Q: I'm looking at buying a digital camera, but I'm a little confused by the different memory cards they use. Some take CompactFlash, others SmartMedia or Memory Stick. What's the difference?
A: Technically, not much. Often, electronics manufacturers manage to unite on standards - all 3.5-inch floppy disks work in all 3.5-inch floppy drives, for instance. Other times, manufacturers alone or in small groups introduce their own formats and try to grab as much as possible of the market.
That's what they are doing when it comes to "flash memory" cards, which are used in digital cameras and some other devices like hand-held computers and digital-music players.
There are five widely used card formats: CompactFlash, SmartMedia, Memory Stick, MultiMediaCard and Secure Digital. They all work the same way and mostly have the same chips inside. But the size and shape of their casings differ, and a card made for one slot won't fit into another.
More formats are coming. This month, Olympus and Fuji announced the "xD-Picture Card," which they said is the "size of a postage stamp" and available with "memory sizes from 16 to 128 megabytes." In other words, it's much like its competitors.
Earlier this summer, Sony introduced a small version of the Memory Stick. It won't fit into a slot for the original, stick-of-gum-sized Memory Stick without an adapter, and the bigger Memory Stick won't fit into slot for the smaller one.
So don't wait for choices to get less confusing - the manufacturers seem determined to cloud this issue.
But to return to your question, some things do set the cards apart, and they might be important enough to influence your choice of camera.
The CompactFlash format is the oldest, most widely used, and physically largest format. Fewer devices are being introduced for these cards, since the slots can be hard to fit into small gadgets, but the format is likely to be around for a while.
Also, since a CompactFlash slot is big, adapters are available that allow the use of the smaller cards in a CompactFlash slot.
If you're a big shooter, a CompactFlash slot may be a good choice, since the big size of the cards allows them to accommodate more memory chips than any other card - up to one gigabyte, enough for maybe 1,500 high-resolution pictures.
But don't expect CompactFlash to be a simple choice, either. There are two kinds of CompactFlash slots and cards. Type I cards are 1/8 inch thick and will fit in Type I and Type II slots. Type II cards are thicker and will fit only Type II slots.
Type II slots, which are standard in professional digital cameras, have the advantage of being able to accommodate IBM Microdrives, tiny hard drives with prodigious capacities.
SmartMedia is the second most widely used format, according to analysts at iSuppli Corp. in El Segundo, Calif. They are smaller and thinner than CompactFlash cards, and top out at 128 megabytes.