Meyer-Optik Helioplan (Praktiflex) 40/4.5 (Spring 2011)

The 40mm Meyer Helioplan is a highly regarded lens, seemingly most often encountered in Exakta or M42 mount. This one is something of a rarity, because it's in the unique 40mm original Praktiflex mount. I think of it as a cousin to my Praktiflex-mount Tessar (here), so I'll repeat most of what I said about that lens here.

You may read, on one website or another, that the original 40mm Praktiflex system had the same register distance as the 42mm Praktiflex (and Praktica) system that came after it. Please take it from me: that is not the case (a fact I've confirmed in conversations with the proprietor of a marvelous German website dedicated to cameras made by Dresden-based manufacturers). The original Praktiflex register is shorter than that of the 42mm system; if you try to jury-rig some arrangement to use a 40mm lens on a Praktica-mount camera (by holding the lens in the camera throat, if all else fails), you'll discover that maximum focus distance is limited to just a few inches. (Update: I am now reliably informed that the Praktiflex register distance is 44mm.)

Candidly, I acquired this lens (and the Tessar) by mistake, hoping they would be Praktica-mount lenses. They've been relegated to a corner of the cabinet: the one reserved for curiosities rather than working lenses.

But the acquisition of a micro-4/3 camera gave me new hope that these museum pieces could be transformed into usable lenses. The process of trial and error is still ongoing - and I haven't managed infinity focus as yet - but at least now I can use these lenses as far away as "portrait" distance.

My current working arrangement consists of a LTM-to-micro-4/3 adapter; a 39mm-to-42mm adapter (39mm on camera side, 42mm on lens side), and two short Exakta extension tubes. (Happily, the diameter of intermediate Exakta tubes is 40mm; the thread pitch is different from the Praktiflex 40mm mount, but Praktiflex lenses will screw in far enough to be held securely.) The two Exakta tubes are literally taped to the 39-to-42 adapter - I won't epoxy anything until I have the distances more precisely worked out! - which screws into the micro-4/3 adapter. The lens screws into the Exakta tubes, and there you are.

I need to shorten the homemade adapter in order to achieve infinity focus. But for now, I'm delighted just to be able to use these lenses at anything approaching normal working distances.

I'm relatively sure I wouldn't have undertaken this project if I didn't already own the two Praktiflex lenses. But since I did, I really wanted to be able to use them. Do they give me anything that their M42 or Exakta siblings wouldn't? No. But there's a certain satisfaction in putting another orphaned lens mount to work.