Thanks For The Memory

Be sure your memory cards are working their best for you

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Memory cards are critical for digital photography. We can’t do without them. Losing a memory card can be worse than losing a roll of film because so many more images fit on a memory card. So most photographers are careful about where they store their cards; usually they’re placed in a memory card holder that keeps them in order and stored in the same location.

A bigger problem with memory cards is when they don’t work properly. That can be frustrating, especially when you’re on an important trip. This came home to me when I was part of the NANPA Road Show in the Philadelphia/Wilmington area this spring and one of my fellow presenters, Mike Francis, talked about memory card problems. He does a lot of field workshops where people photograph wildlife and horses with cowboys and cowgirls. Participants shoot a lot of images, and sometimes they have problems with cards.

This motivated me to learn more about memory card failures. First, I talked to a good friend, Mark Comon, who runs Paul’s Photo with his dad in Torrance, California. He deals with a lot of people who shoot digital cameras and bring their problems to him. His customers have the most problems with mass-merchandised cards like those sold in big discount stores, plus off-brands he has never heard of.

Comon also has found that most card problems of any kind come from “power failures”—either people try to keep their camera going too long with a weak battery and it fails during the writing of images or they remove a card before the camera has written to the card. This was a common theme with many people I talked to.

Comon says almost all brands occasionally have bad cards, but these always show up right away. If you get a card and can’t format it, return it to the store and exchange it immediately. And never buy a card on your way to the airport! That might seem like a good idea. I know how this goes—we’re in a hurry to leave on a trip and realize that we need a new and bigger memory card, so we go to the open-late discount store and buy what we can. Comon finds this is a recipe for disaster—when people don’t check their cards first, too often they find they’re on a trip with a card that doesn’t work. They’re stuck buying who-knows-what-brand at an exorbitant price. This also was a consistent problem, when there were problems, for participants in Francis’ workshops.

I also talked with my friend, Michael Guncheon, the HelpLine columnist for PCPhoto magazine. He says photographers have more problems with cards when they delete pictures rather than regularly reformat the cards. One issue is that people never clean off their cards, keeping a few images on them so the card never gets formatted. In Guncheon’s experience, memory cards need formatting on a regular basis.

He also agrees with Comon. People push their batteries and write to cards when battery power is nearly exhausted; then the battery quits while the camera is writing files to the memory card. This can corrupt the directories on the card, meaning you can’t access the files. And you might not be able to recover the images with recovery software.

I also visited Kingston Technology. Kingston does extensive, 100% testing on all of its memory products. All companies do at least compliance testing, which makes sure the products meet the standards for a certain type of memory, for example, standards for SD cards set by the SD Card Association that cut across all manufacturers. Beyond the compliance testing, Kingston tests every product down to individual memory cells so it’s confident that each memory device is working at 100% when it’s shipped.


I posed many questions to Cameron Crandall, technology manager, technology resource group, at Kingston. He said that in reality, there are a lot of memory cards out in the world from a lot of manufacturers and the percentage of defects is very small. A true failure of a card comes from something wrong inside the card, says Crandall, and isn’t affected by anything the photographer does. However, cards often “fail” in the sense that they can’t be read or written to. In most cases, these aren’t actual card failures. In almost 100% of cards returned to Kingston because of these problems, there’s no actual problem with the card. Usually, the image files are recovered and the problem was due to corruption of the file structure from the way the card was used.


All memory cards are pretty durable. The solid-state memory and controllers inside the card are sealed in plastic. The most vulnerable part of any card is usually the contacts. Damaged pins or flat contacts can make a card not work.

Crandall says that there are a number of things that can cause problems with the use of a card. The camera might not be compatible with the card. Many photographers are unaware that older cameras can’t be used with some of the latest memory cards without updating camera firmware. Most older D-SLRs need to be updated and this information is generally on the manufacturer’s website. Another problem comes from memory card readers. Not all of them work properly with all cards.

