Wow, this is the first full frame camera that can produce raw footage. Something the Canon folks are trying to keep to their $30K high end cameras (you could really dislike Canon for crippling its mirrorless EOS-M and locking out video output with their prosumer cameras in favor of their C line). But their lenses are just incredible (the new 24-70 II and 70-200 II).
But the folks at Magic Lantern have hacked the Canon firmware to allow it to produce RAW video (vs compressed H.264) as Alex says on EOSHD:
Magic Lantern have done the seemingly impossible and given us a continuous raw recording mode on the Canon 5D Mark III. Once activated in the menus the 5D Mark III becomes essentially a full frame Blackmagic Cinema Camera and amazingly mine has not yet exploded. No more short bursts of raw, this is the real thing.
The image is leaps and bounds ahead of any other DSLR. We’re talking Alexa / Red league here, yet full frame. The first ever raw video shooting full frame camera at that. I’m getting continuous recording at a data rate to the card of 90MB/s and the camera hardly breaks into a sweat.
I shot clips in 1920×1280 mode. I also have some 3.6K clips (3592×1320) too unfortunately they are glitchy with some drop frames, but 3K or 2.5K might be doable, especially with a narrower vertical crop… 3000×1000 maybe. That is approximately Micro Four Thirds area of the sensor at 1:1. The quality is the same as a raw photo. 14 bit, 12 stops dynamic range.
The 1080p raw file sizes are similar to 2.5K on the Blackmagic Cinema Camera. Around 4MB per frame for 1920×1280 (great aspect ratio for anamorphic lenses, utilising a higher than full HD vertical res) or a much more space efficient 2MB for 1920×720 (2.66:1).