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Lens Wars: Episode V – Petzval Strikes Back: Digital Photography Review


Petzval Portrait Lens, circa 1890, from author’s collection.

It’s amazing to me that we’re rapidly approaching the 200th anniversary of the first photograph being made: Niepce’s View from the Window of Le Gras, taken in 1827. My last post concluded with the WWF–style camera cage match that was the beginning of photography. Daguerre and Fox Talbot were the main combatants. Sir John Herschel refereed the match rather impartially and helped both sides (and photography) equally. Hippolyte Bayard made a dramatic top rope entrance after the battle was largely over, but really didn’t affect things at all. Finally, Frederick Scott Archer came out of the dressing room to become last man standing in the ring.

When cameras arrived, suddenly nothing was proper and genteel about lensmaking anymore

But that fracas is not what I want to talk about today. The story of early lens development is perhaps even nastier. Lens-making was a respected occupation before anyone was taking photographs – think spectacles, opera glasses, microscopes, telescopes and the like. Lensmakers’ clients were the well–to–do. Proper manners and genteel behavior were the order of the day in lens-making circles. Except for John Dolland; Dolland was sleazy, foreshadowing the future.

When cameras arrived, suddenly nothing was proper and genteel about lensmaking anymore. All of the great photography traditions began: theft, cheating, patent and copyright violation, the use of personal insults to counter facts, and rampant nationalism. That’s what I’m eager to talk about in this article.

Lenses Before Photography

People have been making glass lenses since at least the ancient Egyptians. The invention of eyeglasses around 1300 created a large enough market to make lens-making a worthwhile, if niche, business. The lens market grew throughout the 1600s, as lenses became used in telescopes, microscopes, and camera obscuras. By the 1700s, most cities had several lensmaker’s shops. These tended to be family businesses, with fathers training their sons in the craft.

The lenses were generally simple; single concave or convex pieces of glass. These were fine for spectacles but had massive chromatic aberration which was an issue in telescopes and microscopes. Newton had suggested that different types of glass could be combined to counteract ‘chroma’ making an ‘achromatic’ lens. An English inventor, Chester Moore Hall, figured out a way to do this around 1730. He wanted to keep the idea secret, hoping he would have a better telescope than his colleagues. So, he had paid one lensmaker to make an element of crown glass (low refractile glass), another to make a matching element of flint glass (high refractile ‘leaded’ glass), and planned to combine the elements himself.

Why Did They Call It Crown and Flint Glass?

The term crown glass came from early methods of making windows. It was regular soda–lime glass containing silicon and some potassium. To make a window the glass was blown into a sphere, which was then attached to a rod and spun so that the centripetal force flattened it into a sheet. The flat parts of the sheet were cut into window pains, the thick central part where it was attached to the pipe was called the ‘crown’. If you want to see crown glass being made, check this out.

Crown pieces of glass used in an early window. Angelika Kauffmann–Museum in Schwarzenberg, Austria.

Flint glass contains a high percentage of lead, which raises the refractile index. The original source of lead silicate were flint nodules found in Southeast England. This type of glass was used to make cut-glass goblets and such; the high refraction gives the cuts their brilliant color. Leaded glass is no longer used in lenses because of environmental concerns; today titanium dioxide and zirconium dioxide are commonly used in high-refractile glass.

Back to Making Lenses

The two lensmakers Hall contracted with were both rather busy, so each paid a third lensmaker, George Bass, to actually make the two lens elements. Bass noticed how the two elements would fit together and figured out the achromatic nature of the paired lens elements, but he sent the two separate lenses back to the original lensmakers without saying anything. To them at least. He did quietly make some achromatic doublets himself and a few other lensmakers copied them.

Years later, Bass mentioned this achromatic lens to John Dollond, whose son, Peter, was a lensmaker. Our boy John established the sleazy side of lens making, reproducing these lenses and writing a paper in the 1758 Philosophical Transactions of the Royal Society claiming he had figured it all out himself. Dolland, of course, patented the invention. Bass and about half of England sued Dollond over the patent. The courts agreed Dolland hadn’t discovered the achromat, but because he was the first to state the business application, his patent was upheld. He became quite rich, getting a royalty from every achromatic lens made for several years.

