When you press the shutter or that red record button, you take a photo or video clip, but where does all of the information go? Digital photography and film making is all about recorded data, and that needs to go somewhere. No photo, video, or audio recording can be saved without storage space or memory. Few cameras offer internal storage, so we must then turn to external devices to record our work, like the memory card.
Recording work and data in the form of thousands of pictures or hours of video is made possible by compact memory cards. These devices are the standard for photo and movie storage, saving and protecting your files until you can transfer them safely to a more permanent home on your computer or external hard drive. They are available in an array of different types, with a broad range of capacities and data-transfer speeds.
Card Types, Capacities, and Speeds
The current line-up of memory card types includes Secure Digital, better known as SD cards, as well as various others like CF Express Type B, CF Express Type A, and microSD. These cover the needs of cameras, audio recorders, laptops, and select smartphones, offering the storage capacity and speeds modern devices require.
Currently, memory card capacities stretch across a broad range, from 2GB to 8TB of maximum storage. This range may seem extreme but know that a few snapshots from a point and shoot camera may need only a few gigabytes, whereas hours of 4K or even 8K footage require terabytes. Just remember that while you can use a big card, that doesn’t mean that you should.
Memory cards, unlike the typical hard drive, are short term storage solutions, meant to record media, not to hold it forever. We’ll cover this in more detail later. Aside from capacity, it’s equally important to note how fast cards can process that media. This spec can be read in the cards speeds, which are typically listed in MB/s or Gb/s. If you’re recording video or shooting fast continuous bursts, faster cards are essential. Now, let’s take a closer look at the memory card types.
Secure Digital (SD) and microSD
Among SD cards, the Secure Digital Extended Capacity (SDXC) models have the greatest storage space at more than 64GB, and up to a theoretical 2TB, while Secure Digital High Capacity (SDHC) and SD cards hold up to 32GB and 2GB, respectively. The microSD cards are physically smaller, though they can still feature large capacities and follow the same SD/SDHC/SDXC naming scheme.
SD cards, including the micro type, are divided into classes—2, 4, 6, and 10—where the class number denotes minimum write speed. Class 2 means a minimum of 2MB/s write, while Class 4 means 4MB/s, and so on. The Ultra High Speed Class 1 (UHS-I) rating was established when cards became faster and it was possible for minimum read/write rates to exceed 10MB/s. Now, UHS-II cards offer substantially quicker transfer rates than ever before.
UHS-I and II cards are capable of huge performance boosts over standard cards, in terms of maximum read/write speeds. A UHS Class 1 rating tells you that the technology allows for speeds of up to 104MB/s. Many UHS-1 cards deliver read/write rates of 80―95MB/s, with a lot of others getting up to about 60MB/s. UHS-II denotes even faster maximum speeds of 312MB/s, with the reality being 250―280MB/s for the current SD lineup.
CF Express Cards
The next most prominent card in the industry are the CF Express cards. The CF Express cards were developed by the CompactFlash Association in 2017, using PCIe lane technology, similar to that found in high-performance Solid-State Drives in computers, to communicate directly to the camera’s storage controller for even faster speeds. In the photo and video industry, there are two form factors. We have Type A and Type B.
CF Express 2.0 vs. CF Express 4.0
The first CF Express cards to enter the market were CF Express 2.0. They were notably faster than the older CF and XQD cards. Then 4.0 was announced in 2023. In theory, this new format would double the speeds of the 2.0 cards. Real-world read speeds on CF Express Type 2.0 cards reach around 800-900MB/s whereas 4.0 sees a significant jump to 1800MP/s read speeds and 1650MB/s maximum write speeds with sustained write speeds of 1400MB/s. This means that you probably want a 4.0 card to meet your current camera’s top shooting speeds and for futureproofing.
Type A
Type A cards are smaller and technically slower than their Type B counterparts as well, at least on paper. These cards are unique in that they’re currently only used in Sony Alpha and FX cameras. Even though they have half the technical speeds of the Type B, the Type A format is capable of recording 4K/8K video and high frame rate burst shooting in cameras like the a1 II and a9 III where it reads up to 120-fps full resolution RAW files easily.
