Voigtlaender Heliar 15mm with Infrared filter.
Below you can see, how the infrared filter (2 layers of unexposed and developed slide film) can be attached to the lens
Hi Don, here are pics from yesterday of an art exhibition in Rendsburg.
And pictures of the famous railway bridge there over the Kiel Canal, known as the Kaiser-Wilhelm-Kanal, between the North and Baltic Seas.