Magic Lantern 5D Mark III raw video and camera reliability


Image by Daniel Schweinerr (5D Mark III SSD attachment research)

The EOSHD 5D Mark III Raw Shooter’s Guide – book now available

Raw video recording on the 5D Mark III has been met with an overwhelming reception from users and a fantastic reception from most pros. Some are more guarded as they think their camera will blow up. What are the facts?

Raw doesn’t cook your camera

Uncompressed raw by its very nature is not processed in the camera. You do all the CPU intensive processing in post production with the raw sensor data. With the official Canon firmware the camera actually works harder as it needs to debayer and compress the raw data onboard the camera’s DIGIC 5 chipset, for 1080p video encoded to H.264.

No hardware components are pushed beyond the spec they were designed to operate at –

The Sensor

Raw data is sub-sampled (RGGB) from the 22MP sensor, using an electronic rolling shutter. The sensor sampling modes remained unchanged from the stock Canon spec and the sensor is doing what it does normally with the official Canon firmware. The sensor data is stored in memory during live view operation and Canon’s code uses this data to supply an image for the LCD, HDMI and video mode. Magic Lantern’s code simply addresses the memory containing the raw data and copies it to the compact flash card via the buffer.

Internal memory and buffer

The 5D Mark III’s internal memory is clocked to transfer data at approximately 700MB/s. Compact flash card memory runs far slower. In writing raw 1080p video to the card only 1/7th of the buffer memory’s performance is exploited. The card controller also operates within the spec it was designed for as 1080p raw video writes to the card at around 85MB/s. The card controller is designed for 167MB/s as per the new UDMA7 compact flash card standard.

No overclocking, no stress

Software isn’t the enemy of hardware – heat is. Hardware fails when it gets too hot, not through buggy code. Magic Lantern leaves all the CPU and memory clocks at their default MHZ. Their code is extremely professionally written and efficient. The camera has a temperature sensor and Magic Lantern reads this and displays it on the LCD.  As evident on any computer, merely copying data rather than processing it, isn’t taxing on the CPU. Obviously your Mac doesn’t heat up when copying a large file to a USB stick! Stress for silicon is considered in terms of heat, not how much data passes through it.

Reliability for paid work

Running development code on your camera on critical paid work assignments is not a good idea, no matter how much testing you do beforehand. Raw recording will reach a stage where it is extremely reliable and 100% tried and tested so it really does pay to wait. Magic Lantern for the 5D Mark III is still in the early Alpha stage of development. The raw recording module is even earlier in development and bug fixes are taking place virtually every day. Some confuse these bug fixes with the addition of new features. Instead a lot of the current development is focussed on making existing features work reliably.

Is there still a 4GB limit on continuous raw recording?

Not any more. Although I don’t recommend shooting hours of raw footage for events due to the sheer amount of data it would create.

Does HDMI work in raw recording mode?

Yes. I’ve had no problems with monitoring on my Small HD DP6. The camera currently uses the older 1.1.3 firmware from Canon so the HDMI output is only 720p and not clean, but in the future if Magic Lantern is updated for the newest Canon firmware it should even be possible to record high quality 1080p ProRes proxy files to an external HDMI recorder whilst recording raw video internally. A great feature.

Should I sell camera X since the image is now better on the 5D Mark III?

In my opinion raw video on the 5D Mark III doesn’t take away from the Cinema EOS series. Although image quality is now arguably better on the 5D Mark III than on the Canon C100 and C300, for those who migrated from DSLRs to the Cinema EOS cameras in the first place the reasoning still stands. Built in ND filters, XLR audio jacks, better ergonomics, broadcast ready codec, convenient to use, proven reliability and established workflow. There’s no right or wrong decision, no universally better or worse camera – it depends on the project and on the filmmaker. Personally, I always go for outright image performance and image control over practicality and ergonomics.

Other DSLRs and mirrorless cameras like the GH3, D5200 still have the advantage of being 1/3rd of the price of the 5D Mark III. The GH3 has a more flexible mirrorless lens mount, Speed Booster, 1080/60p and an articulated screen.

What about Blackmagic?

The more people shooting raw the better it is for Blackmagic because they are primarily a post production company. Their software, DaVinci Resolve, is in my opinion hands down the best tool for grading raw video in DNG format. 5D Mark III raw footage doesn’t yet open in Resolve because the DNG files seem to store a thumbnail and the actual full resolution raw image as sub-file. Once Magic Lantern’s Raw2DNG converter gives us Cinema DNG or fully compatible DNG sequences, I will be using it to grade my 5D Mark III footage and cutting out the length transcoding step in After Effects to ProRes. Oddly, considering it is Adobe’s own format, Premiere Cs6 does not yet work properly with DNG sequences – only supporting DNG at 8bit and giving a very poor image.

Blackmagic’s cameras are not very threatened either by recent developments because they still have unique features not found on the 5D Mark III for raw recording. There’s a mirrorless mount on the Micro Four Thirds 2.5K Cinema Camera and Pocket Cinema Camera, 4K, global shutter on the Production Camera, ProRes and Avid DNxHD recording in-camera and forthcoming compressed raw recording in-camera. The fact that Resolve is bundled with the Cinema and Production cameras is also a huge selling point.

Shall I learn a raw workflow?

There are a lot of existing 5D Mark III owners and photographers who now have the chance to shoot raw video with a free firmware update – a great opportunity. Until quite recently raw video workflows haven’t been accessible to enthusiasts, very low budget filmmakers or owner / operators who couldn’t afford Red. Ikonoskop and Blackmagic were the first to capitalise on this, and it turns out that now Canon are the next through no making of their own! As computing power and storage capacities continue to increase hugely year on year, raw video workflows are becoming more and more viable for when image quality matters most. It pays to at least try raw, and get used to the workflow. That knowledge, for pros and enthusiasts alike could be very useful in the future.

Is there any liability for Canon or dealers?

The Magic Lantern project is very mature, with a team of extremely talented open source developers. Canon know their own source code and for their engineers in Japan, raw video probably doesn’t even come as much surprise. If Canon felt raw video recording was going to be a step too far, they’ve had years to block it off. There hasn’t been a single negative word from Canon (officially) about Magic Lantern. I think this is the best thing to happen to Canon DSLR video since it began with the 5D Mark II.

Disclaimer: all the information is correct to the best of my knowledge, based on close contact with Magic Lantern and my own extensive research and testing. I accept no liability for its use or application.