CF

A flash memory storage format originally developed by SanDisk in 1994. It became one of the first widely adopted solid-state storage standards for digital cameras and professional video equipment. Over the years, the CF brand evolved into newer generations, culminating in CFexpress, a high-speed standard designed for modern high-resolution photography and video production.

CompactFlash (CF) Origins

The original CompactFlash cards used Parallel ATA (PATA) technology, with an IDE-like interface similar to early computer hard drives. These cards featured a robust form factor—43 mm × 36 mm × 3.3 mm—and were known for their durability and reliability in demanding environments, such as professional photography and industrial systems. CompactFlash could store hundreds of megabytes to several gigabytes, a breakthrough for its time.

The CompactFlash Association (CFA), an industry consortium founded to oversee the standard, later introduced faster variants such as CF Type I and CF Type II, the latter being slightly thicker to support microdrives and other embedded devices.

Transition to CFast

As data rates for photography and video increased, the CFA launched CFast, which adopted a Serial ATA (SATA) interface to improve read/write performance. CFast offered significantly higher bandwidth than CompactFlash but still fell short of the speeds required for professional 4K, 6K, and 8K workflows that emerged in the late 2010s.

CFexpress: The Modern Successor

Introduced in 2017, CFexpress represents the latest evolution of the CompactFlash lineage. Rather than relying on aging SATA or PATA connections, CFexpress leverages PCI Express (PCIe) and NVMe protocols—the same technologies used in high-speed solid-state drives (SSDs). This shift dramatically increased throughput and reduced latency, making CFexpress ideal for modern imaging and data-intensive applications.

CFexpress Form Factors

The CFexpress family is available in multiple form factors to accommodate different device designs:

• CFexpress Type A: The smallest variant (20 mm × 28 mm × 2.8 mm), often used in mirrorless cameras like Sony Alpha models. Uses one PCIe lane.
• CFexpress Type B: The most common format (38.5 mm × 29.8 mm × 3.8 mm), using two PCIe lanes. It’s physically identical to the older XQD card, ensuring backward compatibility with firmware updates.
• CFexpress Type C: A larger, enterprise-grade variant with four PCIe lanes for maximum speed and capacity, intended for future professional equipment.

Performance and Use Cases

CFexpress cards deliver speeds ranging from 1,000 MB/s to over 2,000 MB/s, depending on the version and PCIe configuration. This makes them essential for workflows requiring:

• Continuous high-resolution RAW image bursts
• 8K and 12K video recording at high bitrates
• Real-time data capture in industrial or scientific imaging
• Ultra-fast file offloading and editing

These capabilities make CFexpress the de facto professional storage standard, gradually replacing older CompactFlash and CFast media in high-end cameras from Canon, Nikon, Sony, and Panasonic.

Backward Compatibility and Transition

One of CFexpress’s advantages is its compatibility with XQD slots, which allows many professional cameras to adopt the new standard through firmware updates rather than hardware changes. This eased the transition for photographers and videographers who had invested in XQD infrastructure.

Future Outlook

The CompactFlash Association continues to evolve the CFexpress specification to support higher PCIe generations, expanding bandwidth for next-generation devices. As video resolutions, frame rates, and bit depths continue to rise, CFexpress is expected to remain the industry benchmark for removable, high-performance flash storage.