Disassembly – Voigtlander 15mm F4.5 III Super Wide-Heliar Aspherical in Leica M mount

This article reflects the disassembly and focusing mechanics maintenance for very interesting ultra-wide lens in Leica M mount – Voigtlander 15mm F4.5 Super Wide-Heliar Aspherical version III. Article is supported by www.fredmiranda.com owner Fred Miranda who generously landed his lens for the purpose of exploring the disassembly path (thank you very much Fred!).

What I like about this particular CV 15/4.5 lens copy – it has custom cut-away petal hood leafs, which makes it compatible with filter systems and resulting in more compact size. I’ll show how to remove the hood frame for more safe cutting for people who decide to DIY such modification.

Rear area disassembly

I’ll start from the classic set of steps – rear area disassmbly and getting access to focusing mechanics. This Voigltander 15mm F4.5 III lens sample has some light play of the focusing ring, so I’m also interested to fix that.

I’ve explored rear lens area first but didn’t see the ring which is securing the lens core inside focusing frame, like it is done in CV 40/1.4 or CV 35/2. . .

It took me few days to figure out that the protruding black cylinder is not the rear glass module frame, but is actually that securing ring I was looking for : ) I noticed light damages on the ring thread made for spanning wrench which indicates that this lens was disassembled before. It typically means for me that there is potentially a strong glue applied so I’m prepared for that and going to use: acetone, rubber strap ring (cut out of bicycle tire tube).

I’m not going to use spanning wrench to avoid metal ring damage. Instead I’ll grab it using rubber ring. But first it’s time to unscrew four silver bolts and remove the mount ring for easier access. Also lens is focused to closest distance to collapse rangefinder couple ring inside.

Now I’m wrapping rubber ring around rear lens black cylinder. Additionally I’m using syringe to accurately apply few drops of acetoneto the inner wall of that ring to make it run down to the glued thread. Then I wait for a minute or two and unscrewing the ring.

At this point whole focusing frame can be lifted up and separated from optical lens core.

There is set of brass radial shims around lens core for precise focus calibration. Green arrow showing metal pin and corresponding socket to fit when assembling lens. If the aperture ring requires maintenance – now you have access to remove aperture transmission and then extract the radial compression ring to release aperture ring. But I’m not doing that today (aperture ring works perfect), instead I’m going to inspect the focusing ring transmission. Do do that I’m unscrewing two black bolts marked with red arrows, and extracting the focusing transmission.

Looks like this brass part has some play when moved horizontally in that socket. To fix that I’m using pliers to precisely and accurately increase the width of the brass guiding plate. It’s hard to explain this process in the article, but the goal is to keep the geometry same and apply accurate pressure to make end of guider just a tiny bit wider (by about 0.05-0.01mm). After correcting the plate wifht it should freely move inside socket but without horizontal play. Then I’m adding lubricant to the part and assembling it back.

After connecting focus frame and securing it with black cylinder I’m focusing lens to infinity mark and cleaning the rangefinder couple cylinder (marked with green arrow). I’m also removing the DOF scale ring out of curiosity by first unscrewing four black bolts.

After removing DOF scale ring you have access to lubricate the area of focusing ring movement limiter.

At this point I’m assembling DOF scale and mount ring back. It’s important to have the rear area completely assembled and cap put on for safe front disassembly steps while keeping rear glas and frame well protected.

Front area disassembly

Front nameplate of Voigtlander 15mm F4.5 need to be removed first. It sits in the filter thread and may be additionally secured with glue, so use few drops of acetone first applied to the filter thread.

Then cut four small pieces of strong adhesive foam and attach them between the front plate text areas (that adhesive glue is strong and may remove the lettering paint, so don’t cover letters with it).

Then take another Voigtlander rear cap, and accurately centering it and attach to that tape : ) So the glass in the center remains far from cap surfaces.

Make a firm press and unscrew the front plate CCW.

I’m wiping the acetone/glue remains from the filter thread and nameplate edges.

Now unscrew three black bolts located closer to the filter thread.

Then remove the lens hood frame. At this point you can also unscrew other three bolts and remove whole front glass module to get access to the aperture chamber. But don’t do it without serious need – front optical frame is precisely centered there for correct optical alignment and even slight shift of it may cause optical misalignment.

IMPORTANT: after removing the hood ring DO NOT put the lens facing down because front glass is protruding and can be easily scratched.

Radial polishing of the hood cut area.

The hood cut area of this Voigltlander 15mm F4.5 Super Wide-Heliar has flat and nice looking finish performed by 220 sandpaper.

If you’d like to have a look closer to classic brushed aluminum surface there is a simple way to do that. All you need is to accurately mask outer ring surface with adhesive tape. Then hold small piece of 320 or 400 sandpaper at the ring front edge and rotate it to slide under the sandpaper. That will generate nice radial grinding trail that will bring more accurate look to the aluminum surface.

Then remove the masking tape and clean ring using 99% isopropyl alcohol.

Conclusions

Finally I’m assembling lens back and checking on camera to make sure focusing ring is moving smooth without radial play. Also I’m testing focus precision on different distances (which is challenging due to extremely wide DOF even at wide open F4.5).

I’m impressed again by the high quality and precision of Voigtlander mechanics design. Cosina engineers making great job by producing easily maintainable lens frame made of durable materials, and Voigtlander 15mm F4.5 Super Wide-Heliar is not an exception. This lens is beautifully crafted and is a joy to disassemble and repair, thankfully to easy separating of optical core from the focusing frame.