Hans Schulz - The father of the VEF Minox lens?

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Reading time: 47 mins | Updated on: 11.06.2026

Minostigmat lens of VEF Minox Riga. Photo by Burkhard Fenner

The lens that really shouldn’t have worked

Imagine you want to build the world’s smallest camera. A mechanical marvel, no bigger than a lighter. But there’s a problem: there isn’t a lens in the world sharp enough to capture an image on a piece of film the size of a fingernail.

The industry giants were in agreement. When Walter Zapp approached Agfa in the 1930s to jointly develop the lens, they coolly turned him down. Too exotic, too risky, simply unfeasible. At Leitz in Wetzlar, the Olympus of optics, they didn’t even deem a response necessary – they simply ignored him. To the experts in Munich and Wetzlar, the Minox was not a stroke of genius, but an optical pipe dream. A “lemon,” even before the first sketch was finished.

But while the market leaders were still explaining why the laws of physics were against Zapp, he found someone who wasn’t intimidated by the big names. In his lab, a brilliant expert set to work on a task that is almost forgotten today: he calculated the impossible.

He ignored the arrogance of the established players and designed a lens so sophisticated and tiny that it didn’t appear in any textbook.

It was the birth of the Minostigmat – a lens that wasn’t supposed to exist, but would change the world of photography.

The Minostigmat:<br>7 mm in length

At this point, I would like to thank Ralph T. Schwarz, without whose crucial clue regarding the identity of Hans R. Schulz this article would not have been written. Furthermore, his research into Schulz’s biography contributed significantly to a complete picture.

I would like to extend my special thanks to Heinz Humberg, who provided me with valuable insights into the optical and physical aspects of this topic.

I would like to thank my friend Burkhard Fenner for the unique photos of the Minostigmat and its accurate dimensions. He also provided me with ongoing inspiration for this article and served as my discussion partner.

Dace Kaprāne looked through the documents on the Minostigmat for me at the VEF History Museum. I would like to thank her very much for that.

I am grateful to Hubert E. Heckmann for sharing valuable insights from his conversations with Walter Zapp and his own reflections on this topic. I would also like to thank him for carefully reviewing the final draft and for his comments on it.

Page Contents<br>The lens that really shouldn’t have worked<br>Who was the man behind the Minostigmat?<br>The Minostigmat – Heart of the VEF Minox Riga<br>Challenges for a lens<br>Hans Schulz – Father of the Minostigmat Lens<br>Design and calculation of a Cooke triplet<br>Result: The Minostigmat<br>Conclusion<br>Minostigmat test photos<br>More information about the VEF Minox Riga<br>References

The Shadow Behind the Monument

Walter Zapp is a name that stands like a monument. His 1935 design for the first Minox is considered the "Big Bang" of subminiature precision engineering—the birth of a camera that created its own legends. Yet every monument casts a shadow, and hidden within that shadow is the single component without which the Minox would have remained blind.

Heckmann1 in his standard work Variations in 8×11 reminds us of the man behind the glass: "After a grueling wait, these [the optical data for the lens] were finally calculated by Prof. Schulz in Vienna."

VEF Minox Riga with Minostigmat

This is all that posterity has left of the man who transformed Walter Zapp’s precision mechanics into a functioning tool. Zapp possessed the vision to build a camera that could disappear into a clenched fist—but he was no optician. He could design the mechanics, but he could not master a lens.

Who was the man behind the Minostigmat?

Anyone looking for the man who gave Minox its eyesight won’t find a Wikipedia entry. All you’ll find is a “Professor Schulz” from Vienna.

"At the time, I had asked Walter Zapp several times about the lens calculator Prof. Schulz from Vienna. Zapp could only confirm this fact, but he didn’t even know the professor’s first name . Based on what I knew at the time, I suspected that Prof. Schulz worked at or for Voigtländer or C.P. Goertz. Unfortunately, Zapp was unable to confirm this." Hubert E. Heckmann tells me.

Prof. Hans Schulz in the course catalog of the Technical University of Berlin 1934/35

To find the true architect of the Minostigmat, one must descend into the dusty catalogs2 of the Technical University of Berlin, 1934. There, buried among the lists of specialists in applied optics, a name emerges:<br>Prof. Dr. phil. Hans Reinhold Theodor Schulz

He lived in Berlin-Lichterfelde. He taught physiological optics and the polarization of light. He was the man who understood not just how glass bends light, but how the human eye—and the film—perceives perfection.

Technical University of Berlin in the 1930s

The industry giants at Agfa and Leitz had already turned...