Apptosd Help Center
/
Sign in Contact supportContact support

CF vs SD Cards: What Is the Difference?

Updated 2 min read 1.7K views
On this page (4)
  1. SD cards
  2. CF cards
  3. Capacity and speed
  4. Use in cameras

SD and CompactFlash (CF) cards differ mainly in the protocol they use, how their capacity has grown, and their physical size. Here is how they compare.

SD cards

  • SD cards use their own protocol. The original standard went up to 2 GB (there were a few 4 GB SD cards, but they were not very compatible).
  • SDHC expanded capacity beyond 2 GB, up to 32 GB.
  • SDXC then added support for up to 2 TB.

The switch from SD to SDHC was particularly painful: most other devices, such as card readers, picture frames and notebooks, took years to catch up.

CF cards

  • CF cards use the IDE protocol, which can address large volumes using virtual head, cylinder and sector coordinates.
  • FAT32 support is needed above 2 GB, but the cards keep working as capacity increases. This makes the protocol more stable and extensible.
  • The next revision, CFast (Compact Fast), is based on the SATA protocol.

Capacity and speed

The larger physical size of CompactFlash gives it an advantage in capacity and a slight edge in maximum speed. This was historically significant, but the gap is now so narrow that it is mostly a legacy consideration.

Use in cameras

  • Both card types have high-quality models suitable for cameras.
  • The Pentax 645D digital medium format camera uses SDXC cards.
  • Canon's top models accept both CF and SD.
  • This leaves Nikon as the only one using CF cards in its high-end models.