I’ve been seeing an intermittent but reoccurring issue over the past couple of days with my 5D mark 3 and 8GB SandDisk Extreme III 30MB/s flash cards. I will, on occasion, get an ERR 2 that the camera can not write to the card. Removing and re-seating the card will fix the problem for the duration of the time the card is in the camera.
Now before people start with the Canon fail drama on this, these are old, fairly well used (but not excessively), non-UDMA cards, and that I don’t see the issue in any consistent way. Nor do I seem to have an issue when using my Lexar 16GB 300x UDMA cards, though I’ve not used them enough to be really sure.
Also the issue seems to be both intermittent and dependent on how much writing the cards are doing. I can blow though the entire card several times over, then all of a sudden at the end of an extended high FPS shoot or while recording a video segment, it throws an ERR 2. I can’t do anything on the camera with respect to shooting or what not that prompts the issue. The only thing I’ve noticed is that after heavy use the CF cards are warmer than they’ve ever been for me—I think this is expected due to operating at near maximum write speed—but at the same time it may be contributory to what I’m seeing.
As it stands I’m leaning towards this being a localized card issue but I thought I’d throw this up and see if anybody else was seeing something similar.
If you’re seeing an ERR 2 or a card write failure and have a Canon 5D Mark 3, if you wouldn’t mind please drop a comment in the comments section with the type of card you’re using, what you were doing (i.e. continuous bursting, recording video, etc.), whether the card is UDMA or not, and approximately how well used it is?
Update 2012-10-23: Just an update to this. I have since tested 3 different Lexar Pro 400x UDMA cards (all 32GB) in my 5D-3 and have yet to see a problem with any of them. So far it seems like the mid-range UDMA Lexar cards work reliably in my 5D3, I couldn’t justify 1000x cards to see if I got issues similar to what Greg reported in the comments.