I bought a used filter holder from B&H that fits just fine. It was $149 plus a bit for shipping. As an aside, the Canon holder with a filter in it costs $88.95 for their 500mm f/4 lens. The Canon site also clearly lists the Canon drop-in holders with compatibility links to show lenses the holder fits. Just too much for Nikon. I am so far into Nikon I cannot get out economically. I wish that were not true.