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LENS MOD: Komura 200mm f/3.5, Converting the Leica Visoflex Adapter From M/SR to N/AI

Komura 200mm f/3.5, Converting the Leica Visoflex Adapter From M/SR to N/AI
Sankyo Kohki Komura 200/3.5 with Leica Visoflex adapter converted to Nikon mount.

Originally Published: 18 July 2017
Updated: 07 August 2017, new video

July 20, 2016

Sankyo Kohki Komura was a well known Japanese lens manufacturer. They were already active in the 1950s. Their lenses were well-known for their build quality -- all-metal, huge, heavy, excellent craftsmanship, beautiful colors. 

Komura also had an interchangeable mount system similar to that of Tamron's Adaptall (the most well known and enduring of them all), and other lesser known like Sigma's YS mount and Tokina/Soligor/Vivitar's TX mount. There were several generations/redesigns of these Komura mounts, but they are all very rare and hard to find, which is the logic behind making this lens mod. The earliest interchangeable mount made by Komura was for the Leica Visoflex. These lenses had an M39 mount and an extension tube. Google 'Leica Visoflex' for more info about the design.

This brings us to the lens I have for modification, the Sankyo Kohki Komura 200mm f/3.5. It has a whopping count of 16 blades. It came with an extension tube adapter in Minolta SR mount. For those who plan to use it on DSLRs, this extension tube is essential so that the flange distance to your camera is correct. Without it, your lens will become 'far-sighted' on your DSLR.

My only solution was to hand saw the flange/mount off and measure the difference. (Minolta SR = 43.50mm, Nikon F = 46.50mm) The reverse ring that I would put in its place has a width of 1.5mm. Therefore, I need to saw off a total of 4.50mm off the extension tube measuring from the flange/mount. It took me a week to finish it sawing off bit by bit every day, but the effort was worth it. Afterward, I glued a Nikon-mount reverse ring to it.

The lens had fog/haze that needs cleaning. The focusing ring was stiff. So there was my usual restoration work other than the mount conversion.

Komura 200mm f/3.5

Adapter with the original Minolta SR mount.

Adapter now has mount replaced.

This end here is an M39 mount.


Sankyo Kohki Komura 200mm f/3.5
Who is Sankyo Kohki Komura?

What is Leica's Visoflex?

Flange Distance

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