The most popular types of flash memory cards for use in digital cameras are: Secure Digital (SD), CompactFlash (CF), Memory Stick (MS), MultiMediaCard (MMC) xD-Picture Card (xD) and SmartMedia (SM).
The type of memory card you use is dictated by which digital camera you buy. These cards are physically different and are -not- interchangeable.
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eBay has become notorious for "fake memory card" sales, thousands of people have been scammed by sellers who are selling inferior or lower capacity cards that have been relabeled and repackaged to look like the real thing. Buyer beware – I recommend that you purchase your cards only from reputable online vendors or brick and mortar stores. If you must buy on eBay then check out this page at Overclockers.com.au for ways to visually identify some (not all) of the most popular fake cards. Also see our public discussion forum for more info.
Secure Digital / MultiMediaCard
As of 2006 the most popular flash memory format for digital cameras is undoubtedly the Secure Digital (SD) card. And in just the first four months of this year we have seen drastic price reductions with the average 1GB SD card dropping from around ~$100 to $35 or less…
SD and MMC (MultiMediaCard) cards are nearly identical on the outside but technically different on the inside. Not all cameras that use SD can also use MMC cards, check your camera’s user manual. SD cards are generally faster than MMC cards.
Lately we have seen many new 2GB and 4GB size cards hit the market – most cameras, even the new ones, won’t work with cards larger than 2GB unless specified by the manufacturer.
SD cards currently range in size from 16MB up to 4GB (if your 4GB card has "SDHC" on it please see the next section.) SD cards come in different transfer speed ratings, SD cards not marked "High Speed" or "Ultra High Speed" are probably only ~2Mb/s capable. The latest cards are capable of transferring data at up to 20Mb/s such as the ATP 150x or Pretec 133x cards. Transfer speed is an important factor if you record high framerate motion video or high quality audio tracks. Many digital camera makers only certify their 30fps VGA motion video capability when using "high speed" SD cards.
The New SDHC – SD 2.00 Specifications
SDHC (SD High Capacity) are the new SD cards larger than 2GB that adhere to the SD 2.00 specification – a design that is required for cards and hosts to support 4GB to 32GB capacities. The specification was developed by the SD Association, which also defined three speed classes for speed and performance capabilities.
SDHC cards adhere to the SD Speed Class Rating specification which defines a minimum sustained transfer speed and use the FAT32 file system. The SD Speed Class Ratings specify a minimum sustained write speed for SDHC cards (Class 2: 2 MB/s; Class 4: 4 MB/s; Class 6: 6 MB/s) – that’s MegaBytes not MegaBits.
Many cameras made from 3Q 2006 and newer support SDHC but the majority of the existing cameras (and external card readers) DO NOT – consult your user manual or manufacturer’s web site before purchasing a SDHC card for your camera or MP3 player. Many manufacturers provide downloadable firmware updates for cameras and are adding SDHC support.
Click here to read the SDHC specifications (Adobe pdf format).
MiniSD card for cellphones, MP3 players, digicams. The miniSD card is both electrically and software compatible with the existing SD standard. It uses the same SD interface, including security features for content protection (CPRM桟ontent Protection Rights Management) as the standard SD card. The miniSD card is 21.5 millimeters (mm) long, 20 mm wide and 1.4 mm thick, and occupies a footprint of 430 square mm and volume of 602 cubic mm.
As of the date of this report we have not seen any digicams using the MiniSD format.
Adapter to allow miniSD cards to be used in devices with regular SD card slots.
CompactFlash cards contain both memory chips and a controller. Most digicams that use CompactFlash (CF) cards can use ANY capacity card up to 2GB with no problems. CF cards above 2GB use the FAT32 file system, the camera must be able to read this format or it won’t work.
There are two types of CompactFlash cards:
Cameras with Type I slots cannot use Type II cards. Cameras with Type II slots can use either.
report for more info about LARGE memory cards
Shopping for the ultimate performance CF card for a pro or semi-pro digital camera? Check out Rob Galbraith’s CompactFlash Performance Database
CompactFlash Type II
Some digicams are equipped with a CompactFlash Type II card slot which can hold either a Type I CF card or the thicker Type II flash cards or memory devices like the IBM/Hitachi Microdrive (340MB, 512MB, 1GB, 2GB, 4GB, 6GB, 8GB).
Click to read my IBM/Hitachi Microdrive review, Hitachi bought the hard drive business from IBM and is now offering up to a 8GB Microdrive. And both Seagate and Western Digital have announced new one-inch hard drives – mostly for portable multimedia devices but also digicams.
CF Type I … Type II … what’s the difference?
Physically a CF Type II card looks like a CF Type I card in every dimension except thickness, CF Type II cards are 5mm thick whereas Type I cards are 3.3mm.
CompactFlash Type II and I cards compared
CompactFlash Type II devices can NOT be used in cameras that have the thinner Type I card slots. Pictured above you can see the height difference between Type I and II cards.