Secure Digital (SD) cards are used by small electronics, mainly cameras, for storage purposes. Every camera needs an SD card, but many people may be tempted to skimp here and get the cheapest SD card; after all, SD cards can be had for less than $10.
But a bad memory card, particularly ones from undependable brands, can slow down your camera or even corrupt files. Whether you are shooting still photos or video, the best SD card, like the SanDisk Extreme Pro SDHC UHS-I, allows your camera to reach full speed while safeguarding the files inside. This is crucial, especially if your job depends on it, like mine as a professional photographer.
I've used many types of memory cards from different brands, at various prices. In my experience, the worst SD cards slow my camera down, while the best can stash lots of files quickly and have even survived an accidental wash inside a pocket. But, the favorite SD card for a professional photographer may be overkill for a hobbyist. That's why considering the card type, capacity, and speed is essential — if you aren't shooting 4K video or action photography in burst mode, for example, you may not need a high-speed card. For this guide, I stuck with brands that are known to be dependable; they may cost more, but the peace of mind — that your media is protected — is worth it.
Looking for a microSD card? Check out our guide.
Pros: Fast, durable, and affordable
Cons: You can faster SD cards but the price also jumps significantly
With the SanDisk Extreme PRO, the best features are right in the name — this SD card is fast enough for professionals, with a durable design for extreme conditions. Available in capacities up to a whopping 1TB, this card hits the sweet spot with the mix of features and price — the 32GB, shown above, sells for less than $20.
The 64GB-and-higher U3 cards can write files as fast as 90MB/s, with read speeds just a bit faster at up to 170MB/s (the 32GB SDHC card is a bit slower). That's enough to capture 4K video as well as RAW bursts of photos. I have half a dozen of these cards, and even in the SD slot of my pro-level, 45-megapixel Nikon D850, they don't have a problem keeping up with the big files that the camera captures.
The Extreme PRO line is also built to withstand water, shock, extreme temperatures, and X-rays. I've accidentally left an SD card in a pocket and sent it through the washer and dryer and the card was unfazed (though I don't recommend putting an SD card through a spin cycle). SanDisk includes a data-recovery program, RescuePro, for a year after purchase and also includes a limited lifetime warranty in the US.$19.25 from Amazon
Pros: Extreme durability and speed
Cons: No write protection switch, expensive
Note: Sony noted issues with some memory cards, including those from the SF-G Tough series, that may damage files when it's being written in-camera. The company is offering free replacements until March 31, 2022. Go to Sony's website for more details.
Why settle for double-digit speeds when you can get triple? While the speeds of our top pick are more than enough for most photographers, the Sony SF-G Tough series hits write speeds of up to 299MB/s, which is good for even 8K video thanks to a V90 video speed class. There aren't many devices around today that require that much speed, but this card is so fast that, theoretically, you likely won't need to update years down the road when the megapixel counts continue to climb and consumers finally can record 8K video.
There's a reason that "tough" is right in the name — the card is built to not only survive a ride in the washing machine but to stick around even after three days under water. The card is also constructed to guard against dust, drops, bends, extreme temperatures, and more. That durability comes from an exterior that's made from one piece, and while the design is solid, it also means there's no write protection switch to keep you from accidentally deleting files on the card.
Another downside is the price. The 32GB version costs around $60 — which is fine if you need all that speed and durability, but is likely overkill for others.$54.99 from Amazon $54.99 from B&H Photo
Pros: One of the more affordable 1 TB cards, fast read speeds
Cons: Less durable design with slower write speeds than our top pick
A 32GB card may be sufficient for most users, but the Lexar Professional 633x series offers capacities all the way up to a terabyte — that's a lot of data on a standard-sized SD card. You probably don't need to shoot a terabyte of video or photos at a time, but high-capacity SD cards are excellent ways to expand the space on your laptop and other devices without carrying around a bulky external hard drive.
