Hi
Is Pi trying to mount the camera when it is plugged in/turned on. (does a screen pop up asking you what to do with it?) if so try to unmount the camera then try Gpgoto2.
I had loads of problems with Gphoto2 at first, it would recognize the camera but not do much. It turned out that I needed to set the camera's USB setting to PTP / MTP and unmount the camera from Ubuntu.