Nikkor-O 55mm f/1.2 Instrumentation Lens: Diaphragm Blade Repair
Originally posted on Instagram. Notes from the repair bench, kept here as a searchable archive. View the original on Instagram
Servicing an unusual lens: Nikkor-O 55mm f/1.2 instrumentation lens. These lenses were designed for close focus work and have no focus helix. They were typically mounted in an oscilloscope to record traces from a CRT.
This particular example is one of a batch of around 200 that were purchased in the 1970’s by a US Government contractor to install in special made cameras to record CRT traces from signals created by nuclear weapon testing operations. These were in use at the Nevada Test Site until the Test Ban Treaty of 1992. During a test, there would be many banks of oscilloscopes with each one having a camera attached for recording.
This lens needed two diaphragm blades replaced as they were damaged (the second photo shows ten blades, there are actually twelve in the lens). The final photo shows all the blades cleaned and installed and ready to go to work.
I have sold many of these lenses and often see them re-mounted in Leica M configuration although I use one on my mirrorless camera for close up work. They have a Leica 39mm thread mount.
