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

April 17, 2012
Canon News
10 Comments

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 statement: In 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.

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).
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.
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.
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?