How to choose a memory cards
Updated June 2026Independently researchedNo paid placement.
The right memory card for your camera depends on three things: the speed class your camera requires for photo bursts or video, the physical size (SD or microSD), and the capacity you need for your shooting style. Start by checking your camera’s manual for supported card types and minimum write speeds, then buy a card that meets or exceeds those requirements from a reputable brand to avoid corrupted files or stuttering video.
What speed class do I need for my camera?
Speed class tells you the minimum sustained write speed a card can maintain. For still photography, a Class 10 (10 MB/s) is the baseline for most modern cameras, but if you shoot rapid bursts or high-resolution raw files, you might need a UHS Speed Class U3 (30 MB/s). Video recording adds another layer: look for the Video Speed Class rating (V30, V60, V90) printed on the card. A V30 guarantees 30 MB/s minimum, enough for 4K at standard frame rates; V60 and V90 are for high-bitrate 4K or 8K. Don’t rely on the card’s claimed “read speed” alone, that’s only for transferring files to your computer. The write speed matters most while shooting. If your camera specs say it needs U3 or V30, buying a slower card will buffer or stop recording mid-clip. There’s no penalty for buying a faster card than you need, aside from the higher cost.
SD vs microSD: which one should I use?
Full-size SD cards are the standard for most interchangeable-lens cameras, from entry-level DSLRs to professional mirrorless bodies. They’re easier to handle, less prone to being lost, and generally offer better heat dissipation during long video takes. MicroSD cards are mostly used in action cams, drones, phones, and some compact cameras. They come with an adapter for full-size SD slots, but that added connection point can sometimes cause issues with high-speed data transfers. If your camera accepts both, prefer the native SD card. Using a microSD with an adapter is fine for casual shooting, but for demanding work (long 4K clips or rapid bursts) a native SD is more reliable. Also, many microSD cards have a lower maximum write speed compared to their SD counterparts at the same price tier.
How much storage capacity is enough?
Capacity determines how many photos or minutes of video you can hold. For a casual shooter using JPEGs, 32 GB or 64 GB may last a whole weekend. For raw shooters, a 128 GB card holds roughly 1,500 to 2,500 frames, depending on the camera’s megapixels. Video shooters need more: 4K at 60 Mbps uses about 450 MB per minute, so a 128 GB card gives about 4.5 hours. For heavy action or extended trips, 256 GB or 512 GB is popular. Beware that cameras older than a few years might not support SDXC cards (over 32 GB). Check your camera’s specifications for SDHC versus SDXC compatibility. Also consider using multiple smaller cards instead of one huge one: if a card fails, you don’t lose everything. Even if your camera can take larger capacities, cards over 512 GB sometimes show slower write speeds per gigabyte, so test one small batch before filling it with important work.
UHS-I vs UHS-II: what’s the difference?
UHS (Ultra High Speed) bus interface determines how fast data moves between the card and camera. UHS-I cards have a single row of pins and reach theoretical speeds up to about 104 MB/s. UHS-II cards add a second row of pins, boosting maximum speeds to around 312 MB/s. In practice, UHS-II cards can be two to three times faster for clearing the camera’s buffer during long bursts and for copying files to your computer. However, UHS-II cards cost significantly more and require a camera that supports the UHS-II bus. If your camera only uses UHS-I, a UHS-II card will work but only at UHS-I speeds, you’ll pay a premium for no benefit. For most hobbyists, a fast UHS-I card (like V30) is plenty. Professionals shooting heavy raw sequences or high-bitrate video will appreciate the speed of UHS-II, especially if their cameras have a dedicated UHS-II slot.
Should I worry about brand and counterfeits?
Yes, absolutely. Counterfeit memory cards are rampant online, especially from marketplaces where third-party sellers list items. A fake card may show a high capacity in your camera but corrupt files when you try to copy them off. Stick to well-known brands like SanDisk, Lexar, Samsung, Sony, Kingston, and ProGrade. Buy from authorized retailers or directly from the manufacturer whenever possible. Even with genuine cards, brand matters for long-term reliability. Reputable brands have better quality control and support. Cheaper, no-name cards often fail under heavy use or provide much slower real-world speeds than their labels claim. A few extra dollars for a reputable card is cheap insurance against losing irreplaceable photos.
What about video speed ratings (V30, V60, V90)?
The Video Speed Class is the most relevant rating for anyone recording video. V30 guarantees a minimum of 30 MB/s sustained write speed, which handles most 4K footage up to around 100 Mbps. V60 (60 MB/s) covers higher bitrates like 4K at 200 Mbps or basic 8K. V90 (90 MB/s) is for extreme codecs like 8K RAW or 4K at super high frame rates (120 fps or higher). Some high-end cameras explicitly require V60 or V90 for their best video modes. If you only shoot stills, the video speed class matters less, but it’s still a useful indicator of consistent performance. A card marked V30 will usually outperform a plain Class 10 or U1 card under sustained writes. Always match the rating to what your camera demands, don’t assume a U3 card matches V30, though in practice they’re often equivalent. Check your camera’s manual or the manufacturer’s website for the exact video requirements.
Frequently asked questions
Can I use a microSD card in a full-size SD slot with an adapter?
Yes, most microSD cards come with an SD adapter. It works for most purposes, but for high-speed continuous shooting or recording demanding video, a native SD card is more reliable. The adapter adds a tiny amount of electrical resistance and heat, which can occasionally cause dropouts with V90 or UHS-II cards.
Do I need to format a new SD card before using it in my camera?
Yes, always format the card in your camera before first use. Camera formatting sets up the proper file system and folder structure, which reduces the chance of errors. Also format after transferring files, rather than simply deleting them, to keep the card’s performance consistent.
How can I tell if an SD card is fake?
Fake cards often have slightly different label artwork, misspellings, or lower-than-expected real-world speeds. Use a free tool like h2testw (Windows) or F3 (Mac) to verify the genuine capacity and write speed. If the card tests at a far lower size than marked, it’s counterfeit.
Is it safe to buy memory cards from Amazon or eBay?
It depends on the seller. Buying directly from Amazon (shipped and sold by Amazon) or from manufacturer storefronts is generally safe. Third-party marketplace sellers are riskier, counterfeits and used cards are common. For important work, stick to authorized retailers like B&H, Adorama, or Best Buy.
Why is my SD card not recognized in my camera after using it on a computer?
Cameras often expect the card to be formatted in FAT32 or exFAT. If your computer reformatted it to NTFS or HFS+, the camera won’t see it. Reformatting the card in your camera will usually fix this.
What’s the difference between SDHC and SDXC?
SDHC (Secure Digital High Capacity) cards range from 4 GB to 32 GB and use the FAT32 file system. SDXC (eXtended Capacity) cards range from 64 GB to 2 TB and use exFAT. Older cameras may only support SDHC, so check your camera manual before buying a large card.