Isn’t it amazing how time flies?! It’s been nine months to the day since I posted my initial reviews of the Canon C300 MKII: Part I and Part II. I’ve gotten so much great feedback from people as they started playing around with the camera, so I wanted to continue the conversation with my initial study of the camera’s newest feature: Canon Log 3 Gamma.
Back in April, Canon announced a firmware update for the C300 MKII at NAB 2016. Features of this update include:
Canon Log 3 Gamma
Improved Image Quality: Reduction in dark noise levels in Log 2, as well as a reduction in streaking and black sun spots.
ACES Output via SDI/HDMI
Magnify Function during recording
Additional Lens Functionality: Including Dual Pixel Focus Guide with the 17-120mm and Cinema Prime lenses.
While there are many features in here that we’re all excited about, I want to spend this post looking at the new Log 3 Gamma.
All of the videos and images included in this post are streaming from Vimeo with originally uploaded ProRes 4444 files, but there is an encoding conversion process that happens on the back-end. You can download them in full quality here. (As long as storage allows…!)
Throughout this review, I will be looking at the presets Log 2/Cinema Gamut and Log 3/Cinema Gamut. Previously, I placed Log and Log 2 together as a comparison, but I think it’s safe to say we won’t be shooting with Canon Log as much anymore, unless we are matching to an original C300. Since we have all had some time to get used to working with Log 2, I wanted to use this as a new baseline to compare against. I’ve heard from many people that they love the way Log 2 handles highlight roll off, but wish they could push it beyond the base of ISO 800. Personally, I am excited to use Log 3 so I don’t have to flip between Log and Log 2, depending on my lighting conditions. Thankfully, the noise reduction algorithms incorporated into this firmware update allow us the real possibility of looking at these two gamma settings side by side. If you remember before, I was recommending to not pushing Log 2 past ISO 800, and if possible, not above ISO 400. Thankfully, that’s not quite the case anymore.
There are some new Custom Picture Preset options available. Following in the footsteps of the Log 2 presets, you now have Log 3 presets in the following color spaces: Cinema Gamut / BT.2020 / DCI-P3 / BT.709. Same as before, each of these Custom Picture Presets allow you to use viewing LUTs on any combination of outputs: Mon & HDMI / Rec Out / LCD & VF. This is helpful if you aren't comfortable / equipped to work in the Cinema Gamut color space, or have specific needs for your final output and distribution.
In this test I look entirely at the Cinema Gamut preset. Since this offers the widest color space, you can see what the possibilities are. When working in a smaller color space, be aware that you may lose out on some color rendering.
I shot all of these tests at 1920×1080 RGB444 12-bit. This setup provides the richest color depth and highest gradient detail the camera can offer, so I chose to test noise with this in mind.
At the time of Canon’s announcement of Canon Log 2, people were in a tizzy of excitement/skepticism about the rating of 15 stops of dynamic range. As I showed you in my review, I found the DR to be more like 14-14.3 stops at the time of review. It also seems that with time, this uproar has slowed to a whisper. With the announcement of Log 3, Canon rated it at 14 stops.
As I said before, using a chip chart to test dynamic range has it’s pros and cons. There are many high quality charts out there that can give you a clear picture of what’s happening, but I tend to prefer the old fashioned method of real-world testing. I set up a gray card and lit it evenly with a soft light source. Then I simply over and under exposed the camera one stop at a time until I flat-lined at either 0% or 100% on the IRE scale. I said it before and I’ll say it again: Despite having minor fluctuations in values based on the lens quality and f-stop characteristics, but these are factors that will exist in the real world, so I am fine having them part of my test. The real reason for doing all of these tests in the first place is to give you a more accurate understanding of the equipment you are working with on a regular basis.
Canon Log 3
With still retaining detail, I’m getting 5.3 stops over middle grey and 6 stops under middle grey. At 5.7 stops over, the highlights completely flatline. You can see how 6 stops and 7 stops under have blended into the same line on the IRE scale, and the colors are indistinguishable. This gives me 12.3 stops of Dynamic Range in Canon Log 3. Again, Canon claims 14 stops with Log 3, so I don’t know if my results differ because of the testing environment or other factors, but I would rather have a real-world test tell me my acceptable range than a sterile testing room. I’m curious to see what others get.
Canon Log 2
Here, I’m getting 6 stops over middle grey and 8 stops under middle grey. That’s only 2/3 of a stop more in the highlights, but 2 solid stops in the shadows. Here’s where you see how Log 2 holds up on the range better than Log 3. This gives us 15 stops of Dynamic Range in Canon Log 2. This is a slight improvement from my initial tests. It may be because of the re-working of the sensor for both Log 3 and Log 2, or it might be as simple as slight differences in the testing environment.
