So last night I shot my very first event, a debutante ball (where I'm the main). Yay! It wasn't so bad.

Anyway, at one point during the reception my 5D was giving me an error message and where the aperture # should be it said 00. Any idea what that means?

I could have panicked but didn't cuz thank goodness I had a 2nd photographer with me and my daughter as an assistant who was praying hard. LOL. I ended up taking the battery grip, lenses, etc. off, waited a few seconds, and it began working again. For a short time there I was thinking I was done for the night.

Thanks for any and all replies!

Most likely your lens wasn't properly seated and the camera couldn't communicate with it.

ditto. Did you try the lens first? Thats usually the solution.

If you are using a heavy lens...you should hold or support the lens as much as possible when shooting. Sometimes a heavy lens (not properly supported) will pull the contacts between the lens and body apart just enough that the camera no longer knows there is a lens attached.

The same thing happened to my 5d at a wedding a couple of months ago and I was freaking out. It was the lens. I had the camera on my front seat on the way there & I think it cme loose during the drive.

I did try the lens first and it still kept giving me the error. I took it apart several times (batteries, lens). Maybe I was doing it all too quickly because after a few tries my daughter told me to leave it off for a few seconds, I did and it began to work.

I'll take it in for a clean and ask Canon, I hope it was just as you guys said.

Anyway, thanks so much for everyone's help, I appreciate it!