CF Card deals

Started Nov 26, 2011 | Discussions thread
fpix Regular Member • Posts: 335
Re: CF Card deals

elfroggio wrote:

For video, you do not need UDMA, an 8Mb/sec is more than enough:

1080p is 1920x1080 at 30 frames per second = 91 Megabytes per second. Canon uses MPEG-4, which is 16 to 1 compression, so now the memory card speed needed is: 91 Megabytes divided by 16 = 5.7 Megabytes per second

Exactly. For video one should buy Class 6 or (for more skeptical people) Class 10 cards. But large cards.

For burst photography the speed of the card influences mainly how quick the buffer is flushing its content in the card. On 7D (cca. 60MB/s write speed) you may expect following results for flushing a filled buffer:

  • 600x card: cca. 6 seconds

  • 400x card: cca. 8 seconds

  • 266x card: cca. 13 seconds

  • 233x card: cca. 15 seconds

  • 200x card: cca. 18 seconds

  • Class 10 card: have not tested, I expect cca. 1 minute or so

Results may vary from brand to brand since real specs of each card, even in same class, may differ (and sometimes specs in data sheets are "inflated"). I use Transcend 600x cards. I found that data sheet specifications of these cards are on par with real life.

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