The Blackmagic Cinema Camera: Can It Run with the Big Boys
You may have read my other article here on Creative COW, "Is the New Blackmagic Cinema Camera the HDSLR Killer?" That article was a direct comparison between the Cinema Camera and HDSLR cameras in general. But what if we went a step further? What if we compared the Cinema Camera to the likes of the ARRI Alexa, the Sony F65, and the RED Epic? Have I completely lost mind by comparing the Cinema Camera with the likes of "the big boys"? Making such a comparison is a very tall order to ask, but is it entirely out of the question? Let's find out. First, let me say from the get-go that in no way shape or form will I pretend that the Cinema Camera is a better camera to shoot a feature film with over the Alexa, F65, or Epic. But on the same token, it's not to say that shooting a feature couldn't be done with the Cinema Camera (if the Canon 5D Mark II did it, so will the Cinema Camera. I guarantee it). Also please note that this is an editorial article, and not a review article. In other words, as of this writing, I do not yet have my pre-release camera from Blackmagic Design in hand. With all that being said, I want to focus on one specific aspect of production that I feel the Cinema Camera will do extremely well in, even when compared to the likes of the mentioned "big boys". That aspect is chromakey production (blue/green screen shooting). Let's do a quick background on chromakeying in general to get up to speed on why this camera could possibly be the ultimate camera for the job. When shooting chromakey footage of an object, typically against green or blue, you want to maintain the highest amount of color data in the image, since that color data itself is going to be used to create a matte, which then in turn places the object you shot within a transparent background. Well, that's the hope anyway, as there are many parameters in which the quality of the pulled key (removing the green or blue background) is attributed from. This includes your set lighting, your chromakey software, and of course, the camera quality itself (lens, sensor, and format quality). So if you're able to produce great lighting, use a great camera, and process through great software, you'll generate an excellent key. But if any of the links in this chromakey chain are broken, the end result will be a poor chromakey composite. Pretty simple.
If you're shooting video on an HDSLR camera for chromakey production, you're missing out on a ton of color data that could otherwise be used to help process the key itself. In a round about way, you're loosing about three quarters of color data by running in compressed 4:2:0 chrominance space, one form of several compression techniques used for HDSLR format encoding. Combine that with 8-bit quantization through its H.264 compressed format (anywhere from a 20 to 35Mbps data stream), and you have multiple forms of compression that will take a toll on your chromakey composites. And then there's temporal compression, where frames after the I-frame (or "keyframe") are based on that I-frame, rather than each frame getting their own unique and complete image of data. Chrominance compression, spatial compression, temporal compression, macroblocking, predictive motion, ISO noise, aliasing, moire; it all starts to add up, and gruesomely so for chromakey production on the majority of current HDSLR technology.
I've been shooting chromakey production with our Sony EX1 for years now, which has an HD-SDI port that gives us full 10-bit output at a much more palatable 4:2:2 color space (half the chrominance data of full 4:4:4). That output then gets recorded to an AJA Ki Pro to ProRes HQ format, again at 10-bit 4:2:2 quality. Quite honestly, the chromakey footage looks stunning and allows us to pull an extremely easy and accurate key (again, combined with great lighting, and using Ultimatte, my preference of chromakey software for about 15 years now).
But this article isn't about the Sony EX1 to AJA Ki Pro workflow (as excellent as that workflow has served us over the years). The Holy Grail is to work with full 4:4:4 footage at a minimum of 10-bit quantization or higher. Enter the Cinema Camera with its 13 stops of dynamic range, fully recorded to 12-bit RAW format, either internally to camera (using its SSD slot) or externally via a Thunderbolt-capable computer. When debayered and brought into your favorite compositing application, you can work at full 4:4:4 resolution, at 12-bit depth no less; say farewell to jaggie edges and chrominance compression artifacts! Okay now, let's take a closer look at this and really understand what this means. There are only a handful of other cameras in the market that allow 12-bit RAW camera data capture, and those cameras cost extremely more by leaps and bounds. We're talking anywhere from 7 to 30 times more. Granted, the 2.5K resolution Cinema Camera doesn't shoot 4K resolution, but 2.5K isn't a slouch, especially considering most digital cinemas are still projecting 2K anyway. Let's not forget the fact that the Cinema Camera will also record at 10-bit ProRes and DNxHD at 4:2:2. So if you do not have the drive space to work in 12-bit RAW, you can just as easily use the ProRes/DNxHD alternative, which will still give you absolutely fantastic results. Granted, the purpose of this article is to explain the virtues of 12-bit RAW chromakey production in comparison to the "big boy" cameras, but sometimes, you just have to use a more efficient workflow due to tight storage limitations, and ProRes/DNxHD will definitely still deliver the quality you need. My EX1 to Ki Pro workflow has proven that to me time and time and again.
