Memory card recovery on Mac OS X: Keep in mind, the less you use the memory card you are going to recover your data from, the higher the chance of SD or CF card recover on Mac. Most cameras don't wipe pictures completely from your camera memory card upon deletion or formatting. In most cases, only filenames and file properties are erased, and your photos and video data remain on the memory card until they are overwritten. If you simply erased files on your memory card right from your camera, Disk Drill has a very good chance of recovering them. However, if you took more pictures and saved them to the same card after the initial deletion, you may have overwritten your old data, making it unrecoverable.
You can recover formatted SD card on Mac OS X even if it can't be read by your Mac – if it's shown as having no partitions or logical structure and you get a message saying it requires formatting, try Deep Scan. It will drill down to the data sectors of your memory card on a binary level to search for remaining pictures, music or other recoverable data.