My Nikon D4 included a free 16GB Sony XQD card and reader. The new XQD standard promises very fast data throughput. Sony’s spec states 125MB/s transfer rates are possible. CF cards currently top out at 90MB/s. In my testing with the XQD card I was able to shoot 83 14-bit lossless compressed NEFs in the D4 before the buffer filled and shooting speed dropped. That’s a lot of frames! Of course, most photographers don’t find themselves ripping off 80 frames at 10fps most of the time. You may as well shoot video if you want to do that.
Sony’s XQD card readers are USB 3.0, with USB 2.0 backwards compatibility. The speed difference between USB 2.0 and USB 3.0 is immense. USB 3 can theoretically deliver 5Gbps per second… that’s faster than eSATA. USB 2.0 is stuck at 480Mbs… just over half the speed of Firewire 800. The good news is that if you have a USB 2.0 slot on your computer, you can still use the USB 3 reader, albeit at a much slower transfer rate.
Sadly for us Mac users, the only readers currently available for the XQD cards are USB 3.0 or Express Card 34. That means plugging the fast reader into a slow USB 2 port to transfer files, or adding a USB 3 card to your computer. If you have a current 15″ MacBook Pro laptop, you’re even more stuck, as Apple abandoned the Express Card slots in favor of a dedicated SD card reader (the 17″ MacBook Pro still has an Express Card 34 slot).
My point here is not to complain about Apple or Sony, but to simply point out this interface limitation for Mac users. Since transfer speed is most important to me when I’m traveling, I’m going to stick with CF cards in my D4 for now because I have a Firewire 800 reader for them. What I hope to see is future support for USB 3.0 from Apple (not holding my breath), as well as expanded interface support (Thunderbolt, anyone?) for card readers. For pro photographers in the field, USB 2.0 readers are simply too slow compared to the alternatives.