So for a camera costing under $3000, you can shoot chromakey footage that is as perfect and clean as anything out there the market can dish out (again, with the only real sacrifice being true 4K resolution if you truly needed it, and from a camera that processed real 4K resolution and not "pretend" 4K resolution). To me, the Cinema Camera is a revolutionary step for chromakey production. Some people will continue to regurgitate the old argument, "Oh, but that sensor is smaller than a Micro 4/3rd sensor." Guess what? For chromakey production, the size of the Cinema Camera sensor won't matter diddly wink. Going back to my tried-and-true Sony EX1 to AJA Ki Pro workflow, that EX1 uses a ½-inch sensor, and as noted, I'd get KILLER chromakey footage out of it. The Cinema Camera has a sensor that is more than twice the size of that EX1 sensor! But let's see other reasons why the sensor doesn't need to be overly large for this application. For starters, when you shoot chromakey footage, you generally want to stop down your aperture to keep it sharp so you do NOT have narrow depth-of-field (DOF). This way your edges stay sharp for the keying process. If your edges are soft due to extreme DOF, your chromakey software is going to have a tougher time keying that soft edge compared to a razor-sharp one. And remember, you can always add that narrow DOF look later in post to your chromakey composites if you want (for both the chromakey footage and your plate shot for the perfect balance in realism). Secondly, you wont need a huge sensor to suck up the light, because you're in a studio environment where you (should) have a lot of light control for both the green/blue screen, and for the talent/subject. So low light sensitivity flies out the window on a proper chromakey set. And as a final touch, bring the ISO value down for the least amount of noise as possible. I'm sometimes hired on set as a chromakey technical director to ensure the footage will key is as best as possible. This typically means I need to bring my own scopes to make sure the blue/green screen's chrominance is on target on the vectorscope, and the blue/green screen's luminance is at the correct IRE on the waveform (optimized for the software that will be doing the keying) and as flat and thin on the waveform as possible. When shooting with the Cinema Camera, I could simply hook it up to my MacBook Pro via Thunderbolt and use UltraScope (comes free with the Cinema Camera) to give me real-time metering of the waveform, vectorscope, RGB/YUV parade, and histogram. It's like this camera was MEANT for chromakey production!
And let's not forget the included license of DaVinci Resolve means you could shoot, key, and perform a quick grade and composite on set to see if you're shooting in the right zone. That's pretty sweet if you ask me.
In retrospect for chromakey production, the Cinema Camera has 13 stops of dynamic range, it records at 12-bit RAW in standard CinemaDNG format, the sensor size is more than adequate, we're not dealing with any chrominance sub-sampling garbage, we're not cleaning up compression artifacts, we're not smoothing out the affects of line-skipping, and we have built-in UltraScope hardware to ensure the entire chromakey shoot is on target. Brilliant. Simply brilliant. I seriously cannot wait to start shooting serious chromakey footage with this camera. For this application, DSLR cameras aren't even in the city of the ballpark this game is playing in. I dare think a Sony F3 or Canon C300 is even in the parking lot. For chromakey production, can this little $3000 camera play at a level with the likes of ARRI Alexa, RED Epic, and the Sony F65? From what it reads on paper, it sure does seem like it and seems like fair game. Time will tell once serious chromakey productions are lined up. http://blackmagic-design.com/products/blackmagiccinemacamera $2995 USD for the Blackmagic Design Cinema Camera available July 2012 Marco Solorio is a multi-award-winning creative media developer. He owns OneRiver Media (www.onerivermedia.com), a production and post-production facility located in the San Francisco Bay Area. Marco has been a longtime Creative Cow leader and contributing editor since 2002. You can also find him online at Twitter, Facebook and through his blog. Tweet #BMDCC to interact on Twitter regarding the Cinema Camera.
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