Tag Archives: Canon EOS 5D MkII

Magic Lantern for the Canon 5D Mark II

What is Magic Lantern?

If you own a Canon 600D, a Canon 60D, Canon 5D Mark II, or certain of their predecessors, you might be interested to hear that you can extend the capabilities of your camera for free (although a donation is requested). This is not by replacing the camera’s internal software by a newer version (recommended, but this mainly fixes bugs), but by adding software from a bunch of non-Canon developers. This Magic Lantern software extends the existing Canon software with many new features that target technically inclined videographers and photographers.

Features for photographers

Magic Lantern was originally created mainly for those who use Canon DSLRs for serious video work. I don’t know much about video, so I will only describe features that help photographers.

The features are somehow largely centered around Liveview and likely benefit photographers most who sometimes need to do “slow” photography: they use a tripod, use tethering in a studio to check focus, have a complex setup or simply want to have maximum control. Having said that, Magic Lantern states that it has benefits as well for photographers that are in a constant hurry: it gives you the option of putting certain options that you use a lot under a particular button.

A few of the key features:

  • focus peaking – whereby the Liveview image displays which parts of the image are in focus. Useful when you want to carefully control what is in focus. This can be seen as an alternative to tethering your camera to a computer via USB in the studio.
  • exposure clipping – the Liveview image can show which parts of the image will be too light and too dark using overlaid zebra stripe patterns.
  • more on-screen data – for example the current main camera mode (e.g. M), focal length and focus distance.
  • focus loupe – you can see part of the image zoomed in 2x or 3x to check sharpness. This feature is fancier that Canon’s counterpart and can even simulate what a split screen focus aid used to look like.
  • interval timer – you can take 100 pictures at 60 second intervals to show a flower opening. Or 1000 pictures at 1 hour intervals of a construction site – all providing you can get your battery to last.
  • triggering exposures – the shutter can automatically fire if the scene brightness or content changes significantly. Essentially a makeshift motion sensor.
  • automatic HDR – not only can the camera take a series of images at different exposures automatically, but it can take the entire series at one press of the button. It can even determine how many exposures are required automatically (or manually) and give you a rough preview of the merged image. Pretty cool. Essentially this gives your 5D2 a feature found in the 5D3, but without the artsy options: you do your real HDR merging afterwards on a computer.
  • improved mirror lockup – flip up the mirror a few seconds before taking the picture to reduce vibrations. The Canon equivalent is relatively tedious to operate.

Display when shooting video using Magic Lantern

The actual list of features is about as long as the list of features that your camera originally came with. So some people only use 2 or 3 of the new features. Others actually do read the software manual and experiment around (takes an evening – just like Canon’s firmware).

Installation and risk

There are risks involved in tinkering with complex equipment. My feeling is that the risk is comparable to opening up PCs to upgrade memory. If you never did something similar, you can get someone else to install Magic Lanterns (ML) and show you the basics.

The risk is lower than you might expect because ML doesn’t simply overwrite Canon’s software: it runs as an add-on and (in most cases) you will not see changes to the menus provided by Canon. There is a simple procedure to uninstall ML entirely.

This is essentially how ML works under the hood:

  1. A minor modification to Canon’s software makes the camera Magic Lantern aware. Comparable to a boot loader on a PC. ML is incidentally not the only party that does this (there seems to be a USB remote controller that uses the same trick to extend Canon’s software).
  2. Whenever you activate the camera, the firmware first checks for the presence of special non-image files on your flash card. If found, it loads Magic Lantern from the flash card. This does not visibibly delay camera operation. The ML software sits alongside the Canon software in camera memory (RAM). If the ML files are not found on the flash card (or you hold  down a button while turning it on), Magic Lantern is not loaded and you get  unmodified camera behavior. Alternatively, you can choose to carry memory cards with and without ML.
  3. Running ML,
    • the optical viewfinder information display is unchanged
    • the LCD viewfinder for LiveView displays significantly different information
    • Canon’s own menus (Menu button) are for 99% unchanged
    • you can view ML’s own menus by pressing the Erase button while in Liveview mode
  4. Whenever you make changes to ML settings this is written to the flash card for the next session. Some changes are also stored in the camera’s non-volatile memory (e.g. when ML menu’s interact with existing Canon features?)
  5. The ML files stay on the flash card, even if you erase the card using the camera. Actually ML formats the card and then writes the ML files back from memory. If you erase or format the card entirely using a PC, you need to reinstall the ML files onto the card. Until then, you will be operating without ML when you use that card.