In 1812, William Hyde Wollasston figured out how to bend lenses, developing the meniscus lens. This reduced distortion and field curvature, making meniscus lenses popular for camera obscuras. Since he was already rich, Wollasston didn’t bother to patent the meniscus.

Left to right: a convex lens, a meniscus lens, and an achromatic doublet lens. Roger Cicala, 2021

So, these three lens types were in use when cameras were being invented: simple convex and concave elements, the meniscus lens, and the achromatic doublet (whose patent was now expired). Niepce used a meniscus lens to take the first picture, but he and Daguerre both moved to achromatic doublet lenses soon after.

Chevalier Was There First

Charles Chevalier, a Paris lensmaker, supplied those lenses to both Daguerre and Niepce for their camera experiments, and probably introduced the two men to each other. As Daguerre progressed in his experiments, he found the achromatic doublets and meniscus lenses were inadequate because of their field curvature and chromatic aberrations. The latter made focusing difficult, especially for Daguerre, since his process was most sensitive to blue light, while he was basically focusing yellow–green light. Chevalier learned that reversing the doublet (which was designed for telescopes) flattened the field somewhat, which helped. Eventually, he developed a meniscus–shaped achromatic doublet that reduced chromatic aberration, further flattened the field, and made the lens much easier to focus.

These lenses, eventually known as French Landscape Lenses, were used in the first Daguerreotype cameras. They had about a 50° angle of view (roughly equivalent to a 45mm lens on a full–frame camera today) and an F16 aperture. Chevalier deserved (but was not given) some credit for contributing to Daguerre’s invention of the camera.

While Chevalier didn’t receive credit, he did OK financially, since he was associated with Daguerre, who was a slick businessman way before he invented photography. Chevalier made the lenses for the first cameras Daguerre and Giroux released right after Daguerre’s announcement and continued to sell his French Landscape lenses as photography exploded.

Charles–Louis Chevalier. Line engraving by E. Rosotte after himself. Wellcome Collection. Public Domain

Chevalier gets first shot

Within months of the announcement, Daguerreotype cameras were everywhere (except England) and Daguerreotypes were being taken of everything (except things in England). But there were issues. Chevalier’s ‘French Landscape Lens’ had an F16 maximum aperture, requiring exposure times of 15 to 45 minutes. It still had significant field curvature and chromatic aberration. And it came in any focal length you wanted, as long as that was 45mm (equivalent).

So, the French Society for the Encouragement of National Industry created a contest, offering a prize for the best wide–aperture photographic lens. This wasn’t meant to be a fair contest. The Society was in France. The judges were French. Chevalier was a minor French national hero; probably the only optical geek in all of history to obtain such status. And the French considered the photographic camera itself to be their invention.

Chevalier found that using two achromatic lenses, rather than one, brought in more light

Chevalier was a good lens designer, though, and immediately entered a cool lens in the contest. He found that using two achromatic lenses, rather than one, brought in more light, making the lens about F6. And in a stroke of genius, he made the lens in several parts, so the barrel between the two elements could be extended. Adding a barrel extension changed the focal length considerably, so basically the photographer got two different focal lengths in one lens. He called it Photographe à Verres Combiné (Combined Photographic Lens) and immediately entered it in the contest. It seemed, for a while, that nobody else would enter and Chevalier would win by default.

Schematic diagram of Chevalier’s Photographe à Verres Combinés lens. Roger Cicala, 2021
Chevalier’s Photographe à Verres Combinés lens Image by Daderot, Public domain, via Wikimedia Commons

Petzval Is Up Next

Jozeph Petzval was not a lens designer. His parents planned for him to become a shoemaker in their native Hungary. Like many sons today, he rejected his parents plans for his gainful employment and spent a decade in college, because even then, college was more fun than making shoes. In college he had a reputation for being a gifted mathematician, a superb fencer, and a man who didn’t mind letting others know they were wrong. He rather enjoyed letting others know they were wrong, actually. He lived for it.

