The Eras of Optics: A Tour Through the People Who Built the Field

I like “eras.” These are named chunks of time. I live in Japan, and we use the Common Era (CE) notation alongside the Japanese calendar — 令和 (Reiwa) 2019–present, 平成 (Heisei) 1989–2019, 昭和 (Showa) 1926–1989, 大正 (Taisho)1912–1926, and 明治 (Meiji) 1868–1912 for modern Japan. Each had its distinct flavor — we still sometimes refer to things having a “Showa feel,” or “that’s from the Taisho era.” Don’t worry, this is a post about optics, not Japanese calendar eras.

For this piece, I was thinking about eras in optics. And because optics has its own lineage, its own cast of characters, and its own vocabulary — the names on the aberrations we correct every day, the books on our shelves, the lens forms we reach for instinctively — it felt worth taking a proper tour.

This is that tour. It starts with the giants of optics broadly, narrows to the giants of lens design specifically, and ends with my own personal eras — how I got from a dusty film camera in my grandfather’s house to where I am now.

Let’s get into it.

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Part One: The Giants of Optics: A Tour Through the People Who Shaped How We See the World

If you’ve spent any time in optics, you’ve probably noticed that we stand on the shoulders of some seriously impressive people.

And I mean that literally — the equations, the instruments, the Nobel Prizes, the names attached to the aberrations we correct every day. All of it traces back to a surprisingly small number of people who, at various points in history, decided to figure out what light actually is and what it actually does.

So let’s take an eras tour of optics. Not an exhaustive one — we’d be here all week — but a highlights reel of the figures who moved the needle the most. (Yes, I called it an eras tour. My daughter is going to have opinions about that. But she doesn’t read this website, so here we are.)

1. The Ancients: Getting the Geometry Right

We have to start with Euclid (around 300 BCE), who wrote Optics — one of the earliest systematic treatments of how vision and light behave geometrically. Now, Euclid had the direction of light backwards (he thought vision worked by rays shooting out of the eyes), but the geometric framework he built was solid enough to influence optical thinking for over a thousand years.

The person who actually set the record straight was Ibn al-Haytham, known in the West as Alhazen, writing in the 11th century. His Book of Optics argued — correctly — that we see because light enters our eyes, not the other way around. More importantly, he backed it up with systematic experimentation. Alhazen is often called the father of modern optics, and honestly, the title fits.

2. Newton, Young, and the Nature of Light

Fast forward to the 17th century, and Isaac Newton enters the picture with a prism and a beam of sunlight. His demonstration that white light is made up of a full spectrum of colours — documented in Opticks — was a foundational moment for optical science. Newton was firmly in the “light is particles” camp, and his authority kept that view dominant for over a century.

Then Thomas Young came along in the early 19th century with his double-slit experiment, showing that light produces interference patterns — behaviour that only makes sense if light is a wave. This set up one of the great debates in physics, one that wouldn’t fully resolve until the 20th century.

3. The 19th–20th Century: Aberrations, Quantum Leaps, and Industrial Optics

Ernst Abbe deserves a paragraph of his own — or even a blog post of his own. Along with Carl Zeiss and Otto Schott, he was one of the three defining figures of industrial optics in the 19th century, building the theoretical and commercial foundation that made precision optical instruments possible.

On the physics side, Max Planck and Albert Einsteintransformed our understanding of light entirely. Einstein’s work on the photoelectric effect gave us hard evidence for the particle nature of light — and together with wave theory, this gave us wave-particle duality, the conceptual cornerstone of quantum optics.

Frits Zernike won the Nobel Prize in Physics in 1953 for inventing the phase-contrast microscope — a tool that lets us image transparent specimens (like living cells) without staining or killing them. If you’ve ever seen a live cell under a microscope, you have Zernike to thank. (His name also lives on in the Zernike polynomials that we use to describe wavefront aberrations — a double contribution.)

Dennis Gabor received the Nobel Prize for inventing holography. Yes, that holography.

