When you delete a picture from the camera's menu, the picture isn't deleted at all.
Al Fasoldt's reviews and commentaries, continuously available online since 1983


Don't let your memory card wreck your holiday photos

October 21, 2012

By Al Fasoldt
Copyright © 2012, Al Fasoldt
Copyright © 2012, The Post-Standard

A picture is worth a thousand words, but some of them might be unprintable if you let your camera's memory card ruin your holiday photos.

This can happen in two ways. Both can spell disaster.

The first occurs when you take the memory card out of your camera while the card is still writing a file -- while it's still recording all the bits and bytes that make up a photo.

This not only messes up the picture -- it probably won't be viewable -- but it can also do something far worse. It can scramble the directory list of all the files on the card. If this happens, your pictures won't show up even if they're still on the card. All the photos your camera saved on that card will be toast.

The obvious solution is to wait 10 seconds or so after you snap the shutter before you take out the memory card. Geeks might argue that 10 seconds is overkill, but cheap memory cards are notoriously slow when writing data.

The second disaster can be just as bad. Based on comments from students in my photo classes, I'd guess most users are clueless about the dangers of repeatedly deleting pictures from a memory card.

The problem lies with the lazy-bones way memory cards and cameras work with files. When you delete a picture from the camera's menu, the picture isn't deleted at all; instead, your memory card simply forgets about the photo and reuses the space the deleted photo took up the next time it's running low on storage.

This is nuts. It's a holdover from the ancient days of computers, when storage cost too much to waste on files that had been deleted.

The problem comes from repeated deletions each time the memory card stores files. After a while, there might be so many "forgotten" pictures and chopped-up directory entries that the entire card gets the scrambled eggs treatment. Pictures disappear and the card becomes, as your camera or computer will tell you, "unreadable."

There's an easy solution. Each time you take pictures off a memory card, make sure all the photos are accounted for and then wipe the card clean by formatting it in the camera. You'll see a menu option for this if you look thoroughly. Formatting removes everything. The card is just like new.

One more thing: While you're enjoying your new-found memory-card reliability, buy a few more. Always carry enough to hold all the pictures you're likely to take on any single day. Cards don't cost much. But lost pictures -- or pictures you missed because you ran out of space on a memory card -- are incalculably expensive.