Jozeph Petzval, 1854, Drawing by Adolf Duathage. Image is in the public domain.

He received degrees in mathematics and civil engineering from the University of Pest. (Pest later joined with the town of Buda, on the other side of the Danube, to become Budapest.) Petzval eventually become the Chairman of the Mathematics department at the University of Vienna. He had exceptionally broad interests, lecturing on optics, differential equations, mechanics, ballistics, engineering, and ‘sound vibrations’. He argued constantly with university administrators about what he considered their outdated teaching methods. (He was apparently correct, as his lectures were among the University’s most popular.)

Petzval Argued with Everybody

Being brilliant is a good thing, but Petzval maybe took it too far; he considered anyone not Petzval to be wrong. He worked for years on what we today call Laplace transformations, writing many papers and a two–volume book on the subject. They might well be called Petzval transformations today, except that Petzval had a bitter feud with a student, who retaliated by claiming Petzval had plagiarized Laplace’s work (he hadn’t) and Laplace ended up getting credit.

Later, in a series of ugly debates that went on for years, Petzval argued with Christian Doppler over the Doppler Principle. Basically, Petzval used mathematical proofs to claim that the Doppler principle was wrong, despite the mountains of experimental evidence showing that it was correct. It turns out while Doppler’s Principle was correct, his mathematics had errors. Petzval found the errors, and therefore considered the Doppler Principle false.

At an Austrian Academy of Sciences meeting, Petzval publicly called Doppler a ‘small scientist’ because he did experiments, while ‘great scientists’, i.e., scientists like Petzval, did mathematics. The trouble was Doppler discovered the principle through experimentation; he was just trying to use mathematics to explain it. Petzval, finding the mathematics lacking, assumed the theory must be lacking, too.

Oh, yeah. Back to Petzval’s lens

After hearing about the French contest, Petzval decided that mathematics and geometry should be used to improve lens design and he set up a laboratory in an abandoned monastery to do so. An Austro–Hungarian mathematician who had never designed a lens, entering a French lens contest against a Frenchman judged by Frenchman seemed as likely to succeed as a winter invasion of Russia. But I’m sure Petzval figured he did ‘great scientist’ mathematics, while Chevalier just did experiments, so it would work out.

The Petzval Portrait Lens was amazingly sharp in the center, had an aperture of F3.6 or so, and had a soft hazy bokeh away from center

The mathematics involved was intense and Steve Jobs hadn’t invented the computer yet (cue comment section meltdown in 3, 2…) so Jozeph took advantage of what was available. Artillery was one area that used advanced mathematics such as trigonometry and logarithms, so Petzval went to General Archduke Ludwig, sworn enemy of all things French, and explained his plan to invade French optics. Ludwig ordered that eight cannoneers and three corporals be assigned to help Petzval with his calculations; basically giving Petzval a human parallel computer. Even with all that help, the calculations took six months.

At the end of that time, Petzval had developed mathematical formulas for field curvature (Petzval curvature) and certain aberrations, figured out some ways to correct them, and designed two lenses. The first, called the Petzval Portrait Lens, placed the aperture in the center of the lens and split one of the doublets, leaving an air space between. This allowed him to curve the elements separately, correcting Petzval curvature. The lens was amazingly sharp in the center, had an aperture of F3.6 or so, and had a soft hazy bokeh away from center.

Petzval Portrait Lens Diagram. Roger Cicala, 2021
A later (circa 1890) Petzval Portrait lens. Roger Cicala, 2020

Petzval contracted with Peter Wilhelm Friedrich von Voigtländer to manufacture this first lens so that he could enter it in the contest.

So, How’d That Work Out?

Surely, you’re wondering if Petzval’s brilliant mathematics, won out, right? Not so much. The Petzval Portrait lens was significantly faster (F3.6) and clearly sharper than Chevalier’s Photographe à Verres Combinés, and had more pleasing bokeh. But the French Society gave a Platinum medal and the prize to Chevalier, skipped over Gold, and awarded Petzval a Silver Medal as a participation trophy.

