One handy free utility that helps ease these processes is DiskDigger, which according to its maker's website can recover files from any type of media that your computer can read — including USB flash drives, memory cards such as SD, CompactFlash, Memory Stick and others, and hard drives too. Recoverable file types include photos, videos, music, documents and other formats.
Bypassing the Windows file system drivers, DiskDigger scans disk drives directly and reportedly can even scan reformatted or badly formatted disks to which Windows can't even assign a drive letter; as well as disks with bad sectors.
The program offers built-in support for the FAT12 (floppy disk), FAT16 (older memory cards), FAT32 (newer memory cards and hard disks), NTFS (newer hard disks), and exFAT (Microsoft's new successor to FAT32) file systems.
A single executable file, DiskDigger is compact and portable, with nothing to install and leaving no trace of having been run.
DiskDigger offers two modes of operation. The first scans the file system for deleted files and is fast and able to recover all file types and file names — although this mode doesn't support all possible file systems and doesn't scan the entire disk, limiting its search to only those files that the file system is aware of.
The second, more extensive mode scans the disk surface for all traces of lost files, thoroughly scanning every sector of your media and going underneath the file system to find hidden files. While it is sometimes much slower than the first method and unable to recover file names or fragmented files and only supporting certain file types, this mode will find all 'existing' and still-accessible deleted files.
DiskDigger is not magic nor is it a "repair" utility. It is strictly a "read-only" tool and does not change the contents of the scanned media nor will it attempt to fix the formatting of the media, if needed.
A work in progress, DiskDigger has new features added regularly, including support for more file formats, more configuration options, and more. It is claimed to be intuitive enough for most people to use without a written guide, but a tutorial is available from TechRepublic.
In my own personal tests, I in fact found DiskDigger able to retrieve image files from a disk that had been cleaned and fully formatted; making the utility handy for retrieving "lost" files and ensuring the total deletion of sensitive information. Try it for yourself.