Backing up a wedding shoot: the 3-2-1 rule on an actual shoot day

Three copies, on two types of media, one of them off site. Everyone can recite it. The failures happen in the eight hours where it is inconvenient.

The window where you are exposed

From the first frame until the files are copied at home, you have exactly one copy of an unrepeatable event, sitting in a bag, at a party, with drinks.

That window is usually eight to fourteen hours long, and it is the single largest risk in the whole job.

Closing it on the day

Shoot to two cards where the body allows it. In-camera backup is the only measure that protects you during the event itself. If your body has two slots and you are not using the second one for redundancy at a wedding, that is the first thing to change.

Swap cards rather than filling them. A full card is a single point of failure holding the whole ceremony. Several part-full cards spread the risk, and cards are cheap next to a reshoot you cannot do.

Never format on the day. Not for any reason. Carry more cards instead.

Separate the cards physically. Shot cards in a different pocket from empty ones, and if there is a second shooter, split the sets between two bags. Bags get left in cars.

When you get home

Copy before anything else — before food, before looking at a single frame. Two destinations, and verify the count matches before the cards go anywhere near a card reader again.

Then the off-site copy, running overnight. This is the one people skip because it is slow and nothing bad has ever happened. That is also the copy that saves you when something does.

The rule that actually holds

Cards do not get formatted until the shoot exists in three places and you have opened files from two of them.

Not "when I have backed up". When you have opened the files. A copy you have not verified is not a copy.