GFX 100 II vs Z 9
A side-by-side readout for dual card slots.
Understanding dual card slots
Two slots means two cards. Modern bodies support multiple write modes:
Write modes
- Backup. Every frame is written identically to both cards. The standard for paid work — if one card fails or corrupts, the second is intact.
- Overflow. Card 2 starts writing when card 1 fills. Doubles capacity for long events.
- Split. RAW to card 1, JPEG to card 2; or stills to one, video to the other.
Slot symmetry
Watch for asymmetric slots: one CFexpress + one SD is common. The slower SD slot bottlenecks backup mode to SD speeds — high-bitrate 4K/8K video may not be writable in backup at all.
Why it matters
For weddings, sports, and editorial work, dual slots are non-negotiable. The cost of a single failed card on a once-in-a-lifetime shoot dwarfs the body price premium. Hobbyist bodies (Canon R8, Nikon Zf in single-slot configs) prioritize size; pro bodies (R5 II, Z8) always ship dual.
This matchupBoth GFX 100 II and Z 9 support dual card slots, so this spec is not a deciding factor between them.
What is dual card slots?
A camera body with two memory card slots. Enables in-camera backup writing, overflow recording, or splitting RAW and JPEG between cards. A defining feature of professional bodies.
Read the full Dual card slots explainer →Other specs on this comparison
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