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Magic Lantern Gives You 4K Raw Video for the 5D Mark III

Magic Lantern is a free software add-on that runs from the SD/CF card and adds a host of new features to Canon EOS cameras that weren’t included from the factory by Canon. Yesterday, Magic Lantern announced a new build that empowers the 2012, 5D Mark III to record 4K Raw Video Recording.

Here’s more from the website:

On the 5D Mark III, you now have the following new resolutions:

* 1920×960 @ 50p (both 1:1 crop and full-frame – 3×3 pixel binning)
* 1920×800 @ 60p (same as above)
* 1920×1080 @ 45p and 48p (3×3 binning)
* 1920×1920 @ 24p (1:1 square crop)
* 3072×1920 @ 24p (1:1 crop)
* 3840×1600 @ 24p (1:1 crop)
* 4096×2560 @ 12.5p (1:1 crop)
* 4096×1440 @ 25p (1:1 crop)
* Full-resolution LiveView: 5796×3870 at 7.4 fps (128ms rolling shutter).

The last feature complements the well-known full-resolution silent pictures – the new implementation will be usable at fast shutter speeds, without the exposure gradient – but with rolling shutter (just like regular LiveView frames).

Credits: Greg (full-width LiveView), g3gg0 (video timer, DIGIC registers documentation and lots of other low-level insights).

Complete list of new video modes:
Code: [Select]
/* 24p 25p 30p 50p 60p */
[CROP_PRESET_3X_TALL] = { 1920, 1728, 1536, 960, 800 }, /* 1920 */
[CROP_PRESET_3x3_1X] = { 1290, 1290, 1290, 960, 800 }, /* 1920 */
[CROP_PRESET_3x3_1X_48p] = { 1290, 1290, 1290, 1080, 1080 }, /* 1920; 1080p45/48 <- 50/60p in menu */
[CROP_PRESET_3K] = { 1920, 1728, 1504, 760, 680 }, /* 3072 */
[CROP_PRESET_UHD] = { 1600, 1500, 1200, 640, 540 }, /* 3840 */
[CROP_PRESET_4K_HFPS] = { 2560, 2560, 2500, 1440, 1200 }, /* 4096 half-FPS */
[CROP_PRESET_FULLRES_LV] = { 3870, 3870, 3870, 3870, 3870 }, /* 5796 */


Where’s the catch?

This is only a very rough proof of concept. It has not been battle-tested and has many quirks. Some of them may be easy to fix, others not so. In particular:

* It feels quite buggy. I’m still hunting the issues one by one, but it’s hard, as Canon’s LiveView implementation is very complex, and our understanding on how it works is still very limited.
* Write speeds are high. For example, 10-bit 4096×2500 at 15 fps requires 180 MB/s. 1080p45 should be a little more manageable at 111 MB/s.
* Canon preview is broken in most modes; you need to use the grayscale preview in the raw recording module.
* High-resolution modes (in particular, full-res LiveView) may cause trouble with memory management. This is very tricky to solve, as we only get 3 full-resolution buffers in LiveView, with restrictions on the order in which they must be freed, and lots of other quirks.
* Since these settings were pushed to limit, the risk of corrupted frames is high. If it happens, decrease the vertical resolution a bit.
* When refreshing LiveView settings, the camera might lock-up (no idea why). Pressing MENU twice appears to fix it.

May I fine-tune the new modes?

Yes! I’ve included some of the knobs on the user interface. Normally you shouldn’t need to touch these buttons, but if you do, you might be able to squeeze a few more pixels.

Does it work with FPS override?

Sort of. It’s not reliable at this point, so it’s best not to try yet.


During my tests, I didn’t manage to get a sensor temperature higher than 60 degrees. Your mileage may vary.

This mod changes some low-level sensor parameters that are not well understood. They were all figured by trial and error, and there are no guarantees about the safety of these changes.

As usual, if it breaks, it’s your fault, sorry.

Will it work on other camera models?

I hope so; however, this is an area where I hope to get contributions from others (yes, from you). If these new features don’t motivate you to look into it, I wonder what else will.

I’ll explain how all this works in the coming days or weeks.

Is it difficult to port to other camera models?

So far, the 3×3 720p mode from crop_rec was ported to EOS M (rbrune) and 700D (dfort). So it shouldn’t be that hard…

Will you port this to my camera model, please?

No, sorry. I have better things to do – such as, preparing the April 1st prank for next year 🙂

Wait a minute, didn’t you say you are primarily a still photo user? Why are you even doing this?

If you look close, the usefulness for video is fairly limited, as the write speeds (and therefore the recording times) are not practical.

But the full-resolution LiveView is – in my opinion – very useful for still photo users. Although the current implementation is not very polished (it’s just a proof of concept), I hope you’ll like the idea of a 7.4 FPS burst mode, 100% silent, without shutter actuations.

Right now, you can take the mlv_lite module with pre-recording and half-shutter trigger: at 10 bits per pixel, you get 5 frames pre-recorded, and saved to card as soon as you touch the half-shutter button. Or, you can capture one frame for each half-shutter press, with negative shutter lag! (since the captured frame will always be pre-recorded).

And if a burst at 7.4 fps is not enough, you may also look at the 4K modes (12-15 fps).

(I know, I know, GH4 already does this, at much higher frame rates…)

The help menu for full-res LiveView says 5796×3870, but MLV Lite only records 5784×56. What’s going on?

The raw recording modules have a couple of alignment constraints (e.g. can only start cropping from a multiple of 8 pixels, and the size of the cropped area (that goes into the MLV file) must be multiple of 16 bytes (that is, W*bpp/8 + H mod 16 must be 0).

To capture the full resolution, you may use the silent picture module. However, this module is not the best when it comes to memory management and buffering. Currently, you’ll get an impressive buffer of 2 frames in burst mode 🙂

But hey – it outputs lossless DNG!

What about that lossless compression routine?

It’s included, although I didn’t manage to test it much. There is a lot of room for improvement, but for a proof of concept, it seems to work.

Use at your own peril

Prior to downloading and using the OS, Canon USA asks you to consider that using Magic Lantern will void your warranty. Any issues you may incur with your camera as a result of using Magic Lantern are your problem. In an effort to achieve these results, Magic Lantern OS may push the sensor or processors of your camera past the point of what they were designed to go. This could cause a hardware failure, and Canon has no intention of footing the bill. A good analogy would be installing a nitrous system on a 4 cylinder Hyundai and driving at its max speed daily. It may, in fact, achieve radical performance, but it most certainly will shorten its life.

For more information about Magic Lantern, and do download the new OS, go to their website at:

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Written by Clint Milby

For more information, go to his website at


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