For DSLR users, CompactFlash is probably the most recognizable format, although some DSLRs utilize other cards or multiple cards within the same body. CF is physically the largest, but that doesn’t necessarily mean it holds more data—though capacities now run up to a whopping 64 GB. Small camera users may never have encountered the CF format, since smaller cards are more popular for smaller cameras.
SD (Secure Digital) media cards are smaller and thinner than CompactFlash, making them ideal for camera and camcorder makers (as well as mobile-phone and other device manufacturers) who are working to shrink the form factors and weights of their devices without sacrificing storage capacity or speed. SDHC is the high-capacity version of the SD format, available in sizes up to 32 GB (for now). The SDXC format announced in 2009 may lead to future developments in SD storage well beyond the 32 GB size—perhaps someday approaching their theoretical 2-terabyte maximum.
MicroSD cards are the smallest commonly available media card on the market, about one fourth the size of an SD card. MiniSD cards are about half the size of an SD card; each is available in HC versions up to 16 GB. Because the cards are so small, they’re often used in very small cameras, phones and other electronic devices. Commonly available adapters allow the use of microSD cards in miniSD devices, as well as for both formats to fit in full-sized, SD-compatible electronics.
Olympus and Fujifilm partnered to release their own variant on the SD format in 2002, called the xD-Picture Card. This tiny format is still used in capacities up to 2 GB, although recent Olympus and Fujifilm cameras have moved toward the SD and SDHC formats.
The proprietary Sony media card format (made in partnership with SanDisk), Memory Stick is used in a variety of digital devices. From the original Memory Stick, many variations (including the PRO, Duo, Micro and XC) have arisen to address the ever-shrinking form factors and ever-changing needs of the consumer electronics industry. In Sony’s newest digital and video cameras, the PRO Duo stores up to 32 GB of data, with a theoretical maximum of 2 TB.