when slot a fills up on canon 5div how to switch to slot b

On the Canon 5D Mark IV, set Record func. + card/folder sel. to Auto switch card so the camera automatically moves from slot A to slot B when the first card fills up. Canon’s support materials also describe this as relay recording , where recording continues on the second card once the first is full.

How to set it

1. Press Menu.
2. Go to the yellow wrench / setup tab.
3. Open Record func. + card/folder sel.
4. Choose Auto switch card.
5. Make sure both cards are inserted and ready to use.

What to expect

• Slot A fills first, then the camera switches to slot B automatically.

• There may be a brief pause at the switch point, depending on the camera mode and media.

• If you want mirrored backups instead, choose Record to multiple rather than auto-switch.

Quick note

If the camera is not switching, check whether you’ve set Record separately or another dual-card mode, since that can prevent overflow to the second card.

TL;DR

Use Menu > Record func. + card/folder sel. > Auto switch card to make slot B take over after slot A fills.