And like everyone else, Crandall says that power failure to the card of any kind while it’s working may damage the file structure of the card. This can come from batteries dying while the memory card is being written to or from pulling out a card while the camera is still working. The latter is common when people shoot a burst of images (holding down the shutter while set to continuous shooting) and pull a card to change it before all of those images have been written from the camera’s storage buffer (especially when working with big RAW files). You can’t hurt a card by erasing images or formatting it.

You sometimes hear that flash cards can be “worn out.” Flash memory works by having individually erasable segments, each of which can be put through a finite number of erase cycles before becoming unreliable. According to Crandall, the useful life of semiconductors used in memory cards is about 20 years. So in one sense, a card could be “worn out,” but that’s actually unlikely for photographers.

For example, lower-performance cards will handle 10,000 write/erase cycles. This isn’t each time you add or erase a photograph. Flash memory cards have built-in wear-leveling technology that arranges data so that erasures and rewrites are distributed evenly across the memory, dramatically increasing the life of the card. The result is that 10,000 write/erase cycles isn’t 10,000 images, but 10,000 write/erase cycles for every memory cell in the card. That’s a lot of photographs that even a heavy card user would have a hard time reaching after many years of use.

So what can you do to gain maximum performance from your memory cards and ensure that you’re always getting the photos on and off them as you expect? Here are some tips:

1.  If a memory card is going to fail, it usually will fail early in its life. Always put a new card in your camera and format it. If it doesn’t format, return to the store and exchange it for a new one.
2.  Never buy a card just before you go on a trip. Be sure your cards are working properly.
3.  Buy high-quality memory cards, not the cheapest, high-volume cards from a box store.
4.  Format your card regularly to clean up its file structure.
5.  If you have an older camera, be sure it can handle the card. Some cameras can have their firmware updated to use the new card.
6.  Be careful of memory card contacts. You don’t have to worry much about the card itself being damaged
short of running it over with a car, but the contacts can give you problems.
7.  Never push batteries to their maximum. Change them as they get low, before they lose power just as your favorite scene is being recorded to the memory card.
8.  Never take out a memory card when the camera is still writing to it. Most cameras show this as a flashing light.
9.  Use a quality memory card reader.
10.  If you have problems downloading images from a card reader, try downloading directly from the camera. Be sure your batteries are fully powered.
11.  If your card fails and there are photos on it, try using image rescue software from companies such as Lexar, SanDisk and Symantec.
12.  If you have a problem, try downloading with a different card reader or through the camera. If all fails, you usually can make the card work fine by reformatting it, but you’ll lose the photos.

Memory cards are extremely robust. Failures of any kind are rare, and by following simple guidelines, you can minimize them even more.

Editor-At-Large Rob Sheppard’s photo information blog is located at His latest book is the New Epson Complete Guide to Digital Printing.


    Thanks for the informative article. My question (RANT) is “Why do camera manufacturors change memory card types?” I have old “memory sticks”, so I won’t go along with Sony. I have large & quality Compact Flashcards. My Rebel XT is great, but I can’t replace it with the “SXi” becaus of the change in memory type (to SD). Why am I dealing with obsolete (I doubt it) memory cards?


    Tom F. Bryant

    Thank you very much for the up-to-date information on Memory Cards. This is a big help as I am very new to D-SLR’s. My husband and I have been taking a lot of photos (300+) at the zoo (9:00am to 12:30pm). We would hate to cause a memory card failure by removing the card before the photos have been transferred.
    Is there anyway to tell a high-quality memory card from a high-volume card? Can the high-quality memory cards be written to faster??
    Keep up the superb writing, I am finding it very fascinating.

    I agree that sometimes older card readers are not up to the task. When I upgraded my camera and got a 2GB SD card for it, the USB multi-format card reader I had no problems with before would not work, corrupting some of the image files on the card. The card worked fine after reformatting it in the camera, but the next day I bought a new SD card reader, which has given me no problems. I still use the old reader for CompactFlash cards.

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