Light Metering Inaccuracy

April 28, 2010



  • Light Metering Inaccuracy
  • Report to Canon




This seems to be an additional function to be fixed in a future update:

While doing many tests with some lenses on the 5D Mark II with Firmware 2.0.4, we also found an inaccuracy we didn’t notice before: the camera has “difficulty” to “read” and display an accurate light metering value whilst in Live View mode.

This inconsistency / inaccuracy happens with ALL lenses (not limited to Macro lenses)


Mount the 5D Mark II on a tripod with any lens and aim it to a fixed scene with constant illumination.

Set the camera to M, Live View to “Stills+Movie-Movie Display” and turn on Live View mode.

Then change the aperture value in 1/3 step using the rear wheel.

You will notice that the light meter bar displayed on the LCD monitor sometimes indicates no change (even when the scene brightness has changed) OR it indicates a change of  2/3 step.

It doesn’t happen all of the times, but very often. Just “play” a bit with the aperture value and you will notice this inaccuracy.

It never happens when Live View is turned OFF, because the light metering system used in that mode is very different.

This clearly seems to be a consequence of a non accurate light metering of the scene whilst in Live View mode (Stills+Movie – Movie Display), and it occurs with all Canon lenses.

No matter if it was present on previous firmware versions or not, it should be fixed indeed.


Please report all issues and malfunctions to Canon. That’s the way we can get them fixed.

You can find the necessary information to contact Canon at the Home Page.

Thanks to every user supporting these efforts and reporting these issues to Canon. We’ll all benefit.


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