For digital cameras, storage card is the same thing that film is for conventional cameras. They are removable devices that hold the image taken with the camera. Storage cards are evolving in the same direction as digital cameras: larger capacities (several GB) and faster write speeds to accommodate higher resolution images and shooting in RAW lower prices per MB or GB of storage smaller form factors for smaller digital cameras. There are so many sizes and formats for card storage that it is difficult to use cards across different cameras, card readers and other devices (PDA, MP3 player).
Compact Flash seams to be ahead of other formats in terms of storage capacity. It is a reliable format, which is compatible with many devices. Capacities above 2.2 GB require that your camera support “FAT32”. There are 2 types for this card: Type II and I. The only difference is the thickness; Type I being the most popular for flash memory, while Type II is used by micro drives.
Micro-drive represents a minute hard disk, which comes in Compact Flash Type II format and offers larger storage capacity at a cheaper cost per megabyte. Micro-dives need more battery power, create more heat and have a higher risk of failure, because they contain moving parts.
Smart Media is a type of card that looks bigger than Compact Flash but much thinner. Known to be less reliable, this format is gradually being phased out of the market. There are no new cameras announced to support this format of card.
Sony Memory Stick
Although Sony sets it, others, such as Laxer Media, manufacture this format. Although on the market you can find fewer and fewer cameras that use this format, the number of this card is gradually increasing. So pay a lot of attention if you buy another brand of camera, it may not support this format of card. The price for memory sticks is higher because there is less competition in the market. Several variants exist such as Sony Memory Stick with Select Function, Sony Memory Stick Pro, Sony Memory Stick Duo, and Sony Magic Gate.
Secure Digital (SD)
This format of card is characterized by a faster data transfer and a built in security function, to facilitate the secure exchange of contents, and by a copyright protection, which makes them more expensive than other cards. Similar to floppy disks, SD cards have a small write-protection switch in the side.
Multi Media Card/ Secure Multi Media Card/Reduced Size Multi Media Card (MMC/Secure MMC/RS-MMC)
Multi Media Cards have the same surface, but are 0.7 mm thinner than SD cards and they have two pins less. Hardware-wise MMC cards fit in SD card slots and many, but not all, SD devices and cameras will accept MMC cards as well. Check out the specs before you buy. Two variants are Secure MMC, similar to SD, and Reduced Size MMC.
XD Picture Card
Developed by Olympus, Fujifilm and Toshiba this format is made for small digital cameras.
Older formats include floppy disks and PCMCIA cards. A few models support writing on to 3-inch CD-R/RW discs. Some low-end cameras don’t have removable storage cards but instead have built-in flash RAM memory.