What fits in each slot
| Slot | Formats | Interface | Workflow note |
|---|---|---|---|
| Card 1 | CFexpress Type B | CFexpress 2.0 / VPG400 supported | Primary path for 6K RAW and highest-rate recording. |
| Card 2 | SD/SDHC/SDXC | UHS-I / UHS-II | Supports stills and movie settings permitted by Canon's table. |
When faster media matters
Everyday recommendation
A fast UHS-II SDXC card for stills and supported compressed movie modes; use CFexpress for the broadest capability.
Demanding recommendation
CFexpress Type B VPG400 or a card meeting Canon's 200–400 MB/s requirement for the chosen 6K RAW setting.
6K RAW Standard at higher frame rates calls for Type B performance up to 400 MB/s; RAW Light settings may have lower requirements.
Plan the complete workflow
Capacity
Canon supports CFexpress Type B plus SD/SDHC/SDXC. Calculate capacity from the selected RAW or compressed movie bitrate.
Reader
Use a Type B reader for Card 1 and UHS-II SD reader for Card 2.
Three checks worth making
- CFexpress Type A does not fit.
- The SD slot cannot record every 6K RAW setting.
- Check Canon's exact frame-rate row before purchase.
Verify the current requirement
StorageSift summarizes the manufacturer's documentation; firmware, card qualification, and recording options can change. Recheck the source for the exact mode and capacity you plan to use.
Canon EOS R3 manual: compatible cards ↗Source checked August 13, 2026