Type B
The Type B is the more commonly used format and is larger and faster by comparison. In fact, Type B cards are capable of achieving nearly double the read/write speeds of Type A cards, though this is like comparing two fighter jets. Both are extremely fast; one is just faster than the other. It shares the same dimensions and connector as XQD cards, which is why select cameras with XQD slots can accept Type B cards.
Other Memory Card Formats
While SD, Micro SD and CF Express reign supreme in the current camera climate, used cameras and even some older models still available may rely on older card types, many of which are still available albeit in limited capacity. These cards were once more commonplace, and while they’ve fallen out of fashion, they’re still available
CompactFlash (CF)
CF cards exist, though their popularity has waned. CF cards are larger in size than SD cards and are known for their physical durability. To denote transfer speeds, they use the Ultra Direct Memory Access (UDMA) mode system, in which a number of 0-7 gives you a rough idea of how fast a card will be. Mode 0 permits up to 16.7MB/s and Mode 7 allows for up to 167MB/s. CompactFlash cards often feature the x rating in their names, helping you compare speeds at a glance before getting a more in-depth look, by examining the actual data transfer rates.
CFast
The CFast card was a sort of successor to the Compact Flash card, combining its form factor with the Serial ATA (SATA) interface to deliver even faster read/write speeds. That said, their similarities are skin deep, as the CFast and CF cards are neither physically nor electronically compatible due to significant differences in the pin layout.
The use of CFast was and is primarily adopted by those looking to record 4K footage in select older cameras, as CFast cards could provide data transfer speeds of up to 600MB/s. This made the card an obvious choice in the early days of 4K. Not to mention, this card type is available in capacities up to 2TB. One could almost see this card as a step towards the future CF Express Type B.
XQD
XQD cards, made by Nikon and Sony, use the PCIe interface featured on certain computer expansion cards. In theory, the XQD format has a maximum possible capacity greater than the 2TB They are currently available in several classes: the standard XQD, also known as the H Series, as well as the N, S, and G series. The H and N class support transfer speeds up to 125MB/s, while the S-series supports up to 180MB/s for reading and writing. The latest class, the G series, supports transfer speeds up to 400MB/s to benefit 4K video recording and high-resolution still shooting bursts.
In Memoriam
Throughout the early years of digital photography, many card types have come and gone, though some cameras that use them have survived. Consider this section somewhat of a memory card in memoriam, even though you may still have one of these cards sitting in a junk drawer somewhere. These are discontinued, thought they see the light of day every once in a while, through the use of older used cameras or by folks looking to salvage old photos from a vacation 25+ years ago.
Memory Stick/Memory Stick Duo
One of the most popular cards of early point and shoot cameras was the Memory Stick (MS) and its successor, the Memory Stick Duo (MS Duo). This proprietary card was used in many Sony devices, Memory Stick PRO Duo cards are similar in size to SD cards and are smaller than the original incarnations of the Sony Memory Stick. That said, it wasn’t long before faster cards with larger capacities like SD and CF cards took the throne.
Even though the card was effectively discontinued in the early 2010s, support lasted quite a bit longer. Believe it or not, cameras were still accepting memory sticks until around 2019, when Sony finally removed support from its new mirrorless Alpha series releases. That’s right, a Sony a7 III supports memory stick, with the appropriate adapter of course.
SmartMedia Card
Why does an obsolete memory card from the mid 90’s have a right to be on this list? Because folks still come in with them asking if they can get more or see what’s on them as covered above of course. As you can probably guess by the term obsolete, this missing link between floppy disks and the modern memory card has been gone for some time.
Introduced in 19995 by Toshiba, the SmartMedia card was ultra-thin and fast for the time. It’s best known for its bright and shiny row of gold contact pads, which also made the card especially vulnerable to static electricity and scratches. That said, it was widely used by early digital cameras, MP3 players, and even some electronic instruments.
Compatibility
Most consumer-grade cameras and camcorders are compatible with SD cards, and several cameras now feature dual memory slots, allowing you to use up to two cards at a time. From there, you can program them to record sequentially, where on fills up and the other picks up from there, or even backup, where the same images and clips are recorded to both simultaneously.
The microSD cards are often used in more compact devices, such as action cameras, certain point-and-shoot cameras, and even smartphones and tablets. All cameras and other devices that support SDXC cards are also backwards compatible with SDHC and SD, and devices that support SDHC will also support SD cards. The same rule does not apply in reverse, though, and devices compatible with up to SDHC cards will often not support SDXC memory cards.
