Re: Final Cut Express help - I want to create such Eff...
Final Cut Express has super limited tools, and may prove problematic to do this. You want to do this photography trick with video clips? That's a very tall order. Normally it is done in camera with Depth Of Field (DOF).
With many video cameras you have to fake this by pulling the camera back as far from the talent as you can, and zoom in on them. Have them a good distance from the background. The background will be blurred.
Cameras that accept interchangeable lenses, you'd select the appropriate lens, set the shutters speed, aperture, and get the DOF effect you're looking for very, very easily.
But to do it in post like we do with still photos is a MAJOR undertaking, a huge effect to pull off. You would have to make a copy of the video in track V1, another of the same in track V2. The top copy, the V2 track, you'd have to create a matte (or mask) and keyframe the points of that mask to move with the talent. This isolates the talent. Then on the V1 track copy, you'd place a Gaussian Blur filter and blur it out.
If I had to do with with a video clip that was not shot with the proper DOF to achieve this properly as it should be done in-camera, I'd use Motion. Same technique I described, but much easier to do (not "easy", it's a lot of tedious work, but "easier" in Motion than in FCP X) in Motion.
The Plesantville Effect isolates colors, not shapes, and would not be the way to achieve this at all, as you have discovered.