4. The Laser Era: When Optics Changed Everything

The invention of the laser is one of those moments where you can point to a clear before and after.

Charles Hard Townes demonstrated the first maser at Columbia University — a microwave precursor to the laser that proved the underlying principle worked. Theodore Maiman then built the first actual laser in 1960, using a cylinder of synthetic ruby at Hughes Research Laboratories. From there, the floodgates opened.

Zhores Alferov — often called the father of the semiconductor laser — developed semiconductor heterostructures that made practical laser diodes possible. He shared the 2000 Nobel Prize with Herbert Kroemer for this work. If you use a laser pointer, a Blu-ray player, or fiber optic internet (and who doesn’t), you are living with the consequences of Alferov’s research every single day.

Roy Glauber rounded out the quantum optics picture, co-winning the 2005 Nobel Prize for his contributions to the quantum theory of optical coherence.

5. The Modern Era: Tweezers, Combs, and Ultrafast Light

Arthur Ashkin had a beautifully simple insight: light carries momentum, and that momentum can be used to physically push and trap tiny objects. He invented optical tweezers — tools that can grab and manipulate objects as small as individual atoms — and won the Nobel Prize in 2018 at the age of 96. (ninety-six! There’s hope for all of us.)

John Hall and Theodor Hänsch shared the 2005 Nobel Prize with Roy Glauber for the optical frequency comb — a technique that turns a pulsed laser into something like a ruler for measuring light frequencies with extraordinary precision. It underpins some of the most accurate clocks ever built.

And Andrew Weiner has been a luminary in ultrafast optics and quantum photonics — not just for the science, but for the way he brought people into the field through education and mentorship.

The Through-Line: Part One

What’s remarkable, looking at this list, is how often the same themes come up: someone questions the accepted model, does careful experiments, and changes what we think light is. Euclid to Alhazen. Newton to Young. Classical wave theory to quantum mechanics.

Optics keeps reinventing itself — and we’re still at it.

Looking at optics eras, I couldn’t help but narrow the focus considerably and look at the people who specifically built the vocabulary and methods of optical lens design. Spoiler: a lot of the action happened in Jena and Rochester.

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Part Two: The Giants of Lens Design: The People Who Built Our Vocabulary

In Part One, we took a wide-angle view (pun intended) of the people who shaped optics as a science. Alhazen, Newton, Abbe, Einstein, Zernike. This time, we’re zooming in — all the way into the specific world of optical lens design.

And what a world it is.

Because lens design has its own lineage, its own vocabulary, and its own cast of characters. When we talk about Petzval curvature, or reach for Rudolf Kingslake off the shelf, or open a SPIE Field Guide — we’re standing inside a tradition that was built, piece by piece, by a surprisingly small number of people over about 150 years.

Let’s meet them.

1. The 19th Century: Mathematics Meets Glass

The story starts with a mathematician who had no business designing lenses.

Joseph Petzval was a professor of mathematics in Vienna — not an optical physicist, not a glassmaker, just a very sharp mathematician who was handed a problem and solved it. His Petzval portrait lens, completed in 1840, was one of the first mathematically optimized lens designs in history, and it was fast enough to reduce photographic exposure times dramatically. Before Petzval, portrait photography required subjects to sit perfectly still for several minutes. After Petzval, it was seconds.

His name lives on in every lens designer’s vocabulary, of course — Petzval field curvature. The field aberration we’re always fighting. I have a section in my Ultimate Guide to Lens Design Forms post dedicated to the Petzval lens and my thoughts about Joseph. (I can call you Joseph, right?)

Around the same time, two designers on opposite sides of Europe arrived at virtually the same solution independently. John Henry Dallmeyer in London and Adolph Steinheil in Munich both produced symmetric four-element designs in 1866 — Dallmeyer’s Rapid-Rectilinear and Steinheil’s Aplanat — that corrected most aberrations to f/8. The fact that two people arrived at nearly identical designs simultaneously tells you something: the solution was almost inevitable once the problem was properly understood. For more on the evolution of the landscape lens, and the rapid-rectilinear, I have a post on that on my website.

