What is the minimum speed CF card required for using a 7D for both recording 1080p video and also continuous shooting for RAW+JPEG?

Similar to Should I get a fast CF card? i essentially want to know if i need to buy a more expensive faster card or wether the standard cards are sufficient. Difference between questions is:

  • a) I want to know what minimum speed is required.
  • b) I will also be using it for video (i have seen in the past on other cameras video not recording correctly because an SD card was too slow).

2 Answers 2


For video I believe the requirements would be a card that can write 10 MB/s (mega bytes per second). This equals to 66x speed for a Compact Flash card. For shooting stills it's possible to get a longer burst with a faster card. If you want maximum burst length, get the quickest CF card you can afford.

The math would be: 66 * 150kB/s = 9900kB/s ~ 10MB/s

  • 66x = 10 mb/s = similar to Class 10 on SD cards
  • 133x = 20 MB/s
  • 200x = 30 MB/s
  • 266x = 40 MB/s
  • 333x = 50 MB/s
  • 400x = 60 MB/s
  • 466x = 70 MB/s
  • 533x = 80 MB/s
  • 600x = 90 MB/s

I can't find any specifics for the 7D that are helpful. Normally I would look to the Rob Galbraith CF/SD Performance Database, though the newest cameras aren't listed there. According to the dpreview.com 7D review's performance section, the camera maxed out when shooting raw with a Sandisk Extreme Pro card. So, one conclusion could be that the camera is working faster than one of the fastest cards made.

Canon says that 15 raw images can be shot continuously. dpreview found they could get 24 with a fast card. It's safe to assume that Canon's 15 image count is then for a slower card.

I'm sure you'd have no problem shooting video with a Sandisk Extreme or Extreme Pro card.

After spending mega-bucks on a new body, buy a fast card to complement it. Fast 4GB cards can be had for as little as $20, so it's a no-brainer to me.

  • \$\begingroup\$ yup, i made this option too (class 10 4GB). I am also assuming the performance degrades with usage...anyway: 4GB ought to be enough for everyone :) \$\endgroup\$ Commented Mar 16, 2012 at 16:18

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