Buying Guide: Memory Cards for Video

How to choose the right memory card

The range of memory cards is vast, but what exactly should a memory card meet in terms of requirements? Below we discuss the differences between memory cards. Beyond the differences in physical form and connection, there are many other differences you should pay close attention to when purchasing a memory card.

Different types of memory cards

The most well-known memory card is the SD card. These are found in most consumer cameras, from entry-level compacts to semi-professional cameras. Alongside the standard SD card, there is a widely used smaller variant, namely the MicroSD card. These are often found in action cameras and drones due to their small size. Other commonly used cards are CF cards (Compact Flash). Until fairly recently, these were the standard in DSLR cameras. At present, Compact Flash cards are found almost exclusively in high-end DSLR cameras.

The increasing resolution of cameras has also created a demand for faster memory cards. The answer to this demand is the CFast and XQD card. These cards are found in various professional (video) cameras that need to write large files. CFast is the successor to the CompactFlash card. A new interface makes it possible to achieve higher transfer speeds. Due to a different connector, CFast cards are not compatible with CompactFlash cards. The counterpart to CFast cards is the XQD card. These are also suitable for reading and writing large files.

(Micro)SD cards examined more closely

Within SD cards, a distinction is made between SDHC and SDXC. SDHC stands for Secure Digital High Capacity and SDXC stands for Secure Digital eXtended Capacity. The difference between the two is simply that an SDXC card can have a higher storage capacity. An SDHC card has a capacity of 4 up to a maximum of 32GB, while an SDXC card can theoretically have a storage capacity of up to 2TB. Almost all recent cameras support SDXC cards; with an older camera, it's important to check whether it is compatible with SDHC or SDXC cards.

UHS I and UHS II

With new cameras, it's important to check whether they support UHS I or UHS II cards. The difference between the two is the connection on the SD card. The UHS II variant has additional contacts to achieve higher transfer speeds. It is possible that cameras which support UHS II cards may have limited functionality when used with a UHS I card.

Memory card speeds

We mentioned earlier that the increase in resolution creates a demand for faster storage. The answer to this demand is UHS II SD, XQD, and CFast cards. With speeds of over 300MB/s, these cards are suitable for the latest cameras recording in high resolution. With UHS I and CompactFlash cards, it's important to carefully check which speeds the cards support. Over the years, the speeds of SD and CF cards have increased, but the interface of the card has remained the same, meaning a camera may not be able to record in Full HD or 4K resolution with an older card.

How important is the speed class of an SD card?
To this question we can give a brief answer: it depends on the purpose. If you only take photos occasionally, speed is less important than if you make frequent use of burst mode or plan to film. That said, a fast memory card is almost always useful, especially with today's higher resolutions.

For video, it's important to ensure that the write speed can handle the bitrate of the video. The bitrate is in most cases expressed in Mbps: megabits per second. Please note: memory cards are classified in megabytes per second. One byte contains eight bits. So if you're recording video at a bitrate of 100 Mbps, you need a sustained write speed of 12.5 MB/s. Speed class U1 is not sufficient for this, as it writes files at up to 10 MB/s. In this case, your best option is a memory card with UHS speed class 3.

Nowadays, many memory cards also feature a dedicated video speed class: the Video Speed Class. This is indicated by the letter V followed by a number. The scale starts at V6 (6 MB/s) and goes up to V90 (90 MB/s). The latter should be sufficient for 8K video. Want to film in 4K? Then a memory card with Video Speed Class V30 is a good choice. For Full HD video, it's advisable to choose a class from V10 upwards. Want to find out more about the different memory cards in our range? Do so here.

Storage capacity

How much storage capacity you need depends on the type of files you'll be storing on it. Are these videos or photos, what resolution or bitrate do you use, and do you shoot in JPEG or in RAW? Below you'll find an overview from SanDisk of how many JPEG or RAW photos and how many minutes of recordings you can fit on a memory card. This can be a useful guide when choosing the right memory card.