GH5 GH5 to Alexa Conversion
- Thread starter Sage
- Start date
Great news!
An EVA-1 version would probably come extremely close to the original ARRI Alexa.
Way better color science already as well as way better dynamic range, AND the lack of visible processing. Footage looks stunning going through the official ACES workflow already. Looking forward to hear about your findings.
Cary Knoop
Veteran
Going through some of the commentary here I would want to confirm that this LUT does not aspire to make a GH5 look like an Alexa, it is merely a tool to simplify color grading situations where both an Alexa and a GH5 are used?
Sage
Well-known member
A rule of thumb for in-between light sources is that if it is above 4300k, opt for daylight, and below, opt for tungsten. However, color spectrums can be highly variable, so feel free to experiment. I'm looking to do something to address this; it won't be in the look-up-table format.
It makes the GH5 look like an Alexa. The core LogC conversion allows it to be used as Alexa footage. There are two additional conversions which give a more ideal starting point than Arri's Rec709
Great news!
An EVA-1 version would probably come extremely close to the original ARRI Alexa.
Way better color science already as well as way better dynamic range, AND the lack of visible processing. Footage looks stunning going through the official ACES workflow already. Looking forward to hear about your findings.
Above all, the greatest priority is current GHa users (such as yourself
). To that end, I finished the code for the new color engine an hour ago. Still some supporting code to write tomorrow. I'm awaiting a few components in the mail - when they arrive, I will be able to test the code in full (also, I now have an Alexa). If everything checks out, exciting times ahead. If not, I have a lot of work to do
Cary Knoop
Veteran
In that case I would have to give your LUTs a big downvote!
Sage
Well-known member
Alright, thanks for sharing your thoughts. I think you'll really get a kick out of what I'm about to release
Cary Knoop
Veteran
I am sure you think it is so fantastic you would feel obliged to charge more than the $35 you charge right now.
Sage
Well-known member
Its a free update. As all updates have been, and will be.
A rule of thumb for in-between light sources is that if it is above 4300k, opt for daylight, and below, opt for tungsten. However, color spectrums can be highly variable, so feel free to experiment. I'm looking to do something to address this; it won't be in the look-up-table format.
It makes the GH5 look like an Alexa. The core LogC conversion allows it to be used as Alexa footage. There are two additional conversions which give a more ideal starting point than Arri's Rec709
Above all, the greatest priority is current GHa users (such as yourself
Sounds cool. Can't wait to see the results.
Blue looks better already, especially with bright saturated reds interestingly.
Sage
Well-known member
Sounds cool. Can't wait to see the results.
Blue looks better already, especially with bright saturated reds interestingly.
The Blue update was the most significant to date; the emotive color component (Main/Soft) uses Arri's specified primaries at its core for the correct interpretation of LogC. All the colors seat correctly (and reds no longer keep me awake at night). Next, LogC.
INTERNET: bringing unlike-minded people to fisticuffs since 1992!
Thanks for the relevant, supportive, and helpful post. On that note, your mama is ugly!
Cary Knoop
Veteran
I am sure you work hard to make things look good but one can't claim the impossible.
No LUT can make a 12 stop camera into a 14 stop camera and no LUT can invent colors from a smaller gamut into a wider gamut.
And why stop with Arri, I am sure there is a market for folks who rush to fan out dollars for a Red LUT as well, you know a LUT that makes your GH5 look like a Red camera.
But the top would be to sell the Ultimate™ LUT, the LUT that makes a GH5 look better than an Arri and Red combined!
And I have not even started with the Hollywood Line™, take a blockbuster film, make a LUT and bingo, your GH5 now turns into an instant Star Wars look.
Why bother color grading at all if you have the Ultimate™ LUT and the Hollywood Line™?
By the way if someone wants to be in business selling products, which I think is an admirable thing, I would expect an About page on the website proudly presenting and identifying the people behind the business, instead of only having an email contact, no name, no business address and a domain registration through Panama.
Last edited:
CONSTRUCTIVE Criticism is GREAT! Just ragging on something is a complete waste of everyone's time. Doubt anyone using GHx cameras is stupid enough to half believe a LUT is changing a cameras Dynamic Range. But, matching usable color look with the world's number one cinema camera? Makes excellent sense. Keep up the good work.
Sage
Well-known member
I hear you. Look-up-tables, by virtue of their accessibility, have been much used - and misused. As an abused tool, they rightfully carry a reputation, and there is a lot of snake oil out there; the burden of proof must be on the creator.
