:lecture:Interestingly, DoF and Bokeh are unrelated in another way. To a good approximation, the DoF of, say, a head shot only depends on the f/stop and not the focal length of the taking lens. A wider angle lens puts you closer to the subject, and DoF narrows accordingly.
However! The size of the distant OOF highlights depend only on the actual aperture, and so a 100/2.8 portrait will have twice as large distant light blobs as a 50/2.8 portrait taken from half the distance.
I am, of course, ignoring the character of the OOF region, which is very important, but the amount of blur is the first thing people notice.
/:lecture:
--Matt