Then came the design that changed everything about how we think about aberration correction. Harold Dennis Taylor, working as chief engineer at T. Cooke & Sons in York, patented the Cooke triplet in 1893 — and with it, effectively invented the modern lens design problem.

Taylor’s insight was elegant. Start with a cemented achromatic doublet of equal and opposite power — net power of zero, but a flat field. Now separate the elements. The air gap between them acts as an additional lens, giving the system positive power while preserving the flat-field characteristic. Split the positive element and place both halves on either side of the negative — and you have a three-element system capable of correcting all five Seidel aberrations simultaneously. Three pieces of glass. Five aberrations. It shouldn’t be possible, and yet there it is.

What makes the Cooke triplet so foundational isn’t just that it worked — it’s that it defined the design space that lens designers have been exploring ever since. The Ernostar is a modified triplet. The Tessar is a triplet with the rear element replaced by a cemented doublet. The Sonnar, in a sense, is Bertele’s answer to the triplet’s limitations. Every time we teach aberration theory and optimization to a new designer, we start with the triplet, because it has just enough degrees of freedom to be interesting and just few enough to be tractable. Kingslake, characteristically, noted that “there is no symmetry to help the designer, and there is no control over distortion” — which is exactly why it’s such a good teaching lens. The difficulty is the lesson.

T. Cooke & Sons were reluctant to manufacture their own engineer’s lens — possibly because of the difficulty in grinding the strong central negative element. The design was licensed to Taylor, Taylor and Hobson, who gave it the name it still carries today. If you’ve spent time on the lens design forms guide on this blog, you’ll know we give the Cooke triplet its own section — because it deserves it.

The person who really cracked the aberration problem wide open next was Paul Rudolph at Zeiss. His Protar lens was the first successful anastigmat — properly corrected for astigmatism, which had been the stubborn holdout. He then went on to design the Tessar and the Planar (Double Gauss). If those names sound familiar, it’s because they’re still foundational reference forms today. We covered both in the lens design forms guide, and if you haven’t read that yet, it’s worth a look.

2. The Early 20th Century: Theory Gets Serious

Ernst Abbe we already met in Part One, but he deserves a second mention here specifically for lens design. His theoretical framework for aberration correction and resolution limits gave Zeiss’s lens development program its scientific backbone. Zeiss without Abbe is unthinkable — which is why Jena still celebrates him today.

A slightly more unexpected entry in this era is Allvar Gullstrand, a Swedish ophthalmologist who won the Nobel Prize in Physiology or Medicine in 1911 for his work on the optics of the human eye. His scientific approach was then applied by Moritz von Rohr at Zeiss to calculate the first axially-symmetric eyeglass lenses that minimized blur when looking through the edges — marketed under the name PUNKTAL. It’s a lovely example of how eye science and lens design feed each other.

Ludwig Bertele is one of the most quietly consequential figures in the history of lens design — a designer’s designer whose name doesn’t always make it into the general optics history books, but whose fingerprints are on some of the most iconic lens forms ever made. One of my favourites, I have to say.

Bertele started young. He was working as an optics assistant at Rodenstock by 1916, at age 15. By 1919 he’d moved to Dresden to work for the Ernemann company, and that same year he began developing what would become the Ernostar — a modified Cooke triplet derivative aimed at dramatically increasing maximum aperture while keeping aberrations under control. He patented the Ernostar f/2 in 1923. The Ermanox camera, which was fitted with the Ernostar, became the first camera fast enough to photograph in natural light without staging the scene — photojournalism, in a real sense, was born from this lens.

