Nikon Z8 Dual Card Recording: Overflow, Backup, and RAW/JPEG Slotting

First, select the task assigned to the secondary card

In the Photo Shooting Menu under Secondary Slot Function, the Z8 allows the secondary card to be used for Overflow (writes to the secondary card after the primary card is full), Backup (writes the same photo to both cards), or dual format recording. First select the primary card slot, then choose the secondary card function according to your workflow; the writing behavior differs for each mode. [G-DC-01]

Backup or RAW/JPEG Separate Slots

Backup will write each photo to both the primary and secondary cards. RAW primary - JPEG secondary is only selectable in SDR tone mode; when shooting RAW + JPEG/HEIF, RAW is written to the primary card and JPEG to the secondary card, while other image quality settings write two identical copies. When HLG is enabled, there are additional options such as RAW primary - HEIF secondary. [G-DC-02, G-DC-03]

Notes on Full Cards and Video Target Card

When choosing an option other than Overflow, the camera displays the number of shots that can be recorded on the card with less remaining space; if either card is full, the shutter release will be disabled. The secondary card function for still photos does not automatically set the destination for videos; the video recording slot must be selected separately in the Video Recording Menu under Destination. [G-DC-04, G-DC-05]

Post-setup Check

Before shooting, confirm the primary card slot, secondary card function, SDR/HLG mode, and target file format; take a test shot and check the files on both cards. When using separate slot recording, do not expect the same files to exist on both cards as in Backup mode. The manual does not provide a uniform writing speed or throughput difference applicable to all card models, file formats, and shooting settings; continuous shooting performance should be tested according to the specific card and settings.