A Guide to Memory Cards

Everything about memory cards

Digital content grows every day. Memory cards help you capture, store, and share that content. This exponential growth of information results in millions of flash memory products being manufactured by producers every day. From cameras to USB drives, the quality and performance of memory technology is becoming faster and more reliable by the day.

What does the speed tell you about a card?

There are various speed levels available when it comes to memory cards. These speeds are usually expressed in MB per second, but sometimes also in CD-ROM speeds, where 1x equals 150 kB/s. Some cameras require high-speed cards to ensure all processes run smoothly. Think of burst shots, where many images need to be written to the card in rapid succession. A high write speed is also important when recording 8K or 4K video.

Write speed vs. read speed

Keep in mind that there is a difference between write and read speed, with the maximum write speed always being somewhat lower than the maximum read speed. Write speed refers to the speed at which files are written to the card. Read speed, on the other hand, refers to the speed at which the photos can be transferred from the card to the computer.

Sometimes write speeds are expressed in CD-ROM speeds. In the overview below, you can see what that means in MB per second.

Which speed classes are there?

The classification system consists of a number written inside the letter C. There are currently 6 classes: Class 2, Class 4, Class 6, Class 10, UHS Class 1, and UHS Class 3. These classes represent the minimum guaranteed data transfer speed that a card can achieve. Ultra High Speed is the new definition for even faster SD cards. UHS Class 2 has the requirement that it must always be faster than the maximum of UHS Class 1. In 2016, the SD Association announced a new standard: the video speed class. This indicates the minimum write speed.

When you're going to film, it's important to look at the write speed. How large your video files are depends heavily on your camera and, for example, the bitrate. That's why a single clear-cut answer is hard to give, but keep the following in mind:

• SD/HD: These days, you can film in SD and HD with almost any card.
• Full HD: Choose at least 30–40 MB/s, unless you do a lot of slow motion — in that case, a higher speed is recommended.
• 4K: Use a card that can write at least 90–150 MB/s. For professional use, we recommend at least 150–200 MB/s.
• 8K: For this high resolution, you need a write speed of at least 250–300 MB/s, but often even faster. For this, we recommend working with an (external) SSD drive as your storage medium.

Want to be sure which write speed suits your camera and needs? Just stop by one of our stores. We'll be happy to figure it out together with you.

How much GB do I need?

You obviously don't want to suddenly be unable to take any more photos or videos because your memory card is full. That's why it's important to know roughly how much you can fit on your card. Using our overview, you can see approximately how many photos you can take in JPG. Please note: the numbers shown are only an indication. This can of course vary per camera and per photo. Your photos will also be considerably larger if you shoot in RAW.

What different cards are there?

There are various memory cards available. When purchasing, it's important to check which memory card fits your camera. The most common type is the SD card, but there are also microSD cards, CF cards, and XQD cards.

SD cards

SD cards are memory cards built with flash memory. They can be used in portable electronics such as cameras. This card type is based on the MMC card but operates much faster.

The difference between SDHC and SDXC

SD cards from 4 GB to 32 GB are called SDHC (SD High Capacity). Their advantage is a larger capacity, and they are compatible with most electronic devices.

SD cards from 64 GB to 2 TB are called SDXC (Secure Digital eXtended Capacity). These can only be used in devices that explicitly state support for them.

microSD cards

microSD cards are used in devices where the size of a standard SD card is an issue, such as mobile phones. With an adapter, however, these smaller cards can also be placed in a regular SD slot!

CF cards

CompactFlash, abbreviated as CF, is a memory card used for removable data storage via flash memory. CF cards are mainly used in professional cameras.

CFast

CFast was introduced in 2009 as the successor to the CF card. It functions as a faster version of CompactFlash. Note that, due to different connectors, it cannot be used in cameras designed for CF cards.

XQD cards

XQD cards are the solution for professional photographers for whom speed is essential. These cards are designed for high-end cameras, including models from Nikon and Sony. Some versions can write photos and videos at speeds of up to 400 MB/s.

CFexpress

CFexpress was announced in 2016. This card combines the best of XQD and CFast in one. CFexpress and XQD are cross-compatible.

Which memory card should I buy?

The very first and most important question during your search for the right memory card is: which card fits in my camera? Many modern cameras require an SD card, while some professional DSLRs use CompactFlash, CFast, XQD, or CFexpress. Always check first which type of card is suitable for your camera.

In addition, you need to consider what you want to do with your camera. If you mainly take photos in standard mode, you don't necessarily need the fastest card. However, if you shoot many photos in quick succession (burst mode), such as in sports photography, it pays off to buy a card that can write photos quickly. Do the math: if you shoot 10 photos per second and each photo is 10 MB, you'll want a write speed of around 100 MB/s. The same applies if you plan to shoot video in 4K or even 8K quality — a fast write speed is highly recommended.

Finally, it's important to think about the storage capacity of the memory card. If you're going to be out for a long time without the option to transfer photos to your computer or an external hard drive, it's wise to take a larger card with you, for example 64 GB or 128 GB. In our overview, you can see roughly how many photos you can store on each card.