Quality and stability

I cannot give you hard numbers, but since version 2.3 the stability seems to be close to that of Canon’s own software. Both have occasional bugs and both try to fix these bugs as soon as possible. ML is an open source project, so anyone with (considerable) programming skills can contribute.

All this doesn’t mean you can never run into a problem: ML software adds complexity to the entire setup, and strange combinations of features may give strange results. But if you stick to mainstream usage of the features (= use them more or less as documented) you should be alright.

Some features are clearly marked as “for very advanced users”. One example is the ability to take pictures in a low-res format while in Liveview mode without any shutter motion or sound whatsoever. A bit weird, and it actually seems to work, but you won’t be using this unless you are a video technician or are motivated enough to figure out how to deal with these “422” encoded frames.

A final example is a menu item called “Don’t press this”. The user manual just says not to press it. Actually it probably doesn’t do any harm (otherwise why give it such a tempting name), but I don’t want to press it just yet. I suspect it contains a game that is totally not camera related. After all, your camera is just a computer with an industrial strength webcam attached as a peripheral (at least that is how geeks tend to see it).

Drawbacks

So far, things are going well with my own use. And ML has thousands of heavy users who rely on it on a daily basis. The documentation is actually pretty good – including the description of the risks involved. But…

  • It will only install on the latest version of Canon’s firmware. So you need to upgrade a 5D2 to v2.12 before you can install ML. A sensible choice by ML to minimize risk.
  • Running ML will slightly increase battery drain. Essentially because it gives the ARM processor more work to do because of extra features. It will increase batter drain a lot if you start using Liveview more than you previously did.
  • ML increases overall system complexity somewhat: it is like upgrading from a 5D Mark II to a 5D Mark III – more features which you may or may not use.
  • ML is not available on all currently Canon cameras (notably not the 7D or 5D Mark III so far). ML is written by volunteers and all this is a lot of work.
  • Something could go wrong. But the manual explains how to get the camera up and running again in the more common cases. As far as I can tell, the risk of loosing images stored on the flash card is absent, but there is a risk that you may need to briefly remove the batter to recover. A quote from the Magic Lantern FAQ:

In practice, we are doing our best to prevent these situations, and thousands of users are enjoying it without problems. However, this does not represent a guarantee – use it at your own risk.

iPad Camera Connectivy Kit

I tested moving photos from a Canon 5D Mark II to an iPad. This can be useful if you need some extra storage, want to view the images on the iPad, or want to mail them.

The 5D2 uses Compact Flash memory cards, so the iCCK’s  SD card reader (right side of photo) won’t work. But you still have two options using the iCCK’s USB adapter (left side of photo):

  1. Plug a Compact Flash card reader into the iPad via the iCCK. This didn’t work for me: the iPad complained that it couldn’t handle the power drown by the reader.
  2. Connect the camera via its miniUSB-to-USB cable, via the iCCK to the iPad. This kind of works. After reading a several files, the program crashes.

Apple states on its website, that repeating the process helps: the import restarts where the previous one failed, and you will ultimately reach the end. The number of files you can read between crashes is variable: sometimes one or two, sometimes dozens.

So the good news is that the iPad can reads heavy-duty RAW files from a Canon 5D Mark II and display these (although you can’t zoom in all the way). But the crashing Photo application and Apple’s workaround are not very user-friendly. This problem was known back in April and is still an issue in iOS 3.2.2.

Red UFOs during long exposures with Canon 24-104mm f/4L lens

If you thought the Canon 5D Mark II’s black dot problem was obscure, here is an even stranger defect in some Canon cameras. The issue (red flare on multi-minute exposures) was originally attributed to the a problem with an LED on the Canon 5D Mark II – but this proved to be wrong. In January 2009 a DPReview forum user known as “darksbrother” posted:

Ok, I’ve got a conundrum. I need to find a way to disable the blinking red LED to the right of the wheel on the 5D Mark II. I’m doing long night exposures and that LED keeps creating a red streak on sufficiently long enough exposures.

