Memory cards are a great way to store data from your camera and computer if you choose the right one. You get the choice of the current SDHC, the new SDCX, the older smaller SD, the odd Olympus xD, the original CompactFlash, and a dozen others. Which is the best type for you?
SD is Secure Digital and is a slight advance on the MMC style flash memory card. SD uses the FAT16 file system to store up to 4BG but was originally released when cards were available up to only 1 GB. Some cameras will accept only 1 GB or 2 GB. Both the cards and cameras are obsolete. Go straight to SDHC.
You can reformat the card using other file systems if you only use the card for computer data storage. The maximum SD size of 4 GB is too small to hold a DVD and has few other uses.
Your camera will require the SD card formatted in a specific way and should have a format option in the camera menu. Your camera may not support all the features of FAT16 and may work only when the card is formatted in the camera, not when formatted in your computer. You may also find problems if you delete images using your computer instead of deleting them in your camera.
SD cards are sometimes marked with a speed class where class (6) means the card should be good for 6 MB per second and that should be suitable for recording old style video. Newer high density video with multiple channels of sound will require faster write speeds. Class 6 is about 40x in the old style of classifying speed. There are lots of cards with speeds of 133x and higher. Class 10 is 133x and suitable for modern video.
SDHC, Secure Digital High Capacity, is the step up from SD and is the card you buy today. If your camera accepts only the older SD format, it is time to upgrade your camera.
SDHC stores up to 32 GigaByte using the FAT32 file system. Some cameras say they accept SDHC but in the fine print, state they accept only 8 GB or 16 GB. Check your camera documentation carefully before buying the camera or card.
When buying in a shop, you can request permission to open the camera and card in the shop then test the camera writes to the card by taking a photograph. You can check the capacity displayed somewhere in the camera menu. In Australia and some other places, you can state your intention to use the card with the camera then return either the card or camera or both, if they do not work together, because the products are unfit for the purpose you stated when purchasing.
When buying online, a good precaution is to go to the camera manufacturer's Web site then download the manual for the camera and read the fine print in the manual. Again in Australia, you can state your purpose in the special instructions section of the order. If there is no special instructions section, send the shop an email first asking about the use of the specific card size in the camera.
I purchased 16 GB cards for my current camera because the 16 GB cards store more photographs than I normally take in one day and are often a lot less than half the price of 32 GB cards. I looked at a smaller Canon pocket camera for occasional use as a second camera and found the smaller camera worked only with 8 GB cards. The two cameras would not be able to share the same cards. I will wait for a camera that can share the same cards.
Some current examples of SDHC cards with prices in Australian dollars delivered:
Class 10 (20 MB/s read and write):
Transcend 32 GB $70.85
Lexar 32 GB $111.71 Class 10 (20 MB/s read and write)
UHS Speed class 1 (45 MB/s read/write):
Sandisk Extreme Pro 32 GB $162.45
The Sandisk Extreme Pro is waterproof.
The Sandisk Extreme range, at 30 MB/s, is the fastest card I have used. The faster read speed of the Extreme range is definitely worth the price when you copy gigabytes of work from the card to your computer. It is worth jumping from $70 to $110 for the extra speed of the Extreme range compared to ordinary SDHC cards. Is it worth jumping from $110 to $162 for the extra speed, 45 MB/s instead of 30 MB/s, of the Extreme Pro range? I will probably not bother with the extra cost of the Extreme Pro range just for the speed.
The Sandisk Extreme range is the most reliable card I have used and is not claimed to be waterproof. Sandisk claim their Extreme Pro range is waterproof. Is it worth jumping from $110 to $162 for the waterproofness of the Extreme Pro range? My camera and notebook are not waterproof. A flood would kill them. My memory cards are stored in waterproof containers and would survive most floods. The waterproofness is probably worth the money when you live or work in tropical areas, where condensation ruins everything, and want to protect the images on the card in the camera. I would pay the extra cost for the combination of waterproofness and speed if I spent a lot of time photographing at the beach or in the tropics or while scuba diving.
SDXC is the next step after SDHC and stores 2048 GB, yes a full 2 TeraBytes. The largest card for sale in Australia is a Lexar 128 GB class 10 133x card. SDXC, by default, uses the exFAT file system. You can format the card using any file system but your camera will expect exFAT.
SDXC will further screw up life by arriving in two versions. The first is SD version 3.0 which is SDXC built the same way as SDHC and compatible in a way that makes life easy for cheap manufacturers. SDXC cards of 32 GB or less can be formatted with FAT32 and used as SDHC cards in compatible devices.
SD version 4.0 is SDXC with a new interface giving you higher speeds but not compatibility with the first SDXC cards. SD 4.0 also requires the use of exFAT. To use the faster SDXC cards at full speed, you will need cameras and computers with the second version of SDXC, not the first version. Hopefully all manufacturers will skip SD 3.0 and go straight to SD 4.0. When you are buying a camera in 2012, look for SDXC based on SD 4.0.
xD is an odd format used only by Olympus and Fuji. Fuji cameras are irrelevant. Olympus cameras are everywhere. Fortunately Olympus is switching to SD.
xD never had the range of sizes achieved by SD. xD cards were never as fast as SD. The only reason for using xD was the initially excellent range of Olympus cameras at low prices. Now Canon and everyone else has equivalents using SD cards.
CompactFlash used to be the choice of photographic professionals and SDHC made CompactFlash obsolete a few years ago. Think about designing a new professional camera. You can get SDXC cards that are the same speed and capacity as CompactFlash for a lower price. You can fit two SDXC cards in the same space as one CompactFlash card. You could write to the two SDXC cards at the same time and provide an automatic backup, similar to using two disks in a RAID 1 array in your desktop computer. Using a CompactFlash card instead of one or two SDXC cards is insane.
Sony memory sticks
I used to respect Sony products many years ago. Over the last decade I purchased a variety of Sony products and every one was trash with some really poor design choices. In every case there were several brands with similar products at half the price with better features, better performance, and better reliability. I am not going to buy anything Sony, either their memory sticks or their products that use memory sticks.