SanDisk's turn to announce 32GB Class 10 SDHC
(Credit:
SanDisk)
SanDisk chose the Photo Marketing Association show in Australia to debut its latest-generation SDHC card, as well as announce some much-needed rebranding. In August, the company will ship the new Class 10 32GB cards as SanDisk Extreme SDHC, simultaneously rebranding the current Extreme III line as simply Extreme. Which is what it used to be called.
I've ranted before about the FUD surrounding the whole SD speed and Class rating issue, and in response to articles like that, SanDisk's PR team included an FAQ (which doesn't seem to be available online) to clear up our seeming confusion.
On one hand, the FAQ does clearly delineate the difference between minimum sustained (Class ratings) and burst transfer rates (maximum attainable speed); video requires a certain level of performance for the former while dSLRs need the latter for optimal burst shooting results. And it also points out, as I've said, that past a certain fixed point, the camera or camcorder cannot take advantage of a faster card, though a reader might be able to.
However, it fails to say that some cards--many of which are SanDisk's, ironically--already offer sustained transfer rates far higher than their Class ratings. Which it then proves by announcing when it rebrands its 30MBps Extreme III SDHC their Class rating will magically rise from Class 6 to Class 10. Because now there's a Class 10 spec. Of course, the company's Ultra II SDHC cards have tested with sustained transfer rates greater than 6MBps, the necessary speed for a Class 6 card, yet they're only rated as Class 2. Of course, they're also cheaper than the company's VideoHD-branded cards, rated as Class 4. But the ones labeled "Video" say "Video" so you know to buy them for video. Helpful!
Of course, there are still no Class 10 needy camcorders on the horizon, so for a while these not-faster-but-higher-rated cards will only be good for delivering more burst frames in a dSLR or faster reader-to-PC transfers. Which has nothing to do with the Class ratings, but that other transfer rate spec.
Senior Editor Lori Grunin has been covering digital imaging for two decades, but her memory's kind of sketchy on the details. You can hear about it every week on Indecent Exposure, the podcast she co-hosts with Matt Fitzgerald. 
- by scarhawk July 14, 2009 7:05 PM PDT
- It's true that 1080p h.264 only writes to the card at 24Mbps or 3MB/s, which is much slower than even Class 6 (6MB/s spec). 720p, which is showing up in pocket digicams, is even slower. So a Class 10 card is overkill and an unnecessary expense from only the perspective of recording video. The camera will not drop frames when shooting video with a Class 6 card.
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(3 Comments)However, transfer rate to the computer is almost as much a part of the camera user experience as shooting the photos/videos. A card that can transfer at 30MB/s means emptying out a 16GB card will take about 8.5 minutes, while a Class 6 card at 6MB/s would take about 45 minutes. For some people that's worth extra money, especially if you shoot lots of video and need to empty the card daily.