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Sony/Arri color explained


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#1 Robin R Probyn

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Posted 08 February 2018 - 11:54 PM

Credit.. Alister Chapman..   just read this .. and its the first time I have ever seen someone make this comparison /explanation of the ever discussed "Arri look -Sony look"..  makes sense to me.. and typical of the Japanese mind set for everything to be incredibly accurate .. over the actual greater goal.. to make a video camera that produces nice images..  

 

"Arri's colour gamut is very limited compared to Sony's. The Alexa sensor has nowhere near the gamut of the F55 or Venice. But that is what gives the Arri cameras their out of the box look. One of Sony's problems has always been the effort to produce an accurate large gamut image rather than a pleasing image. Point a Sony at almost any test chart and you will see very few problems in the colorimetry. But often accurate isn't as pleasing to look at as more artistically adjusted colors. "


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#2 Mark Kenfield

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Posted 09 February 2018 - 10:26 AM

Would explain why the Sonys yield nicer images with the more limited Sgamut3.cine
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#3 Albion Hockney

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Posted 09 February 2018 - 11:54 AM

This is interesting - but the idea that Sony color is accurate and Arri color is optimized for a "pleasing image" feels very vague. Why wouldn't accurate color be pleasing? Is there any information on what is actually going on inside the Arri and how an engineer is "artistically adjusting the colorimetry"


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#4 Phil Rhodes

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Posted 09 February 2018 - 12:06 PM

The "Alexa look" is, at the end of the day, just a colour lookup table that can be approximated in any reasonable camera (the Sony "Rec. 709 Type A" is far from unreasonable.) 

 

It is reliant, to some extent, on the behaviour of the sensor, which is very low noise, but that sensor is now far from leading-edge technology and its capability in terms of colorimetry and dynamic range is not unmatched.

 

The fundamentals of it are desaturated highlights and some fairly tricky multiplicative and divisive stuff (video engineers would call it "matrixing"). This has been much talked about as effectively emulating the subtractive colour model of film in the additive colour model of a digital cinematography camera, but it seems intended to prevent saturation falling off with luminance, at least as much as is practical.

 

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#5 Albion Hockney

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Posted 09 February 2018 - 12:12 PM


but it seems intended to prevent saturation falling off with luminance, at least as much as is practical.

 

 

Most of this is over my head! but the last thing you said - this seems quiet important. As the Alexa has very rich color in shadows. Looking that the Venice footage this is something I noticed was lacking.


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#6 Robin R Probyn

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Posted 09 February 2018 - 07:40 PM

The "Alexa look" is, at the end of the day, just a colour lookup table that can be approximated in any reasonable camera (the Sony "Rec. 709 Type A" is far from unreasonable.) 

 

It is reliant, to some extent, on the behaviour of the sensor, which is very low noise, but that sensor is now far from leading-edge technology and its capability in terms of colorimetry and dynamic range is not unmatched.

 

The fundamentals of it are desaturated highlights and some fairly tricky multiplicative and divisive stuff (video engineers would call it "matrixing"). This has been much talked about as effectively emulating the subtractive colour model of film in the additive colour model of a digital cinematography camera, but it seems intended to prevent saturation falling off with luminance, at least as much as is practical.

 

P

 

Yes there is that saturation with luminance thing..emulating film and it looks great .. but thats only in 709..(you can get the same from a Sony but you have to shoot Slog and add a LUT.. quite a few Arri look out there..but in Log (well Slog3).. and RAW that wouldn't apply..and as you say then its all down to LUT,s.. and or the skill of the colorist ..?  Arri have been clever to get a very nice out of the box look in 709.. where as Sony seem to not bothered with that.. and just stuck with getting the most accurate look..


Edited by Robin R Probyn, 09 February 2018 - 07:50 PM.

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#7 Robin R Probyn

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Posted 09 February 2018 - 07:52 PM

This is interesting - but the idea that Sony color is accurate and Arri color is optimized for a "pleasing image" feels very vague. Why wouldn't accurate color be pleasing? Is there any information on what is actually going on inside the Arri and how an engineer is "artistically adjusting the colorimetry"

 

"Why wouldn't accurate be pleasing.". you want to put Rosco,Tiffen and every colorist out of a job ..  :)..   from what Ive read.. Arri in 709 mode as luminance goes up.. they do some clever thing with saturation levels... emulating what film does.. in 709 mode


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#8 Ryan Emanuel

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Posted 09 February 2018 - 08:19 PM

Personally speaking, I think the issue with the sony look is not about color hues or color saturation, as much as its about color luminance.  At least from what I have read, over 75% of the code values assigned to reproducing colors are above middle grey.  Sony really wants to produce clean images so it maps colors to be brighter to get a higher bit depth for colors.  Darker colors feel richer and more filmic, but with digital cameras they usually producer a noisier image since those bottom stops have the least amount of code values.  And you will hear a larger uproar about noise than color, so sony didn't map the colors lower. Total speculation, but when I drop the luminance of the colors with a YUV color space node, the sony look starts to fade. 


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#9 Feli di Giorgio

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Posted 13 February 2018 - 05:06 PM

I think Arri spoke to a lot of DoP and what they came away with was that people wanted a digital incarnation of Kodak Vision.

There are many tests out there with Alexa shot side by side with Vision and they are extremely close. Of all the digital cameras the Alexa reacts to exposure the most like film. Just look at what happens when you overexpose it. The Alexa fails 'gracefully', like film does. 

 

In the 1990's and early 2000's Arri had already done an enormous amount of research into digitally quantifying film with the Arri laser film scanner and laser film recorder. I would eat my hat if a lot of that R&D didn't end up in the Alexa color science.

 

Here is an article about Alexa color and saturation.

 

http://www.dvinfo.ne...-in-common.html


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#10 Bruce Greene

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Posted 14 February 2018 - 12:07 PM

I've color graded a few films now that I shot with Alexa.  And... I don't feel that the basic "Alexa" look is really film-like.  It looks pretty good by itself, but some technique is involved if one wants it to look more "cinematic" or film-like.

 

I've seen a few films recently at the cinema, most or all shot with Alexa and all of them have strayed from the "standard" Alexa "look".  And, I think one could get a similar look from any of the good digital cinema cameras that are in use today.  "Lady Bird" in particular had the look of 16mm film, sort of :)


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#11 Phil Rhodes

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Posted 14 February 2018 - 02:24 PM

I think it's also worth being aware that even Sony isn't giving us a true, accurate, by-the-book Rec. 709 look by default. Such a thing would look utterly horrible, with screaming colours and terrible highlight clipping that nobody would tolerate. Everyone is tweaking for prettiness, which is one reason I have little time for the real pixel peepers who like to sit there with vectorscopes and macbeth charts and voice criticism as if there's anything objective about any of this. One is free to dislike the look of a camera and to criticise it, but one is simply disagreeing with the opinion of the engineering team who designed it. That's fine, but the camera isn't wrong. Unless it's an AJA Cion, then it's wrong. And in a few other cases. OK, sometimes people are pretty stupid, but it's rare.

 

There is a well-known web commentator who often complains about separation of certain hues in Sony cameras and tweaks the matrixing (a dicey proposition at the best of times) to produce what he perceives to be a fix. I think he makes everything look slightly wrong, but that's just an opinion. What's actually happened is that he's ended up carefully characterising his own visual preferences in terms of a vectorscope trace and airs the results with the air of a scientist presenting a carefully-prepared research paper.

 

Mutter, grumble.

 

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#12 Robin R Probyn

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Posted 14 February 2018 - 11:01 PM

Only one :)... 


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