If you're starting to shoot more than a little HD video direct to SD cards, you might be starting to take more notice of the card's Class as well as capacity. Now Lexar has announced new SDHC cards delivering Class 10 speed rated options in 4GB and 8GB varieties.
While many of the multipliers thrown around for flash cards relate to burst fire or maximum speed ratings, the Class system of SD and SDHC cards aims to guarantee a minimum sustained transfer speed. Damn important if you want to push high bitrate HD video to the card over an extended period of time.
Class is basically a reference to the number of Megabytes per second the card will sustain. Class 2, 2MB/s; Class 4, 4MB/s; and Class 6, 6MB/s. That's actually where the current version 2 spec for SDHC ends.
A few makers have started pushing ahead with version 3 spec cards that take the Class up, up and away. Panasonic announced Class 10 cards last year, for instance, but now Lexar joins the party with Class 10 SDHC cards in 4GB and 8GB sizes. At the same time, these Class 10 cards claim a minimum sustained speed of 20MB/s. Which, by current definitions, would make them the equivalent of Class 20, if such a class existed?
What we're thinking is that these cards will basically be speed limited by your hardware, and short of any other weird technical incompatibility (and we haven't heard any exist) that's a good place to be.
The Lexar Professional 133x SDHC 4GB: RRP $56.80 The Lexar Professional 133x SDHC 8GB: RRP $117.20