At this year's Last Gadget Standing event that Yahoo! Tech and I host at CES, the audience voted for the Eye-Fi, an SD card with a wireless chip that allows your camera to move photos wirelessly to your PC or a photo-sharing site. A few days later the Eye-Fi went on to win Best of Show at MacWorld. It is, in fact, a great and well executed product, but now that I've spent some real-world time living with Eye-Fi, I'm bumping into its limitations. It still gets a big thumbs up from me, but the weak spots are showing.

After a photo-rich trip to the Grand Canyon a week ago, I wrote to Eye-Fi's CEO and offered these observations. First, my camera (a Kodak V series) took a long time (nine seconds on average) to go from "completely turned off" to "on" with the Eye-Fi card installed. (You can only imagine the shots that got away.) Second, the battery on my camera drained considerably faster with the Eye-Fi card in use. (Typically my camera will run for two or three days without a charge on a trip like this. This time I was nearly out of batteries by the end of day one.)

Transferring images wirelessly is a major improvement to cables, cradles, or moving memory card, but it's also not problem-free. My camera, with its automatic timer, shuts down after a period of inactivity. I changed the automatic timer setting to the maximum allowable (10 minutes), but after a trip where you take lots of photos you'll need to transfer in batches based on your camera's timer.

My bottom line is that if you're taking lots of photos just use the Eye-Fi as a regular memory card and skip the wireless transfer. Better yet, use a non-Eye-Fi card on photo-intensive days. Also, I'd like to see a version of the card where you could turn the wireless transmitter off since it uses the camera battery for power. Having my photos moved from camera to Facebook without touching a button is cool, but flawed.

Phil Askey at DP Review noticed similar issues and gives a good summary of Eye-Fi limitations. Here are a few:

• Only works with associated access points which have no additional "login" layer (i.e. only home/office access points, not public access points) and this can only be carried out with the Eye-Fi Manager software running on a computer.
• Requires a good Wi-Fi signal to work properly, has less range than typical Wi-Fi devices.
• For single images, demos, and entertaining, transmission times are acceptable; however, if you came home with a card full of images (2GB), it would take three hours to download all images (if the camera battery could last that long).
• Requires that the camera does not power off; otherwise obviously transmission is interrupted.
• Unknown additional impact on camera battery life.
• Performance is made to look pretty poor in comparison to most cheap USB 2.0 card readers which can manage ~10MB/sec (some 50 times faster than the Eye-Fi card).