No amount of spare human parts can substitute for co-operative weather ... It's rain and fog outside now, a hopeless situation for the exploration of an expensive optic the welfare of the review sample for which I'm entirely responsible while testing. I would probably never get the shimmering bulbous front clean again if subjected to the dreary inclement conditions outdoors at present.
Then, as I could not steer my curiosity away, I commenced experimenting with adding extension to the 19 PC-E. Anything from PK-11/11a or thicker would bring the plane of focus into the optical assembly itself, thus not very helpful. The K-1 did work though if focus was set away from the native near limit. However, sooner or later you get the focus plane touching the front element so be extremely careful and don't blame me if you blatantly ignore Nikon's stern advice NOT to use such an item in combination with the 19 PC-E. Getting the lens stopped down from the f/4 maximum is easy, though, by setting aperture on a camera supporting E lenses, then press the stop-down concurrently as the lens is removed from the camera. The aperture will stay put at whatever setting you selected. An insider's trick making it possible to use 'E' lenses on even the oldest of Nikons such as the F and F2 models.
Doing this with a hand-held camera indoors, and the K-1 ring added to the lens, in rather poor light is an exercise in Zen approach to the impossible. Any way, here is the tangible proof of the impossible. (one of my staple medications with a nice Braille inscription for the visual impaired on the box). Df, 19 mm f/4 PC-E at f/8.
Don't forget this goes against ALL recommendations from the Mothership.
