GRAPH LEGEND
12.9-INCH USB3 ADAPTER = 12.9-inch iPad Pro connected to Lightning to USB3 Camera Adapter which in turn was connected to both Power Adapter and the Lexar USB3 Reader with SDXC Card inserted
9.7-INCH USB3 ADAPTER = 9.7-inch iPad Pro connected to Lightning to USB3 Camera Adapter which in turn was connected to both Power Adapter and the Lexar USB3 Reader with SDXC Card inserted
12.9-INCH SD ADAPTER = 12.9-inch iPad Pro connected to Lightning to SD Camera Adapter with SDXC Card inserted
9.7-INCH SD ADAPTER = 9.7-inch iPad Pro connected to Lightning to SD Camera Adapter with SDXC Card inserted
CONNECT TO SD CARD AND INVOKE IMPORT MODE
From the time you connect the Lightning to USB3 or SD adapter, a few seconds pass until the Import mode is invoked and the thumbnails of images start to appear. (SHORTER graph bar means FASTER)
SAMPLE AND RENDER THUMBNAILS
Once the 'ghost' of the images appear on the IMPORT screen, one by one the thumbnails are created. (SHORTER graph bar means FASTER)
CONVERT TO JPEG AND IMPORT
We clicked IMPORT ALL to begin the conversion from NEF to JPEG and IMPORT process. (SHORTER graph bar means FASTER)
INSIGHTS
At first I was enthused about the the release of the Lightning to USB 3 Camera Adapter. That's because when I tried to mount a Lexar 2000x SDHC/SDXC UHS-II memory card using the Lexar SDHC/SDXC UHS-II reader (U3, Class 10) connected to the 12.9-inch iPad Pro's Lightning port via the bus-powered Lightning to USB Camera Adapter, it produced the dreaded "Cannot Use Device LRWM04U: The connected device requires too much power." error message.
The Lightning to USB 3 Camera Adapter has a pass-through Lightning port that enables you to connect the iPad Pro to both the power hungry SuperSpeed SD reader and to the power adapter, thereby supplying sufficient power to the reader. Great! -- except there are two gotchas:
GOTCHA #1: The Lexar SDHC/SDXC UHS-II reader and the Lightning power cable crowd each other so much that you can only connect one at a time. I had to order a Female to Male USB 3.0 extender cable before both could be simultaneously connected. (Design flaw? Or is the Lexar reader the oddball?)
GOTCHA #2: The Product Overview for the Lightning to USB 3 Camera Adapter 'confesses' a key deficiency in the 9.7-inch iPad Pro. To quote, "The 12.9-inch iPad Pro transfers data at USB 3 speeds, while the 9.7-inch iPad Pro uses USB 2."
As you can see from the graphs above, 12.9-inch iPad Pro using the Lightning to USB 3 Camera Adapter sampled and created thumbnails of the 13 NEF images 604% faster than the 9.7-inch iPad Pro. And it converted and imported the images 164% faster. Photo import speed is critical for PROfessional photographers. Why wouldn't Apple equip the 9.7-inch iPad PRO with the same speedy Lightning port as the 12.9-inch iPad PRO?
But here's the 'KICKER': Just for fun I tried the 'plain old' Lightning to SD Card Camera Reader (bypassing both the Lexar reader and the power cable). Even without the 'USB 3' moniker, the 12.9-inch iPad Pro created the thumbnails 232% faster and converted/imported the images 108% faster than the 9.7-inch iPad Pro.
(After posting this article initially, a reader pointed me to the Product Information on the 'powerless' Lightning to SD Card Camera Adapter which states, "It supports data transfer at up to USB 3 speeds on iPad Pro, and up to USB 2 speeds on all other iPad and iPhone models." However, that verbiage was written before the 9.7-inch iPad Pro was introduced. It should be modified to read "up to USB 3 speeds on the 12.9-inch iPad Pro, and up to USB 2 speeds on the 9.7-inch iPad Pro and all other current iOS devices.")
CONCLUSION
The Lightning to SD Card Camera Reader is more convenient if not the fastest. The Lightning to USB 3 Camera Adapter is faster and more versatile since it can be used with any compatible USB device whether it requires external power or not. And both are fastest when used with the 12.9-inch Mac Pro.
RELATED ARTICLES ON THE IPAD PROS
Check out our article summarizing key feature differences between the 9.7-inch and 12.9-inch iPad Pro.
Check out our article comparing the CPU, memory, and GPU performance the 9.7-inch iPad Pro with the 12.9-inch iPad Pro, the iPad Air 2, and the iPhone 6s Plus.
