With the most recent Z9 firmware updates, we now have a choice for in-camera formatting: Full format or Quick format. It’s important that you understand one key difference between the two choices. A longer explanation will come in my next Complete Guide to the Z9 update, but I’m finding people not understanding the basics, so here goes:
- Quick format — A zero is written to the first character of each file’s name in the card’s directory, and the file allocation table is reset. No image data is changed, but all parts of the card are now marked as “usable.”
- Full format — The partition and file information table are renewed, and the directory is erased. It’s likely that some form of Trim operation is also being done on the card. All data still on the card is decoupled from any useful reference data and thus considered “unmapped”.
In the case of a Quick format, recovery software tends to still have enough information it can find to stitch an image file back together (and even all but one character of its name). That’s because the recovery software can look in the directory at any filename that starts with 0 and still follow the sector allocations that are saved in that directory. If you continue to use a card after a Quick format, over time it will get more difficult to recover files that were “erased,” because new files are writing over previously-used sectors.
In the case of a Full format, there’s no help left behind for recovery software to lean on, as there are no tables or pointers left that would allow you to easily understand how the NAND cells were used. I don’t believe Nikon overwrites all data cells on a Full format. Doing so is something you want to avoid on NAND memory, as you have a limited number of times you can do that for each individual cell. Instead you use what’s called a Trim operation that lets the card repurpose the cells—so I suppose someone could still grab all the data in all the cells and then play a giant game of jigsaw puzzle trying to put files back together. But that’s a deep, time consuming, and expensive forensic process.
So, use Quick format. Period. The only time I’d use Full format is if there was information on the card that I didn’t want someone else to be able to recover, if using the card on a computer somehow messed up the data structure, or if I’ve been using the same card for a long period of time (Trim is a useful tool to prolong card integrity).
Updated: clarified wording in format descriptions. Simplified sentence structures to be more clear. Added final note about Trim.
