Tamara wrote:
The newer Canon DSLRs seem to support SD now in addition to CF.
CF cards are becoming less and less common in
consumer digital cameras - current max data transfer speeds for CF cards are 3 times those for SD cards, which is important for high-end dSLRs that shoot high megapixel images at high frame rates (a Class 10 SDHC card at 30 Mb/s would become rate-limiting shooting 18 megapixel images at 8 fps on my Canon 7D, for example).
They support SDHC as a convenience (you write to both cards at once, or copy from CF to SDHC, or use the SDHC as a second card once the CF is full). The SDHC card cannot keep up with the 10 fps burst rate once the buffer fills up.
Canon's own press release for their newest high-end (1-series) dSLR states, +"Full compatibility with the latest UDMA 6 standard Flash memory cards also ensures that image data is *rapidly written* to the EOS-1D Mark IV’s *CF memory card*. In addition, the flexibility to also record to a Secure Digital/SDHC memory card allows photographers to keep shooting for longer until they get the shot they need."+
Bottom line, the pros will want an easy way to get CF card images into an iPad, if they're going to use an iPad for storage/display (instead of the other standalone devices for that). But, it's a small market...