SD vs CFexpress vs microSD Cards

SD vs CFexpress vs microSD Cards

Memory cards are the storage medium for your photos and videos, and the type of card you use affects how fast your camera can shoot and how quickly you can transfer files. The three most common card formats today are SD, CFexpress, and microSD. Each has different speeds, capacities, physical sizes, and use cases. Choosing the right card for your camera and shooting style is important.

SD cards are the most common and compatible format. They come in different speed classes that indicate minimum write speeds. Class 10 is the minimum for 1080p video. UHS Speed Class U1 and U3 indicate 10 MB/s and 30 MB/s minimum write speeds respectively. Video Speed Class V30, V60, and V90 indicate minimum write speeds of 30, 60, and 90 MB/s. For 4K video, you want at least V30. For high bitrate 4K or 6K, V60 or V90 is recommended. SD cards are relatively inexpensive and work with most devices.

CFexpress cards are the newest and fastest consumer card format. They use the NVMe protocol, the same technology found in high-end SSDs, achieving read and write speeds of over 1000 MB/s. CFexpress Type A is smaller and used by Sony cameras. CFexpress Type B is slightly larger and used by Canon, Nikon, and others. These cards are essential for high resolution, high frame rate video and rapid burst shooting. The downside is that they are much more expensive than SD cards.

microSD cards are the smallest format, used primarily in smartphones, action cameras, drones, and some compact cameras. They are available in the same speed classes as SD cards but typically have lower maximum speeds due to their smaller size. Action cameras like GoPros and DJI drones use microSD cards. For these devices, a high-speed microSD card with V30 or higher rating is important for smooth video recording. microSD cards usually come with an SD adapter so they can be used in standard SD card slots.

The key specification to look at is sustained write speed, not just read speed. A card might advertise 200 MB/s read speed but only write at 40 MB/s sustained, which is not fast enough for 4K video. Look for cards that specify their minimum sustained write speed. For photography, buffer clearing speed matters. A fast card clears the buffer quickly so you can shoot another burst without waiting. For video, the card must maintain its write speed continuously without dropping frames.