How do I export my DVX100B Footage in 16:9?
The camera IS outputing your footage in 16:9 (really its 4:3 with a letterbox for 16:9) but it's final cut thats ingesting the footage as 4:3. You need to go into your capture preset settings and either change or create a new default capture preset.
Here's a link that explains how to do that:
Hope this helps.