BASIC QUESTION about creating depth of field with moving subjects! please help!

[Finalcutprorory]

Hi all, so I'm new to Smoke and Flame etc.

I essentially have one thing I'd like to do. That is:

Create depth of field on moving images to simulate a much more expensive camera with good depth of field.

Can somebody please tell me which program (Smoke, or Flame, or something else?) would be best for this?

Also, I see the Smoke 2015 version will have a 3d motion tracker. Is this the answer to what I'm trying to do?

Please help. I've tried basic programs and plugins for FCPX, and I know there are some ways to do this in AE, but it seems like the tracking can be quite limited and very time intensive and manually done.

I'm interested in a basic and very dependable way to track moving objects and blur the background to create a fake depth of field.

WHICH PROGRAM AND BASICALLY HOW TO DO IT OR WHAT I'M LOOKING FOR WOULD BE SO APPRECIATED!

THANKS SO MUCH!

[BKM]

You would use the Depth of Field Node in either Smoke or Flame.

http://www.premiumbeat.com/blog/smoke-depth-of-field-node/