This is a Tessar-type aerial photography lens that was designed around 1937 and was the most numerous, with 1,500 units produced until just before the end of the WWII. This lens is for use with the Second Version of the First Automatic Aeronautical Camera.

A lens for the second version of the first automatic aeronautical camera. With this camera, operations from exposure control to film rewind were automated using a motor. Nikon produced approximately 600 units of this model in approximately one year up till the end of the Second World War, production numbers for large-size aeronautical camera that were revolutionary at the time.

Hello to the members of Nikon Kenkyukai and visitors to its website. I am delighted to have the opportunity to discuss a special restoration project of a historically significant vintage Nikkor lens.

One of the very few 50cm R-Aero-Nikkor lenses, survived the WWII. Development of 50cm Nikkor finished around 1937 with roughly 1500 lenses produced. 50cm f5.6 Aerial lens is mentioned in Nippon Kogaku 40th Anniversary book. This particular lens was found by collector in Canada in Seatle in 1990. It was then stored for over another 30+ years in great collection, but in humid conditions which affected the lens surfaces badly. On the home trip back to Japan, lens landed shortly in my hands for cleaning and gentle restoration.

Lens is about 4.5 inches in diameter and is fitted in cast aluminum housing that is 9 inches wide. Housing fits aeroplane mount and has remote control of the shutter assembly that is part of the outfit. Height of the set is 5 inches. Lens is 4 element uncoated Tessar type with an image size of 24x28cm. R-marks indication that this lens could be used for infra red photography. Right in the middle of the lens, between optical elements, there are five black shutter blades, that could be operated via the outputs on the aluminum housing. R-Aero-Nikkor 50cm lens was designed for military use and was never available for general market. This unique lens is also presented in 100th Anniversary book (Nikon - 100 Anniversary, November 2016) written by Uli Koch. I have seen only few of these 50cm lenses and 4 ended up in my restoration lab. It is possible that less then dozen of these war history warriors exist till today. One of them is in new Nikon Museum in Saint-Bonnet-de-Mure near Lyon, France.

After dismantling the whole lens and cleaning the fungus from the optical elements, it was quite clear to me, that the glass surface is has marks and without polishing it will never get the right light permeability. For the polishing i used cerium oxide abrasives, which could be obtained by glass polishing companies or sometimes available in the car accessories stores. Polishing needs a lot of time and it is better to do it by hand and not use any electrical tools. Cleaning of the metal rings and other body had to be done with soft cleaning approach and only "soap" based cleaning tissues or liquids. No dissolvents or any alcohol based cleaners ! Old Nippon Kogaku paint is quite fragile and one has to be extremely gently in any direct surface contact. I used brushes mostly and some areas were wiped with cleaning tissues only.

Most enjoyable part of restoration process, is to assemble all restored and cleaned pieces back and inhale the aesthetical freshness of the reborn crown lens. Successful project brings always nice feelings and awaitings for the new adventures to come. Lens was then packed with a lot of protection and sent to its final home in Japan. Arrived well and the new owner was extremely pleased with the beauty of this optical masterpiece.

Several photos show original condition before restoration, after disassembly, after cleaning and finally the restored and reborn 86 year old optical jewel. Please enjoy the journey into the optical history and restoration enchantment.