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Compact Flash Cards: 30 MB/s versus 60 MB/s?
I was wondering if anyone might be able to shed some light on the difference between compact flash cards with transfer speeds of 30 MB/s and 60 MB/s. I am going to be shooting on a Canon 7D, 1280 x 720 both at 23.98 and 50 fps. I’m not particularly concerned with how long it will take me to transfer this footage to my computer rather I am more concerned with the camera functioning optimally while I’m shooting. Any help would be appreciated. Thanks.
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4 Replies
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I use the Kingston pro x133 cards in my 7D the specs are, 25MB/sec read, 20MB/sec write, I have no problems using them for video at 1080p.
The other cards I use are SanDisk ultra ll I think these are around 10Mbps, again no issues with video and the 7D. -
The 7D transfer video (both) 1080 and 720p at approx. 330 MBytes/minute. This corresponds to around 5.5 MB/sec. You will be fine with either 30 or 60 MB/s cards. The difference is how each manufacturer arranges the given data internally.
We’ve had excellent results with SanDisk products. We tested a SanDisk “Extreme Pro” 90 MB/s (32 GB) card recently. Even though, some may say that it is an “overkill”, we found it did not drop any frames even at 90% capacity.
“Always remember that you’re unique. Just like everyone else”.
Confucius
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Thanks for the info, guys. If anyone else has any wisdom on the matter, it’d be great to learn more.
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It seems that speed is not such a factor as sustained speed. Many cards can write fast bursts for photos, but have problems with video. To be on the safe side, get a card specified as UDMA.
BTW, you won’t experience dropped frames, just drops in quality. I can’t speak for the 7D, but the 5D reduces the data-rate (i.e. more compression) when it senses a slow card.
Director of the Institute of Media Research (IMF) at Braunschweig University of Arts
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