Then in 1931, working now under Zeiss Ikon after the great German optical consolidation of 1926, Bertele introduced the Sonnar. The name comes from Sonne — German for sun. The Sonnar’s key innovation was reducing the number of air-glass interfaces by grouping elements into thick cemented groups, which meant less scatter and higher contrast. The f/2 Sonnar was followed a year later by an f/1.5 version for the Contax — extraordinarily fast for its era. We’ve covered the Sonnar in depth in the Double Gauss vs. Sonnar comparison post, and the two forms competed vigorously for the fast normal lens crown throughout the postwar period. (Spoiler: both are still alive and well.)

Around 1934, Bertele turned his attention to wide-angle design and created the Biogon — a symmetric configuration that set the template for compact wide-angle lenses for decades. And in 1935 he designed the Olympia Sonnar 180mm f/2.8 for the Berlin Olympics, which became one of the most celebrated telephoto lenses of the 20th century. What Bertele is known for is speed. Every major form he created pushed the boundary of what maximum aperture was achievable with practical image quality. In that sense, he was the original fast lens specialist — and we’re still living in the world he made.

3. Mid-to-Late 20th Century: The Canon Gets Written

This is where lens design as a discipline really consolidates — and a lot of it happens in one place: Rochester, New York.

Rudolf Kingslake is the towering figure. The American father of lens design, full stop. He was a founding faculty member of the Institute of Optics at the University of Rochester in 1929, and he kept teaching until 1983. Think about that for a moment — over five decades of teaching lens design, at the institution that arguably defines the field in the United States. Concurrently, from 1937, he headed the lens design department at Eastman Kodak until his retirement in 1969. He authored Lens Design Fundamentals, Optical System Design, and A History of the Photographic Lens, among others, and accumulated at least 70 scientific papers along the way.

Kingslake lived to 100. His wife, Hilda Conrady Kingslake, was also an optical researcher — and also lived to 100. Hilda’s father was A.E. Conrady, who wrote the magnum opus Applied Optics and Optical Design, which his own son-in-law completed after Conrady’s death. (I’ll let you guess who the son-in-law is.)

Warren J. Smith is the other name that comes up the moment you ask any working lens designer which books are on their shelf. Modern Optical Engineering, Modern Lens Design, Practical Optical System Layout — if you’ve been in this field for more than a week, you’ve reached for one of these. Smith had a gift for making the material genuinely usable rather than merely rigorous, which is harder than it sounds.

Walter Mandler is the lens designer most closely associated with the golden era of Leica — the person who, more than anyone else, defined what a Leica lens felt like in the postwar decades.

Mandler joined Ernst Leitz at Wetzlar in 1947, working alongside the veteran designer Max Berek. In 1952, when Leitz established Ernst Leitz Canada (ELCAN) in Midland, Ontario, Mandler was sent over for what was supposed to be a short posting. He stayed for over fifty years, became a Canadian citizen, eventually rose to Vice President of ELCAN, and earned his PhD in physics — summa cum laude — from Giessen University in 1979, with his doctoral dissertation centered on a novel method for optimizing Double Gauss designs by computer. He was simultaneously a bench designer and a theorist, which is a rarer combination than you might think.

Over his career, Mandler designed more than 45 Leica lenses across both the M and R systems. The Summicron 50mm f/2 (the 1974 version, still in production). The Noctilux 50mm f/1.0, the fastest lens for 35mm format for many years — designed in 1969 before computer optimization was even introduced at Leitz Canada. Let that sink in. The Summilux 75mm f/1.4, which Mandler himself named as his personal favourite. And dozens more, from retrofocus wide-angles to ultra-long telephotos for the US Navy.

His designs aren’t just optically excellent; they have a recognizable character — a specific rendering quality that photographers have argued about lovingly for decades. The best evidence that a designer’s work has genuinely stood the test of time? A Chinese lens company recently named itself after him and released a recreation of his Summicron 35mm f/2 at a fraction of the original cost. It sold out in hours.

We covered the Double Gauss — the form Mandler mastered — in the Sonnar comparison post, so if you want to see what made his approach so distinctive, that’s a good place to start.

