Why you should not delete images on your memory card using your camera

As many of you know, I spent many years of my life as Director of Marketing at Lexar dealing with the ins and outs of the memory card business. And in all that time, I have never written a blog about the do’s and don’ts of memory cards. Now that I have left Lexar and not on that side of the business any more, I feel that I can write this objective piece for you without any conflict of interest.

And if you are taking digital photos on a memory card (and you probably are), YOU WILL WANT TO READ THIS!

First, let me explain the memory card in simple terms for you.

Most people look at a memory card as a piece of plastic or metal, and they don’t think much about them. But inside those covers, there is a LOT of intelligence. There is flash memory, a controller and much more. The quality of that memory and controller often determines the speed and quality of your card.

Your memory card has something called a File Allocation Table, otherwise known as a FAT Table. Think of your memory card as a book and the FAT Table as a Table of Contents. When you format a memory card, you are not actually erasing the card, you are just clearing the FAT Table. So…you have removed the Table of Contents, but the chapters of the book still remain. Yep, all the images will remain on your card until you shoot more and overwrite them. This is why you can use a program like Lexar’s Image Rescue, SanDisk’s Rescue Pro or other data recovery software to recover images from a card even after it is formatted.

And now for the tips, which I am going to write in the order of importance:

1. DO NOT erase images from your memory card in your camera! Clarification: What I mean by this is: Do not go through your photos and delete them one by one using your camera. I see people (including professional photographers) doing this all the time and it is a REALLY bad idea. Your camera is awesome at taking photos, but it is not very smart at managing the data on your memory card. Deleting individual images from the card using your camera is a great way to scramble the FAT Table. DON’T DO IT! And heck, memory cards have gotten so inexpensive and large, that you should not have to delete images to save space. Just pop in a new card and keep shooting. Once you have downloaded to your computer, and backed up the images THEN format your card to use it again.

2. Format your memory cards in your camera, not on your computer. I have seen countless web sites which tell people to format their memory cards on your computer. This is just bad information! You want to format the cards in the camera. And you should do this on the camera your are shooting with. I am currently shooting with the Canon 1DX Mark II, Canon 1DX, Canon 5D Mark IV and Canon 5D Mark III, and I format the card in the camera I am using. You are reading this correctly…I do not format in one Canon camera and move it to another. Will they work? Yes, they will. But it could cause issues down the road. Speaking of this, it is not a good idea to pull a memory card out of one camera model and putting it into another without formatting. I have seen people shooting with a Canon camera, pull the card out and start using it in a Nikon camera. They like to be formatted a certain way and each manufacturer does it their own way.

3. Speaking of formatting, it is a good idea to format your cards after each shoot. Once you have downloaded your card and have the images IN MORE THAN MORE PLACE, you should format that card before it’s next use. It keeps things cleaner on the card.

4. Use a good card reader! I can not tell you how many times I have seen professional photographers take a high quality card out of a $10,000 camera and put it into a cheap no-name reader. Ughh, it just kills me. When I was working at Lexar and a customer would call me about a corrupted memory card, one of my first questions I would ask is “What card reader are you using?” Folks, those memory card readers have intelligent controllers inside them, just like the cards! I have seen way more cards corrupted in a reader than in a camera.

5. Don’t fill a card completely. Even though most memory cards are built really well and have all kinds of intelligence in them, it is not a good idea to fill a card completely. One of the reasons that I love shooting with large memory cards, is so that I have tons of head room to shoot a lot of photos and not worry about overfilling the card. FYI, I also have the same mentality with my computer hard drives. I never fill them, because their performance suffers a lot when they are full. I usually fill a hard drive to a maximum of 90% and then start writing to a new one.

6. Don’t pull a memory card out of your camera or card reader when data is being written or read from the card. If data is being transferred to / from the card and that process is interrupted, it is quite possible that you will lose some or all of your photos. And don’t always trust the red light on your camera to determine is data is being transferred. Before I pull my memory cards, I always wait an extra couple of seconds after the red light on the cameras goes off, signifying that the data is done being written to the card.

7. If you have two card slots in your camera, write your images redundantly to both cards to have more peace of mind. This way, if one card gets corrupted, you can most likely get the images off of the other card. I always do this!

8. Purchase name brand memory cards. As you may have guessed, I use Lexar memory cards in all my cameras, but that is not to say that they are the only good company out there. SanDisk makes a good product as well. There are others too, but make sure that you do not use one of those cards made by a no-named company. Remember, you are trusting your images to the card! And you are going to be using the card over and over, so spending a couple of dollars more to get a better product, in the long term, will not cost you much more. Nothing kills me more than seeing someone shooting with a great camera, expensive lens and a crappy memory card. Yep, this gets to me even more than someone using a crappy reader.

And just for fun, here are some common misconceptions about memory cards:

* If memory cards get dropped in water, the data will be lost forever!

This is not true. Because memory cards are made with solid state memory, it is not uncommon for them to go through the washer and dryer and still be useable. Would I keep using that card after a situation like this? Probably not. But most likely your data will still be on the card and can be recovered. I used to jokingly say to people, “If you put your card through the washer, make to put it in the dryer too!”

* You must keep your cards in covers.

I hate to tell you this folks, but I have my cards loose in my bags all the time. I do not use the little jewel cases that come with the cards. I do use the ThinkTank Pixel PocketRockets, but also have countless cards thrown in my bags. This has never been an issue.

* (Added) Going through airport X-Ray machines can damage your cards

I have had many people ask me how they should travel with their memory cards, especially at airports. In the old days, the X-Ray machines could damage 1000 speed film, but they pose no threat to the solid state memory cards you own today.

To sum all this up…

After reading this blog post, I hope you have a better understanding of your memory cards and readers and appreciate them a little more. There is so much technology packed into these devices, but they are so small and unassuming that it is easy to take them for granted.

These are simple tips that could save you from a disastrous situation. I hope that these help all of you to keep your memory cards and images safe now and in the future.

In case you are wondering…here are the cards and readers I am currently using:

About the Author

Jeff is a world renowned, five time Olympic photographer having covered Beijing, Vancouver, London, Sochi and now Rio. He is one of the most sought after presenters and educators in the photography space. You can find out more about Jeff on his website, follow his adventues on his blog, or reach out to him through Facebook. This article was also published here, and shared with permission.