Could it be a serious problem with Canon 5D Mk2?

Hello everyone.
Today, at the end of the photo shoot all of a sudden my camera has droped the appeture to a -2 and wouldn't let me corect the exposure. The digit on the display screen showed 00, and i've tried everything (took the battery out, memory card out, switched it off and on etc.) Nothing.... so had to finish the shoot with my old camera and in the mean time leave my 5D switched off. After about 40 minutes switched the camera on, still everything was the same. Again off and on and the camera now seems to be working fine.
Could anyone explain what has happened and whether i need to service my camera?
Thank you

Did you try a different lens?

no, i did not. but if it was a lens problem why then it went back to normal after some time?

Maybe you accidentally de-attached the lens?

Cherepashka wrote in post #11232158
no, i did not. but if it was a lens problem why then it went back to normal after some time?

stuck aperture blades? flakey contact?

Probably just dirty contacts on the lens.
Same thing has happened to me several times over the years.

Ok, let me get this right: dirty or flaky contacts... more possible that it could have been the problem with the lens then? Any suggestions what shall i do next? Service the camera or the lens? I've only bought them (canon 85mm f/1.4L) like a month ago?

It's definitely a lens contact issue, just be careful, clean the contacts.
Some users have reported accidentally pressing the lens release but I've never done it.

Hey, one more quastion about the lens then: aren't 85mm 1.2L lenses helping to find the focus automatically after you press the shutter button half way? I think my lenses use to do this, but they doesn't anymore? And how come the lenses can be dirty all ready if i've only used them for 1 month or so?

I won't guarantee it's the lens or the contacts, but that is as likely a culprit as the body is.

If you've fingered the contacts, they certainly could be dirty after only a month, fingering them could also lead to something stuck or bent. Canon specifically says to avoid touching the contacts, not saying you have, but this could certainly lead lens communication problems.

As far as AF goes, yes at the half press the lens should attempt to focus. Have you switched focus to AI servo? This will be a continuous focus and there will be no confirmation beep, just a gentle hunting all of the time you are half pressed.

When you focus the lens is wide open (at max aperture) the lens has the most light for the AF sensors in this condition, and this helps with the AF. If the blades are stuck this may mess with the AF because it's too dark, if you are in AI Servo you'll never get confirmation because the focus is looking for moving subjects.

hey guys, thank you a lot for all your replays. You are live savers!