Before making a decision, make sure you are working within the limits of your camera or other device. Many older entry-level and intermediate-grade cameras are not capable of supporting cards with capacities over 64GB. Simply put, when they were released, those larger capacities didn’t exist, so they cannot recognize them. This is especially true for older point-and-shoot cameras, which had limited capacities even in their heyday.
Choosing the Correct Capacity
As we touched upon earlier, it’s easy to think that bigger is better when it comes to capacity, but it really depends on the application. Many photographers prefer several lower-capacity cards to a single high-capacity one, because that way, if one breaks or fails and work is compromised, they still have the data they’ve saved on the other cards. Another advantage to this approach is that when traveling, photographers can use one card per day to keep a succinct and orderly record of which day’s images are on which card. Those who shoot high-speed bursts, such as sports and wildlife photographers, and those who record lots of high-resolution video, often prefer one card with lots of storage space, since it allows for more continuous shooting without having to stop and switch to a new memory source. Though this isn’t always the best approach.
Many photographer prefer to use a series of smaller cards across a trip so as to not put all their eggs in one basket so to speak. This may mean we carry a few 64GB cards or even a few 256GB cards depending on the camera. Those sports and wildlife shooters may opt for even larger sizes as both file sizes and frame rates have increased to borderline ridiculous levels in recent years. The fact remains that like all devices, a card can fail. That said, it’s better to lose half a day’s work instead of an entire trip’s worth.
Another consideration when deciding upon card capacities is the type of files you shoot, generally, and how large your average file size is. If you are working with a small 12MP point-and-shoot camera and only shooting JPEG files, you can record upwards of 8,000 images to a single 32GB memory card. But if you are dealing with a full-frame mirrorless or DSLR camera and recording both RAW and JPEG file types simultaneously, you might only get a few hundred or so images per 32GB, hence why 256GB and larger cards exist.
As of the writing of this article, we’ll make these recommendations. UHS-II is really a must for pros using SDHC/SDXC, while those who use CF Express cards ought to go for 4.0 card. Unless you’re shooting very casually and are really not concerned about speed, we recommend that you choose a card with read and write speeds of at least 100MB/s. If you’re a professional working with today’s high-resolution cameras, try for at least 45―60MB/s. And if you’re a sports shooter or a 4K-8K video shooter, get the fastest card you can.
Protecting Your Work
Apart from capacity and speed, data protection is a concern. A lot of cards feature Error Correction Code (ECC), which enhances reliability by automatically detecting and fixing transfer errors. This is a great asset in any application but would be especially important in situations in which you have to work quickly and deliver results in a very short time, such as professional sporting events or news coverage. When you need to upload or send files so that your work can be seen by the world before your competitors, having a reliable card with a small chance of failure or errors is critical.
Picking a Card that's Built to Last
A card’s durability may also be an important point of consideration. There are really two types of toughness for a memory card: the ability to withstand a large number of insertion/removal and read/write cycles, and the ability to survive environmental factors. Most of the better cards on the market permit 10,000 or more duty cycles as a standard. Those that offer wear-leveling management ensure that data is written evenly across various regions of the card—preventing excessive wear and prolonging card life.
There is a greater degree of variation in the other kind of durability. Certain cards are built to live through bumps, drops, and even heavy burdens that would break or crush most devices their size, while others are designed to last through extremely cold or hot temperatures that would render most electronics useless. There are cards that are water resistant, and even those that are completely waterproof. Additionally, some models are built to survive exposure to magnetic fields and X-rays.
If you’re a travel photographer, such as a photojournalist, or just an avid explorer or adventurer who loves shooting in extreme locations such as the mountains, tundra, jungle, or desert, these tough cards are made for you. Fortunately, some of the real rough-and-tumble cards also feature very respectable speeds—up to 90MB/s or greater for read and write—so you can get the benefits of their strong build quality without having to compromise in other areas of performance.
Whatever your needs, B&H has you covered with a comprehensive array of options spanning all memory card categories. To learn more about memory cards, their applications, and all things photography and videography, consider checking out our other guides and articles on the B&H Explora site.
