iPhoto treats two identical video cameras in totally different ways

I own two Canon Vixia HF G20 video cameras. The two cameras are, as far as I can tell, configured in completely identical ways. And yet for some reason when I connect them to my Mac to import video, completely different things happen:

• When I connect one of the cameras, iPhoto launches automatically, the camera appears under "Devices" in the iPhoto sidebar, and I have the option to import video directly into my iPhoto library.


• When I connect the other camera, iPhoto does not launch automatically. If I launch it manually, the camera does not appear under "Devices", and there does not seem to be any way to get iPhoto to recognize that the camera is connected, or to import video from it. Instead I have to navigate to the AVCHD file in the Finder, open video clips using Quicktime Player, and then use Quicktime Player to Save the clips to my hard drive. (This method works on the other camera, too, of course.)

Since I am able to save video from both cameras to my HD, this difference in behavior is not mission-critical, but it is annoying and mysterious. I am not sure if the difference has to do with a setting in iPhoto, or on the camera itself, or what. Can anybody explain to me why these two cameras -- same model, same configuration (AFAIK) -- are handled by the OS so differently?