Magic Lantern firmware boosts dynamic range of Canon 5D III, 7D










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The folks at Magic Lantern are no stranger to adding new features to Canon DSLRs, courtesy of their EOS Camera Tool software. Their latest creation – called Dual ISO – dramatically increases the dynamic range of the 5D Mark III and EOS 7D by four stops, bringing the total dynamic range to 14EV. This allows you to pull detail out of the shadows with a lot less noise than with the ‘stock’ firmware. The technical details are complex, but simply put, it works by interlacing two rows of pixels captured at ISO 100 with two rows taken at a higher sensitivity (usually ISO 1600). The low sensitivity rows capture highlight detail, while the high ISO rows capture shadow detail. When they are combined, you get relatively noise-free shadows without blowing highlights.

According to Magic Lantern, there are some downsides to using the Dual ISO firmware, though. Vertical resolution is reduced by half and there’s more moiré and aliasing in over and underexposed areas. The author also warns that since this software modifies the sensor’s operation, you could end up frying your camera. If you’re feeling brave, you can find details on how to install the software here.

Dual ISO works for both stills and movies on the EOS 5D Mark III and for stills only on the EOS 7D. 

This example shows good shadow detail in the foreground, while the highlights in the windows are not clipped. Unfortunately, the author doesn’t provide a ‘before’ image, so it’s hard to see exactly what’s improved.

If the example above was filmed at ISO 100 to preserve highlights (in other words, underexposed), the foreground would be dark. If you tried to bring up the shadows in post-processing, noise levels would be very high. Filming at ISO 1600, on the other hand, brightens the foreground but clips the highlights in the windows. By combining these two images, you get the best of both worlds.









Comments


Henrik Herranen

One thing worth mentioning is that vertical resolution is halved only on the brightest and darkest areas where there is no tonal overlap in the two half-images. Midtones are at full resolution. And, if you use a less dramatical setting than ISO100/1600 (e.g. ISO100/400), the full-resolution overlap area is larger. Perhaps DPreview would like to correct this in the news blurb?
It’s all thoroughly explained in Magic Lantern’s documents, with graphs and all.


mini23

Come on DPR guys – I’m not a native English speaker but even I know approximately how to use apostrophes – what is sensor’s supposed to mean?

…this software modifies the sensor’s operation…
means as much as
…this software modifies the sensor is operation…


Robert98

It’s a possessive apostrophe – the operation “belongs to” the sensor, so it’s the sensor’s operation. Your example shows a different use of the apostrophe, to indicate a missing letter.


jadot

Native english speakers have learned how to use the possessive as well as the omissive. It’s the correct use.
The internet is rife with pedantic spelling and grammar policing, and I’m all for it, but it’s now got to the stage where people are getting upset at the mere appearance of an apostrophe.
Often, re-reading what is before you can save you from making an embarrassing mistake, grammatically speaking.


yabokkie

maybe +4 stops dynamic range from 70D at no cost of resolution,
but at the cost of near 1 stop worth of SNR ?


Photog74

Sounds like an excellent trade-off to me.


yabokkie

exactly. 1 stop worse SNR in highlight is not a big deal, especially at low and mid-range ISO settings. for high ISOs underexposure works well now (in a different direction though) and there is no difference between Canon and Sony sensors for ISO > somewhere between 800 and 1600.


planetMitch

This update from Magic Lantern will not work on anything but the 5D3 and the 7D. Our original report (which petapixel used as the original source and I wish DPR had used me as the source :) shows it only works on these 2 cameras — http://blog.planet5d.com/oylb


yabokkie

please do explore possibilities of 70D as soon as you could, from dynamic range to 3D.


Adam2

How does this differ radically than say doing a HDR with two images? Obviously, it might be better when shooting moving subjects but otherwise, what’s the point?


yabokkie

at least it’s an ideal tool for moving subjects when we get blurred image most of the time (either shutter or focus).


makofoto

Magic Lantern is mainly used for video, ie. no HDR


planetMitch

Magic Lantern is used for all kinds of photos – and has some great HDR functions as well as things like an intervalometer built in (which I still can’t believe Canon doesn’t include)


solarider

Re: “Vertical resolution is reduced by half and there’s more moiré and aliasing in over and underexposed areas. The author also warns that since this software modifies the sensor’s operation, you could end up frying your camera.”

Yikes.

Simple, for 14.1 stops get ye the Pentax K5, K5II, of K5IIs, pull all you want from the shadows and forget about all of the ML downsides.

Best Wishes


Henrik Herranen

The vertical resolution thing is incorrect. Resolution is not lost in all of the image, “only” in the brightest and darkest areas. At midtones where both of the two half-images contain tonal information, full resolution is available.
Also, about the “frying” part: that’s a disclaimer they need to say just in the unlikely case the modification breaks something. However, just setting two ADC amplifiers to different positions doesn’t sound too likely to break anything.


Mr Blah

Just an FYI: This doesn’t seem to be available for use with the regular video modes on the 5D Mk. III or 7D. It only works in tandem with the previous raw video/time-lapse hack or with regular raw photographs.


ImagesToo

I think this is not correct and doesn’t do anything. You get ISO1600 by amplifying the signal which the sensor captures. You don’t get any better noise performance because the noise is the square root of the number of photons in a pixel and you haven’t changed that. You might just as well amplify the ISO100 signal (ie increase the brightness of the shadows after processing) and you will get exactly the same result without all the moire. All it is doing is effectively a really crude hdr processing on an image and compensating for the poor RAW to jpg conversion in the camera. Bracketing exposures and using hdr will give better results.


