topic Question about formatting memory cards in EOS DSLR & Mirrorless Cameras

Question about formatting memory cards

StanNH — Mon, 16 Oct 2017 21:13:07 GMT

Recently, in response to someone who was having trouble with a camera after switching an SD card between a Canon and a Nikon camera, I suggested that the card always be formatted in the camera it was going to be used in. In response to this, I was told I was completely wrong and, with modern cameras and cards, this was totally unnecessary and unrelated to the user's problems.

I have always been taught that any card should be formatted in the camera that it would be used in. After reading up on this, it looks like that is no longer the case. Is there no longer any reason to format a card in the camera it's being used in?

The manuals for my Canon cameras specifically state that cards should be formatted in the camera if they were used in another camera or are new ... so now I am confused.

Re: Question about formatting memory cards

kvbarkley — Mon, 16 Oct 2017 21:16:50 GMT

It just eliminates another variable. It is clear that formatting in the camera creates a card prepared to work *with that camera*, while any other formatting tool should work - it is a standard PC format after all - I always say why take chances?

Formatting - whether in the camera or not - periodically is a good idea to eliminate fragmentation

Re: Question about formatting memory cards

Waddizzle — Mon, 16 Oct 2017 23:40:17 GMT

@StanNH wrote:
Recently, in response to someone who was having trouble with a camera after switching an SD card between a Canon and a Nikon camera, I suggested that the card always be formatted in the camera it was going to be used in. In response to this, I was told I was completely wrong and, with modern cameras and cards, this was totally unnecessary and unrelated to the user's problems.

I have always been taught that any card should be formatted in the camera that it would be used in. After reading up on this, it looks like that is no longer the case. Is there no longer any reason to format a card in the camera it's being used in?

The manuals for my Canon cameras specifically state that cards should be formatted in the camera if they were used in another camera or are new ... so now I am confused.

Whomever told you that is wrong. Memory cards are not pre-formatted. They are tested during production, and what appears to be formatting is actually residue from the testing. That formatting needs to be completely erased and wiped out. End of story.

Using a computer to format a memory card, may seem to work, too. But, computer data can be stored in blocks of varying size. While the computer may use the correct file format, the block size could be incorrect for optimum read and write speeds by the camera. Any card formatted in a computer should still be formatted in the camera.

NOTE: Whenever someone says “format in the camera”, that means perform a low level format in the camera!

Re: Question about formatting memory cards

TCampbell — Tue, 17 Oct 2017 15:20:02 GMT

Whoever told you it was not necessary to format a card in the camera you were going to use it in... is simply inexperienced and wrong.

Cards do indeed come pre-formatted ... do not trust the format. Which format they have will depend on the card size. Cards with more than 32GB space are typically formatted with the "exFAT" format. BUT... this format has variable block sizes and (here's the clincher... ) not every camera or computer support every block size.

Cards that are less than 32GB are usually formatted with the FAT-32 filesystem format and those tend to be pretty well behaved across products.

But the other reason to format in-camera with the "low level" option checked... is that cards can have bad blocks and a "low level" format will test and map-out the bad blocks so that the camera wont try to use them. From time to time (since cards do technically "wear" as you write and re-write to the same blocks again and again and the "writing" is actually a physically destructive process) a block that may have been working ... could eventually stop working reliably.

There's another reason to format in-camera... and not share cards between cameras unless you re-format them. And that is that in addition to the filesystem format, the camera also typically lays out a directory structure that it wants to use and if it sees directories created by other cameras and then doesn't understand the data inside them, you can end up with problems.

I have legitimately seen problems with sharing cards between cameras without reformatting them... and the problems vanish as soon as the card is reformatted.

Re: Question about formatting memory cards

StanNH — Tue, 17 Oct 2017 15:30:32 GMT

Thanks for the responses. I was sure I was correct in recommending a formatting of the card in the user's camera, but I was told by others I was giving misinformation and was completely wrong in suggesting that. The user had swapped between a Canon and a Nikon, and his Nikon would not read the card. I told him that was a bad practice and he should reformat. I was very pointedly told that that could not be the issue, and it was likely just a bad card.