Digital photo recovery

After the appropriate connection to the media is arranged, the data recovery software is used. There are two conceptually different approaches for the software to utilize, each having its own advantages and limitations.

Data-based recovery

In this case, only the file data is taken into account. Program searches the media for data files (knowing, for example, that all JPEG files start with a certain sequence). To implement this, program has to know about internals of all file formats it can recover. As a side effect, the file name and directory structure information are not recovered with this approach. You get all the files in one list, sorted by their type.

If one uses the data-based approach to recover data from a media of significant size (like a hard drive or a RAID), the lack of the information about the file names and folder tree structure makes the result pretty useless. So the data-based approach is limited to small and simply organized media, like a photo camera memory card.

A couple of the recovered files may turn out very large in size. Typically, they can still be used normally. In case of the photo files (like JPEG), you can open the file with the graphics editor and save it back. This gets rid of the excessive data.

Filesystem-based recovery

The digital camera memory is essentially the same as your regular disk drive, albeit smaller. Hence, the same procedures that are used to unformat the regular drive may be applied to the memory card. This approach does not require an advance knowledge of all the file formats, and can be applied to the files of any type.

The software

Being developers of Zero Assumption Recovery (ZAR), a data recovery tool utilizing both of the above techniques, naturally we advise that you try it (free for digital image recovery applications).

The data-based process is described in the digital image recovery tutorial, and the filesystem-based one is the same as the unformat procedure.

The other tool of choice is TestDisk (freeware), which operates in data-based mode and knows more file formats than ZAR does.

If you want even more choice, take a look at this page which lists most widespread software, both free and paid, in a side-by-side comparison.

For the digital photo recovery, the output would be pretty much the same; for a lightweight device other than a digital camera (like a cell phone or PDA), TestDisk would probably produce better results; for anything more complex than a digital camera or PDA, ZAR result would be better.

Continue to Photo recovery limitations.