Color Science Versus Color Art with the Canon C300
As artists of a visual medium, we know when something looks "good" or "right" and we know something doesn't. Of course, "good" is a lot more subjective than "right," and that's part of the beauty of what we do. One of the things that directly determines such qualities of an image is the color science of the given camera we're working with. The color science of every manufacturer is different, and depending on the guts of the camera, each camera may differ as well. Art Adams at ProVideo Coalition has just posted a great, in-depth analysis of the various color matrices of the Canon C300 and what individual flair they bring to your imagery. Read on for some of his findings.
Sometimes I get so caught up in how inexpensive, convenient, or small new camera technology is -- not to mention the quality of imagery it can produce -- that I sort of forget the importance of video monitoring devices like waveform monitors and vectorscopes. I suppose if we're working on a set equipped with a DIT, this is something we can let them worry about, but I think it can certainly help us in the creation of an image to know the nuts and bolts of what's going on to produce it. Mr. Adams's post reminded me of the value such awareness can have. To incorporate a likely-overused metaphor, it's a bit like a painter who knows his paints, brushes, and canvas, who is then able to use all that to his advantage. This is why I've always loved being a geek for gear -- in the hopes of one day being able to use some of the tech to the benefit of an artistic endeavor.
To get back to the C300 specifically, Art's findings are really interesting. Not to mention the fact that I'm a bit out-of-touch (literally speaking) with Canon gear as of late, so plenty of his post was new to me. Here's Art on the basic interactions of gamma and color matrix settings:
In the past I’ve leaned toward using Cinema1 or Cinema2 gammas and one of the Norm color matrices, usually Norm1. “Gamma” is all about how the camera maps brightness values and is completely separate from color matrices, even though they share the same names—for example, there’s a Norm1 color matrix and a Norm1 gamma, but they don’t need to be used together. The color matrix controls, in a very fundamental way, how the raw colors captured by the sensor are combined into a “look,” and this look is not only unique to each matrix but, to some extent, unique to each camera.
He goes on to discuss trying to find a balance in color matrix choice -- one with the amount of saturation (or desaturation in this case) he wanted, but also with accurate color rendering. He says that the C300 matrices generally push a little green into the reds, while blues and greens tend to be undersaturated. He does note that all the settings seem to preserve a healthy skin tonality, saying his "the reason most of their matrices skew red toward green is [likely] to make sure flesh tones -- which contain both red and green -- always look good."
He also explains the tendency of some colors to become noisy given the dominant temperature of a scene: blue can pick up noise in tungsten light because the camera must gain-up to maintain the right overall color balance with the low blue levels of 3200 K. Something similar can occur with red in daylight, where greens can become noisy due to gaining-down reds:
At first this makes no sense: why would subtracting a noisy signal from a clean signal result in noise? As best I can tell it’s because when you subtract a noisy signal from a clean signal you introduce noise into the clean signal, because you’re basically leaving holes in the clean signal where the noise was in the noisy signal. That’s a little bit of a mind blower, and it’s really cool if you’re a geek like I am.
Whoa. Art also differentiates accurate and "pretty" colors, just like the "right" versus "good" mentioned above. He says that "some of the prettiest blues have some green in them," but your color matrix rendering pleasing colors may not be what you're after from a technical standpoint: "This is the difference between accurate color and pretty color: all of these matrices can look very pretty in certain circumstances, but not all are color accurate." He says that during vectorscope demonstrations he was doing at NAB, he discovered the EOS Standard matrix to be the most dead-on accurate, but not desaturated enough for his tastes when used in the field -- he explains he had to gain down saturation settings significantly to arrive at the look he wanted (coupled with Cinema2 gamma setting for its handling of highlight detail).
I won't take anything else away from Art's great post, there's a lot more detail and insight there -- not to mention the color red screaming into the camera, in a manner of speaking. How has the C300's color performance compared to other cameras you've shot with (assuming you've shot with it or played with footage)? Has it struck anybody as noticeably different from other Canon models?