Firstly, apparently that LED on the back of the camera is on during long exposures. Which is in itself surprising, and lead to some discussion because users were not aware of this. Secondly, the original poster cared about that red LED only because it seemed to cause a red spot in the lower part of dark images during multi-minute exposures. In other words, the poster thought that light from the LED somehow leaking via the internals of the camera and managed to reach the exposed CMOS sensor. Within a few days, it was announced on the DPReview forum by its_RKM that this was a problem with the Canon 24-104mm f/4L lens rather than with the camera body: infrared light from an infrared LED inside the lens (used to detect motion for the USM mechanism) leaked into the camera at certain zoom ranges (notably 24 mm). The Canon 5D Mark II sensor understandably registered this infrared light as red light – despite the infrared absorbing filter that is the light needs to pass through before reaching the sensor. If you expose long enough (e.g. 15 minutes) and set the camera to automatically subtract a 2nd image (also 15 minutes!) taken with the shutter closed, the resulting noise-reduced image will show red “flare” as shown in the image

Red UFO image posted by RKM to DPReview (15 minutes, 24 mm, f/4)

Image posted at DPReview by its_RKM on January 31st (15 minutes, 24 mm, f/4, no external light)

On March 31st 2009, the original poster summarized the forum thread as

Thanks to extensive testing by RKM, we can in fact conclude it’s the lens. I have tried the test with the body cap and have gotten no red streak. What was concluded was that it was an internal infrared LED within the lens which helps calibrate focus/read information on the position of the lens that was leaking through into the sensor area causing the red streak.

but Canon technical support is so far unwilling/unable to confirm the situation. Technically interesting questions are:

  1. Does this show up with all SLR cameras using the same lens? So far, it has been seen on a 5D and 5D Mark II. The problem may be less visible on an APS-C sensor as the worst parts would be cropped off anyway.
  2. Does the problem still occur if you disable autofocus? Manual focus may turn the LED off (although that’s less likely).
  3. How much infrared does the IR cut filter actually block (this link suggests at least 5 stops for 800 nm light)? An ancient Canon 10D might be sensitive to it because it said to have a weak IR cut filter (on the other hand, the sensor is noisy by current standards anyway).
  4. Are there other Canon USM lenses with the same problem? Most high-end lenses have a similar USM focus technology.

Canon 5D2 – black dot plague and its cures

The black dot problem

The Canon 5D Mark 2 was announced on Sep 17th 2008 and many early orders were fulfilled around Christmas. Unfortunately, the camera turned out to have a defect that was particularly noticeable in pictures featuring Christmas lights. The problem shows up as black dots directly to the right of small bright lights. Here “to the right” assumes landscape mode and this translates to top (or bottom) in portrait mode. The problem shows up on RAW images and presumably in JPG images as well.

I have only photo showing this, taken during a Winter evening (Canon 70-200mm f/4L IS, 800 ISO, 1 stop underexposed, f/4, 1/60 s, 21 MPixel Raw, camera firmware 1.0.6).

The black-dot problem is exhibited in the Christmas lighting along the edige of the roof

The black-dot problem is exhibited in the Christmas lighting along the edige of the roof

100% crop of the image of the inn

100% crop of the image of the auberge

Pixel peeping to the max

If you would plot the intensity scanning from left-to-right through one of these small highlights, you expect to see pixel brightness rise to  the maximum measurable intensity, a plateau at this maximum intensity (255 on an 8-bit scale), a decrease down to background intensity. BUT (see actual scan at the end of the article), the ramp down “overshoots” and forms a small black dot.

Enlarge (11x) crop of same lamps, but showing too bright and too dark pixels.

Enlarge (11x) crop of same lamps, but showing too bright and too dark pixels.

Enlarge (11x) crop of same lamps, but showing too bright and too dark pixels.

Enlarge (11x) crop of same lamps, but showing too bright and too dark pixels.

