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Finding some photo magic in an old Meyer-Optik Trioplan

Create: 04/24/2016 - 10:40
Dogwood blossoms


  • Lens was taken from a Pentacon Pentona
  • Optic is bonded permanently to a Leica M to Sony NEX adapter
  • Trioplan is known for its ‘soap bubble' bokeh

One of the great things about mirrorless interchangeable-lens cameras is the ease with which you can attach lenses from the film era.

With the recent interest in the Meyer-Optik Goerlitz Trioplan, I decided it was time to try this lens for myself.

The problem is that I don’t have a Trioplan in an interchangeable lens mount. However, I do own a non-working Pentacon Pentona camera that is fitted with a coated f/3.5 45mm Trioplan. Actually, I own two of them. The Pentona, a simple viewfinder camera, was available in the mid-1950s. The Trioplan first appeared in 1916. It's a triplet, as the name Trioplan indicates.

How difficult would it be to attach the lens from this camera to my Sony NEX-7? That’s what I set out to learn.


My first task was to remove the lens and shutter assembly. Here’s the problem: the lens and shutter aren’t contained in a single unit, like they are in many cameras. Both are integral to the front panel of the camera. At least, that was removable.

Obviously, for this to work, I was going to have to keep the shutter open at all times. The solution fell into my lap. It literally fell into my lap. When I removed the front of the shutter housing, the two blades that comprise the shutter fell out. Problem solved.

With the Pentona, the rear element and aperture blades (five of them) are part of the lens panel. There wasn’t an easy or obvious way to remove the rear element and have an aperture assembly. My only choice was to keep the lens panel.

I also had to remove a long rod that trips the shutter. That was very simple.

There was a protrusion on the rear of the panel, but a few minutes with a Dremel and a cutting disk took care of that. I finished with a file and fine sandpaper. (Caution: When you use a Dremel, wear protective eye gear and put the piece into a vice, because it can become very hot.)


After cleaning the lens and relubricating the helicals, it was time to figure out a way to mount it to an NEX-mount adapter. Luckily, these adapters are plentiful and inexpensive on eBay.

The one that worked was for the Leica M mount, and it cost me less than $8 with free shipping.

My next challenge was figuring out how to attach it to the adapter. My choices were to fashion a type of bracket that would secure the lens panel to the NEX adapter. The big problem with this approach would be light leaks. The lens panel wasn’t made to be placed against a lens adapter, obviously. I could use foam to block the leaks. I’d need to create the clips to hold the entire thing tightly against the lens adapter without allowing it to shift.

I decided to create a permanent bond between the panel and the lens adapter. Informal testing showed that the proper distance required me to remove the lens adapter's mounting ring.

For this, I mixed some J-B Weld Kwikweld epoxy and placed a thin layer onto the lens adapter. The idea would be that when I pressed the lens panel onto the adapter, the epoxy would spread and fill the gaps and create a light barrier. The epoxy layer couldn’t be too thick, or the lens plane might not be parallel to the sensor.

This epoxy has a quick set time of about six minutes and takes four to six hours to fully cure.

With that in mind, I pressed the two items together. This gave me a couple of minutes to ensure that the lens was centered on the adapter. I did a quick test shot, and it seemed to work.

I allowed the epoxy to set, checked for light leaks (there was just one – more epoxy) and added some flat black construction paper to the inside of the lens chamber to reduce reflections.

In the morning, I set infinity focus. Done!


It wasn’t a pretty thing, and the lens panel got in the way of holding the camera. I did some further work the next day, trimming the ends of the lens panel and rounding the corners. I painted the panel black. I might go back at a later date and further trim the panel. I'll need to pick up some more cutting disks for my Dremel.

In all, this work took about four hours. I could do it again in about two, now that I know what to do.

Total cost was $8 for the lens adapter, six inches of black construction paper, epoxy and “Canyon Black” spray paint.


At f/3.5, it’s one stop slower than the f/2.9 50mm Trioplan. One stop slower also means more depth of field at its widest setting.

The NEX-7’s 1.5x crop factor means this 45mm lens is a full-frame equivalent 68mm – still very usable as an everyday lens.

It’s likely that my lens isn’t precisely parallel to the lens plane because of the imprecise method of attaching the lens panel to the NEX adapter. Again, in real world use, you aren’t going to notice. Pixel-peepers might detect it, but that’s not the point of photography.

This is a very nice optic. Sharp in the middle and average performance to the edges wide open and sharp by f/5.6.

But that’s not why people like the Trioplan. It’s the out-of-focus part of the photo – otherwise known as “bokeh.”

Meyer-Optik describes it as “soap-bubble bokeh.” My daughter and I call it “swirlies,” referring to the round out-of-focus areas when shot at certain distances with the aperture wide open. You sometimes see this with the Carl Zeiss Tessar.

This doesn’t appear in all of the photos that were shot wide open, and I would guess that it has something to do with the f/3.5 maximum aperture, as well as the close-focus distance. It probably also is connected to the fact that I’m not shooting with a full-frame camera. The APS-C sensor uses only the center of the image.

For sure, the Trioplan can produce unique images. I think you could describe them as “dreamy.”

Because this lens came from a viewfinder camera, this Trioplan can focus to just a shade under 3.5 feet (1 meter). The marked distance is 3.5 feet, although the lens rotates beyond that point. I would guess that it's close to 3 feet. That seems inadequate when many single-lens reflex camera lenses can focus to about half that distance.

One option would be to grind down the block on the inside of the focusing ring, but I think this could create more problems than it solves.

The focusing ring is tiny. Luckily, I can focus the Trioplan with one finger. The rotation from infinity to its closest distance is about 300 degrees. While this allows for precise focusing, it does mean that the act of focusing takes much longer. Win some, lose some.

For sure, the better idea would be to find a Trioplan in a standard SLR mount, such as M42 or Exakta, and then get an adapter for it. Plus, you have the added benefit of a shorter close-focus distance.

You also can buy one of the Trioplans that have been put back into production. These lenses look very attractive, particularly the 50mm version that lets you pull out the front element for shooting as close as 11 inches (compared with 36 inches for my Trioplan).

What are we to conclude from this? Obviously, there is plenty of life left in older cameras and their lenses – whether you use them for film or digital.

The Trioplan performs very well in a digital world and allows you to take photos that differ markedly from modern lenses with aspherical elements that eliminate the type of distortion that this lens creates.

I had a lot of fun with this project and can't wait to try another soon.

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About the Author

Mike Elek is a longtime journalist and was one of the original editors for The Wall Street Journal Online. He also has worked as a reporter and editor in Pittsburgh; Philadelphia; Vineland, N.J.; Poughkeepsie, N.Y.; New York City; and Hong Kong. He is a U.S. Air Force veteran. He shoots with film and digital cameras.