SanDisk and Lexar dominate the market for memory cards, but Kingston is creeping into the space. Kingston has long been known for their high quality computer memory. However, more professional photographers use SanDisk and Lexar cards than any other. They have unique features that are not usually present in other memory cards such as a higher capacity, faster operation and the ability to operate under extreme conditions. When looking for memory cards, you need to consider these options along with selecting the correct type of memory card.
Memory cards come in three main types CFII (compact flash II), SD (secure digital) and XD (extreme digital) and one minor type, Sony Memory Sticks. The majority of digital cameras on the market use either the CFII or SD while the XD cards are only used by Fuji and Olympus. All of the memory cards reviewed in the Best of the Best section will be CFII. Also, CFII cards are used exclusively in medium format and professional DSLR cameras. However, Nikon is starting to make some of their entry-level DSLR's SD only. While this is good for somebody migrating from the consumer level, it is not ideal for those photographers in the DSLR space. Plus the small size of the SD cards makes them easier to misplace or loose. I recommend you purchase your memory cards separately and never in a kit with your camera. The ‘kit' memory cards have a lower capacity, are slower and might be an older model.
Most memory cards are rated to last over 10,000 uses and they can usually withstand an accidental dunk in the pool or the full effects of a high-powered washing machine. However, you always need to have a backup card in case you fill the main one to capacity, if it gets damaged or if you loose it. While some people like to purchase the largest capacity card possible, I don't think it's the best idea. This means you will be putting all of your images in ‘one basket' and if you loose the card, you loose your assignment.
For example, it makes better sense to have four different 4GB memory cards than one 16GB card. Again, this spreads the risk and allows you to have backups. However, if you are set on having high capacity memory cards, then you need to exercise a certain amount of discipline. This means transferring the contents of the cards on a regular basis after your assignment or vacation, which could mean after 2-3 GB. Remember you don't want to wait for the card to fill to capacity.
Another way to think about the intended size of your memory card is to consider which types of images you store, RAW, TIFF or JPEG. All DSLRs and a few specialty consumer based digital cameras store RAW and JPEG. TIFF is also an option on some DSLRs, too. The RAW and TIFF files take up more room and thus a larger memory card is needed. JPEG takes up anywhere from 2-4MB per file, so a smaller card is ideal for these types of files.
In addition, you want to purchase the memory card with the appropriate speed for your camera. The fastest memory cards (266x – 300x) measured in read/write speed or in a factor of ‘x' are ideal for medium format cameras or professional DSLRs. Medium speed cards (133x) are best for mid-level DSLRs and the slower speed cards (67x – 133x) are good for entry-level DSLRs or consumer based digital cameras. The winner for Best of the Best memory card is the SanDisk 16GB Extreme IV CFII. It has a capacity of 16GB, nearly the fastest speed on the market, 40-45 mb read/write speed or 266x-300x, and can operate in temperatures ranging from -13 to +185 degrees Fahrenheit (-25 C to +85 C).