But photographers didn’t care about platinum medals; they didn’t like Chevalier’s lens and he sold very few. Petzval Portrait Lenses became THE lens every photographer had to have. To really rub it in, more Petzval lenses were sold in Paris, Chevalier’s hometown, than any other city on earth. Why Paris? Because Paris in the 1850s was one of the few places on earth where it was legal to print ‘artistic’ (pronounced ‘pornographic’) photographs. The “French Postcard” (so called because of its size; it was illegal to mail them) supported more photographers (including many of the early great ones) than all other image types combined.

Despite his lens’ success, Petzval also struck out financially. Petzval patented his lens, of course, and sold Voigtländer the rights to produce 600 of them to use in an all–metal one–piece camera Voigtländer had designed, sort of the 1845 equivalent of a point and shoot.

A replica of the original Voigtländer Daguerreotype camera. Exhibit in the Tekniska museet, Stockholm, Sweden. Daderot, CC0, via Wikimedia Commons

Voigtländer proceeded to make thousands of Petzval lenses, not just for his camera but for anyone’s camera. When Petzval sued him, Voigtländer packed up his factory and moved to Braunschweig (today this is in Germany, of course, but at the time it was an independent state) where Petzval’s patents were not in effect. Voigtländer sold almost 60,000 Petzval lenses without paying royalties and made a fortune. Petzval made almost nothing.

Petzval had designed a second lens, called the Dialyte. This was a landscape lens with smaller aperture but excellent edge–to–edge sharpness. In 1856, he went into business with another Austrian lensmaker, Carl Dietzler, to produce this lens, but Dietzler went bankrupt before the lens could be manufactured. In 1859, Petzval’s house was robbed. The only things stolen were his lens designs and all of his optical manuscripts. Voigtländer almost immediately began producing the Orthoskop, which was basically a carbon copy of the Dialyte, about that time. Coincidence? Petzval didn’t think so and was adamant that Voigtländer had burglarized his home, but he couldn’t prove it.

Peter Friedrich von Voigtländer, 1843, photograph by Johann Baptist Isenring. Image in public domain.

And Then…

Petzval did a lot of other stuff you may not know about. He designed better opera glasses, binoculars, and floodlights, as well as improving microscopes and refracting telescopes. He developed mirror lamps used in the projectors of the day (most of which also used Petzval lenses) and published the theory that heating certain solids until they glowed emitted far more light than simply burning gases – setting up the invention of the Lime Light.

In 1851, Doppler suggested to the Austrian Academy of Sciences that they hold their own contest for improvements in photography, like the French had done. Petzval vetoed the proposal, although we don’t know if it was because he disliked all things Doppler, he felt it was an infringement on his area, or it was just another example of Petzval being Petzval.

After the loss of his manuscripts in 1859, Petzval abandoned optics completely and never did any more work in the field. He moved into his abandoned monastery workshop and married his housekeeper. She died a few years later and Petzval retired from teaching and lived alone in the monastery until his death in 1891, with only his horse for a companion. The Petzval Glacier in Antarctica and Petzval Crater on the dark side of the moon are named for him. Somehow, the location of these tributes seems fitting.

Chevalier, meanwhile, continued his moderately successful optical business until his early death in 1859.

Voigtländer largely let his business run itself while he dabbled in Austrian and German politics until his death in 1878. Voigtländer Optics became a public company in 1898, then a division of Schering AG, and later a part of Zeiss. Zeiss eventually sold it to Rollei, which went bankrupt. Ringfoto and ALFO Marketing bought the Voigtländer name from Rollei’s bankruptcy proceedings and licensed the name to Japanese lensmaker Cosina who uses it to brand some of their lenses today.

Things have come full circle. Today’s Voigtländer lenses, just like those first Voigtländer lenses, are basically the Voigtländer name slapped on someone else’s good design.


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