The SONY HDR-FX7 can record both DV and HDV 1080i (even in combination on the same tape), but the MiniDV tape you have must be a MiniDV HDV tape (make sure it says “HDV” on the tape’s label).
Also, make sure that your camera’s REC FORMAT is set to HDV1080I if you want to record in HDV (On your camera, press MENU->IN/OUT REC->REC FORMAT).
In FCP, your Audio/Video Settings should look like this for the SONY HDR-FX7:

Before you ingest, make sure you first rewind your tape on your camera in VCR mode, then connect using a firewire/ilink cable, connect from the computer first then to your camera (“or else static electricity can damage it” -manual).
Once connected, run FCP and go to Log & Capture (COMMAND + 8), it will ask you for a name to prepend to all the clips, enter a short name and click Ok.
If everything works correctly, a window will pop up showing the capture in real time. Press ESCAPE when you are done. Note that it will capture to separate files depending on record start/stop points.
The captured files (hopefully) will be in prores 442 format and 1920×1080 resolution in the Capture Scratch folder.
Hope this helps.