The 95MB/s read speed will help when using the SD card for data storage, and when you do write to the card, it has a respectable — though not best-in-class — 70MB/s write speed. That's enough for 4K video, 3D video, and RAW bursts as well as handling other large files.
Lexar doesn't advertise any durability claims with this card outside of temperature, however, so it won't withstand abuse like the Sony Tough or SanDisk Extreme Pro. High-capacity cards are expensive, but this one is a little less so — the Lexar slides in at approximately $200 less than the 1 TB SanDisk Extreme Pro.
If 1TB is overkill, the 633x-series comes in many different capacities. As of this posting, a 64GB card costs just $12, making it a budget option. This is the card that Insider Reviews Senior Editor Les Shu has been using the past year in cameras like the Nikon Z5, and found it reliable and capable of shooting videos up to 4K without issues.$169.93 from Amazon
Pros: Fast read speeds
Cons: Slower write speeds and less durability
The 95MB/s speeds of our top pick is good, but it's not as great as the file-transfer speeds of the Lexar Professional 1000x UHS-II, with a 150MB/s maximum read speed. The 60MB/s write speed is still enough to handle 4K and RAW bursts, while the higher read speed allows for faster transfers, which means quicker file transfers from camera to computer.
Like the Lexar Professional 633x on our list, this SD card doesn't offer the same durability as the SanDisk Extreme Pro or the Sony Tough series. A handful of reviewers claim they've lost data from card read-errors, but this is another card that I and many photographers have used without any issues.
This Lexar comes in capacities of 64GB, 128GB, and 256GB, starting at $40.$39.99 from Amazon
When it comes to the card type, the two main kinds you'll want to consider are SDHC (Secure Digital High Capacity) and SDXC (Secure Digital eXtended Capacity). The difference between the two is how much storage they offer and speed. SDHC cards contain 4GB to 32GB, while SDXC cards typically range from 64GB to 2TB.
How much capacity do I need?
Chances are, you'll want an SD card with more than 32GB of storage, so you'll be looking at SDXC cards. A 32GB card is fine for casual photographers or people who prefer to have multiple smaller-capacity cards for security (if you lose your card, you don't lose everything). We typically recommend 64GB cards in this guide because you'll want that extra space for high-resolution photographs and video, but you may want to get even more if you're shooting 4K video.
What is the right speed for an SD card?
Speed class is where things get complicated. SD cards for your average user come in four speed classes: 10, 6, 4, and 2. Class 2 cards are the slowest and class 10 cards are the fastest. The class number refers to the minimum write speeds in megabytes per second (MB/s), so Class 2 = 2MB/s, Class 4 = 4MB/s, Class 6 = 6MB/s, and Class 10 = 10MB/s.
On the top high-end cards, the speed class rating is designated with a U symbol, instead of a C symbol. U1 supports at least a 10MB/s write speed (like a Class 10), and U3 cards offer at least a 30MB/s write speed. If you shoot in 4K, you need a U3 SD card. All the SD cards in this guide are U3 or U1.
UHS speed refers to the absolute top theoretical speed of each card, instead of the minimum speed indicated by the card class. It's a good way to gauge burst shot speeds. UHS-I Cards have a maximum speed of 104 MB/s, while UHS-II cards have a maximum speed of 312 MB/s. (A new UHS-III theoretically supports up to 624 MB/s, but isn't widely available yet.)
The SD Association also classifies cards by a video speed class standard, which currently ranges from V6 to V90. For 4K, a video speed class of V30 or more is ideal.
It's generally a good idea to get a high-speed SD card, especially if you are shooting in RAW or filming high-resolution video. In that case, you'll want a class 10 SD card or higher with a UHS (Ultra High Speed) classification.
You'll want to check to be sure your camera supports those speeds. Otherwise, you won't get the full effect of the card.
Is it safe to buy SD cards from no-name brands?
Avoid counterfeit cards by sticking with known brands and clicking on our links. We recently purchased a two-pack of no-name 32GB cards for $10, but one of our cameras consistently had issues recognizing them.