I'm currently capturing video into FCP 7 with my Z5U, and the image is a little fuzzy, like the camera did not capture in 1080p. I used the auto-focus, but I turned off all of the auto-functions that I think would make the camera not record in it's true 1080p.
Scale the image in the Canvas to 100%. How does it look now? The Canvas and Viewer aren't really designed to show you full quality images...just show you what you are doing reasonably well while you edit. But if you blow up to 100%, and look at a paused image you should see the full quality.