As digital SLR and 5-plus megapixel digicams have proliferated so has the need for higher capacity memory cards. Having even a 64MB card seems insufficient these days, especially with so many people choosing TIFF or raw image file formats as their mode of choice. Enter the new 4GB CompactFlash card from Lexar, now the largest card available in this or any other memory card format. At 4GB you needn't worry about running out of card space when shooting even the biggest events, even when shooting with the largest file size producing image file formats. That means that one card might do the trick for a wedding, a sports event, or even breaking news...or that two week trip taken by even the most avid digital photo fan.

Alas, there is a catch to this bonanza, and while we might expect digital camera makers to catch up to this technology in future versions of their cameras there are only a select few that can use the card now. While you might be content with a 512MB card, or even a 1GB card now, being able to use this new card, and its new regimen, is something that requires some checking.

The reason behind all this is that digital cameras that take CompactFlash cards use one of three versions of FAT. Not another acronym, you might be moaning, but yes FAT is a term you might like to know. FAT stands for File Allocation Table, a system that keeps track of where each picture is stored on the card. The FAT file system gets onto the card via formatting, during which the various components of the filing system, including File Allocation Table, Master Boot Record (which includes the Partition Table, which lists the start and end points of partitions on the card), and more are added to the card's data storage area. In essence, all this gets the card ready to receive the data from your digital camera.

That might be more than you need to, or want to know but the FAT setup is key to being able to reference locations where data is stored on the card. Perhaps the most common FAT setup now is FAT 16, which means the system uses 16-bit reference numbers to indicate those locations. For those who use CompactFlash cards between 16MB and 2GB in capacity the FAT 16 file system is used. But here's the catch--FAT 16 was not designed to track files on cards with capacities exceeding 2GB.

Following the process mentioned, what's needed for larger capacity cards--such as the new 4GB card--is FAT 32, which uses 32-bit numbers as pointers to file location. For those looking way into the future, FAT 32 can handle media up to 2TB (terabytes) in size. But any card beyond 2GB must be formatted to FAT 32 to both handle the capacity and be compatible with PC and Mac operating systems. The simple fact is that FAT 16 support is common in digital cameras today and FAT 32 isn't.

In the words of Lexar, if you use a 4GB card that has been formatted to FAT 16 (which it will be if it's placed in and formatted with a non-FAT 32 camera) your computer will "choke" when you go to download, and anything you might have recorded past the 2GB capacity will not read.

There's more. Because of the new formatting (organizing the card so it can read data) there are some additional housekeeping matters to keep in mind. Even though some cameras might be FAT 32 capable, they still need to have a firmware upgrade to make it work. Such is the case with Kodak's DCS line-up. You should also avoid using the card in anything but fully compatible FAT 32 cameras. Although you can format a 4GB card to FAT 16 (you're advised not to, but if you do) then you will in essence turn that card into a 2GB, FAT 16 card. But that's not the only reason not to do this--your computer might not even be able to read the re-formatted card anyway. You can, however, restore the FAT 32 format using Lexar's Image Rescue. The same applies if you get a corrupt notice on the card, usually a result of pulling the card out of the camera while it is writing.

You should also be aware that even though you have higher capacity your write speeds might slow down, due to the fact that camera systems constantly update the file system as they write to the card. Even high-speed cards, such as Lexar's 40x, will show somewhat slower write speeds than the 40x 2GB card.

Another matter to be aware of is that because of the incredible capacity your camera frame counter might not be able to show frames remaining over 999. In other words, if you load the card and you're shooting JPEG the frame counter will go to its highest number--999. You may shoot and shoot and still see 999, and it will be quite a while until you see 998. No, the card does not break the frame counter; it supplies more capacity than the frame counter can indicate.

Nobody ever said that leaps in technology don't come with some bumps in the road, and having such high capacity cards--with even greater storage media coming--is a good thing. But understanding what the new capacity cards can and cannot do--at least for now--is something everyone should understand before they make the investment. At around $1500 street price per 4GB card it pays to read the instructions. But for those who need the capacity and can make use of it in their camera (see sidebar for compatible cameras as of this writing, and check out the Lexar website for updates) the new 4GB cards are a welcome addition to the digital camera field.

Current List Of FAT 32 Compatible Cameras

Canon: PowerShot G3, G5, S45, S50; EOS 10D, 1Ds (Note: The Canon EOS-1Ds will FAT 16 format any card that is unformatted.)

Kodak: DCS 720x, 760 (these cameras require a CompactFlash to PC card adapter), DCS Pro Back, DCS Pro 14n (Note: Kodak DCS cameras need a firmware upgrade for FAT 32 compatibility. Go to www.kodak.com for upgrade procedures.)

Olympus: E-1
For an updated list please go to www.lexarmedia.com/fat32

For more information, contact: www.lexarmedia.com.
--George Schaub