!!  I am not joking when I say this, but a big incentive for me in probably buying the S1 would be emotive @Sage

Can't wait.

Thank you for the kind words! It may be a minute, so be sure to hang on to your 5 for the time being.

When a new camera is supported, it must be absolutely, sans compromise (on par with the 5)

[mirekti]

@Sage I was thinking of experimenting with HLG a bit, but didn't find much description in v3.0, only that PRE needs to be used.
What about the input Color Space in Resolve, is it supposed to stay Panasonic VLog or something else should be used?

[buggz]

22 hours ago, mirekti said:

@Sage I was thinking of experimenting with HLG a bit, but didn't find much description in v3.0, only that PRE needs to be used.
What about the input Color Space in Resolve, is it supposed to stay Panasonic VLog or something else should be used?

I found this a long time ago on another forum, I have been using GH5 opengate mode almost exclusively since then.  I like it.

- In Project Settings, under Color Management, Change to Davinci Color Managed
- Under Color Management select:
-- Rec 2020 HLG ARIB STD-B67 for Input Color Space
-- Rec 2020 HLG ARIB STD-B67 for Timeline Color Space
-- Rec 709 HLG ARIB STD-B67 for Output Color Space

[mirekti]

3 minutes ago, buggz said:

Rec 2020 HLG ARIB STD-B67 for Timeline Color Space

Should I have HDR monitor for this to be used on timeline? Rec 709 sounds correct to me, but of course I might be wrong.

[buggz]

18 minutes ago, mirekti said:

Should I have HDR monitor for this to be used on timeline? Rec 709 sounds correct to me, but of course I might be wrong.

Probably, I however do not have such, and the output looks okay to me.

Please let us know how you fare, eh?

Thanks.

[Sage]

On 3/16/2019 at 12:17 PM, mirekti said:

@Sage I was thinking of experimenting with HLG a bit, but didn't find much description in v3.0, only that PRE needs to be used.
What about the input Color Space in Resolve, is it supposed to stay Panasonic VLog or something else should be used?

Hey guys, just wrapped up the shoot I was on. For HLG + Resolve, keep the settings at default. The Pre is the CST, and is preferable as it is measured. One would either use CST/Color Management, or the PRE.

[Maxbrand]

I find that using the pre and then working as if I had shot in V-log works very well when using HLG. I was somewhat forced into this workflow when I bought the Ninja V because of the whole video levels thingy making v-log impossible to use if you want a reliable preview on the monitor. I find HLG more or less as good anyway though, so doesn't really matter much to me.

Some examples of using HLG with GhA: