What is CFexpress Type A? Sony A7S III's new memory card explained

Sony A7S III supports CFexpress Type A cards
Sony A7S III supports CFexpress Type A cards (Image credit: Sony)

One of the most remarkable features of the new Sony A7S III isn't something we'd usually get that excited about - the type of memory card it uses. But in this case, the announcement that (in addition to normal SD cards) the camera supports the previously unreleased CFexpress Type A card format is big news.

• See the Digital Camera World A-Z Dictionary of photography jargon

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CFexpress types compared
Header Cell - Column 0 Type AType BType C
Dimensions20mm x 28mm x 2.8mm38.5mm x 29.8mm x 3.8mm54mm x 74mm x 4.8mm
PCIe interfaceGen3, 1 laneGen3, 2 lanesGen3, 4 lanes
Maximum theoretical performance1000MB/s2000MB/s4000MB/s

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Ben Andrews

Ben is the Imaging Labs manager, responsible for all the testing on Digital Camera World and across the entire photography portfolio at Future. Whether he's in the lab testing the sharpness of new lenses, the resolution of the latest image sensors, the zoom range of monster bridge cameras or even the latest camera phones, Ben is our go-to guy for technical insight. He's also the team's man-at-arms when it comes to camera bags, filters, memory cards, and all manner of camera accessories – his lab is a bit like the Batcave of photography! With years of experience trialling and testing kit, he's a human encyclopedia of benchmarks when it comes to recommending the best buys.