For what its worth, I've never made a claim to match dynamic range or widen the gamut. There is an accelerated rolloff, and if anything, the perceived dynamic range is lessened with needed clipping corrections (though all data is preserved). For saturation extremes, I've done my best to place the curved color range in the correct space, and correct for the curvature. In practice, the visible impact of this color region is *very, very minor (least of the difficulties in development)
Random aside about Red; in '08 I was absurdly fanatical about Red! But in 2011 I promised to myself I would never use their cameras, after what happened with Scarlet. I have since kept the promise (though people have been requesting Red to Arri... I'm torn about that)
Anyway Cary, I appreciate your critique
That's a good idea. As a design/Apple obsessive, the original single-minded thought was: 'Clean, simple and only three pages!', with the About Me info relegated to the opening video. My name is Alex, and my address is my home (which is private - perhaps a PO Box is in order). This needs more mustard, and will be amended
For what its worth, I've never made a claim to match dynamic range or widen the gamut. There is an accelerated rolloff, and if anything, the perceived dynamic range is lessened with needed clipping corrections (though all data is preserved). For saturation extremes, I've done my best to place the curved color range in the correct space, and correct for the curvature. In practice, the visible impact of this color region is *very, very minor (least of the difficulties in development)
Random aside about Red; in '08 I was absurdly fanatical about Red! But in 2011 I promised to myself I would never use their cameras, after what happened with Scarlet. I have since kept the promise (though people have been requesting Red to Arri... I'm torn about that)
Anyway Cary, I appreciate your critique
That's a good idea. As a design/Apple obsessive, the original single-minded thought was: 'Clean, simple and only three pages!', with the About Me info relegated to the opening video. My name is Alex, and my address is my home (which is private - perhaps a PO Box is in order). This needs more mustard, and will be amended
Last edited:
Sage
Well-known member
Thank you! And - will do.
Cary Knoop
Veteran
I appreciate your reply!
Cary, I think you're being a little unfair with your comments. People make a big deal out of a camera's DR, but overlook the fact that DR often evaporates as you raise your shooting ISO. For example a Sony A7SII starts out with 13 stops of DR at 200 ISO and this shrinks to 11 stops of DR once you reach 2500 ISO. So unless you shoot everything at the base ISO (which you might do with a cine crew and proper lighting), your DR could end up being a lot smaller than you might think it is. Also 14 stops of DR might have no advantage over 12 stops of DR depending on the subject you are shooting and your lighting.
I agree that you can't turn a GH5 or an A7SII into an ALEXA using a LUT, but you might be able to get the color and look of the non-ARRI footage to match close enough that many people will have difficulty spotting the difference between the two. ( I remember Zacuto's "Revenge of the Camera Shootout" from 2012, where they had several scenes shot with everything from the lowly Panasonic GH2 all the way up to the ALEXA and ARRI film cameras. Looking at the results many people were having difficulty determining which camera shot what, and this included a few well known Hollywood folks )
Sure if you have a full production budget almost everyone would shoot with ARRI cameras, but being able to imitate the ARRI look with a low cost LUT is a handy thing to have.
filmguy123
Veteran
Sage is nice. Sage makes a good LUT.
"Looks like an Arri" is a big statement but I don't think the implication is that it makes it an Arri or equates DR. A GH5 looks like A Panasonic; an EVA1 looks like a Panasonic; a VaricamLT looks like a Panasonic. They all have different specs. A LUT, which is concerned with color, created to make a Panasonic look like an Arri, seems implicitly clear that it is referring to the color rendition.
Valid questions, but I don't understand the implicit aggression without any pre-existing provocation.
Just my 2 cents - appreciate the resultant constructive dialogue though
"Looks like an Arri" is a big statement but I don't think the implication is that it makes it an Arri or equates DR. A GH5 looks like A Panasonic; an EVA1 looks like a Panasonic; a VaricamLT looks like a Panasonic. They all have different specs. A LUT, which is concerned with color, created to make a Panasonic look like an Arri, seems implicitly clear that it is referring to the color rendition.
Valid questions, but I don't understand the implicit aggression without any pre-existing provocation.
Just my 2 cents - appreciate the resultant constructive dialogue though
Cary Knoop
Veteran
I agree.
I certainly appreciate the work in trying to match the look of two different cameras. Certainly that is a time consuming thing to do. But it has limitations as well, unless you were to map the full color range over the full dynamic range there will have to be shortcuts. For instance matching two cameras with a single or even a few charts does obviously not address the full color space over a full dynamic range. That that is the case is already proven by the fact the author has two LUTs for different lighting conditions. Color correcting to match two cameras for a given scene is a more manageable task than trying to make an all-round matching LUT.
But I definitely see value. If you have a production with Arri cameras and GH5 cameras you might benefit from these LUTs. ACES is the alternative but you would have to tinker with the colors because the GH5 is not V-Log gamut, if you use it your colors will become too saturated. Making those changes under ACES is not easy and runs counter to the philosophy of ACES.
With respect to the Zacuto test, I think what differentiates cameras most with respect to image quality is how well the image can be manipulated in post production without breaking down. Nowadays practically every prosumer camera looks good but many quickly break down in post. For instance personally I love the GH5, I own one, but the weakness of the GH5 I find in the poor color quality of the highlights and the bad highlight roll off also the noise in the blue channel is bad.
Last edited: