January 22, 2014

Magic Lantern Has 'Magically' Pulled More Dynamic Range Out of Canon DSLRs for Free

Magic_Lantern_logo-whiteThose part of Magic Lantern are always hard at work tinkering away to give us mere mortals better cameras at zero cost. They were able to pull a rabbit out of a hat and give us RAW video on Canon DSLRs, which is a huge step up on video quality from the standard H.264 files the cameras normally record to. Now they've got another trick up their sleeve that can actually improve dynamic range about half a stop -- but there are some caveats at this early stage.

I had been following this story for a little while since Magic Lantern originally tweeted that a "sensor upgrade" was coming, and even though I was reading the exact thread related to the "sensor upgrade," the situation still wasn't all that clear, especially since the tech talk is pretty dense (not unlike how some NFS posts must feel to people just starting out -- including this one). This new hack has been tested the most on the Canon 5D Mark III and has a greater effect on RAW photos than RAW video, but a1ex has posted a detailed Q&A explaining exactly what's going on:

So, what's all this stuff about "sensor update"?

Just a small improvement in dynamic range in photo mode (around 0.35-0.5 stops). We were able to fine-tune the amplifier gains in order to squeeze a little more highlight detail.

Wait a minute, that means less noise, right?

Well, it means you get a little more detail in highlights. This doesn't mean less noise per se (the new ISOs will be just as noisy in shadows as the old ones), but it will let you shift the exposure to the right by 1/3 or 1/2 EV and collect more photons. This will result in lower noise.

For example, on 5D Mark III I could lower the ISO by 0.37 stops from 100, resulting a new ISO 77.

Magic Lantern Dynamic Range 5D3 77 ISO

And how the magic is actually happening:

How exactly are you getting more highlight detail compared to Canon firmware?

The signal from the sensor seems to be amplified in 2 stages: a CMOS amplifier (which operates in full stops - powers of 2 - and we have tweaked it when implementing Dual ISO) and an ADTG amplifier which can be configured in finer increments. After these two stages, the signal is digitized (with an ADC), probably tweaked digitally, and saved to CR2. We have noticed the ADTG amplifier tends to run a little "hot" (that means, it gets saturated a little too early - nothing to do with temperature).

To get the extra highlight detail, one has to reduce the gain for the ADTG amplifier until the ADC will no longer be saturated. At this point, the white level (maximum recorded level in the raw file) will begin to decrease and no more detail will be recovered (since now the CMOS itself or the CMOS amplifiers will get saturated instead).

Does this mean Canon did not fully optimize their sensor for low noise?

I'd say they simply left a safety margin in their code to make sure the ADC is always saturated (that is, to make sure white is always recorded as white).

The big gains are currently happening with the 5D Mark III, but it may also work with some other cameras:

- If you have a 550D or newer camera, it will most likely work.
- If you have a 7D, no idea yet.
- If you have a 5D Mark II, 50D or 500D, don't get too excited. I've barely got 0.15 stops of improvement on 5D2. 

Essentially what's going on is that Canon left themselves some headroom to make sure that the absolute white point is correctly recorded, so Magic Lantern has dug in and changed these registers to allow the user to shoot into that headroom.

It should be noted that this has nothing to do with the Dual ISO that we talked about last year. That is a different process entirely, but Dual ISO will work with this new dynamic range tweak, giving you well over 14 stops of total dynamic range. Dual ISO, as it turns out, is a bit easier to control in Photo mode, but it has quite a bit of aliasing in Video mode, which makes it less useful for those shooting video. This dynamic range tweak, on the other hand, shouldn't affect your shooting in any way except to give you more latitude to expose with.

So this is great news, but right now it's really only effective in photo mode -- in video mode it's not doing much of anything (0.1 stops according to a1ex). For a free dynamic range improvement, it's hard to complain, even if it's only 1/3 to 1/2 a stop improvement. Development is very early on this, so it's possible that RAW video might benefit more at some point in the future, but for now there is a definite improvement on the photo side. I'm always optimistic about what might be capable out of these cameras, so I wouldn't rule anything out yet for any of the Canon DSLRs.

