GH5 to Alexa Conversion

[tihon84]

15 hours ago, Sage said:

Skintone Raw Footage Side-by-Side

Download Here

GH5 VLog

Alexa LogC

White balance placed a touch magenta on the GH5, but I opted to only use GHa Main sans pre WB tweak

Perfect! Did you use white side of X-rite color checker for a custom wb?
Correct wb settings is still pain for me...

Here is a 2k PNG tests...

I set exposureto 42 IRE  using 18% grey card 

And custom WB using true white paper

Heheh :))) 

I noticed some contrast issues using AE2018. If you set Color settings to none, you will have more flat image... Keep it in mind... So i change it to sRgb... Looking to Waveform i conclude, that with sRgb Color settings i`m in right luminance level, i guess.

Next I attached the same vlog images, but with  sRGB color settings 

I don`t know why, but after GHa conversion it looks really overexposed... Strange

 

[deezid]

3 hours ago, tihon84 said:

I don`t know why, but after GHa conversion it looks really overexposed... Strange

Noticed this as well. To V-Log L to Log C conversion is pure magic though.
Very contrasty as well, in some images shadows are getting crushed.

[Sage]

Yes, I used the white side of the Video CC reflecting the key light, just a simple custom white balance with both cameras. I didn't do it with the raw test, but as long as you're close, you can always tweak in post (granted you captured the card, you can check if RGB values are the same etc.) E2, for example was shot entirely with presets, sometimes the wrong ones (at the time I thought the conversion would be preset based)

I haven't tested AE, but that sRGB setting looks correct. You can always check a workflow by looking where pure white and black place on the luma waveform, and crosscheck color with Premiere (w/ PREs) and Resolve. I do know that AE's 'Apply Color Lut' function can cause artifacts, so I'd recommend a 3rd party Lut plug-in if possible.

V2 handles exposure differently:

"Indeed, its quite surprising with Daylight at first view. Before, clean DR was rolled off into the noise floor for Daylight. This was not very smart; now the range is shifted to match the exact image that would come out of the Alexa at the given settings (for LogC). The Emotive Color component, in turn, extends the IRE ceiling upward, to achieve ideal contrast just above the noise floor, with logarithmic highlight rolloff. Shooting for this will, in effect, result in more meaningful highlight range.

When the exposure is bright (which material shot for V1 Day will likely be), this can be easily adjusted (thanks to the logarithmic approach) to return an ideal shadow floor and image gamma. This is covered on Page 8 ('Luma Placement')"

Linearity is always maintained, and luma isn't allowed below zero. The noisefloor is compressed, and a bit lower than V1. Everything is done on a very accurate calibrated Ips monitor, checking the image at 40fl in a darkened room. That said, black level is a tricky thing, as it can depend on back light, screen brightness, context contrast etc. Soft is the lower contrast, higher noisefloor variant of Emotive Color; this may serve you well

[Sage]

@tihon84

Following up on this, I've been testing AE with Premiere, and have found that the default 'none' setting is correct for Color Settings.

Is it native Log, or encoded to an intermediate format?

V2 Day exposure handling is notably different, and surprising at first - but when you get familiar with it, you'll love it. It's like 'swimming' in dynamic range

Here's an example of VLog with middle gray (that upper gray line) a bit above 40 IRE (you can safely target 40, this is a bit high)

[Sage]

5-10-18 Update to V2

- Emotive Color component branched into three routes: Main/Soft/Pop

- Main/Soft have V1-like luma placement (for brightly exposed footage)

- Pop maximizes highlight range (for base ISO darkly exposed footage)

- Relaxed Noise Floor

(The default no longer requires luma placement for bright exposure, à la V1)

[buggz]

I really need to learn how to use this...

[jns]

Hey,

first of all: I'm really intrigued by this idea! Sounds too good to be true  But I got a question. Inside of Resolve there's the color space transformer. If you'd put the transformer on the first node to turn vlog to arri clog und then on another node another transfer clog to rec709 (turning on luminance and color mapping), does it behave similar to your lut? Just curious.

 

PS

Any chance to get a student discount? *crossed fingers*

[Sage]

10 hours ago, buggz said:

I really need to learn how to use this...

Hehe, its not too tricky. The main things are:

 

1. Accurately white balance the shot

2. If you're not shooting V-Log (or you're using V-Log in Premiere), use the [PRE] file that matches the footage format ahead of the conversion

 

That's the gist of it. The PDF has all the fine points if you want to go further in depth.

