Am using a 2GB SD-card with a Canon IXUS 50/SD400 Digital ELPH. I tried a 4GB card but got an error saying the card is "locked". The card is not write protected, and works fine in a couple of other devices. The menu option to format the card is not active.

I have not been able to find any useful info on the web regarding maximum size of card, or file system requirements etc. The 4GB card was formatted in Win 7 with default settings (FAT).

Does anybody know the maximum size of SD-card that the IXUS 50 supports? And/or the exact requirements on the formatting? There are something like eight different types of FAT, I believe.

  • \$\begingroup\$ The storage cards must be formatted in the camera. Try please and add the result in question. \$\endgroup\$ Commented Mar 29 at 11:47
  • \$\begingroup\$ The format option is greyed out, presumably because of the error. I'm pretty sure it is not necessary to format it in the camera, it just needs to be the right format. I am not sure exactly how picky this particular camera is. \$\endgroup\$
    – Tomas By
    Commented Mar 29 at 11:49
  • 1
    \$\begingroup\$ See here. SD cards accept FAT12 or FAT16. \$\endgroup\$
    – xenoid
    Commented Mar 30 at 17:49

2 Answers 2


According to this site the maximum size of cards for this camera is 2GB. So you should stay with this size. And I do not think there is option to use bigger SD cards.

And the best way to format the card is to do it in camera.

  • 1
    \$\begingroup\$ As pointed out by @xenoid, FAT16 can only support up to 2Gb. \$\endgroup\$ Commented Mar 31 at 23:53

Almost any device that only supports SD will top out at 2GB. SDHC, which supports 4-32GB is a later extension of the standard. It's not just the filesystem but some things about the addressing that are different. Technically the addressing of SD might allow a 4GB card if it used an out-of-standard FAT32 instead of FAT16 but compatibility would probably be limited so a 4GB card is almost guaranteed to be SDHC.

SDXC which supports cards larger than 32GB is a further extension on top of that.


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