Disk Doctors Mac Data Recovery is an application that lets you scan your hard drives, flash memory, and memory cards and recover lost files. It is not commonly known, but simply deleting a file won't prevent people from recovering it if they use software like this. Formatting a memory card is also not a definitive measure. This means that even accidentally lost data can be sometimes averted.
The first window that you will see when you launch the application lets you select the drive or volume that you want to scan. If you select a physical drive, you will be asked to select a volume as well, or you can carry out a full drive scan. The last few steps before initiating a scan can be very helpful to speed up the process. Here, you can tell the app what files you are looking for and you can set a maximum size for the files that you want to recover. The start position and end position of the drive can also be specified. Although this is an abstract concept, it may help narrow down the location of the files that you are looking for.
In my testing, I used an SDHC memory card, which I formatted using my digital camera. Then I scanned it with this app, and only after 5 minutes I was able to recover 2 gigabytes worth of JPEG photos and MOV videos. I could preview the photos from within the application, but the videos didn't play.
In short, Disk Doctors Mac Data Recovery does a good job of finding files that might have been thought to be lost. It is very easy to use and it has good filtering options.