Friday, January 26, 2007
June 2005 HelpLineMemory Card Considerations
Q) I'm considering buying an 8-megapixel digital camera. These high-megapixel cameras are no doubt memory-hungry, so I'd likely buy a 2 GB card for whatever camera I purchased. Regarding Lexar's Write Acceleration (WA) card, Lexar's ad makes it sound like the WA feature is something that works with WA-enabled cameras. Are they talking about cameras with some special kind of buffer? They state that in cameras without WA, the card still functions at 80x speed. Can you explain this?
How would this card compare to the SanDisk Extreme 2 GB card? It has transfer rates of 9 to 10 MBps, while the Lexar states a speed of 12 MBps, but I don't know if that's the 80x speed or the WA speed. Finally, what about Microdrives?
A) Memory cards that support Write Acceleration depend on technology inside the camera to take advantage of speed improvements. The current cameras supporting WA include all Kodak Professional cameras and pro camera backs, the Nikon D1x, D1H, D2H, D100 (with firmware upgrade), Sanyo DSC-MZ3, Sigma SD9 and SD10, Pentax *ist D and Olympus E1.
The 80x specification uses the same speed ratings as optical drives like CD-ROMs. When CD-ROM read and write speeds are specified, they're given as 12x or 32x, and the "x" refers to 150 KB/sec. At 80x, you're talking about 12 MBps While you might get close to this speed when you use a card reader attached to a computer, the speed will be less than half of that with most 8-megapixel cameras.
As for Microdrives, they will be slower than the cards you've listed. Also, since they're actually miniature hard drives, they have moving parts and can be delicate pieces of technology. If you're expecting your media to go through any type of rough treatment, I'd keep that in mind.
Regarding memory cards, you're correct that the cameras need lots of memory. One thing to consider is using several smaller cards, rather than putting all your money into one large card. There are several benefits. If you lose a card or one fails, you won't lose all of your images or your ability to take pictures. Smaller cards also mean shorter download times per card.
Finally, depending on your workflow, archiving can be a little easier if you have cards that are about the size of your archive medium. For example, I travel with a couple of 1 GB cards. I never fill them up all the way. After I edit out the bad images, I can archive the good ones to a CD.
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