Rick. I already have cameras, and DoF is enabled.
The issue is that this pseudo 3D text animation is achieved by randomly increasing the text size of individual words as they "expand" outwards and increase in size. In fact it remains a 2D layer, so each word remains the an identical distance from the camera. Therefore traditional DoF has no affect.
For the same reason, a lens blur will blur parts of the same plane, even those words which appear to be nearer the camera - which isn't the same effect as true DoF.
I suppose that what I'm trying to create is a true 3-dimensional comp of tracking a camera through pre-placed words. I was hoping that the text animation preset would same time!