When attempting memory card recovery for the purpose of rescuing lost or damaged digital image files aka digital photographs one should specifically purchase a digital media recovery program as opposed to a general purpose file recovery utility. There is one particular reason for this and that is because many camera manufacturers store the digital information created by the camera in the form of a proprietary file format. These files known as RAW files have unique extensions and file structures. Most general purpose photo recovery programs are only able to recognize digital image files after they have been converted by a twain download.
After download those same RAW files will be seen on your computer as simple JPGs or other popular image file types. Until then when we attempt to recover memory card files we must target the original file type. Most quality digital media recovery programs will support all proprietary file types as established by the original high end camera manufacturer.