Yes, the Sony FX3 is compatible with the Sony SF-G Tough 128GB.
Sony SF-G Tough V90 writes at 299 MB/s. Sony FX3 SD slot supports 4K30 XAVC S recording at ~200 MB/s minimum. 299 MB/s meets that floor. 4K60 and above requires CFexpress Type A — the SD slot cannot sustain those rates regardless of card.
“Sony FX3 Help Guide: XAVC S-I 4K at 600Mbps requires SDXC V90 or higher; XAVC S 4K at 280Mbps requires SDXC V60 or higher — S&Q XAVC S-I 4K at 1200Mbps requires CFexpress Type A.”
“Class 3 (UHS Speed Class), V90 (Video Speed Class)”
Last verified:
Confidence: inferred