MOD - Removing focusing knob – Voigtander Nokton Classic 40mm F1.4 S.C

Voigtlander 40mm F1.4 is very compact Leica M mount lens, it remains quite small when adapted on Fujifilm X cameras. This lens does not have textured focusing ring, instead there is a focusing knob – quite classic approach for small rangefinder lens. It works great, however I personally prefer operate focusing ring and there is a nice and relatively easy modification (fully reversible) to change that on VM 1.4/40mm lens.

First part of the plan is to completely remove focusing knob from lens body. That requires partial disassembly of mechanics, which is not influencing optical alignment and is relatively safe to do (I’m also mirroring these steps in older article on Voigtlander 40mm F1.4 disassembly)

First unscrew CCW ring that is securing optical core in focusing frame. Pull out lens core.

Now unscrew four black bolts holding external focusing ring, otherwise it will not be possible to unscrew bolts holding focusing knob.

Finally unscrew two bolts holding focusing knob.

Now it’s time to assemble focusing ring back, than insert lens core and secure it using spanning wrench.

Technically if you have access to 3D printer, you may design a focusing ring frame with flat connecting area repeating focusing knob connector. In my case I decided to simply use rubber band attached to focusing ring surface using strong double-sided adhesive tape.

Rubber focusing ring is easy to operate, here’s how it looks from the side.

I decided to leave distance scale uncovered, so it still can be used.

Once lens is mounted to Fujifilm X-E2s through adapter, it allows much more precise manual focusing by holding focusing ring with two fingers, and rubber surface makes it easy.

Now all my compact CV lens (35mm F2, 40mm F1.2 and 40mm F1.4) have same focusing approach using radial focusing ring, which makes it more convenient when switching lens.