Henrik Herranen

It is actually you who are not correct.
The thing that is compensated for is the noisy ADC (analog-to-digital converter), which follows after the ISO amplifier. There is nothing wrong with 5D3’s and 7D’s RAW handling; the error happens at the ADC before ever getting to the RAW stage. That is what the new modification helps with.
As for bracketing exposures: it is all good and fine if you have a non-moving subject. But Magic Lantern’s page specifically tells that it addresses the situation where there is movement. In such cases multi-image methods naturally fail.


Sergio Rojkes

…wake me up when upgrades stop, please…


AbrasiveReducer

Wow. If this is true, the one area where Canon is significantly behind Nikon is fixable.


AngryCorgi

As long as a 4.5MP 7D or a 5.5MP 5D3 is acceptable to you.


Thanatham Piriyakarnjanakul

Do it at your own risk, only rich kid will do that.


Henrik Herranen

AngryCorgi: DPreview misrepresents the resolution issue. Resolution is halved only at the brightest and darkest areas. And only vertical resolution, not horizontal. Midtones are presented at full resolution.
Thanatham: Magic Lanters has always had the disclaimers there, nothing new there. Still many many people have used it during the last years.


mr.izo

hmm, 7d only for stills? hope they’re working on 6d too, or it’s already integrated?


Revenant

Apparently, only 5D3 and 7D have two signal amplifiers, which is necessary for using two ISO values simultaneously.


mr.izo

so, no need for d800 any more, hehe? if this new feature can solve shadows etc like mentioned nikon, than 6d is more an more option for me..


vincent__l

As with the new Aptina Clarity+ sensor just announced, Sony’s BSI sensors, Foveon sensors, Fuji’s X-Trans, and most likely Canon’s new dual diode phase detect sensors, there’s no free lunch. It’s a trade-off. You will improve something while sacrificing something else that is hopefully less important to you.


JJ Rodin

Yes, that ‘physics’ thing getting in the way again! :(

You can engineer around limits but physics is the master of all things, that BA$TURD.

Fool the brain is what it is all about, politics and photography ! :)


iAPX

Great work, and incredibly interesting paper, I hope they patented it because this is something that should have been implemented in any modern sensor to enable very high dynamic capture!

It means that many actual sensors might be used in extended HDR mode, not actually faking HDR by changing the curves, but with real dynamic extension. Very interesting!

The most interesting part is that could also be applied to compact-size sensor or even smartphone if they have 2channels to read their sensors! ouch!


liviutza

Unfortunately channel readout is not the only involved part – you also need a dedicated controller line able to set EV (or ISO) at a different level every other pixel. Doable (see Fuji), but not a must for Bayer sensors hence not present in most of them.


mpgxsvcd

I wish they had shown the full size image. It has horrible moire and the resolution really is cut in half.

My Panasonic GH3 does the exact same thing in video and stills. It is called the High Dynamic mode and it really isn’t that great.

First off it doesn’t increase the dynamic range. It simply compresses the dynamic range of the scene you are capturing. Those are two totally different things.

I applaud their efforts. However, the actual results are far worse than what is illustrated here.


imsabbel

Actually, those two are NOT different things, as long as you operate in RAW (as the 14bit available are not even remotely used by the native sensor SNR)

Of course, you WILL need to compress the dynamic range for any kind of output medium (be it print, which only has somthing like 100:1, or screens where even the best top at something like 2000:1)

Also, while the moire is crap, thats not unfixable. You would just need to write an optimized raw decoder taking that into account. Different ISO per scanline is much less bad an artifact that the basic baeyer pattern, in terms of reconstrution..


vincent__l

It looks like this is a feature that Canon has implemented in hardware but disabled in firmware. I’m wondering how Canon will react to this given that they often use firmware to differentiate their product line.


tkbslc

If they are just switching ISO every other frame, then it is not something special Canon would have had to hide.


vincent__l

ML claims that the feature, which requires “dual ISO amplifiers”, is implemented in hardware but disabled by Canon. They also claim that only the 5D3 and 7D have this feature. Seems like Canon has been experimenting with it but were not ready to go into production.

Source:

http://www.canonrumors.com/2013/07/magic-lantern-improves-5d-mark-iii-dynamic-range-to-14-stops/


NetMage

I’m not sure it is an experimental feature so much as a consequence of the multiple readout channels that require separate amplifiers in order to provide faster performance. What we normally consider a problem (scan lines in the picture slightly differently amplified if the amps aren’t tuned identically) ML has turned into an advantage.


Mr Blah

@tkbslc
It’s not switching ISO each frame (though that can also be enabled via a different part of the Magic Lantern firmware). Instead, it’s exposing different pixels on the sensor at different ISOs at the same time. The post-production workflow interpolates an even exposure for each image, resulting in complete frames.


liviutza

Fuji experimented with this idea in their HR sensors (photo receptors with different sizes) and EXR sensors (similar receptors with different exposures), and their DR performance has always been great – hell, the S5 PRO was about 5 years ahead of its time in this respect. The idea does require some special hardware as well as processing, and one must have great control over the manufacturing and development pipeline in order to do it – Nikon / Pentax for example would be limited by whatever Sony decides to do with the sensors, but Canon does have some freedom in this respect. It would be great if this feat were technically possible with the sensor inside the 70D (no idea, but that’s built with dual receptors for each pixel). Anyway. Canon not working on it themselves or at least officially supporting ML is quite a disappointment.


Bill Bentley

I supported Alex & Co. for enhancing my 600D. I’m looking forward to supporting them again after I upgrade to the 70D. Keep up the good work boys.


Gesture

Didn’t Olympus E-10/E-20 have something similar for boosting ISO. But one would think we’d have seen more ideas like this.

Source Article from http://www.dpreview.com/news/2013/07/17/magic-lantern-firmware-expands-canon-eos-5d-mark-iii-dynamic-range

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