Today I'm tearing down one of the smallest 35mm Leica M mount lenses, the Voigtlander 35mm F2 Ultron Vintage Line.

This is a beautifully crafted Japanese lens with very high quality components. It's often difficult to figure out how to take apart a Voigtlander lens, so it took some time to learn it. This article shows you how to disassemble the focusing mechanism, an area that may require more maintenance than the optical assembly.


It looks like Voigtlander engineers often use glue to further secure the assembled lens mechanics. It can be seen when viewed close up. The surface of the adhesive is glossy and reflective. There is no point in using a spanner wrench until the adhesive has been removed, applying too much force to the retaining ring seat may simply damage it instead of unscrewing it. Just look at how thin this black ring is with two slots for an adjustable wrench.

So I use acetone and a syringe to apply it to the inner diameter of the circlip. Acetone spreads over the entire inner wall of the ring and dissolves the glue. After a minute, I try to gently unscrew this ring counterclockwise with a box wrench, using moderate force to loosen it.

Then I take out this ring.

At this point, simply pull the lens barrel up and the lens block will remain on the table surface. You will find a set of shims around it. The shims are used to fine-tune the focus of the Leica M rangefinder.

At this point, you have access to the diaphragm ring as well as the brass retaining ring. I will skip the disassembly of the front part for now, since everything works fine there.

Please note that there is a pin on the opposite side, it must match the internal spiral socket when assembling the lens.

Now it's time to disassemble the spiral ring. First, unscrew the three black bolts on the top of the focus ring and remove it.

Now mark the exact position of the outer brass drive guide of the focus ring and unscrew the two black bolts, then carefully remove it. Note the position of each bolt so you can put them in the same place during assembly.

I removed this guide at infinity, so when assembling, you will need to put the focus ring in this position.

Here's a close-up of this brass rail. My lens had very little focus ring play, almost imperceptible, but slightly annoying. I fine-tuned the width of the guide to fit more snugly into the socket, which eliminated this play.

To remove the focus ring, you first need to unscrew the four light-colored flat head screws that form the lens mount ring. Then simply turn the focus ring counterclockwise until it fully unscrews.

On the opposite side of the ring, there is a rectangular pin right next to the focus knob. This pin limits the rotation of the ring when moving inside the curved slot of the depth of field ring.

When reassembling the lens, position this pin next to "Made in Japan" and rotate both rings together clockwise until the focus ring is fully screwed in. The infinity point should line up with the curve of the rangefinder socket of the lens mount ring.

Remove the DOF scale ring.

You now have access to the focus ring bayonet threads. I opened this area to clean out the old grease and replace it with new.

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