What should I do about this strange CF behavior, where I lost tonight's pictures?

Question

I have taken over 14,000 photos with my Canon 7D and loaded them into my Windows 7 desktop computer the same way, by inserting the CF card into my computer's reader. The point is that I know how it usually works so this "empty folder" problem is definitely out of the ordinary. To shorten the post I always use the "Safely Remove Hardware and Eject Media" utility before removing the CF. My workflow has been folder based:

• Shoot into a folder.
• Copy the folder to both an internal hard drive for editing etc. and an external hard drive I swap every few days as off-site backup.
• Create a new folder for the next batch of photos, unless the card is about out of space. In that case I format another CF card and remind myself to swap offsite HDs soon. The full card goes in my camera bag, which is my semi-offsite backup against the house burning down.
• When I swap offsite disks I format the CF card in the 7D and move the other CF cards to the "Ok To Use" pocket of my camera bag. If I have time I'll format them as I move them.

I shot tonight's sunset into folder 102EOS7D. Folders 100EOS7D and 101EOS7D had the photos of the two prior shoots since the last offsite backup swap. I put the CF card in the PC and both the last two folders were empty, 101 and 102. I put the CF card back in the 7D and confirmed that both folders 101 and 102 had pictures in them. I attached a USB CF card reader to the PC and inserted the CF card. Folders 101 and 102 were still empty. I put the CF card back in the 7D and the folders were empty! By just trying to read the CF card two shoots of photos went away! Bummer!

I have the photos from folder 101 and tonight's sunset in folder 102 was boring so I decided to troubleshoot rather than try to recover the CF card. I ran Windows Update and nothing was missing. I reformatted the CF card and shot some photos. I found a USB cable that fits the 7D and successfully downloaded the photos in the new folder 100EOS7D.

Any suggestions? The card is fairly new, only in its second or third offsite-backup-swap cycle. It is the largest capacity I've ever had, a Transcend 400x 64 GB CF card.

More details:

• I always format in the camera, not Windows.
• Losing photos is serious, how do I help keep it from happening again?
• Is this likely a CF card problem, a Windows problem, a problem with my 7D, or ... ?
• I don't know if this is a possibility, but could there be "bad blocks" in the "FAT" (or whatever, don't know tech details) of the CF card that could produce these symptoms?
• Is there a low-level format utility for CF cards that could identify "bad blocks" and "mark them unusable"? Again, I'm not familiar with CF card details.
• Is there something, given the symptoms, I don't know enough to ask?

Asked by Mark Jerde

Answer

CF cards – just like any other storage media – fail every now and then.

In general, when a storage media fails, the symptoms may "look strange" from the perspective of the computer, camera, or any other device that tries to access it. Don't try to over-interpret them; it just failed. You might be able to recover something – for recovery tips, see these two questions: [1], [2].

There is nothing you can do to completely prevent failures, no matter what kind of best practices you try to follow.

To make failures less frequent, you can try to use well-known brands, expensive high-end cards, and cards with a long warranty period. Also remember to throw a card away (or have it replaced) immediately as soon as you notice anything strange.

But most importantly, make sure that losing a single CF card is never a catastrophic event. Use two cards in parallel if your camera supports it. Transfer photos from the card to your laptop or some other backup device frequently. If you don't have access to any kind of computer for a while, use more than one card and rotate them; etc.

Your card will fail, sooner or later. And your hard disk drive will fail, sooner or later. Just plan ahead so that you won't be too upset when it happens. Sure, you may lose some photos, but make sure you don't lose a whole week of memories.

Answered by Jukka Suomela

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