Canon's color science is wrong in the right way / Matching Alexa Color

[jcs]

Canon cameras sell very well because they make people look great by creating very pleasing skintones. Apparently for technical reasons (silicon sensors, etc.), Canon makes skintones look great at the expense of color accuracy. ARRI is the undisputed* King of Color Science and reading about how to make a C300 somewhat match an Alexa may be helpful in setting up new cameras such as the GH4 and A7S to produce more pleasing skintones (at the expense of color accuracy): http://provideocoalition.com/aadams/story/color-matching-a-canon-c300-to-an-arri-alexa

 

Art noted that digital cameras do the best in daylight (~5500K) due to sensor response to blue. While I too have noticed that Sony, for example, does much better in sunlight, I've found that cameras also do well in Tungsten (~3200K). While Tungsten doesn't have much blue, it is a continuous spectrum light, and that I believe is the most important issue.

 

Cameras have the most trouble in mixed light (fluorescent + incandescent + LED, etc.) or light sources with large gaps in the spectrum (some fluorescent and many LED lights). I had no idea what kind of light this was, however AWB with the A7S wasn't too far off (minor WB adjust in post: still a bit magenta but that's the look I wanted):

 

In the Art Adams article above, he had to make custom profiles (mostly the special Color Matrix) for each desired color temperature (two provided). This makes it clear that getting pleasing (and/or accurate) color for a wide variety of color temperatures and light sources is a very challenging technical problem. Face/skintone detection is one way manufacturers try to deal with the problem (regardless of race, all skintones have similar color properties (along the 'skintone' line on the vectorscope: ).

 

It's not likely there's anything we can do to picture profiles on cameras to improve color performance vs. factory settings for general use. If we tweak colors for a particular WB and light source, it won't be correct for another light source with different spectral properties. Thus, if someone posts a tweaked color profile that changes WB colors or general color matrices, keep in mind those tweaks might not work correctly for your particular situation.

 

 

_{* this is the internet, so the likelihood of disputing is much greater than zero. The Sony F35 and F65 can produce great color, and the new RED Dragon and associated color science is looking very good. The camera system most people prefer in terms of color is the ARRI Alexa (now +Amira).}

[Germy1979]

The Alexa.... The guys that designed that camera are still second to none.

[jgharding]

I like the Alexa/Amira best too! It still enhances certain tones it seems (like teal), but I don't particularly desire 100% accuracy, I just want something pleasant!

 

Sony colours are still very cool, with very blue greens. But then the Canon C series can't really do chroma green too well either...

[Guest Ebrahim Saadawi]

It's really interesting how every manufacturer has a specific colour science and a unique way of handling every specific colour.

Unfortunately, there isn't much discussion or information anywhere on the web to read into this. In fact if you search, you'll find that whenever this subject comes up, many claim it's not true and colour science is a myth.

so I hope this thread develops further. After all we have an incredible group of scientests in the EOSHD community ;)

[AaronChicago]

Art noted that digital cameras do the best in daylight (~5500K) due to sensor response to blue. While I too have noticed that Sony, for example, does much better in sunlight, I've found that cameras also do well in Tungsten (~3200K). While Tungsten doesn't have much blue, it is a continuous spectrum light, and that I believe is the most important issue.

 

 

Agree 100%. I've noticed that using either 5500, or 3200 works very well for true colors. LUTs also seem to shine on those 2 temps.

[GMaximus]

It's not likely there's anything we can do to picture profiles on cameras to improve color performance vs. factory settings for general use. If we tweak colors for a particular WB and light source, it won't be correct for another light source with different spectral properties. Thus, if someone posts a tweaked color profile that changes WB colors or general color matrices, keep in mind those tweaks might not work correctly for your particular situation.

That's why they use those small boxes, don't they?

[Pierre_move]

Some people even say that when a camera records raw, you can get the colors any way you want. Such bs it makes my head spin.. most of the color corrections made in the cam make it impossible to recover even the original color information back - it's lost forever. I really wonder what BM uses in their BMCC and BMPCC cameras - as the look they have gone the way to simulate some of the Kodak Vision3 features (the blue channel is a suspect) - but it ends up in a very big mess.

 

Also It's really astonishing that the only company which gets it right is Arri and to a small degree there was a success with Sony F35. Sadly.. analog is still the king and the more the company pushes to get the color to match the analog features, the easier the work with the cam is. Either it's just a matter we grew up on analog and therefore we love it, or that the analog really makes a better emotional connection to our primal brains. The first time I was photoshoping first pics from pro digital SLRs I was like "What the hell is this crap? What's with the colors?"

 

Btw that pic from a7s looks atrocious.. the skin tones, the weird magenta stuff in the background.. yuck

[jcs]

GMaximus- it would be cool if cameras had built-in software which could process a color calibration chart: shoot chart (pattern recognition lines up all the cells) then get accurate colors for those exact conditions.

 

Pierre_move- my favorite film stock is Eastman EXR 100T 5248 (Men In Black II, The Last Samurai, Fight Club, Kill Bill, Lost, Rear Window, more info here: http://shotonwhat.com/film-negative-stock/eastman-exr-100t-52487248?view=more). Would be nice to get that look straight from the camera.

