The CompactFlash Association (CFA) has released the specifications for CFexpress 4.0. The new specifications will increase the performance of the existing CFexpress 2.0 standard while maintaining backward compatibility. The CFA is the organization responsible for professional removable media specifications such as CompactFlash, CFAST, XQD and CFexpress.
Backwards compatibility
Under CFexpress 2.0 there are three different types of cards: Type A, Type B and Type C. The CFexpress 4.0 specification adopts these same form factors so cards with the new specifications will have the same dimensions as those currently available. CFexpress type A cards are used as an alternative to SD cards in some Sony cameras such as the FX3. However, you can use CFexpress Type B cards with Nikon, Canon and Panasonic cameras. Type C cards are designed for use with computers and solid-state drives rather than cameras.
Performance
CFexpress 4.0 uses the PCI Express (PCIe) Gen4 bus and NVM Express (NVMe) 1.4c logical interface. Theoretically PCIe Gen4 has double the throughput compared to the PCIe Gen3 employed by CFexpress 2.0. In practice, few memory cards ever reach the theoretical maximum transfer speeds. However, the new specification will certainly lead to faster cards.
PCIe bus
CFexpress Type A cards use a PCIe bus with one lane while Type B cards have two lanes. This is why Type B cards have maximum speeds which are twice that of Type A cards. With the speed increases that come with CFexpress 4.0 and PCIe Gen4, the new Type A cards will match the speeds of current Type B cards. In addition, CFexpress 4.0 Type B cards will transfer data at double the rates of the current Type B cards.
Canon
Hiroshi Noda of Canon and co-chairman of the CFA board said, “Adoption of the higher performance CFexpress 4.0 for removable media storage will support current and future needs of professional photographers, videographers and cinematographers enabling higher resolution, frame rates and color depth leveraging PCIe Gen4. CFexpress 4.0 will further cement CFexpress as a standard in the imaging industry.”
Nikon
Nobuhiro Fujinawa of Nikon and co-chairman of the CFA board said, “With the evolutionary approach in defining the new CFexpress 4.0 specifications, end users can preserve their investments made in CFexpress 2.0 removable media cards while enjoying cutting-edge use cases with the higher performance CFexpress 4.0 cards. This is a win-win for the installed base and the growing CFexpress ecosystem.”
Sony
Hiroshi Machida of Sony Corporation and CFA board member said, “With its three form factors maintaining a consistent electrical, logical, and physical interface, CFexpress 4.0 will allow professional photographers, videographers, and cinematographers to scale seamlessly amongst the various use-case scenarios demanded by the host cameras. It is also a welcome approach for host manufacturers since the development cycle can be reduced significantly”.
What we think
As video resolutions increase, so does the need for faster memory cards to keep up with the data transfer rate for high quality video. This becomes even more important if you want to shoot at higher frame frames for slow motion playback. Alongside this, the CFA is also preparing a new specification for VPG (Video Performance Guarantee) for higher sustained video recording which will be released soon. The new CFexpress 4.0 specification will enable manufacturers to keep developing ever more powerful cameras. Of course, higher data rates also mean larger video files so we will all need higher capacity cards and more storage for editing.
