Low Light Color Correction Test with the Canon EOS C700 FF

September 17, 2018
Gear News and Ideas
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It can be hard to differentiate yourself from the pack sometimes. We the filmmakers are absolutely spoiled for excellent choices with the current full frame cinema camera lineup. The Canon EOS C700 FF has frame rates, resolution, and bit depth in spades. But then, so do ARRI and RED. What is unique is the induction of the low-light capabilities of the C200 and C300 Mark II into the highest echelons of cinema technology. Canon cameras are known for their ”organic" noise at high ISOs, and the extent to which they hold true to their colors in the dark. So of course we had to put it to the test while we still had access to the C700 FF and our lovely Canon K35 cinema primes. And it did not disappoint, trust me. You’re gonna want to see this.

Should I Shoot RAW in Low Light With The C700 FF?

If you do intend to push the ISO on the camera, or really on any camera, you need to seriously consider shooting in a RAW format, or the least compressed options that you have. On the C700 FF, this means recording to the optional Codex CDX-36150 recorder instead of the default CFAST cards. It’s a bit pricier and more of a hassle, but in this scenario very much worth it. Compression and noise do not mix well, and in the worst cases, create nasty blocks of colors in the shadows and an overall loss of detail.

You want your shadows to be more even and smooth, even with noise.

In a compressed image, the camera tries to find similar-looking sections of the image and average them together. For example, a solid blue wall is incredibly easy to represent as just “blue.” But if that wall is filled with color noise, the compression might average every section of wall slightly differently. Your compressed image can end up creating sections of blue-green next to greenish-blue that weren’t present in the wall itself. In the worst-case scenario, the noise overwhelms the camera’s averaging algorithms, and the result is a mushy, blocky image.

Canon Cinema RAW footage has a very distinct advantage because of its uncompressed picture, which makes it much easier to clean up in post production. In our blue wall example, Cinema RAW would record every single pixel’s specific blue, ready for you to work with in post. And because it is a straight sensor readout, it will, by definition, be sharper than a ProRes or XF-AVC file would be. This gives you the neatest noise structure possible, for the easiest cleanup effort and the most pleasing final product. And while colors may begin to shift slightly in the high ISO range, shooting RAW gives you the most latitude to correct for this.

Best Practices for Maximizing ISO Performance

Whether you choose to shoot RAW or not, there are a few other things you can do to maximize your results in any lighting scenarios you might come across. The first is to simply pay attention to which ISO you choose. For example, when shooting with the C700 FF, throughout the camera’s whole range, you will want to stick to multiples of 800. So 1600, 3200, 6400, and 12,800 ISO will be your best choices. This is because these ISOs are created purely with analog voltage across the sensor.

Not to mention fast lenses. Those help too.

Digital ISO increases have a nasty habit of creating blocking and banding, as they push the already-captured image beyond its comfort zone and reveal its weak spots in the shadows of the image. Some call the resulting grid-like noise pattern the “screen door effect.” An analog increase in ISO will still generate noise, of course, but that noise will be much more scattered and random because it is organic, electrical, and evenly distributed across the sensor. And just to top it all off, finishing in 4K but recording a 5.9K image (read more about how) on the C700 FF will minimize noise even further. The pixel-averaging algorithm will be able to draw on the surrounding "true" colors, and in doing so average out some of the chroma noise. What's not to love?

Post-Production Pointers

Having shot all of your footage, you can now begin the post production process! If you have shot ProRes or XF-AVC, you can import directly to just about any grading for editing platform available today. For those of us that shot RAW, however, we will likely be evaluating different options for debayering.

There are many options available to you, but it should come as no surprise that Canon recommends their own software as the best solution for debayering the raw files, proxy creation, and even first–pass color correction. Within Canon Cinema RAW Development, your RAW footage can be debayered and exported in any of the three variations of Canon log. Canon Log, Canon Log 2 and Canon Log 3. That said, you can also move straight to a program like DaVinci Resolve if you prefer.

Canon Log 2 and Log 3 are such a breeze to work with

Our Real-World ISO Test - No Light, No Problems

Theory is all well and good, but we would be poor reviewers indeed if we didn't take the Canon C700 FF out for a test drive. So we ventured out to Chinatown in Los Angeles at night, and we found exactly what we expected – strong colors and controlled noise, from 800 to well above 10,000 ISO.

The next day, in Canon’s editing suite, we took our footage into Canon Cinema RAW Development, where we tweaked and played back our RAW footage. It cleaned up phenomenally.

4 Stops of ND, 16,000 ISO, 23.98, 5.9K

In shots like this, you can immediately see the advantages of analog gain-boosting over purely digital ISO. The still image doesn’t do it justice, but the noise in this shot is so alive and broken up that it is hardly noticeable in the moving image. Some noise is always going to be unavoidable at high ISOs, but that doesn’t mean it has to be ugly. The final, graded image shows off all 15 stops of dynamic range, and how much detail is preserved in the highlights, skin tones and the shadows.

No ND, ISO 800, 23.98, 5.9K

What amazes me about this image is the detail in her face, the soft highlights, and the amazing lack of noise anywhere but the extreme blacks. And even there, we see more issues from the compression of the export than the image noise itself. I think a lot of this detail and lack of noise can be attributed to the 5.9K supersampling - the pixel averaging algorithms in Canon Cinema RAW Development are simply outstanding. And you can tell that even from a compressed-for-web JPEG!

2 Stops of ND, ISO 2500, 23.98, 5.9K

The last image I want to highlight is this shot of Sarah standing under the extreme blue lights. This is truly a demonstration of the C700 FF’s superb handling of colors. The icy tinge of the blue is easily preserved in the grade, while the skin lands just about where you want it to - it hasn’t shifted magenta, it doesn’t feel yellow-ish. The lighting and the grade are harsh, but her face still feels grounded and true to life.

In Conclusion

Shooting RAW on the Canon C700 FF is not a decision to be taken lightly - it will incur tremendous data-storage costs, and complicates your post production workflow. But it is a tremendous tool to have in your pocket, as the 5.9K super-sampling and uncompressed straight-from-the-sensor image make noise reduction and color grading a breeze in high-ISO shooting situations. I wholeheartedly recommend it to anyone that can afford it. Just make sure to stick to your intervals of 800!

And if you want to test this camera for yourself, you can download some of our clips here, and download Canon's Cinema Raw Development tool here. Show us what you can do with it, and let us know what you think!

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Andrew Collings

I'm a filmmaker who sets up shop at the crossroads between a technician, a storyteller, and an artist. I enjoy reverse-engineering everything I see, whether that's a popular film, a vintage lens, or a rusty bicycle. I live for that moment when the solution to a once-unsolvable problem snaps into focus; when the purpose of a specific lever or edit or shot becomes clear.

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