4. The Japanese School: Precision Pushed to a New Level

While Zeiss and Rochester were defining the Western canon, a parallel tradition was quietly taking shape in Japan — and for me, two names stand above the rest. I’ll admit upfront that I’m partial here, given our history of lens design at Nikon, Canon, Olympus, Pentax, Konica, Minolta, and Ricoh. But partiality and accuracy aren’t mutually exclusive.

Zenji Wakimoto at Nippon Kogaku (now Nikon) was one of the great designer-inventors of the 20th century, and if his name is less well-known outside Japan than it deserves to be, that’s a gap worth closing.

His most celebrated achievement might be the Micro-NIKKOR C 5cm F3.5, developed in the early 1950s in collaboration with Professor Zyun Koana of the University of Tokyo and fellow designer Hideo Azuma. This was the lens that demonstrated — at an academic conference in the United States, to an audience that reportedly didn’t know what to make of it — that photographic lenses could resolve 100 lines/mm across the full frame at maximum aperture, with potential to push beyond 200 lines/mm under optimal conditions. The Nikon documentation on this lens puts it plainly: the three of them may have laid the technical groundwork for the IC fabrication optics that eventually made modern semiconductors possible. That’s not a small claim, and it’s hard to argue with.

But Wakimoto wasn’t just a micro lens designer. The NIKKOR-O 2.1cm f/4 introduced what Nikon’s own historians call the “Wakimoto type” — a symmetric wide-angle inner group arrangement that allowed a larger maximum aperture with less aberration than the competing Biogon approach. The principle was still being used at Nikon — and elsewhere — more than twenty years later. Good ideas age well. He also received Japan’s Emperor’s Purple Ribbon Medal for his work developing the Ultramicro-NIKKOR lenses used in IC fabrication.

Keizo Yamaji came up through Canon and left his mark on the field in an entirely different way: he solved the zoom lens problem.

But here’s what makes Yamaji’s story so compelling — he wasn’t originally an optical designer at all. He’d been aiming for theoretical physics, working on a unified theory of unsteady-state fluid dynamics, until his professor suddenly passed away in his third year at university and his entire laboratory collapsed with him. Rather than scramble for another physics position, he made a deliberate choice: find a company where physicists could stand at the core of technical activity, not just on the periphery. After visiting various companies, he concluded optics was the best fit — and spent his remaining university months cramming aberration theory before joining Canon.

He never stopped thinking like a physicist. And it shows.

In the autumn of 1956, Yamaji was assigned to design a zoom lens — a task that, at the time, had no proven mechanical compensation solution. Nobody had made a practical one. His approach was exactly what you’d expect from someone trained in theoretical physics: start from a basic three-group convex-concave-convex structure, systematically analyze what happens as you vary each element, map the entire family of solutions, and pick the one with the best performance potential. He described lens type selection as experience and intuition meeting art — “a lens suited to a purpose has a characteristic form, and its cross-section exhibits a certain beauty.” The optimization process, meanwhile, he compared to climbing multiple peaks in a multidimensional space simultaneously. If that sounds familiar, it’s because it’s exactly how we think about it today.

What came out of that process was the “Yamaji-type zoom” — a series of designs with no equivalent anywhere in the world at the time. His first completed design was a field zoom for outdoor TV broadcasting. Then came the one that made history: a zoom for 8mm cine cameras, delivering f/1.4 at a 4:1 zoom ratio. Canon packaged it into the “Zoom Eight” camera, and it sold far beyond anyone’s expectations — reportedly saving the company at a critical moment.

Yamaji eventually formalized his intuitions into a unified theory of zoom lens design — one that reduced the aberration design of complex zoom systems with moving groups to that of fixed lens groups, and even enabled prediction of zoom capabilities. Not content to just design lenses, he wrote the theory down. He then became President of Canon in 1989, making him one of the very few people on this entire list who went from the lens bench to the top floor of a major corporation (my contention on this is that Yamaji systematically patented all future lenses at Canon, thus publishing fewer works from Canon since he became president). His motto throughout: “stillness is retreat.”

