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The EOS 5D Mark III light-leaking problem – An analysis

These are not rumors, but a logical analysis of the possible scenarios related to the light-leaking issue that some customer experience on their EOS 5D Mark III bodies. I reported about this issue, in short: metering gets altered by light leaking trough the top LCD panel of the camera. Canon’s official statementIn extremely dark environments, if the LCD panel illuminates, the displayed exposure value may change as a result of the AE sensor’s detection of light from the LCD panel. Unfortunately, this seems to happen with both the backlight of the LCD panel and strong direct sunlight hitting the panel. Next, we heard that some new batches of the 5D Mark III had a different top LCD panel cover than previous ones. And then there are rumors that the EOS 5D Mark III could be recalled by Canon. So, what is going on? How will Canon fix the problem? I try to outline different scenarios. Again, not new rumors I heard but my very own analysis of the issue.

  1. The light-leaking problem is a serious design issue. A serious design issue is something that affects a device in its very being. Addressing a serious design issue may have the consequence that other components or the overall design get affected. That means it can’t easily be corrected in subsequent production batches. In this case Canon not only would have to recall the delivered 5D Mark III bodies, but also to redesign and reengineer those components that are causing the problem and eventually modify the overall design. This is the worst scenario, and the least probable in my opinion (given that the 5D series has almost 7 years).
  2. The light-leaking problem is a minor design issue. A minor design issue is an isolated design error that affects a component. Something like a shortcoming in the intricate and sophisticated design of a contemporary electro-optical device. In this case, addressing the problem would not affect other components or the overall design of the camera. Canon would have to spot the problem, make a design correction and reengineer the faulty component. Delivered bodies have to be recalled, shipment of the 5D Mark III would be delayed.
  3. The light-leaking issue is a production flaw. Something got wrong in the assembling of the device. In this case, Canon would probably have to recall the shipped cameras, and to spot and then correct the problem in the production or assembly chain. Shipment of the 5D Mark III would be delayed, but not for much time. It’s still heavy stress, but not the nightmare that scenario 1 would be.
  4. The light-leaking issue can be addressed by a firmware update. Theoretically possible. A firmware update could switch off the backlight of the top LCD panel while the camera is metering (and when shooting) and then turn it on again. Not the most elegant solution, but at least a possible solution. Don’t think Canon will go that way. Don’t think customers will be really happy with this.
Beside this four cases, there must also be said that the issue we are discussing will plausibly never alter the quality of your images. At least not in more than 90% of the real-world settings where people shot pictures. The issue only shows up in extreme settings. Most of the tests and measures used to spot the problem have been made with mounted lens or body caps: that’s the setting where the issue can be best observed and replicated. None of us is shooting with a mounted lens cap. Nevertheless, the issue is real. Whatever will happen, Canon will not let its customers out in the rain.
I am very curious to know what my readers think about the light-leaking issue of the EOS 5D Mark III, so i made the poll below. Feel free to contribute and thanks for your support.

What do you think about the EOS 5D Mark III light-leaking problem?

  • It is a minor design issue (39%, 90 Votes)
  • It is a serious design issue. (26%, 59 Votes)
  • I don't care/it will not affect my pictures (23%, 53 Votes)
  • It is a production flaw (10%, 22 Votes)
  • It can be addressed by a firmware update (2%, 4 Votes)

Total Voters: 228

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For a list of shops that have the 5D Mark III in stock click here. For the latest 5D Mark III pics uploaded to Flickr click here.
  • Bob B.

    Well….i guess the recall should significantly eat into their $1000 mark-up from the 5DII. Karma perhaps! :-)

  • Frank


  • Peter

    bullshit stuff made up by website who don´t have anything other to do or write about….. get a real job.

    but canon has to react to such nonsense.

    i have yet to see prove that this affects even night shots.

  • While in real world terms, I feel it is a minor issue, the fact that a $3500 camera has such a glaring “minor” issue at all is troubling. Will people still be able to use this otherwise great camera? Sure, in most shooting situations, but if I’d personally preordered or purchased one already, I’d be pissed. Tis is something that should have been remedied during the beta phase and the fact that Canon haven’t set concrete terms as to how they will be addressing it is troubling to me. I was planning on waiting a while on a mk3, and will continue to do so, but I will say that it seems less likely that I will spend the budget I already have put aside for one,and may start to look to upgrade another of my systems. Any product is capable of shortcomings, but it’s how a company reacts to them that will determine my confidence in them, and right now I’m not very confident with Canon (especially after the never ending run of lens and now 5d line price hikes over the last couple of years).

    • Bob B.

      Tyson…I had actually decided to not buy a 5DIII (I have a II) and mainly because of the amount of improvement in the III versus the added cost. ($1000 more). I shoot most of my images at ISO 800 or below…so IQ improvement is not there for this photographer. I plan to buy the new 24-70mmII AFTER I read sufficient reviews to be comfortable with the fact that it is worth it’s $1000 increase. (if that is even possible LOL!). I understand that Japan has had hardship….but it seems to me that there is little justification to remake a mediocre $1300 lens, (not add IS) and to justify a price of $2300 and unknown delays. I am heavily invested in the Canon system..and for all practical purposes…I just cannot “changeover” to another, even with these absurd price increases. I guess I am going to sit tight for a while and concentrate on my image making. This situation is getting out of hand for this modest income photographer, though!~

  • Mike Kobal

    minor issue in practical terms, it certainly won’t affect the outcome of my work, however, at 3.5k I expect a flawless product, needs to be fixed and not via firmware.

  • Pete

    How does this get by Canon’s QA? I am very disappointed, Canon has always set the bar.

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