[Oliver Daniel]

18 hours ago, Sage said:

5-10-18 Update to V2

- Emotive Color component branched into three routes: Main/Soft/Pop

- Main/Soft have V1-like luma placement (for brightly exposed footage)

- Pop maximizes highlight range (for base ISO darkly exposed footage)

- Relaxed Noise Floor

(The default no longer requires luma placement for bright exposure, à la V1)

Awesome. 

I've used this on my previous 2 videos and I'm loving the results. 

Just something to think about @Sage.... ...

I feel V-log can really hurt Variable Frame Rate footage, so I've been capturing it in Cine-V with the highlight /shadow curve on -2 / +2. In post, I've used a Cine-V to V-log conversion, then I've used your "Main" GHa conversion before any extra styling. It can look very clean and pleasing compared to shooting VFR in V-log. There's no room for error on exposure though! 

Wondered if you've thought about doing anything similar for your product range? 

[Sage]

8 minutes ago, Oliver Daniel said:

Awesome. 

@SageI've used this on my previous 2 videos and I'm loving the results.

Please, share your results! I always enjoy that

Try Cine-D (with the noted settings) - I made that PRE conversion (and tested all the settings) just for that purpose

That being said, with V2 I'm definitely a VLog guy. For accuracy and smoothness, nothing beats the directness of that conversion (even counting 8-bit concerns), and its something I might look into at some point for Cine-D

[tihon84]

On 10.05.2018 at 8:29 PM, Sage said:

5-10-18 Update to V2

- Emotive Color component branched into three routes: Main/Soft/Pop

- Main/Soft have V1-like luma placement (for brightly exposed footage)

- Pop maximizes highlight range (for base ISO darkly exposed footage)

- Relaxed Noise Floor

(The default no longer requires luma placement for bright exposure, à la V1)

can you send me this v2 update, please?

i got GHAv2 at 6 of may, so i dont have this v2 update yet

thank you

[Sage]

7 minutes ago, tihon84 said:

can you send me this v2 update, please?

i got GHAv2 at 6 of may, so i dont have this v2 update yet

thank you

Did it go to spam? What's your email?

[salim]

@Sage - any plans on  making this for Sony A7Riii or A7iii? 

[Sage]

2 hours ago, salim said:

@Sage - any plans on  making this for Sony A7Riii or A7iii? 

I could; its really a matter of access to the cameras. Is there any way to get 10 bit out of them?

I'm considering whether to expand beyond the GH5. If so, I want to pursue an absolute precision standard.

 

I've been using it on some of my footage today without grading,

Very happy

[tihon84]

21 hours ago, Sage said:

Did it go to spam? What's your email?

Yep, it`s in spam folder. Thank you!

[Jonesy Jones]

19 hours ago, Sage said:

I could; its really a matter of access to the cameras. Is there any way to get 10 bit out of them?

I'm considering whether to expand beyond the GH5. If so, I want to pursue an absolute precision standard.

 

I've been using it on some of my footage today without grading,

Very happy

 Sage I love those images. I will most likely be buying this coming week. Will probably have some questions but from what I can tell your PDFs will probably explain everything for me.

[Sage]

1 hour ago, Jonesy Jones said:

 Sage I love those images. I will most likely be buying this coming week. Will probably have some questions but from what I can tell your PDFs will probably explain everything for me.

Thanks Jonesy Jones, now I've got to go shoot a movie with it hehe

Feel free to reach out.

Stills from David L'Abbée:

[heart0less]

21 hours ago, Sage said:

I could; its really a matter of access to the cameras. Is there any way to get 10 bit out of them?

Unfortunately, there is no way. Neither internal, nor external capture.

[Sage]

6 minutes ago, heart0less said:

Unfortunately, there is no way. Neither internal, nor external capture.

I'd likely avoid log in that case (it'll be a lot of testing)

[salim]

On 5/8/2018 at 10:20 AM, tihon84 said:

set exposureto 42 IRE  using 18% grey card

@tihon84 - I'm curious how do you know you're precisely at 42 IRE? What is your workflow. I just a SmallHD and I have the waveform in one of my cards, but I didn't realize you can get that kind of a precise reading. Can you share some screenshots (that would be awesome) that shows your IRE regarding? Is there a different method than the waveform. I'm still fairly new about video stuff (despite doing photos for 20 years) so trying to absorb as much as possible from other group members. thanks!