I love my Canon DSLR for the flexibility of selecting high-quality lenses, a plethora of shooting modes, the faithful color renditions, and the high storage capacity I can get with inexpensive SD cards. But I find myself also shooting a lot of photos with my iPhone simply because I want to share those images with the world immediately. The Eye-Fi Mobi Wi-Fi memory card (starting at US$49.99 for an 8 GB capacity) offers a simple way to quickly "shoot and share" from a DSLR through your iOS device.
I'm no stranger to Eye-Fi cards. I currently use the company's Connect X2 card when I'm shooting review photos for TUAW, since I can have them automatically transferred to my Mac without needing to remove the SD card and put it into the computer's SD card reader. You can find out if your DSLR or point-and-shoot is compatible with Eye-Fi's products through a compatibility program that's available through any of the Eye-Fi product pages.
My Canon DSLR, for example, integrates well with the Eye-Fi cards. It keeps the camera powered on until the Wi-Fi media uploads are done, displays a Wi-Fi icon on the camera's touchscreen that shows the status of uploads, and allows enabling/disabling of the card from the camera's menu.
Setup of the Eye-Fi Mobi card for use with an iOS device is fast and easy. First, you install the free Eye-Fi app (universal, also available for Android and Kindle). The installation process requires that you enter the activation code that's on the back of the SD card case on the package; once that's done, the app installs a profile onto your iOS device. Next, the app asks for access to your Photo Library so that images sent from your DSLR can go right in without a need to be moved manually.
Your next step is to pop the card into your camera and enable it. Once that's done and you take a picture with the camera, the card sets up a secure Wi-Fi network that's tied to the app you activated. Select that network in the Settings app, and you're ready to roll.
Upon launching the app again, the photos are quickly uploaded to the iOS device. When I mean quickly, I mean that it takes only a few seconds for DSLR-quality images to be transferred at full resolution. I find this quite interesting, since the Eye-Fi to Mac connection on my home network is slower. In the future, I may use my iPhone as the intermediary for image transfers for reviews, since an Eye-Fi to iPhone to Mac (via Photo Stream sync) transfer is faster than what I've been seeing with a direct to Mac Wi-Fi connection.
One more great thing is that you can share the DSLR images while Eye-Fi transfers are taking place, since enabling the ad-hoc Wi-Fi network still keeps your cellular data connection up and running.
The Eye-Fi Mobi card comes in both 8 GB and 16 GB versions, and is available from many online retailers including Photojojo and Amazon as well as direct from Eye-Fi.