Yes, the Lexar Professional 2000x 256GB SD is compatible with the Sony FX30.
Lexar Professional 2000x (256GB) is an SDXC V90 card. The FX30's SD floor is V60 for standard XAVC HS/S 4K and V90 for the higher-bitrate XAVC S-I 4K -- V90 clears both.
“XAVC S-I 4K 600Mbps CFexpress Type A memory card (VPG200 or higher) SDXC V90 or higher”
Last verified:
Confidence: inferred