Even without such a buffer, formatting only rewrites the "file allocation table", which is an index of where files are on the device. With no files allocated, the card appears empty after formatting, but the data is still sitting where you left it, albeit no longer indexed. Recovery software can search through the device and find patterns like the beginning and end of a jpg, and guess where the files might have been. Most of the time it's very successful. Once the allocation table is clear however, any space is up for grabs, and some of the old data may be corrupted or completely overwritten. So, if you think you'll need to do a recovery, stop using the card immediately and only let the recovery software touch it.