Most cameras (if not all) uses the same chip, or a variation of
it, to handle the FAT-file system as this makes it cheaper to
implement support for cards and so on. The drawback security-
wise, is that they all offer the same functionality. Deleting a
file only deletes the header of the file and such the file can
easily be reconstructed. Simply full-formatting the card helps,
but with forensic techniques it is possible to get those data
back (picking up and amplifying weak electric/magnetic residue).
With quick-format only the file table is cleared, content is
left untouched. So what you can do to achieve high security with
a common camera is the following: After you have transferring
the pictures use the following procedure: - Format the card
(important: full format, not quick). - Turn off flash and take
as many pictures you can to fill up the card. Point the camera
to the sky f.ex. This is to overwrite the old left-over traces
with "noise". - Re-format again with full format And repeat once
more (or twice) t