You normally only see these black dots when viewing at 100% and can miss them unless you are looking for them. They appear to be a digital processing artifact. One clue is the phrase “to the right of..”. The lens itself has axial symmetry, so will not know what we users consider to be the right side of the image. The sensor itself (at the photosite level) also cannot behave like this. So the problem apparently lies in analog or digital signal processing inside the camera.

Speculations on the cause

One likely culprit seems to be the “highlight tone priority” feature which attempts to avoid blown highlights. This presumably gives a local HDR-like treatment: the area around a highlight is digitally underexposed to compress the scene’s dynamic range. This helps keep the bride’s bright white wedding dress from showing burnt out highlights.

If the “highlight tone priority” algorithm works left-to-right, you could imagine that a bright spot will result in a local adjacent dark spot – just like you are temporarily blinded by the headlights of an oncoming car at night: the feedback loop in your vision which reduces the pupils and probably sensitivity of the retina itself needs some time to adjust to the “normal” darkness again.

But this assumes that “to the right” is somehow associated with “later” in time. A digital filter is normally design to work symmetrically: the information needed to compensate in all directions (left, right, up, down) is available once you have a bitmap stored in memory. So the “black dot to the right” is reminiscent of analog processing whereby the photo sites are read out left-to-right and first processed using analog circuitry. The fundamental reason for this is that an analog filter which fed with a time-dependent signal can only react to the present (current signal) or past (previous signal values) and not to the future (the still to be processed pixels). A simple analog gain control loop (e.g. used to regulate audio levels) shows such behaviour: after a strong signal, it may temporarily be blinded.

Firmware fix

Fortunately, speculations about the detailed cause of black dots are no longer relevant. Canon supplied a firmware upgrade (1.07) in early January which fixes the problem.

The fact that it could be fixed by a digital modification may suggests that it is a digital algorithm problem (you can design algorithms that have this blinded-to-the-right phenomenon simply by emulating an analog filter), or that the analog processing is digitally controlled or that the problem can be masked by digital means. Current collective Internet opinion suggests that critical users seem satisfied with the patch. Unfortunately the firmware patch has the side-effect that the raw convertors created for the Canon 5D2 now need software upgrades but this is a one-time inconvenience for early adopters. So either this patch is fixing the problem rather than masking it, or the masking simply works well enough.

Since I took the above picture, I have upgraded to the 1.0.7 firmware and will hopefully not run into the problem again.

The details are even weirder

Intensity scan done manually at 11x magnification in Lightroom 2.2
Intensity scan done manually at 11x magnification in Lightroom 2.2 (using Adobe Camera Raw version 5.2)

The graph shown above shows the intensity of the Red, Green, and Blue channels when I scanned manually (Lightroom) from left to right throught the topmost (of the the two) Christmas lights. The basics are obvious: the light has a width of about 16 pixels. Blue is a little less intense on the left side, leading to the yellow color. There is indeed a dip around X=2 which is clearly lower than that around X=16. The peak at X=6 is due to the proximity of a second light source.

But there are some puzzles:
  1. The dip at X=2 is not convincingly lower than the intensity at X=-18 or X=13. This might be explainable by strong linearity: you firstly need to combine R/G/B into a single number which might just be lower at 2 than at 13. And you apparently need to subtract a black level from that. Some have reported that the dip is actually lower than the black level you subtract, leading to a negative light intensity.
  2. The RGB readout of Lightroom shows the dip at X=2, while the darkest spot on the screen is clearly at X=0. This is likely a bug in Lightroom 2.2, but needs validation.
  3. The RGB readout of Lightroom (at 11x) shows 11×11 pixel squares. Strangely the Lightroom cursor seems to read out varying intensity within a square (as if you could read out the intensity at sub-pixel resolution). So the actual values will tend to vary a bit if you repeat the experment.

Canon 5D2 – mode dial and target audiences

The Canon EOS 5D Mark 2 doesn’t have the traditional mode-dial settings for Sports, Landscape, Macro, etc. These settings mainly impact shutter- versus aperture trade-offs and possibly burst mode settings.

Prosumer market?

