How do I blur the background, but not a moving subject in FCPX to create a depth-of-field effect? So I am using my camera to make vlogs for youtube and sometimes interview people. I have a background that doesn't move and I have a person in front of the camera who sometimes moves from left to right.

My camera already has a subtle depth-of-field, but I want to make it more noticeable. Now I know that photobooth in OS X has a trick where you step out of the frame for a moment and then when you step into the frame it can separate you from the background. I guess FCPX can probably do the same trick, but I haven't found that feature yet. Is it in there? Can I use it to create the effect that I want to create?
FCPX can't do this automatically (like Photo Booth) unless the background is a single colour.

As a workaround, if possible…


Take a picture of the background.
Film the vlog in front of a green screen.
Key the background leaving the alpha channel.
Place the picture behind the video layer.


There is a full guide in this Apple KB article:


Final Cut Pro X: Use chroma keys