 

Regarding the A7S still- I'm guessing the light source was sodium/mercury, etc., with a limited spectrum. The colors (lights) in the background are accurate. 

 

Here's another version where the skintones are precisely aligned to the skintone line on the vectorscope:

 

How would you change the skintones for your preferences?

[hmcindie]

 

Btw that pic from a7s looks atrocious.. the skin tones, the weird magenta stuff in the background.. yuck

 

It's funny how much people give credit to different cameras. Newsflash, give a pro a 5dmarkIII/a7s and it will still look good. The crew will complain like hell but in the end, they will make it work.

 

For example, that "atrocious" picture you complain about... would look about 99.5% the same on an Alexa. Funny. The difference is that an experienced crew would've changed the shot and white balance it around until the background looked slightly better. But it's not the camera doing it. Yeah weird, I know.

[jcs]

hmcindie- the skintones are right per the vectorscope- it looks right on all my monitors, MBP, iPhone, etc. The best way to improve the color on location would have been to illuminate the skin with a broad spectrum light. What exactly is wrong with the color? How would you improve the color for this shot in post?

[Pierre_move]

It's funny how much people give credit to different cameras. Newsflash, give a pro a 5dmarkIII/a7s and it will still look good. The crew will complain like hell but in the end, they will make it work.

 

For example, that "atrocious" picture you complain about... would look about 99.5% the same on an Alexa. Funny. The difference is that an experienced crew would've changed the shot and white balance it around until the background looked slightly better. But it's not the camera doing it. Yeah weird, I know.

99,5% the same? ROFL Well that's some bunch of ugly and smelly bollocks for sure.. you're probably colorblind or just way too biased. And when it comes to experienced crews... well of course if you can erase the shortcomings of many cameras with enough lights but that's not what we're talking about here. We're talking about the picture straight out of the camera, with average lighting, with mild color correction. Alexa can do magic even with less than perfect lightning and that's why pro filmmakers love it - the colors just never look wrong and the dynamic range saves the day in a lot of cases.. there's just never a color that looks totally out of place like with the most of the cameras.

 

Just check Shane Hurlbut's tests - the difference between the Alexa and the others is astounding in many many situations. Or check what does Art Adams write in other articles about the way that Alexa handles the colors http://www.dvinfo.net/article/post/making-the-sony-f55-look-filmic-with-resolve-9.html .. his articles are the best on the whole internet when it comes to the way that cameras spit out the colors.

[sunyata]

Turns out a lot of stuff I have was shot on an Alexa, so I thought I'd post two very different shows, 3 examples, to show how a wide range of final skin tone grades is typical. I think the main thing with the Alexa is it's flexibility, due in large part to how close they've come to a 2k film master in dynamic range, log-c profile, motion blur, sensor noise etc. In some cases all the stuff about pleasing skin tones is gone in favor of a dark, colder and often noisy look. In #1 you can see the softness of the 2k image - not just color science - helps with softening skin, concealing lines and make-up. In #2 you can see how grainy and dark the image can look - the cold fill light - the camera sensor isn't too dense. #3 almost no skin tone left in final grade. The motion blur overall looks like a film shutter. I have lots of examples of chase scenes, fights or explosions where this is really apparent. It's the opposite of the high density and sharp, but smaller sensor of the GH4, or the 4k with low bit depth, more compression of the A7s. Making an "Alexa-ish" LUT for the A7s couldn't hurt, but the image is still going to be totally different, especially with motion. But it doesn't really matter because soon we're all gonna be dead from Ebola, was just informed, have not yet verified. 

 

 

 

look at how blown out the neon sign is.. and no banding in the shadows.

[Nikkor]

I have been working with some Canons and ML raw this month and I think the "colorscience" sucks bigtime. The stills are the same. It might be pleasant to some people but they are horrible in my opinion. I wasn't happy with some colors in the raw files on the d800, but they are so much better than the canon stuff (h264 video obviously not). All the skins look too dark, too tanned, sometimes red... and there is no way to fix that if not by keying, but to me that's an extra step I don't want to do. Oh and the skins look too even, seems like it doesn't capture variations. That might be nice for pastel weddings, but that's it.

[sunyata]

I have been working with some Canons and ML raw this month and I think the "colorscience" sucks bigtime. 

 

If you're outputting RAW, wouldn't it mainly be due to bad interpolation from your software? Maybe you need to make a custom color transform for that camera?

[Nikkor]

If you're outputting RAW, wouldn't it mainly be due to bad interpolation from your software? Maybe you need to make something custom.

Ehm, raw stills in adobe camera raw, I don't think the mushy plastic pastel comes from adobe.

[sunyata]

Ah, ic... 

[hmcindie]

We're talking about the picture straight out of the camera, with average lighting, with mild color correction. Alexa can do magic even with less than perfect lightning and that's why pro filmmakers love it - the colors just never look wrong and the dynamic range saves the day in a lot of cases.. there's just never a color that looks totally out of place like with the most of the cameras.

 

Sure it looks pretty good. Still, the difference is 99,5%. Ever seen comparison videos where Alexa is straight up shot with other cameras? They are very difficult to spot from one another. Alexa has great highlight handling and an easy way to work with files with straight prores shooting. But don't spew this "magical never looks wrong" stuff, it just makes you look silly. Sony F65 is in many ways better.