Today, there’re many variations of memory cards available, differing not only in speed and capacity but also in brand and compatibility, not even to mention price.
Although SD remains the most widely used format, there are other formats, including Compact Flash, microSD, XQD, CFexpress, and others that have different advantages and are compatible with different cameras.
Since camera technology continues to improve, and 4K video recording is quickly replacing Full HD recording (and 8K is just around the corner), storage media must be fast and high-speed to keep up with the demands of these new technologies.
Increasingly, memory cards require not only a large capacity to store all those images and videos, but also a data transfer rate that allows them to handle all those gigabytes of data. They also need to be able to keep up with the incredibly fast continuous shooting speeds of the latest generation of premium cameras.
So, here’s more about one of such memory cards – the CFexpress card.
What is CFexpress
CFexpress is a removable storage standard proposed by the CompactFlash Association. The standard allows a PCIe version 3.0 bus from 1 to 8 lanes, with data transfer rates of 1 gigabyte per second on each lane. The NVMe protocol is used to ensure low latency and reduced overhead. There are several CFX form factors with different numbers of PCIe lanes in the slot.
One of the goals of the standard is to unify the removable media ecosystem and use the widely used PCIe and NVMe standards. There’s a wide range of controllers, drivers, and drives that use these standards.
Why is CFexpress so valuable
The reason is that the new format offers significantly higher speeds compared to the current generation media – XQD or SD. It also has serious potential for improvement and several form factors for use in different types of equipment. Moreover, there’s already the second generation of CFexpress themselves, with new sizes and increased speeds.
There are currently three main types of CFexpress cards available – two of them are already available for purchase and the third will be available on the market shortly. The two types you will see in a consumer photo and video equipment are Type A and Type B.
Type B cards are much more common at the moment. CFexpress Type B cards use exactly the same form factor and connectors as XQD cards. That’s why many cameras, such as those from the Nikon Z and Panasonic S lines, that were originally compatible with XQD cards have been able to add compatibility with CFexpress via a firmware update.
At the same time, XQD already offered a number of advantages over more traditional memory card formats, and XQD cards are significantly smaller in size than competing CFast cards. So it’s not surprising that CFexpress started their expansion with a similar form factor to XQD.
Can you use a CFexpress card in any camera
The answer to this question is no. While many cameras today are designed for SD cards, CFexpress cards are still in rotation. The CFexpress card types are also each different in size.
- The Type A cards are 20x28x2.8mm and have a maximum theoretical speed of 1GB/s.
- The Type B cards are slightly larger, 38.5×29.8×3.8, and can reach speeds of 2GB/s.
- The Type C is a larger format (54x74x4.8mm) and has a higher potential speed of 4GB/s, but none of the manufacturers have used it for their devices yet.
These size differences mean that the card slot has to be designed specifically for them, so you can’t use a CFexpress card in an SD card slot. Cameras with CFexpress card slots are usually compatible with SD cards, which is useful if you can’t afford or don’t need the extra power and want to stick with SD.
The Sony A7S iii camera has two memory card slots that accommodate either CFexpress type A or SD cards. Some CFexpress type B cards can also work in the XQD slots.
Another important factor when buying a CFexpress memory card is its sustained write speed. A sustained write and data transfer speed is maintained when the card is in constant use over a long period of time, which means a good overall average write speed of the card.
