SD cards for your digital device
For years, Secure Digital cards have been the most popular form of flash memory used to store files on digital devices. They’re most often associated with cameras and digital sound devices. Many capacity, speed, compatibility and price options are offered by several manufacturers.
Selecting the best SD card for your device ensures you get the best performance. For example, a photographer who spends the afternoon shooting still photos in the country may have ample storage space with a 16GB SD card. However, a videographer who shoots all day could get frustrated with having to repeatedly swap low-capacity cards.
Types of memory cards
Memory cards are the primary portable format for storing and exchanging digital data such as photos, word files, music files and other personal content. Memory card slots are found in cell phones, digital cameras, notebook computers, tablets and many other digital devices.
All memory cards and other gadgets such as USB flash drives and MP3 players are based on flash technology or EEPROM (electrically erasable programmable read-only memory) chips.
The most common types of flash memory cards are:
Secure Digital (SD/SDHC/SDXC)
MicroSD (MicroSDHC/SDXC)
XQD
Compact Flash (CF)
xD Photo Card
Memory Stick
MicroDrive
Smart Media
Multimedia Card (MMC)
Memory cards are distinguished primarily by the form factor, but speed and capacity are also important classification features.
What capacity SD do you need?
The SD requirement will depend on the file sizes you store. For a business that works with Microsoft Word and Excel documents, the storage requirements are minimal.
According to LexisNexis, 1GB of memory will store 64,782 Microsoft Word document pages and 165,791 Excel documents pages. A 32MB SD should be ample for almost any text-based application.
On the other hand, image file sizes are much larger.
A typical printable 300 dpi image is about 8.7 MB in file size. So, a 32 GB SD would hold approximately 3,678 jpeg images (1000MB/8.7 MB) (32GB).
An amateur photographer using a Canon EOS 5D Mark IV camera to capture images of wildlife, sports, weddings and family creates raw image files of approximately 30.4 megapixels each.
A typical Image from a Canon 5D2 SLR is about 32MB, so a 32GB SD would hold approximately 1,000 high-res raw images (1000MB/32 MB) (32).
A professional camera like the Canon 5D4 generates 14-bit RAW files of about 53MB. A 32GB SD would hold approximately 603 high-res raw images (1000MB/53 MB) (32) from a Canon 5D4 SLR.
A 16MB SD would be sufficient for most amateur photographers, while the professional would benefit from a much larger capacity.
New SD cards have a capacity of up to 2TB of data and permit speeds of up to 624 megabytes per second. The SDXC is the most used SD card type today because of its compatibility with modern devices.
With the advent of cell phones, the SD card was deemed too large for mobile devices, prompting a smaller microSD format, including the microSDHC and later, the microSDXC card.
With dimensions of 11 millimeters wide, 15 millimeters long and 1 millimeter high, these are the smallest memory cards on today’s market.
Data transfer speed
DS speed cards are rated 2, 4 or 6 (slowest to fastest), while HS speed cards are rated 10. SD card manufacturers place a rating on their products that indicates how fast data can be read from the card:
DS (12.5 MB/s)
HS (25 MB/s)
UHS-I (104 MB/s)
UHS-II (312 MB/s)
UHS-3 (312 MB/s)
Although these are laboratory test maximum speeds under ideal conditions, they’re good indicators of relative performance. An example is a 600MB file copied to your SD card using a class 2 card requires 200 seconds. A UHS-3 class card would perform the same operation in 20 seconds.
Best SD memory cards
These top-of-the-line SD cards will provide your digital device with peak performance. For more information, take a look at the best SD memory card guide from BestReviews.
High performance and reliability
Transcend SDXC UHS-II U3: available at Amazon
Our take: The outstanding speed of the Transcend makes it an ideal card for 4K, HD video, high-resolution, rapid-fire still photography and 8K video.
What we like: The Transcend boasts blistering speeds, taking advantage of the UHS-II interface to deliver up to 285MB/s read and 180MB/s write speeds. The cards, available in 32 and 64GB capacities, are waterproof, shockproof, X-ray-proof, static-proof and temperature-resistant.
What we dislike: While the UHS-II card is backward compatible and will work in UHS-I and standard SD devices, the best performance is achieved in UHS-II devices.
Best for shooting 4K video
SanDisk Extreme Pro SDXC UHS-I: available at Amazon
Our take: The Extreme Pro SDXC UHS-1 from legendary SD card manufacturer SanDisk is a reliable card suitable for photographers who want to shoot stills and 4K video.
What we like: The manufacturer’s rated 128GB/s read speed minimizes the time it takes to transfer photos and videos from the card to a computer. The 300MB/s write speed ensures images are captured quickly, especially when you’re shooting in burst mode.
What we dislike: Pricey compared to other SD cards with similar characteristics.
Good performance at a budget price
PNY Elite Performance SDXC: available at Amazon
Our take: The PNY Elite Performance SDXC offers good performance and outstanding resistance to the elements with its magnet-proof, temperature-proof, shockproof and waterproof design.
What we like: The low-priced card provides read speeds up to 128GB/s and write speeds up to 100MB/s, making it suitable for photography and HD video.
What we dislike: The average write speeds are not fast enough for heavy users.
Best for capturing rapid bursts
Lexar Professional Class 10 UHS-II 2000X: available at Amazon
Our take: A fast, reliable card designed for power users and professional photographers, especially those shooting sporting events and fast-moving wildlife.
What we like: The card works well for filmmakers who want to capture 4K and 8K on cameras and other occupations requiring rapid bursts of high-resolution photographs with its read speed of 128GB/s and write speed up to 300MB/s.
What we dislike: The maximum capacity offered is only 128GB.
Best for 4K video filmmakers
Lexar Professional 1667x SDXC UHS-II: available at Amazon
Our take: The 1667x SDXC UHS-II offers relatively fast speeds, consistency and a limited lifetime warranty to photographers seeking to capture scenes at high resolution.
What we like: The card is rated up to 256GB/s read speed and up to 250MB/s write speed. Although slower than the best high-speed write cards, it’s more than sufficient for most DSLRs and Mirrorless systems.
What we dislike: The card has a maximum video limit of 4K.
Professional-level performance
SanDisk Extreme Pro SDXC UHS-II: available at Amazon
Our take: For professionals and serious hobbyists, SanDisk offers lightning speeds and an exceptional lifetime warranty providing peace of mind when saving your images or videos.
What we like: SanDisk claims a read speed up to 128GB/s and a write speed up to 300MB/s. The UHS-II card is backward compatible with UHS-I and standard SD devices, although at reduced operating speed.
What we dislike: The card is more expensive than competitors.
Jeffrey Harper is a writer for BestReviews. BestReviews is a product review company with a singular mission: to help simplify your purchasing decisions and save you time and money.
BestReviews spends thousands of hours researching, analyzing and testing products to recommend the best picks for most consumers. BestReviews and its newspaper partners may earn a commission if you purchase a product through one of our links.
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