The slot (CF or SD card slot) selected as the primary slot using the “Primary slot selection” item.

The primary slot is used as follows.

- If “Overflow” is selected for “Secondary slot function”, images are recorded to the primary slot as long as there is space available. The card in the secondary slot is used only if the card in the primary slot is full.

- If “RAW primary, JPEG secondary” is selected for “Secondary slot function”, RAW images are recorded to the card in the primary slot, JPEG images to the card in the secondary slot.

- If two cards are inserted in the camera, only the card in the primary slot will be used for firmware updates, saving and loading camera settings, and optional Picture Controls.