Lastly, I get 4.3 stops over middle grey and between 5 and 6 stops under middle grey. You can see how you lose all detail in the highlights between 4.3 and 4.7 stops over, and you flatline at 6 stops under. This gives me 10.3 stops of Dynamic Range in Canon Log.
With the Daylight Exterior footage, we will exclusively look at the gamma settings as they relate to ISO 800, their baseline setting. At ISO 800, you get the maximum number of stops below and above middle grey. If you lower the ISO from there, you will end up compressing your highlights, with only 4 stops above middle grey ISO 160. I do not recommend going below ISO 800 with either gamma setting. And since you have internal extended ND filters up to 10 stops, why would you??
With the Night Exterior footage, I will look at ISO 800 as the base, but then push both gammas up to ISO 10,000 in a real-life scenario. All of these shots are un-graded, so keep in mind some of the noise you see in the deepest blacks of the shot will most likely be eliminated once you put a simple curve on the shot. For demonstration purposes, I wanted to show you what the footage looks like straight out of the camera. I’ll let you take on the grading tests yourself!
In this first series of shots, we are looking at Canon Log 2/Cinema Gamut. The series begins at ISO 800. While there is some noise in the lowest end of the shadows, these will basically disappear in the grade. As we move onto the next shot, we jump to ISO 5,000. The reason for doing this is I primarily want to look at the higher end of the ISO range and see how far I am comfortable pushing the camera. For a more incremental look at the Log settings, refer to the last video in the section. There is definitely noise in the image at 5,000, but if you remember the amount we had with the previous firmware (refer to Canon C300 MKII Review: Part 2 under ISO Noise), it has certainly improved. If I had to push the ISO with Log 2, its at ISO 5,000 I would draw the line. At 6,400 the noise is really starting to creep in, and by 8,000 its dominating.
In this next series of shots, we are looking at Canon Log 3/Cinema Gamut. Again, we begin with ISO 800 and move directly to ISO 5,000. ISO 800 is incredibly clean at Log 3. And at ISO 5,000, you can still barely see any noise. In fact, the little noise you do see (even up to ISO 10,000!) appears to me more of a textural element than anything else. There seems to be a difference in how Log 2 and Log 3 register the noise components of the sensor. I don’t know if this is true, or if there is something happening with the internal noise reduction, but there is definitely a difference in the grain structure of camera noise between Log 2 and Log 3.
Lastly, here is a side-by-side comparison of Log 2 and Log 3 as we incrementally step from ISO 800 to ISO 10,000.
Here, I will show you each incremental ISO from 800 to 25,600 for both Log 2 and Log 3 on the naked sensor. This is rolling the camera with no lens attached, just the port cap. I chose to not shoot ISOs below 800, because 1) highlight retention is compressed and yields ugly roll-off and 2) there is no noise in either Log 2 or Log 3 anyways. At the top of frame, I included a slice from the waveform monitor (showing just o-20 IRE in an RGB scale) to see when the noise begins to appear. As the ISO increases, you will see the black “line” incrementally get stretched taller. With Log 2, take notice what happens with the color beyond ISO 2000. The green channel begins to dominate the image. With Log 3, the balance of the green and red channels stays consistent throughout the ISO range. This has a significant impact on how the noise is rendered over your image and why the noise that is present in Log 3 is less noticeable and more pleasing.
CUSTOM LOG3 LUT
Working with LUTs in post-production is crucial when using Log footage. There are many LUTs floating around the internet, both from the manufacturer, as well as custom ones from third party companies or individuals. For myself, I have never been able to find a LUT that works for me. Since I do most, if not all, of my shooting with the internal BT.709 camera LUT, I figured this would be the best place to start. If this is what I’m seeing in the camera during production, it might as well be what I’m using as a starting place in post-production.
Unfortunately, the pre-built LUTs from Canon have never worked for me. They are always way too contrasty and never match what I’m seeing in camera. I took it upon myself to build my own. To build the LUT, I recorded a color chip chart (X-Rite Colorchecker Classic) in both Log3 and BT.709 straight from the camera.
In DaVinci Resolve, I placed both shots side-by-side and graded the Log3 footage to match the BT.709 footage. From here, I exported the grade as a LUT and voilà! I now have a 3D LUT I can apply to all my Log3 footage. Here is the LUT I built, so feel free to use it on your projects. Despite me loving it, I make this available to you at your own risk. Be sure to play around with the LUT and see if it works for you, and if not, feel free to tweak it or build your own. Happy shooting!
I hope you’ve found this initial breakdown of Canon Log 3 as useful as it was to me putting it together. I find that Log 3 does a great job sitting between the Log and Log 2 gammas. Log has much more contrast and less dynamic range, but retains the ability to push your ISO. Log 2, on the other hand, is very flat, has high dynamic range, but cannot handle a dramatic ISO push. Log 3 does a great job of balancing contrast and dynamic range with the ability to shoot in low light. Please share your comments and own findings below and I look forward to the next round of tests!