The cult of BOKEH !

An enthusiastic new light recordist could be forgiven for thinking that photography is all about the BOKEH !! – a Japanese word meaning the aesthetic quality of the out of focus area of a photograph, typically produced by a shallow depth of field, specular highlights, and a wide aperture setting. But a little research suggests that the word has only been in use for a few decades, if that. It’s a characteristic used to sell many a new lens and draw hobbyists to the cause of ever more attractive blur. There are even entire Flickr groups dedicated to it. No Group f/64 here !

In feeding this need for lovely bokeh,  lens manufacturers have provided us ever larger apertures and ever larger lens barrels to go with them.

My own thoughts on that matter are that characteristics like bokeh are simply one tool of many. They are not an end in themselves. Rather, the technical aspects of the photographic process contribute equally to the entirety of expression.

The cult of Soap Bubbles and Meyer Optik

Now we have a relatively new sub-cult focussed on soap bubble bokeh, made famous by the legendary Meyer Optik Trioplan line of triplet based lenses, and recently revived by the new brains behind the thoroughly modern incarnation of the Meyer Optik Gorlitz outfit (further research confirms that this new group is a subsidiary of a large branding and marketing group and has zero to do with the original company). That they managed to raise $359 451 of a modest $50 000 goal speaks volumes about the frenzy for such special blur in the photographic community. Of course, you’ll also need a hefty wallet to buy into this sub-cult.

A cheaper Meyer Optik Trioplan lens

As much as it’s not all about the BOKEH for me, I do like a good soap bubble blur now and then. But I don’t have the fat wallet to pay for either the old Trioplan lens from the 1950s, or the revived modern Trioplan. But, what I do have is some PVC piping, a hacksaw and an uncommonly known triplet lens from Pentacon; the 1960s incarnation of the old Meyer Optik company.

But, before I get to this cheap alternative, here are some results from my dabblings to show off this so-called soap bubble bokeh:

Bokeh lights soap bubble style

Bokeh lights soap bubble style

This is your classic defocussed lights image to show off the Bokeh. Please excuse the dusty bits and pieces. I made this through my car windshield at night! Note that the bokeh circles are quite heavily outlined. This is one optical signature of the Meyer Optik Trioplan lenses, and this particular cheap alternative. Here’s a photo with a more recognisable subject:

Flower with classic triplet bokeh highlights

Flower with classic triplet bokeh highlights

You can see the soap bubble bokeh in the top left corner. Here’s a cropped version so you can see it more clearly:

soap bubble bokeh cropped

cropped version

You’ll also note the subtle glow around bright subjects; yet another optical signature of this particular lens design.

Here’s another:

More Meyer Optik styled soap bubbles

More bubbles

The soap bubble blur is particularly evident here. With the lens wide open at f2.8, the subject close to the focal plane, and a background featuring specular highlights further away, the bokeh is emphasised. These lenses do suffer from lower contrast, but that can be a boon for certain subjects. Once again, you can see the subtle glow around the cherry blossom buds in the above image. Used for portraits, and with subtle lighting, this glow would be especially suitable to enhance lighter skin tones.

Red leaves and bokeh background

Red leaves and bokeh background

I can’t resist one more photo. It’s a fun lens to use and can yield some fantastic results! Now that you’ve seen what it can do, here’s how to get that Meyer Optik Trioplan optical signature much more cheaply.

Introducing the cheaper Meyer Optik lens

Given that those old Trioplan lenses go for hundreds of dollars regularly on eBay, what alternatives are there? Well, if you’re ready for some home-grown modification and DIY, you can obtain the same optical signature using a different lens with the same (or very similar) optical design. Meyer Optik (and later Pentacon) produced a range of projector lenses in a variety of focal lengths using the classic triplet design, and featuring the same optical aberrations. Meyer Optik produced the Diaplan projector lens in the useful 80mm and 100mm focal lengths. It’s true that it lacks an adjustable aperture, but the fixed aperture of f2.8 results in the unique optical signature you’re looking for to achieve that distinct Trioplan aesthetic.

Unfortunately, because the Meyer Optik name is attached to the Diaplan, photogs still go nuts for these lenses. They’re usually cheaper to get than the Trioplan classics, but still require some fatness in the bank account to obtain without breaking a sweat. So, my cheaper alternative is the Pentacon AV 80mm 2.8 projector lens. Once Meyer Optik Gorlitz had become part of Pentacon in the 1960s, the Diaplan lens was simply renamed. The 80mm focal length is still useful for that bokeh and is usually priced less than the 100mm version.

Adapting the Pentacon AV to a modern digital camera

So, you have your Pentacon AV lens (or Diaplan if you’ve just received a modest tax return), but what do you do now? It lacks a focussing mechanism, so you’ll need to build one and mount it on your camera. I don’t claim to be a DIY wizard, so here’s my rough and ready game plan:

  • Choose a mount adapter to use on your flavour of digital camera. I used a C-Mount to Micro Four Thirds adapter because it’s the lightest and thinnest mount I have. You’ll later use this as the rear mount piece for your new home-made lens.
  • Measure the outer diameter of the Pentacon lens (51.5mm) and go out and buy some PVC plumbing pipe from a hardware store. Just make sure that the inner diamater of the pipe is wide enough to accept the lens (53mm inner diamater pipe measurement).
  • Mount your adapter on your camera.
  • At this point, you’ll need to turn on the camera and simply freelens the Pentacon in front of your digital sensor (freelensing is where you focus a lens by hand without it being mounted). My Olympus mirrorless camera will still meter without a lens attached when in Aperture priority mode. For other cameras, it might be Manual mode.
  • Manoeuvre the Pentacon lens  so as to achieve infinity focus. You’ll need to try and focus on a distant subject to do this. Once infinity focus is achieved, measure either by eye, or with the help of another party, the distance the rear of the lens barrel is from the flat of your mount adapter.
  • Add the length of this rear distance to the length of the Pentacon barrel behind the larger front lens element, and then cut the PVC tube to that length with approximately 15mm of additional length. It’s always best to allow some play here and cut the pipe so that the lens can focus beyond infinity when using it. You’ll have so much focus play with this home-made trombone focussing mechanism that the extra length won’t matter. Best to have a longer barrel than one that is too short and won’t allow infinity focus.
  • Once cut, you can paint or spray it matte black. I used some acrylic spraypaint to do this. Make sure you paint the inside of the tube black, if nothing else, so as to cut down on any reflections inside the new lens barrel.
  • Once the paint is dry, superglue the PVC tube to the mount adapter (with the adapter removed from the camera!).
  • You now have yourself a classic triplet lens with character and a way to mount and focus it ! Who needs that pricey Meyer Optik !
Mounting the Pentacon AV 80mm lens

Mounting the Pentacon AV 80mm lens

Triplet Lenses – the secret of soap bubble bokeh

Buying and modifying the Pentacon AV is not the only way to get yourself a cheap meyer optik bubble lens. In fact, the Trioplan is so named because it consists of a triple glass element optical forumla; hence the trio in the name. You can find this triplet optical formula in quite a few projection lenses actually, including a Russian made 150mm f3.5 projector lens. Of course, if you manage to score one, you’ll still need to DIY it to focus on your digital camera, but at least it’ll be fun !

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