Leslie Wilkes Photography BlogPosts

MEMORY CARD BREAKDOWN

The Numbers & Symbols on Your Card Explained

Capacity: SD/microSD cards range up to 2GB, SDHC/microSDHC cards range from 4GB to 32GB, and SDXC/microSDXC cards range from 64GB to 2TB.

Speed Class: Speed Class (Class 2 to 10) and UHS Speed Class (U1 or U3) indicate the slowest speed the card will write. UHS Speed Class 3 (U3) rated cards offer a minimum sustained write speed of 30MB/s and are able to handle flawless 4K video recording without corruption or dropped frames & RAW burst photography.

Video Speed Class: Ranging from V6 to V90 (minimum sustained write speed of 90MB/s), the latest Speed Class is optimized for high-resolution & high-bitrate video and simultaneous multi-file recording, such as RAW + JPEG, multiple video streams created by 360º cameras, video + still + GPS data & time-lapse.

Maximum Read Speed: The fastest speed that data can be transferred from the card to a computer. The higher the read speed, the less wait time.

Maximum Write Speed: The fastest speed that data can be written to the card. The higher the write speed, the more you can capture in a certain amount of time.

X-Rating: Another way of identifying a memory card's maximum transfer speed. To determine a memory card's maximum transfer speed in megabytes per second (MB/s), multiply the X-rating by 150 and divide by 1,000.

Capacity: CompactFlash cards range up to 512GB.

UDMA Rating: The UDMA rating determines the maximum bus speed at which a card can transfer files. UDMA 1 supports speeds up to 16.7MB/s, while UDMA 7 can reach up to 167MB/s (10x faster).

Video Performance Guarantee (VPG): VPG indicates the slowest speed the card will write. VPG-20 rated cards offer a minimum sustained write speed of 20MB/s and are able to handle flawless 4K video recording without corruption or dropped frames & RAW burst photography.

Maximum Read Speed: The fastest speed that data can be transferred from the card to a computer. The higher the read speed, the less wait time.

Maximum Write Speed: The fastest speed that data can be written to the card. The higher the write speed, the more you can capture in a certain amount of time.