Eye-Fi does not support the use of SD to CF card adapters with the Eye-Fi Card. Eye-Fi has not tested the Eye-Fi Card in cameras designed to use CF cards and has no explicit knowledge to share about the success of these adapters when used with an Eye-Fi Card. We only support the Eye-Fi Card in cameras designed to use SD or SDHC cards.

We are aware that many users want the Eye-Fi Card functionality in their CF-based cameras and have opted to use a CF card adapter to get the functionality offered by an Eye-Fi Card. The following list of known issues with CF card adapters is a collection of information gathered directly from customer and blogger descriptions of issues they have experienced. By sharing this information Eye-Fi accepts no responsibility for problems encountered when using the Eye-Fi Card and a CF Card adapter.

• Wireless range of the Eye-Fi Card is noticeably reduced.
• Formatting the Eye-Fi Card in a CF adapter has caused the Eye-Fi Card to fail.
• File corruption of photos.
• The Eye-Fi Card will not work in Canon 20D, 30D and 40D cameras when used with an “SD/MMC” CF adapter. Use of the newer “SD/SDHC” CF adapters appear to work with the Eye-Fi Card in these cameras. For more information Refer to the Photojojo’s article, What to Do if your Eye-Fi + CF adapter won’t work with your Canon 20D, 30D, or 40D.