As an evolution of the XQD format, CFexpress is one of the best memory card formats around. However, it's currently only available with a limited number of high end cameras (mostly from Canon, Nikon and Panasonic). However, it's worth noting that the release of the Sony A7S III brought a somewhat confusing split into two different variants of CFexpress cards. Up until this point, all CFexpress-compatible cameras used CFexpress Type B cards (yes, 'B' does come before 'A' in this case!). Meanwhile, CFexpress Type A cards are smaller and slower. Crucially, Type B and Type A cards aren't interchangeable, so a camera such as the Nikon Z7 won't be able to accept a CFexpress Type A card. The Transcend did superbly in its speed tests, excelling the claimed write speed (180MB/s) with a whopping 224MB/s, but falling slightly short on the read speed with 224MB/s. Overall, that makes this card an impressive buy at a reasonable cost. This card is ideal for high resolution, rapid-fire stills photography and 8K video, with 4K and HD video being recorded comfortably, too.

One of the most obvious ways to differentiate between memory cards is how much storage they have. A 16GB card might be fine for an afternoon wandering around your local wildlife reserve, but videographers looking to shoot all day could get frustrated with having to constantly swap over cards. The extra capacity that an Extreme Pro card also gives it an extra boost if you store media in large formats. Again, 4K videos are good examples. This can also be useful if you save in RAW format, which stores a greater amount of information that can be useful in post-processing and color grading. CompactFlash used to be the preferred format for higher-end DSLRs. However, with the improved performance of SDHC and SDXC cards (and the introduction of newer memory card formats as well), this memory card format is growing more rare. ProGrade Digital also has a 160GB Type A card you can buy, but it's not as readily available as this Sony equivalent, and is only marginally cheaper. Delkin has Type A cards coming soon though, so hopefully prices will start to fall further. XQD Up to 200MB/s read speeds, engineered with proprietary technology to reach speeds beyond UHS-I 104MB/s, require compatible devices capable of reaching such speeds. Write speed up to 140MB/s. Based on internal testing; performance may be lower depending upon host device, interface, usage conditions and other factors. 1MB=1,000,000 bytes. X = 150KB/sec. [64-128GB] Up to 200MB/s read speed. Write speed up to 90MB/s. Based on internal testing; performance may be lower depending upon host device. 1MB=1,000,000 bytes. X = 150KB/sec. [32GB] Up to 100MB/s read speed. Write speed up to 90MB/s. Based on internal testing; performance may be lower depending upon host device. 1MB=1,000,000 bytes. X = 150KB/sec.Card classifications like V30 or U3 are just categorizations of these speeds. There are three main classes: Speed Class (denoted with a number in a circle), UHS Speed Class (a number in an open beaker-like icon), and a Video Speed Class (V followed by a number). The numbers indicate the minimum writing speed when put under data transfer. Speed class is categorized into Class 2 (a minimum write speed of 2MB/s), Class 4 (4MB/s), Class 6 (6MB/s), and 10 (10MB/s). Choosing the best one for your camera depends on your camera's resolution, buffer size and burst shooting speeds. An additional clue is the UHS Speed Class rating, which is U1 or U3. U1 means it can write a minimum of 10MB/s (like Class 10), while U3 pushes the write speed up to a minimum of 30MB/s. More interested in shooting video? The Video Speed Classes are V6, V10, V30, V60, and V90, with V6 suitable for standard definition video recording and V90 capable of 8K video capture. 4K UHD video recording will require a minimum of V10 ideally, and HD video can utilize V6 or below at a push. How we test SD cards It is not just cameras that use microSD cards, of course. And one of the most popular devices to use this memory type at the moment is undoubtedly the Nintendo Switch handheld console, and its baby brother the Nintendo Switch Lite. The slot in memory is not only great for expanding the number of games you carry, but also for taking screenshots and videos of your victories and adventures. When you think of a memory card, you'll likely find that the popular SD card format comes to mind. However, if you're using a newer camera, or one of the best professional cameras, then you'll likely need to look for a CFexpress or XQD card. However, Compact Flash, microSD and CFast cards are still all regularly used as well. Rated UHS Speed Class 3 (U3) and Video Speed Class 30 (V30) 2, the SanDisk Extreme PRO SD UHS-I card lets you capture sequential burst mode shots without missing a beat. Taiwanese company Transcend is another long-term player in the memory card market – and still makes many low-capacity cards, meaning they’re accessible to those on a tight budget.

As an upgrade to the standard SD card, SDHC (Secure Digital Extended Capacity) cards offer memory capacities between 4GB and 32GB. This makes them great for everyday use and entry-level users who don't have large storage capacity needs. The difference in write speeds is also apparent in the speed rating of each SD card. The Ultra has a U1 (UHS Class 1) speed rating, pertaining to the 10 MB/s write speed. The Extreme and Extreme Pro both have U3 (UHS Class 3) and the additional V30 (UHS Video speed class 30) rating, which means that it can sustain a video capture rate of 30 MB/s. What do they have in common?

How does a microSD card work?

With shot speeds up to 140MB/s 6 the card is perfect for capturing the action as it happens, without missing a beat. The Extreme is an excellent middle-ground option, especially because of the large price drop from the Extreme Pro. While its read and write speeds are impressive, its glaring shortcoming is that it’s just a little too slow for 4K video recording. Still, it provides the best value for money considering relative cost and speed rating. As you can see, the jump from one model to the next best one is minimal at around 7 to 8 dollars. This is a fairly small difference unless you’re looking to buy five to ten SD cards at the same time.