UPDATE – April 10, 2012 #2: Updated report by Ron Risman. He demonstrates (video included) how the 5D3 metering is affected under ambient light.
It’s already known that you need to cover the viewfinder in bright light conditions since light can get into the metering system, but not so well known that it can also affect in normal room/ambient light. You should know about this, because it CAN affect your normal shooting: Canon EOS 5D Mark III – Light Leak Example Photos (updated)
UPDATE – April 9, 2012: Added video & stills examples showing night shooting metering being affected by turning LCD backlight on or illuminating by LED light.
UPDATE – April 8, 2012: More tests results coming… It’s still not clear if it “really” affects metering under bright light with lens cap off. Since it’s affected with lens cap on, it will be affected with lens cap off, the big question is “how much“.
You will not be able to use top LCD backlight in dim light or at night to check your exposure metering unless Canon fixes it. Not good for a $3,500 camera.
UPDATE – April 7, 2012: More videos added. Even with lens mounted, under bright light or when turning the LCD backlight on the exposure metering is affected. Check below.
There are several reports coming from users about Canon EOS 5D Mark III suffering from some kind of light leak issue.
This is absolutely frustrating. How can Canon release a $3,500 camera body without carefully testing this? Just by turning LCD backlight on, or under bright light you get a wrong exposure metering?
We have already said when the EOS 5D Mark II was released, and now again: Canon must improve quality controls. Although this would fit much better under “Designing & Testing” process instead. Even more in such expensive camera bodies.
It’s important to mention that we have thoroughly tested the Canon EOS 5D Mark II body we have and it does NOT suffer this issue in any situation.
The codec implementation for ALL-I video mode has some issues (noise at low ISO and bad macro blocking compression compared to a cleaner and sharper IPB mode) that needs to be fixed via firmware update. Also the sharpening algorithm has to be improved when sharpness is set higher than “0”, since it’s almost useless, even when the camera has improved the moire/aliasing artifacts so much (* read more at bottom)
But this kind of light leak issue may require a different fix.
Below there’s a quote from Canon Rumors with a demo video clearly showing this issue:
Canon 5D Mark III Light Leak?
A light leak? Really?
A light leak issue in the 5D Mark III has been reported over the last couple of days. It seems the top side LCD may be to blame. I can confirm this is happening on at least one of the 5D Mark III’s I own (the rest are out for rent), I will look into the issue with more bodies in the coming days.
Simple Test Procedure
- Put your body cap on the camera body.
- Put the viewfinder cover that came with the camera over the viewfinder.
- Set the camera ISO to 800 and put the camera in “P” mode.
- Turn on the backlight for the LCD panel and watch the exposure change
Below is a video showing the issue.
Other light sources cause the issue?
Yes, shining a flashlight on the top LCD causes the exposure to change, as does sunlight and bright overhead lights. All of which happen with the body cap on.
Does this matter in the real world?
For the moment, I’m not sure. I haven’t noticed any issues with metering on the 2000 or so shots I’ve put through the 5D Mark III. I’m sure we’ll know more in the coming days.
Thanks to Canon Rumors for posting about this. We all hope that Canon acts quick to fix this problem (and the other ones).
It is important to note that this issue can be clearly reproduced with the lens cap on. But if the metering system is affected with the lens cap on, it will also be affected without it, that’s obvious (probably in much less amount, but still affected). That is NOT normal in any camera. This would prevent the user to turn on the LCD when shooting at night (when it’s needed), for instance. It’s still not clear how much impact it can do when shooting in bright light conditions without lens cap.
Bright light affecting metering WITH lens mounted
LCD backlight affecting metering WITH lens mounted
Check what happens around 1:00 when the user turn LCD light on (exposure metering changes, affecting final shot):
Image credits: Andrew K.
Check the written description by Ron Risman from CameraTown on this video: http://vimeo.com/39982919
NOTE: We encourage all customers to contact Canon to request fix and improvements to all these issues, including ALL-I poor implementation, poor sharpening algorithm and now the potential light leak issue. You can send an email, it will take you only few minutes!.
Please consider supporting this site. Make your purchases through the links posted on this site or the following ones, there is no additional cost to you:
Follow us on Twitter for special news, technical articles, important promotions and rebates . We try to keep everyone informed about promotions, since they are great to save when buying.
Thank you very much for your support.