Odd that Apple don’t seem to have heard of Digital SLRs or CF cards, only SD. I’ve a Canon EOS 30D which needs access to portable storage, so my iPad seemed the logical choice. This pulls together what I discovered along the way.
As of writing, there’s only one third party dedicated CF card connector for iPad2 and current reviews suggest it could be flaky, so I purchased the Apple Camera Connection Kit. The plan being to use the USB adapter to accept a card reader and get my photos in that way. Plugging in the reader resulted in message “Accessory Unavailable: The attached accessory uses too much power”
Apparently Apple reduced the power available to the port to drive USB devices from 100 milli-whatnots to 20 milli-whatnots when IOS 4+ was introduced to improve the battery life of the iPad 2, users of IOS 3 did NOT generally experience the issue.
Finally I had to dig out the box to my EOS 30D, safely hidden many years ago, and retrieve the dedicated USB cable supplied by Canon. It was with some trepidation that I plugged this cable into the Apple USB Connector and switched on my camera but it just worked! Spookily the cable is white and matches the rest of the iPad accessories :-).
What you’ll need is: EOS 30D + Canon supplied USB cable + Apple Camera Connection Kit.