(Credit: Sarah Tew/CNET)
As the successor to the 5D Mark II, the camera that jump-started the video SLR revolution four years ago, the 22-megapixel 5D Mark III has big shoes to fill. The new update will surely help professionals who need better quality, even if ordinary folks need not care much. Here's what Canon had to say about the news:
When shooting video, HDMI output makes possible the recording of high-definition uncompressed video data (YCbCr 4:2:2, 8 bit) from the EOS 5D Mark III to an external recorder via the camera's HDMI terminal. This, in turn, facilitates the editing of video data with minimal image degradation for greater on-site workflow efficiency during motion picture and video productions. Additionally, video being captured can be displayed on an external monitor, enabling real-time, on-site monitoring of high-definition video during shooting.
If you're not familiar with the mumbo-jumbo, 4:2:2 refers to the camera's "chroma subsampling" behaviour, and it's a significant step up from the 5D Mark III's current firmware, which compresses video down to 4:2:0 for HDMI output.
Video cameras capture both colour and brightness information, but typically don't capture colour information for every pixel. Moving from 4:2:0 to 4:2:2 means that the camera records colour information for twice as many pixels. (Adobe Systems has a good explanation of chroma subsampling if you're curious.)
The 4:2:2 rate means the 5D Mark III can be used to record higher-resolution colour information with an external recording device. That's useful for situations for such cinema usage where editors expect to adjust the colours through colour grading.
It's also a competitive step up. Nikon's D4 and D800 SLRs can output uncompressed 4:2:2 video via HDMI.
Note that the announced improvement is only for those recording video via HDMI output with an external recording device, meaning that they're not available for people recording video on a flash card.
"We cannot discuss future plans, but the current codecs in use on the 5D Mark III do not support 4:2:2 colour sampling," said spokesman Kevin McCarthy. Codecs are video and audio compression technologies, and the 5D Mark II and 5D Mark III use the H.264 codec.
Canon also said that the firmware will improve the camera's autofocus.
Currently, the camera can autofocus with a lens with an aperture of f/5.6 or wider. That means that Canon's 100-400mm zoom lens will autofocus at 400mm and its widest setting of f/5.6, but if you mount it to a 1.4x teleconverter to extend to 560mm and f/8, autofocus will stop working.
The new firmware will enable autofocus with this f/8 minimum aperture, though. That's something that's only been present on Canon's higher-end EOS-1D SLRs.