What you need to know about memory cards :: Digital Photo Secrets

What you need to know about memory cards

by David Peterson 1 comment

Hey, do you remember when taking photos meant you actually had to know something about film? There was black-and-white film, there was color film. There was daylight-balanced film and there was incandescent film. There was high ISO film and there was low ISO film. To acquire all the knowledge you needed to have about all the different film types available, you practically had to have a degree in film.

Now thank goodness we no longer have to worry about film. Today you just pop in a memory card and you're good to go. Because all memory cards are pretty much the same… except that they aren't. Read on to find out why.

When you got your very first digital camera, the chances are pretty good that you just bought an inexpensive memory card to go with it—in fact it’s probable that your camera even came with a card, which meant you didn’t have to do much thinking about what sort of card it was, except perhaps for that GB (or MB, if you’re as old as me) number printed on the side of it. Why would you? You've probably heard people say that all memory cards are pretty much the same. Brand doesn't matter, what matters is capacity.

Unfortunately, I'm going to have to break the news to you that you were misled. Memory cards aren’t all the same, and if you’re not using the right one for your camera you could be making a pretty significant mistake.

Memory card brands

Now, for a budget model point-and-shoot camera, it is actually true that brand matters less. Those cameras don't need high-speed memory cards, for example, and the chances are good that there is no recommended brand of memory card for those basic models. But as you get into the more advanced, feature-rich cameras, all of that changes. Brand does start to matter, not because one brand is necessarily superior to another, but because some card manufacturers have actually designed their cards to work with specific cameras. So, for example, when you buy a Nikon camera, you may be advised to buy a SanDisk memory card to go with it. That's because SanDisk has agreed to design their memory cards in such a way that they can take advantage of the full processing power of Nikon brand cameras. That’s an agreement that the memory card manufacturer made with Nikon, and it’s a very good reason why you should buy a SanDisk brand memory card if you own a Nikon brand camera.

So how do you know which card manufacturer (if any) has made a similar deal with your camera’s manufacturer? That information will be right there in the manual. Now, does that mean you can’t use other brands of memory card with your camera? No, but you may be sacrificing speed and reliability if you do.

Memory card speed

Another thing you may not even be aware of is that memory cards come in different speeds. Now, it was once understood that you really only needed that high-speed memory card if you were going to be shooting video. That is not completely true anymore, and if your camera has a decent burst mode feature it's even less true. If you shoot a lot of high-resolution images in burst mode, especially if you're using the RAW file format, you need a high-speed memory card or you may run into some problems, and the end result of those problems will be missed shots. In fact, it is actually true that shooting a series of RAW files in burst mode takes up more space on your memory card than a similar amount of video frames. So make sure you know what the minimum recommended memory card speed is for your camera model (again, check your manual) and use only that speed or faster when shooting photos with that camera.

Erasing memory cards

Erasing is just erasing, right? Actually, no. If you load that memory card onto your computer, copy images to your hard drive, and then erase all of the files off the memory card using the Select All > Delete command, you can actually corrupt that little miniature database that exists on your memory card. If you shoot with a Canon, you may get an “ER–99” error message, which basically means that you should start planning a little memory card funeral. That's going be a huge problem for you if you are still in the middle of a shoot, because it means that the images on the card are more than likely lost, and you won’t be able to shoot any more, either.

The same is true if you use your camera's menu to navigate to "erase all images." Wait, then why is that option in your camera's menu system in the first place? The answer is, I don't know. There's never really a good reason to use the “erase all images” command, and if you do you're adding database errors to the card just as you would be if you used the computer to “erase all images.” Instead, you should always format your card every time you want to empty it. Formatting the card basically starts everything over from scratch, so you get a clean slate to work with, free of database errors.

Similarly, don't edit your photos directly from the card. Again, this can introduce errors into the system. Instead, copy the photos onto your hard drive and edit from the copies. Delete the originals using the “format card” option on your camera’s menu system. If you do find yourself editing directly from the memory card—I've personally done it by accident without realizing what I was doing—just copy the files over immediately and format the card.

Take care even in-camera

Always stop shooting when you’re within two or three photos of the end of your card’s storage capacity. That’s because that number you see on your camera’s display (the number of shots remaining) is really just a guess—all photos are slightly different sizes, so your camera has no way of accurately knowing exactly how much space remains on that card. If you overshoot—that is, if you take a photo when there isn’t enough room left on the card—you may cause corruption on the card.

And turn off your camera before you remove the memory card, too. Pulling your memory card out of a powered-on camera can—you guessed it—cause database corruption. Similarly, wait a few seconds after you’ve shot your last image before you flip that power switch. Shutting off your camera before the image is done writing means that you’ll lose that image.

Handle with care

Memory cards—especially (physically) smaller memory cards—are delicate objects. They are not made of particularly tough plastic and can be easily bent or broken. Always be gentle when you put them in and take them out of your camera, but also when you put them in and take them out of the memory card slot on your computer.

If compatible, buy brands that offer file recovery protection. Lexar and SanDisk are two good examples—both of these brands (if you buy the professional level versions), come with free software that will help you recover accidentally deleted photos. And accidentally deleting something, as you might already know, is something that can happen to anyone.

If you do accidentally delete a photo, stop shooting immediately—if you're not done with your shoot, switch the card out with a spare. When you get home, you can use the software to recover the deleted images. I haven't personally tried this, but I'm told it works even if the card was formatted.

If the recovery software doesn't work for some reason, another option is to send the card back to the manufacturer. First check to see if the manufacturer of that particular card offers this service (not all of them do). If they can recover the file, they will put it on a DVD and send it back to you.


One final thing to keep in mind is that the capacity of your memory card does matter. Now you may think that a single high-capacity memory card is the best thing to have with you when you travel, and there was a time I would've agreed with you. But the truth is that memory card failure does sometimes happen, and if you have only a single high-capacity memory card you're kind of stuck. If you're lucky enough to be using a brand that offers data recovery, you can put it away for the remainder of your trip, but you won’t be taking any more photos until you are able to stop at what is likely to be an overpriced tourist destination to purchase a new memory card.

And if you don't have the ability to recover that data from the memory card, then you've just lost everything–your entire trip from the time you arrived until the time the memory card failed. It's always best to travel with spares. I like to bring along a small case full of smaller capacity cards, that way I’m not putting all of my eggs in the proverbial memory card basket.

And finally, high-capacity memory cards do have greater draw on the battery than lower capacity cards do, so if your camera is already a battery hog that is certainly something to keep in mind.

How many memory cards do I need?

I recommend you have at least two memory cards for your camera. The professionals usually carry a number of memory cards and when they run out of memory on one they swap to the next, but unless you’re taking LOTS of photos, that’s overkill. With two cards, you can normally work with one but you have a spare just in case you run out of the first, or you go on a long vacation and need to store more images than you normally would.


Understanding memory cards is not quite as complex a topic as understanding all of the different varieties of film, so hopefully you’re not too intimidated by all of this extra information. It is definitely worth knowing these facts, though, because memory card corruption and data loss is a serious, often heart-wrenching matter. While it is true that the type of memory you card you use doesn't affect the quality of your photographs, it certainly affects the quality of the time you spend with your camera—especially when disaster occurs.

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  1. Barry James says:

    Did not know about SanDisk use in Nixon cameras, going to buy SanDisk from now on.

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