If you want to experiment with this, the post over on the Magic Lantern forum has some links to the research tools. This means that these modules are experimental and really more for people who understand how to code and what they're looking for (but the links are there regardless). For more information, check out that thread.

Link: CMOS/ADTG/Digic register investigation on ISO -- Magic Lantern Forum

Your Comment

47 Comments

Finally something that'll light a fire under Canons but and start putting out real gear, well... We can hope right? RIGHT?!

January 22, 2014 at 10:38PM, Edited September 4, 11:45AM

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These dudes just overclocked the dynamic range on a camera...incredible.

January 22, 2014 at 10:39PM, Edited September 4, 11:45AM

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Won't be long before people start bricking their 5D's.

January 23, 2014 at 8:31AM, Edited September 4, 11:45AM

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Jorge Cayon

From all that we've seen so far I don't see why any cameras would get bricked at this point. And if that does start happening it will happen to the developers first and word would spread pretty quick not to try whatever build was responsible. But I suppose it is possible. Maybe Canon is banking on something like that happening and squashing the whole ML movement.

January 23, 2014 at 12:01PM, Edited September 4, 11:45AM

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Mark

If you understood how a 5D is actually made to record raw, you'd understand that the only thing in danger is your CF card.

Normally, a 5D is always recording raw and then encoding it to H.264. Magic Lantern just tells the camera to skip the labor-intensive encoding process and just dump those raw files on you card.

That's like ordering a nice steak at a restaurant and then having your waiter pour A1 steak sauce on it and then throwing it in a microwave before you get it. I'd rather walk over and get the steak myself and not have the waiter ruin it.

January 23, 2014 at 1:39PM, Edited September 4, 11:45AM

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Josh

So you prefer your steak ... raw. haha, you chose the best example, josh !

January 23, 2014 at 2:28PM, Edited September 4, 11:45AM

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feed_me_video

Nice one :)
But yeah home cooked meals are the best ones aren't they.. May be 'time-consuming' and 'lot of effort' to cook the final product but it will retain all the 'nutrients' :)

January 26, 2014 at 3:29AM, Edited September 4, 11:45AM

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Archie

Sorry, but that comment is based on misinformation or not knowing the ML development process.

In fact, even some Canon Reps. like and use ML...

HOPEFULLY Canon will improve their own firmware at least with some of Magic Lantern's Features, or hire these guys to work at Canon...

IT IS FRUSTRATING to see how Canon limits or "cripples" the BIG potential of so many cameras, including the 5D3 which is one of the most expensive DSLR today ($600 more than Nikon D800)

January 23, 2014 at 2:24PM, Edited September 4, 11:45AM

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I guess you work for Canon

January 24, 2014 at 1:20AM, Edited September 4, 11:45AM

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Guest

Bravo. Just goes to show you how the things in your hands are SO HELD BACK from what they can really do. Companies have gotten so big and so greedy they cock-block everything they make before you get it. They'd cripple their own mother to save a buck and charge you more.

January 22, 2014 at 11:15PM, Edited September 4, 11:45AM

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Bar

Still nothing for the 70D, eh? :(

January 22, 2014 at 11:26PM, Edited September 4, 11:45AM

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Brandon

Going by the rumors, 7D MK II ought to be announced shortly.

January 22, 2014 at 11:31PM, Edited September 4, 11:45AM

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DLD

Eh, you can't blame Canon for not squeezing the last ounce out of its sensors and processors. One never knows what this does to the reliability of the unit, etc. Fuming in this case is akin to blaming a car manufacturer for derating his engine to 300 hp rather than to its maximum possible of something like 350. (and, yes, that can be easily done by increasing the internal pressure, which would then lower the lifespan of the engine parts ... there's always a trade-off).

January 22, 2014 at 11:30PM, Edited September 4, 11:45AM

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DLD

I'm with you, it's sweet to hack but it comes with the "no guarantee" caveat... but if we buy a camera that fails because it's been pushed beyond it's limits we'd be blaming Canon.

January 23, 2014 at 12:31AM, Edited September 4, 11:45AM

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As article says: 'I’d say they simply left a safety margin in their code to make sure the ADC is always saturated (that is, to make sure white is always recorded as white).'
@DLD this has nothing to do with Maximum Ratings for electronics or sensor point of view. Similarily as digital thermometer doesn't last any longer does it show 37.0C or 99.9C it is just a digitized reading ftom analog signal from sensor. In theory snesor now gets a bit more light, but in practise it doesn't burn off (unless you leave it in sensor cleaning mode under direct sunlight, which is the case with most smartphone cameras without mechanical shutter:-).

January 23, 2014 at 2:25AM, Edited September 4, 11:45AM

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targon

Tell that to my two GH2's that got bricked while hacked. One ran for 30 minutes in a Ferrari GT3 doing laps @ 144Mbps and the other @88Mbps while shooting a music video with takes no longer than 3 minutes. Things don't tend to be over engineered, especially at this price bracket.

January 23, 2014 at 8:34AM, Edited September 4, 11:45AM

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Jorge Cayon

gh2 is different - not raw

ml is safer

January 23, 2014 at 3:36PM, Edited September 4, 11:45AM

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heather

@targon - you're making a compelling argument. My reply is that marginal improvements will most likely entail only marginal risks. Large scale mods might entail much larger risks. And, with regards to ML's crowning achievement of providing Raw capabilities to 5D MK III videos, almost simultaneously Canon released its own firmware upgrade, which allowed a clean HDMI out. After that point, you could connect an external recorder such as Atomos Samurai and record ProRes. Or you could take some risks and go with the free ML Raw hack. Given the odds of bricking a $3,500 camera, adding an external recorder was a worthy alternative. Fortunately, the ML hack proved to work in most instances but they don't always work as intended.

January 23, 2014 at 8:43PM, Edited September 4, 11:45AM

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DLD

That makes no sense. They are the manufacturers, they are the ones who know the limits of their products, because they should test them extensively. So they do know up to where they can be pushed. The "no guarantee" comes from the ML team, who are working blindly, pushing a product which they didn't design. They do what they can without any help from the manufacturer.

January 23, 2014 at 5:52PM, Edited September 4, 11:45AM

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maghoxfr

Question - I've still got my 550D, is there any more news if I can use ML to record continuous RAW 25fps 720p or higher? many thanks

January 23, 2014 at 2:57AM, Edited September 4, 11:45AM

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shaun wilson

The max on continuous raw recording is 1152x432 on the 550D.

January 23, 2014 at 8:55PM, Edited September 4, 11:45AM

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Henry

Still no sound during RAW shooting?

January 23, 2014 at 3:18AM, Edited September 4, 11:45AM

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VinceGortho

here:
http://www.dvxuser.com/V6/showthread.php?317907-5DmkII-MLV-Raw-Video-now-with-48khz-Sound

January 23, 2014 at 4:05AM, Edited September 4, 11:45AM

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Thanks!

January 23, 2014 at 11:17AM, Edited September 4, 11:45AM

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VinceGortho

Hats off to the ML devs. You probably know it, but you are awesome.

January 23, 2014 at 4:06AM, Edited September 4, 11:45AM

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But to reiterate what I'm getting from the article, this little extra dynamic range is only good in photo mode, not video. So... nothing really for us video shooters to get excited about? Is the point of this article to drum up excitement that ML might be able to make it work in video mode down the road? Don't get me wrong, it's pretty cool that they were able to hack this for photo mode. But this headline being posted on a website primarily geared towards video shooters is a little misleading, don'cha think?

January 23, 2014 at 5:29AM, Edited September 4, 11:45AM

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brent

It's interesting, get over it dude.

January 23, 2014 at 6:27AM, Edited September 4, 11:45AM

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Kraig

Many of us use DSLRs for stop motion work and time lapse films. So this is useful for many of us.

January 23, 2014 at 1:56PM, Edited September 4, 11:45AM

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Martin

still no video at 10 bits?

January 23, 2014 at 7:03AM, Edited September 4, 11:45AM

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Nelson

14bit raw video thanks to the the ML team. Canon should just hand over the company to these guys.

January 27, 2014 at 9:55AM, Edited September 4, 11:45AM

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Lcky

Can't wait till they port this to the GH2

January 23, 2014 at 7:05AM, Edited September 4, 11:45AM

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Norm Rasner esq

I need this for Nikon already!

January 23, 2014 at 7:30AM, Edited September 4, 11:45AM

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Fabrice

Dont most newer Nikons have in excess of 14 stops dynamic range anyway?

January 23, 2014 at 7:59AM, Edited September 4, 11:45AM

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South of JHB

Not in video.. ;) and after iso 2000 the nikon sensor has less dynamic range when compared to the 5D3 any way, not life changing but something to have in mind..

January 23, 2014 at 10:42AM, Edited September 4, 11:45AM

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Michael

Yeah sure, but is this article talking about a dynamic range upgrade in video mode? Or stills?

January 24, 2014 at 2:05AM, Edited September 4, 11:45AM

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South of JHB

I got about 13.5 stops dynamic range on my Nikons (D800's) in video mode, that was a huge upgrade from the 5D2 (8 stops maybe)...
Also it's much more detailed than the 5D3 video and doesn't become unuable soft above iso 800.
Even iso 6400 looks multiple times better on the D800 with some noise reduction than the 5D3 without noise reduction (noise reduction is automatically applied and cannot be turned off on the 5D3).

January 23, 2014 at 1:42PM, Edited September 4, 11:45AM

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Henri

uh no

you do not have the same dynamic range with your Nikon as an Arri Alexa

lol nice try kid.

January 23, 2014 at 3:41PM, Edited September 4, 11:45AM

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heather

Not a single thing you've said in that post is true.

January 26, 2014 at 12:11AM, Edited September 4, 11:45AM

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Hubert

canon should work together with the guys of magic lantern. thew owe them a lot.

January 23, 2014 at 7:57AM, Edited September 4, 11:45AM

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geraldo

From what I have read ML has to wait for Canon to come out with a firmware update. Before they can try anything on the 70D.

January 23, 2014 at 7:59AM, Edited September 4, 11:45AM

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Michael Bishop

i hope it wont take long

January 24, 2014 at 8:39AM, Edited September 4, 11:45AM

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hellboy80

1. When using this hack, are you still shooting .CR2 files or are you shooting .DNG or some intermediate RAW file that has to be processed?

2. If .CR2, does this affect post processing (in LR or ACR)?

January 23, 2014 at 9:14AM, Edited September 4, 11:45AM

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Both DNG and CR2 files are fully usable right out of the box in Lightroom and Adobe Camera Raw. No change in the workflow is required.

January 26, 2014 at 12:12AM, Edited September 4, 11:45AM

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Hubert

I don't think it alters the raw file format or the workflow

January 23, 2014 at 1:03PM, Edited September 4, 11:45AM

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BTW, JPEG has just come out with a new set of standards that includes "lossless compression" as an alternative to Raw.

January 23, 2014 at 8:12PM, Edited September 4, 11:45AM

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DLD

+1 Interesting

January 26, 2014 at 3:33AM, Edited September 4, 11:45AM

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Archie

All the latest Nikons shoot about 12 stop in video mode which is already very good. The latest report is from eoshd who is testing the latest Nikon D5300 and his first report is that it is on par to the Blackmagic pocket camera in Proress mode.

Another thing is that the latest cameras like the Nikon d5200/d5300/d7100 are better in video (low light and no moire/aliasing) than the D800. I have both and I use the d7100 primarily for my video.

January 24, 2014 at 2:42AM, Edited September 4, 11:45AM

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Daniel