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Formatting Memory Cards


Here are a few questions regarding Memory Cards (both CF and SD) that I've had for a number of years. 


1. I've been told that you should format your memory cards rather than just erasing the images, provides better performance and there is a less chance of failure. Ture of False?


2. I've been told that if you have two or more cameras, and they are the same model camera, you should format the memory cards in the camera they will be used in and only use them in their respective cameras, provides better performance and there is a less chance of failure. True of False?


3. I've been told to never used a memory card formatted in one model camera in a different model camera although the manufacturer is the same. True or False?


4. I've been told that SD cards should be low level formatted frequently. True of False?


I'm truly interested in your thoughts based on experience and/or actual technical data. If there is an in-depth article/reading material that touch on these questions, please point me in that direction.










"...all my cards are preformatted and could end up in either camera ..."


On the other hand if you are just out for funsy, go for it. Don't sweat it.

EOS 1DX and 1D Mk IV and less lenses then before!

@Joel4JC wrote:
"2. Technically False, though true in practice. Why move a freshly formatted card to a new camera?"

In my case, I use two 5D Mark III to cover an event and all my cards are preformatted and could end up in either camera, unless I keep them separate and labeled, which I don't! So I am glad your answer is "Technically False". Thanks!

I think the reason this notion got started is that file systems have changed a bit over time (e.g., to accommodate higher capacity cards). If you were to format a card on a newer camera, then try to use it in an older camera, you run the risk that it may not work. But if you're swapping cards between two identical cameras at the same firmware rev level, I can't imagine that you'd have a problem.

Philadelphia, Pennsylvania USA


1. I spoke at some length with a number of engineers at several companies that manufacture memory cards utilized by Canon cameras I own, and deciphering the technical jargon, they agreed on one fact: while erasing photos you don’t want in the field is perfectly fine, erasing photos as opposed to formatting the card is a really bad idea.


They were unanimous in their recommendation: in their experience, most cards that have been sent to the manufacturer for data rescue have been repetitively erased and obviously not formatted following use.  Cumulative errors are apparently introduced in the memory cards over time while only erasing photos; these errors are not generally found with memory cards routinely formatted, especially if deep formatting is an option, in cards sent back to the manufacturer for data retrieval.


One caveat: while I’m not new to photography, I only have 4 years experience using Canon DSLR cameras. There is an entire world of DSLR photography out there I haven’t learned about, and while I consider myself a novice, I did take the time to talk with several companies after a brand-new memory card died on its second day of use. Ugh.


Chris P. Bacon

EOS 6D Mk II, 7D; 7D Mk II

Chris P. Bacon
F-1; AE-1; EOS 1V, EOS-1D X Mark III, 5D Mk IV, 6D, 6D Mk II, 7D, and 7D Mk II; scads of Canon, Zeiss, and Sigma lenses.
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