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GH5 to Alexa Conversion

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11 minutes ago, Sage said:

Right, all adjustments (apart from white balance) should follow the conversion.

Ok cool, that makes sense. But if we ettr should we bring that down before the lut? And that said, do you recommend ettr or are you of the belief that there is better tonality from exposing properly and not to the right?

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Sure; it depends on what you'd like. Fuji and BMD have very good, usable color. I personally will use P4K with GH5; I hope to have EC to do a production this summer. 8 bit is tricky; I'd prefer t

"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 ever

Emotive Color Version 3 Core LogC Details - Rewrote engine to work at 65x65x65, main files are now at eight times resolution (supporting files processed at that resolution) - Fine tuned mu

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Yes, all exposure adjustments should follow the conversion. Technically speaking, exposing to the right will maximize signal to noise ratio, resulting in less noise. With native color, there is a penalty to ettr because rolloff is problematic. With GHa, there is no rolloff penalty, so you can center the choice around protecting highlights as need be. Practically speaking, it will interact with GHa Soft for a different starting look. An underexposed image will be more saturated, and ettr will be less saturated and cleaner. Overall, the Main and Soft profiles were made for middle gray at 40 IRE.

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46 minutes ago, Oliver Daniel said:

@Sage, just bought your LUTS after seeing all these examples, looks like a no brainer. 

I'll let you know how I get on ;)

Excellent, please do. With current progress, I think it is reasonable to say that there may be some exciting news later this year.

Here are stills shared from David L'Abbée:


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Ok, so I have been running some tests under fluorescent lighting that I am pretty sure is somewhere around 4800-5200(not sure because it is ceiling light at work). I have some stills here with the GHa tungsten then daylight applied and I am curious what everyone thinks looks best? @Sage Do you recommend using Tungsten for fluorescent or daylight? I also attached my film print graded version. I am really liking the way the GHa lut is grading! The highlight rolloff really is fantastic.





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Hey Jeremy; It can be a matter of taste, as technically there is no correct way at the moment. If above 4500, it is closer to daylight, and below, tungsten. And each tube will differ in it's spectrum, so the most fitting conversion may vary from it's proximity to one end or the other. Go with what feels most right ; )

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Its probably the cheapest working Alexa ever sold, at $7800 for the body only (best offer). With shipping and minimal accessories, there was another 1.5k added on.

The seller neglected to mention (or didn't know?) that it had a history of salt water damage (I called Arri about the serial number). What this amounted to is that the SD card slot wasn't working when I received it. I got creative and cleaned the contacts in there, and it worked (the electronics in the cam are water-sealed after all). The upside of this is that it is a very recent model, with only 536 hours on the body.

I intend to make a reference quality color conversion for a variety of cameras, with side by sides to document the conversion. And then, I'll probably use it for close ups and 120fps slow motion for a narrative thereafter

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Which display do you use to record patches from? We discussed earlier that you don't want to tell what you do with out-of-gamut colors, but maybe you can tell me if those are simply extrapolated or you use some other kind of sorcery, maybe recording a few values from real life? You can reply in private if that's better. The reason I ask is because I also do conversions the same way you do, with my own software, and the values my monitor can't show are extrapolated, which is always to be taken with a grain of salt. I could use some hint from someone with more experience. I'm no competition btw, if that matters.

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So I've been doing a ton of testing with VLog L and various conversions, techniques, profiles, etc. I ended up doing a head to head test with the Alexa Soft (Daylight) Rec 709 vs VLogL to V709_100 (Panasonic's default VLog conversion). Using ONLY curves and MAIN saturation slider they look extremely similar. I did no modifications to color channels.

Alexa Soft 709:


Varicam conversion LUT:




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