Yes. Activate 'camera', click the 'Effects' tab. DOF is in there... (I am talking C3 here). Otherwise, the method I prefer, is to render as a .psd file and let Carrara render a 'Distance' channel. You can use that in postprocessing to make a DOF effect. You will have more control that way, and you have to possiblity to first clean up your render and then blur some stuff.