What caused my Canon 5D Mark II to power off suddenly and corrupt my CF card?

[ElevateThis]

I was on a video shoot using my Canon 5D Mark II. The CF card was a Sandisk 32GB UDMA 7 120MB/S. During the video shoot my camera randomly shut off while I was recording. I assumed it was the battery and changed it immediately. The camera turned back on after replacing the battery, and funcioned as normal. Footage continued to record to my CF card.

After the shoot I could review the footage on the camera and all was fine. When I returned home to download the images onto my Mac, I was notificed that a certain video file could not be found on the card and thus the videos could not be copied. I was given this notification even if I just tried copying one random video clip at a time.

I decided to unplug the card reader from the USB port and re-insert it. When I re-inserted it, it would not mount and my computer would not regonise/show it. I then decided to try putting the card back in the Canon. I turned on the camera and it said "This card is not formatted with this camera. Format now". I could not access any of the data on the card. After unsucessfully trying to retireve the footage, I tried formatting the card. During this attempt I recieved an error message on the Canon and the card could not be formatted. 

At this point, I had lost my footage and the CF card was bricked and unusable. Was it an intital error with the CF card, or with the Canon 5D that caused this issue? Should I be prepared for the Canon to randomly turn off like this in the future? I will be going tomorrow to buy a few new CF cards and update the firmware on my 5D.

Any suggestions/advice appricated. Thanks! Michael

[TCampbell]

Are you using a battery grip?  If so, is it Canon vs. 3rd party and is it snugly attached?

Check the fit of the door to your battery compartment.  Check the fit of the door to the memory card slot.  Are both doors undamaged and fit perfectly when closed?

There are micro-swiches on both doors.  A tiny tab in the edge of the door engages a switch in the door frame.  If either of these switches are opened, then the camera will immediately shut down.

Check the battery condition via the menu.  Press menu, navigate to gold wrench #3.  There's a "Battery Info." button.  It should indicate the battery life and re-charge performance.  Make sure the "recharge performance" is not red (indicating that the battery is probably very old and wont hold much of a charge anymore.)

Also, how long are you running the camera with allowing time to cool down?  The 5D II is the first camera that was used heavily for video.  But for best results, videographers would generally avoid running it longer than about 10 minutes with time to cool off.  You have to remember that this is a "still" camera that happens to be able to shoot clips of video -- but was not designed for primary use as a video camera.  You'd want to avoid over-heat situations.