CFexpress Type A vs Type B: Which Card Fits Your Camera?

Quick answer

Pick the card type your camera slot accepts, not the one with the bigger number. Type A fits compact Sony bodies and prioritizes capacity and durability; Type B fits larger cinema and hybrid bodies and prioritizes raw speed.

The slot decides before the spec sheet does

CFexpress Type A and Type B use different physical formats, so a Type B card will not seat in a Type A slot and vice versa. Check your camera manual or the slot label before comparing read and write speeds. No adapter changes the electrical and physical mismatch, so a wrong-format purchase is a return, not a workaround.

Where the Sony 640GB Type A earns its price

The Sony card's headline advantage is capacity: 640GB in a Type A body means fewer offloads during long event days or multi-day shoots. Its catalog listing also specifies shock, UV, and X-ray protection and resistance to 70N of force, which matters if cards travel loose in a bag or get handled roughly on set. File Rescue recovery software support adds a safety net for accidental deletions, though it is not a substitute for a backup workflow.

Where the SanDisk 256GB Type B earns its price

The SanDisk card is built around throughput: up to 1700 MB/s read and 1400 MB/s write, with the catalog noting smooth raw 4K capture at resolutions up to 4096 x 2160. That write ceiling is the reason Type B is the common choice for cinema cameras recording high-bitrate raw. Backward compatibility with older CFexpress hosts is listed, but confirm your specific camera's firmware supports the card before relying on it.

Capacity vs speed is the real trade-off

The Sony 640GB Type A gives you roughly two and a half times the capacity of the SanDisk 256GB Type B, but the SanDisk's listed write speed is higher. If your camera accepts Type A and you shoot long interviews or events, capacity usually wins. If you shoot short high-bitrate raw takes on a Type B body, speed and offload time matter more than card size.

What the catalog does not tell you

Neither listing supplies sustained write speed, minimum write speed, or tested camera compatibility lists. Those are the numbers that predict dropped frames in long takes, so treat the advertised peak speeds as a starting point and verify sustained performance with your camera model before a paid shoot.

Trade-offs to weigh before checkout

• Format compatibility: Type A and Type B are physically different. Match the card to your camera slot; no adapter bridges them. Check the manual if the slot is unlabeled. A card that does not seat is not a slow card; it is the wrong card.
• Capacity vs speed: The Sony 640GB Type A offers more than double the storage of the SanDisk 256GB Type B, while the SanDisk lists higher peak write speed. Choose capacity for long event coverage, speed for short raw takes. Estimate your shoot length in minutes before choosing capacity over speed.
• Durability and recovery: The Sony Type A listing specifies shock, UV, X-ray, and 70N force protection plus File Rescue support. The SanDisk listing emphasizes speed and backward compatibility. Neither replaces a backup routine. Cards that leave the case benefit from rated physical protection; all cards benefit from a second copy.

Product facts at a glance

• SanDisk 256GB Extreme Pro CFexpress Type B: Read speeds up to 1700 MB/s and write speeds up to 1400 MB/s, with catalog support for raw 4K capture up to 4096 x 2160. High write throughput reduces buffering during high-bitrate raw recording on Type B cinema and hybrid bodies.

  

• Sony 640GB CF Express Type A Memory Card: 640GB Type A capacity with shock, UV, and X-ray protection and resistance to 70N of force. Large capacity cuts offload frequency on long shoots, and the durability claims suit cards that travel outside a case.

  

Who should buy which

Best for

• Sony camera owners with a Type A slot who need long recording capacity and travel-ready durability
• Cinema camera operators with a Type B slot who record high-bitrate raw and prioritize write speed

Not for

• Cameras with only a Type B slot, which cannot use the Sony Type A card
• Shooters who need maximum capacity in a Type B body, since the SanDisk card is 256GB