Apparently you are supposed to know what you are doing if you purchase a camera like this. After all, the camera caters to advanced amateurs willing to lug the extra weight around, buy fancy (and heavy) lenses and pay the price premium for all this. The Canon 5D2 and its successor, the Canon 5D, were seen as the camera of choice for professional wedding photographers, professionals on a budget, or even simply as backup cameras for professionals with a top-of-the-line Canon 1D or 1Ds. It is also suitable for the enthusiasts with enough time to worry about equipment details and enough commitment to save up quite some money to make their peers envious with at fancy equipment. All these groups are supposed to know what they are doing, and know how the camera is intended to be used. So you also won’t find a pop-up flash (unlike the comparable Nikon D-700).

Or anybody who can afford it?

But  interestingly, the mode-dial also has two separate “fully automatic” modes for dummies: Full Auto (green, classic) and the new Creative Auto. In the latter mode you get a slider for “light or darker picture” and even one for “blurring the background”. In addition, unsafe settings which may cause problems are locked. So apparently Canon’s product managers didn’t want to rule out users who don’t even want to bother learning about shutter speeds and apertures.

One explanation might be that some people have enough money to buy a camera like this. But don’t have the interest to learn how to use it. So if I owned a large yacht, I guess I would be unhappy if I bought an expensive quality camera but I couldn’t get it to take a decent picture. Let’s hope the salesman was smart enough to tell me to buy a flash unit (although that is still a nuisance to charge and mount).

Interestingly “dummy modes” are conceivably useful if more than one family member shares the same camera. But on the other hand, this may not be the kind of equipment you put in the hands of kids. So what is “creative mode” good for on a camera like this?

Canon Picture Styles and the 5D Mark 2

Picture Styles is a feature is present in Canon models sold in the past year or two. It impacts subtle post-processing settings: 

  • sharpness,
  • contrast,
  • saturation,
  • tone.

The current opinion on the Internet appears to be that Picture Style settings do not change the pixels stored in RAWimages but are available as metadata for use by Canon’s post processing software, DPP. Lightroom and other post-processors currently seem to ignore the selected Picture Style (although the information is stored somehow in the EXIF data). Instead, Lightroom, for example, has presets which aim to provide much the same result as the Canon Picture Styles. These are, however, not identical to Canon’s Picture Styles because everyone uses slightly different algorithms.

It would be nice if Canon could explained this a bit better. They do explain how the Picture Styles impact the sharpening, contrast, saturation, and tone parameters. Canon says that all goes well automatically when you use Canon’s own DPP software o process JPG files. But many people use other software – especially for cameras in this price range.
The latest Adobe Camera Raw 5.2 (used by Photoshop and more to read Raw files) also emulates Canon’s Picture Styles. Interestingly, users seem to start believing that Picture Styles from Canon have some magical authority, compared to say other presets you can find from Adobe, DxO or users.

See manual p59.
See brief discussion on RAW format and pictures styles from Chuck Westfall.

Canon 5D2’s Auto ISO setting

The Auto ISO mode sets ISO values between 100 and 3200 ISO. Compared to what I am used to (no auto-iso at all on a Canon 10D) this is pretty convenient. Some thoughts so far:

  • I noticed that Auto ISO has a strong tendency to go for 100 ISO. That’s nice if there is enough light to get a short shutter speed and a safe amount of depth-of-field. But the camera also used 100 ISO on a 28mm, 1/30 s, f/4 shot in the evening. Arguably this still adheres to the old 1/f-rule for shutter speed. But the quality (noise, dynamic range) difference between 100 ISO and 200 ISO is minimal (although visible in DxOmark ‘s measurements). I thus wonder how often that stop could be put to better use like having a 2x faster shutter speed or getting more depth of field.
    Update (16-Mar-09): a work-around to increase the minimum ISO from 100 to 200, is to enable “Highlight Tone Priority”. This, as a side-effect, sets the minimum ISO value to 200.
  • Maybe this is overoptimistic, but are the “only” conditions when one would overrule Auto ISO might be for either landscapes using tripods (where 100 ISO is a good idea) or sports photography (where increased ISO is a good idea).

See manual page 58.