EL Nikkor 2.8 is, in fact, a screw mount lens for an enlarger. I DOUBT seriously if there is any adapter available. My EL Nikkor's are about the size of a silver dollar.
Any of the old "AI" or even the "F" series lens will bayonet to the new digital Nikon SLRs, BUT, they are manual focus and must be used in "stop down" mode.
Sorry, but I'm 90 percent certain that you can not adapt this lens.