I have a Sony a7 iii digital camera.

I was wondering if it will damage the camera to put an SD card in it that has files OTHER than photos or videos on it?

I saved an Adobe Premiere editing project on to my camera's SD card. I went to put the SD card back in my camera to shoot some things, but I stopped myself. I thought maybe the large Adobe editing project on the SD card could somehow mess with the camera since it isn't a typical file format (photo or video) that the camera is used to.

Is this a legitimate concern, or can you put an SD card in the camera with any kind of files on it?

Thank you for any help you can give me.


3 Answers 3


Unexpected files on a memory card will of course not harm a camera. What harm could they do?

Cameras write files in a predefined structure – see for example Design rule for Camera File system – but otherwise the camera behaves pretty much like a computer (which, arguably, it is), i.e. it writes the files it needs to in the available space on the memory card, and ignores everything else.

Cameras have the ability to format memory cards – obviously if you perform this action, you can expect to lose your files.

The main thing though is that you shouldn't use memory cards as general storage. They are not designed for this, and you just run the risk of losing data; it's not worth it. If you value your data more than your storage devices (and you should), then just dedicate a memory card to a camera, and use it exclusively for one purpose. If you need more cards/storage, buy more – it is not expensive.

  • \$\begingroup\$ What harm could they do? Paranoïd me think that they could for instance cause some decoding piece of code to loop indefinitely and make the camera firmware freeze solid when the user tries to review pictures. Obviously my camera seems to ignore them (doesn't even try to display regular JPGs). But then maybe someone can come up with what looks like a Canon-sanctioned JPG that exploits a bug in the firmware. Very, very unlikely, but not impossible 😈 \$\endgroup\$
    – xenoid
    Commented Jan 5 at 15:20

Very, very unlikely.

I just tried, polluting the SD card currently in my camera and adding many files of various file types in the directory that receives images (currently DCIM/101CANON), and:

  • The camera still takes pictures normally
  • The camera playback only shows the IMG_nnnn.JPG taken by the camera.

If the files you added were not even in the camera directory (normally a DCIM directory) your camera probably didn't even notice them (it just found a little less free space on the card). But when it can notice them, it ignores them.


It will not harm the camera.

The camera will generate a new DCIM folder (still photos) and Private folder (videos) if needed. Or it may continue to use the existing folders if present.

However, best practice is to format the card in-camera before recording new files. Failure to do so poses some risk to the file structure, new files, and your Premiere project files. Obviously, this means you should use a separate card that can be formatted without deleting your project files.

Most manufacturers recommend regular in-camera card formatting to prevent file system issues... this is from Nikon

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Red Digital recommends formatting the card before every use if accessed by a Mac, due to the indexing file Macs write to the card. They are very specific that there should be no non-native files on the card.

  • 4
    \$\begingroup\$ If you format the card in-camera you will definitely destroy the Premiere project files that are on it :). Otherwise the file system on the SD card is defined by a standard (FAT32 for SDHC, exFAT for SDXC), and if the SD card is used (copying+erasing the files) on a decent computer the file system won't be damaged in anyway. The initial format-in-camera is the easiest way to create the camera's file structure, but that's the only necessary one. The rest is folklore coming from buggy filesystem implementation by cameras of yore. \$\endgroup\$
    – xenoid
    Commented Jan 3 at 21:41
  • \$\begingroup\$ @xenoid, I thought that was obvious that formatting would delete the project files and a separate card should be used instead. I'm also not sure that it's "buggy file systems of yore". \$\endgroup\$ Commented Jan 5 at 14:58
  • 1
    \$\begingroup\$ Sadly, @StevenKersting, it's not so obvious that "format - DANGER! This will delete ALL your files" isn't the right thing to do when you're trying to preserve data. (Experience on file server support boards has shown an incredible number of people who think formatting a drive is the right path forward to data recovery... :shrug:) \$\endgroup\$
    – FreeMan
    Commented Jan 5 at 18:26

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