Buy a memory card by matching your camera’s requirements, not by choosing the largest speed number on the packaging. The important details are the supported card format, the recording mode you intend to use, the relevant speed markings, and enough capacity for your work.
Research-based buying guide. Use your camera’s manual for model-specific requirements.
Start with the camera and recording mode
Find your exact camera model’s supported-media page. Then identify the setting you plan to use: still photographs, burst shooting, or a particular video format and frame rate. Different settings can have different media requirements. If the camera has two slots, check the requirements and capabilities of each slot as well.
Write down the required card type, supported capacity, and speed-class markings. For example, SD, microSD, and CFexpress describe different card families or physical formats; they are not interchangeable shopping categories. Follow your manufacturer’s instructions about adapters and supported media.
Separate the interface from the recording class
UHS-I and UHS-II identify bus interfaces. They do not, on their own, specify the card’s minimum sustained recording speed. The camera, card, and reader each matter when considering a transfer workflow. Kingston’s speed-class guide explains the distinction between bus capabilities and speed-class ratings.
The headline read-speed figure is another separate detail. Reading files to a computer and continuously writing a video recording are different jobs. A fast-looking read figure is therefore insufficient evidence that a card meets your camera’s recording requirements.
Read the Video Speed Class marking
The SD Association defines Video Speed Class markings for minimum sequential writing performance under the standard’s conditions. The number following V represents the corresponding minimum in megabytes per second.
| Marking | Minimum sequential write performance |
|---|---|
| V10 | 10 MB/s |
| V30 | 30 MB/s |
| V60 | 60 MB/s |
| V90 | 90 MB/s |
These figures describe a class, rather than a promise that every recording mode will work. Match the class symbol requested by the camera. Do not treat different rating systems as interchangeable merely because their numbers appear equivalent. See the SD Association’s speed-class explanation for the standard and host/card matching guidance.
Treat capacity as a separate decision
A higher-capacity card gives you more storage; it does not automatically provide a higher recording class. Estimate capacity using the recording-time table or file-size guidance for your camera and settings. Leave room for a longer session than expected instead of planning to fill the card completely.
Card capacity also belongs in your backup workflow. Decide when you will copy files, how you will verify the copies, and when the card can be reused. Keep important photographs in more than one location. A larger card does not replace a backup.
Check the reader and test your actual settings
Choose a reader that supports the card interface and connects to your computer. Before an important shoot, make a short recording or burst sequence using the settings you intend to use, then read the files back. Back up existing files before following the camera’s formatting instructions. This practical check can reveal a setup problem, but it is not a substitute for published compatibility requirements.
Keep the packaging or a note of the exact card model. When you need another card, you can compare its format, capacity, and ratings deliberately rather than relying on a similar-looking label.