The Sony a7R IV takes two memory cards (both are UHS-II slots), and you can format each one independently. Sony also creates an image database on the cards as part of the formatting and setup process. You don’t have to do anything special for that–it’s done automatically. And in case you’re wondering, no, you don’t need to fill both memory card slots, and the cards don’t have to be the same size, brand, or specs.
Here’s a quick step-by-step guide on how to format memory cards in the Sony a7R IV.
If you’ve used another Sony camera recently, the Format function will be in a familiar place. You go to the settings tab (the toolbox icon). You’ll find Format near the bottom of page 5 (Setup5).
You’ll then get presented with a page that lets you choose which of the two memory cards you want to format. You have to do them individually; you can’t format them both as part of a single operation.
The next step is the normal confirmation to ensure that you know you’re wiping everything off the card. (If you format the card or delete photos accidentally, all is not necessarily lost. It might still be possible to recover the data so long as you haven’t started writing over it again. I’ve put together some information on how to recover accidentally deleted photos and videos separately.)
Once you confirm, you’ll see a progress bar. It should only take a few seconds to finish.
Finally, you’ll see a simple “Formatting completed” message. You’re then good to go.
Tip: If you’re new to Sony cameras, you might get caught out with the way in which they’re set by default not to roll over automatically from one memory card to the next. I’ve put together a guide on how to change that behavior here.