Understanding Canon's Wide Dynamic Range (WDR) Profile

Log gamma modes serve as the “digital negative” used to create the complex and nuanced images that devices of convenience can’t yet achieve. However, many productions stand on an uncomfortable middle ground. They often find themselves looking for an image that is clearly higher production value than what the common DSLR/Mirrorless or mobile devices can provide, but without the budget, time, or crew needed for the extreme high end. They need something better than the normal gammas and REC709 settings found in most consumer-grade gear, but a full Log Gamma and wide color gamut is prohibitive for their post-production workflow or would add too much time to the process. Canon’s Wide Dynamic Range or Wide DR gamma is just such a happy medium. We’ve talked before about Wide DR, but it seems especially relevant now as we move into this new world of remote productions and live streaming.

As the name implies, Wide DR is a gamma setting in many Canon cameras designed to fix some of the limitations of standard gammas, like poor highlight protection and too linear of a distribution of exposure values. That name might confuse, since expanding the dynamic range is the purported benefit of Log gammas, but the idea of Canon’s implementation of Wide DR has always been to give videographers, corporate clients, and new media professionals some of those Log benefits without the additional work required in post to finish those images. While it does expand the range significantly (especially for highlights), Wide DR is designed in such a way that it can be sent out with a minimum of adjustments to contrast, as well as be paired with a normal REC 709 color space without looking unnatural. It’s not unthinkable to shoot a scene in Wide DR and not need to make adjustments before shipping, if exposed properly. In fact, Wide DR is the gamma used in Canon's BT.709 Picture Style preset, available on a number of Cinema EOS cameras.

For that reason, it’s actually got another interesting use besides facilitating faster workflows – as an expanded gamma for a camera used primarily for streaming. AbelCine's instructors have been adapting by moving many of our courses online with virtual presentations and live streamed demos. Proper distancing and safety often dictate that the camera operator is also the subject. It can be a challenge to find a camera that performs well in this “unmanned” capacity, while also providing a good image.

One common issue is getting a good exposure for the presenter or instructor, while also making the various pieces of filmmaking equipment (which tend to be black on black, on even more black) visible, let alone clearly seen. In an educational capacity, it’s critical that attendees in the session can understand what’s happening with the gear, especially if it can’t be done in person. If the exposure is adjusted to highlight the equipment being taught, then the instructor is inevitably overexposed. Even with control of the lighting in the environment, it can be very challenging to get a balanced exposure. Certainly, other situations that have this problem are easy to think up. Especially for streamed content, there are many reasons to want one or two more stops of latitude where a full Log image, which must be color graded, is not an option. Especially if your content is going out live, it’s a bit too much to ask anyone to be the talent, camera operator, and live colorist at the same time.

To demonstrate the point, here are some sample clips, showing our Technology and Education Development Manager, Megan Donnelly, in our live streaming studio. These images are unprocessed “straight out of camera,” created by routing the signal from a Canon C300 MK II into a Blackmagic Design Mini Recorder and then simply recording the input through QuickTime Player on an iMac. I did it this way to simulate how the camera's signal might be translated through a video conferencing, meeting, or streaming software.

This clip is the standard REC709 Custom Profile on the C300 MK II with a typical exposure. While it has a pleasant enough look that doesn’t violate any expectations, it suffers from the obvious limitations of the gamma. Note the slightly too red skin tone that seems a bit too saturated.

Now we can compare to the same lighting and exposure settings with the CP settings changed to Wide DR gamma and REC709 color. Notice how the over saturation in the skin tone is gone, and Megan looks much more natural.

For a fair comparison, here is a version shot with Canon Log3, but still using the REC709 color gamut. Certainly highlights are well protected, and there is obviously a lot of latitude, but if we were to try to send this image out without grading it, it would be perceived as desaturated and flat. It would not be unfair to say that it lacks a bit of life. Again, Log gammas are not intended to be a finished image. They are expected to be put through at least a minimum of contrast, saturation and exposure adjustments to create the final image.

In these samples, the exposure has been intentionally pushed to the point that white in the image just reaches clipping. Obviously, these would be near a worst case scenario, but notice how the Wide DR image is extreme, but not ruined, and could likely be reined in if some exposure corrections could be applied. The 709 image is clearly destroyed, however, with many unrecoverable highlights.

For the sake of comparison, I’m also including clips shot with Canon’s EOS Standard profile, meant to more closely match legacy EOS picture profiles from cameras like the 5D Mark III, as well as directly from the webcam of the iMac used to record these. The very saturated look of the EOS profile will be familiar to anyone who shot in the early days of the DSLR revolution, and serves as a good stand in for consumer/prosumer cameras without the Wide DR mode. The computer webcam is comically overexposed despite the auto exposure functions and singlehandedly justifies the need to search out better equipment with gamma modes like Wide DR.

A C300 MK II was used for these clips, but the great thing about the hybrid nature of the Wide DR profile is that it is the meeting point of many of Canon’s cameras. Since it’s available on all cameras in the Cinema EOS line, it is fairly ubiquitous in Canon’s lineup, and Canon has even released official LUTs to convert Canon Log video from mirrorless and DSLR cameras, like the EOS R or an upgraded 5D Mark IV, to Wide DR to take the guesswork out of color matching.

So, if like me, you’re returning to trusted cameras like the C300 in these uncertain times, don’t forget about Canon’s Wide DR mode. It can save a lot of time and give you one less thing to worry about if you are finding yourself dealing with workflow complications. It’s a surprisingly simple to use and reliable tool to keep your images looking polished and professional, whether you need to have a quick editing turn around on your documentary, or you just want to have the best looking camera in the Zoom meeting.