5. The Contemporary Era: Passing It On

The most recent generation on this list is defined by two things: education, and raising the bar on what optical performance even means.

Julie Bentley and Craig Olson at the University of Rochester (Rochester again!) co-authored the SPIE Field Guide to Lens Design, which has become standard reading for practitioners entering the field. It’s compact, practical, and does exactly what a field guide should do. I’ll also mention John Greivenkamp and his SPIE Field Guide to Geometrical Opticshere — more optics than lens design, but essential reading.

Robert Fischer authored Optical System Design, which takes a deliberately accessible approach — written for a broader audience that includes program managers and mechanical engineers, not just optical designers. In a world where lens design increasingly happens in multidisciplinary teams, that matters.

Yoshiya Matsui is one of the great figures of Japanese lens design education — and if his name isn’t as widely known outside Japan as it deserves to be, the reason is partly that his most important work was written in Japanese.

Matsui spent his career at Canon, where he became a central figure in lens design and earned a reputation that colleagues described, without apparent exaggeration, as that of a “god” (神様) in the field. He authored two landmark books — *Lens Design Method* (レンズ設計法) and Aberration Theory (収差論) — that became foundational texts for generations of Japanese optical designers. His teaching style was characteristically Japanese in the best sense: he would listen carefully, let you finish explaining, identify the one key thing you’d missed — and leave you to work out the rest yourself.

Matsui also contributed directly to the optics of the Subaru Telescope — Japan’s 8.2-meter optical-infrared telescope on Mauna Kea — advising on the primary focus corrector system. The fact that one of Japan’s finest camera lens designers ended up contributing to one of the world’s largest astronomical telescopes says something about how deep and flexible his understanding of optics actually was. Aberration Theory was eventually translated into English and published in 1993 as Fundamentals of Practical Aberration Theory. If you haven’t come across it, it’s worth hunting down.

Herbert Gross is the person who finally wrote the book that the lens design field had been quietly needing for decades — and then kept going and wrote several more. Gross studied physics at the University of Stuttgart and joined Carl Zeiss in 1982, eventually heading the central optical design department from 1995. He received his PhD from Stuttgart in 1995, on the modeling of laser beam propagation — which tells you something about the range of his interests. His work at Zeiss spanned simulation methods, optical design software and algorithms, laser system modeling, physical optics, tolerancing, and system measurement. In other words, pretty much the full map of what a serious optical design department actually does.

What he’s most known for outside Zeiss is the Handbook of Optical Systems — a multi-volume reference published by Wiley that covers the field from first principles through advanced system design, aberration theory, image quality, tolerancing, and manufacturing. Before Gross, the field had Warren Smith and Kingslake and a handful of specialist texts. After Gross, it had something closer to a complete reference library in a single coherent framework.

He subsequently moved into academia, spending twelve years teaching and conducting research at the University of Jena — fitting, given that Jena is where so much of this story began. His more recent Lens Design for Imaging series continues that project of bridging the gap between rigorous theory and practical application that defines the best books in this field.

Peter Karbe is the living link in the Leica chain — the person carrying the torch that passed through Max Berek and Walter Mandler, and doing so in the era of sensors, computational optics, and tolerances that would have seemed implausible to earlier generations.

Karbe started out, unusually, as a trained photographer — formal apprenticeship in a small studio in Sundern, Germany, covering everything from portrait to still life. He came to optics through university, drawn to the mathematical and physical side of imaging, and eventually joined Leica where he rose to head of optics. It’s a rare background: someone who deeply understands what a lens is supposed to produce, not just how to calculate it.

His most celebrated designs are the APO-Summicron-M 50mm f/2 ASPH and the APO-Summicron-SL 75mm f/2 ASPH — lenses that set a new benchmark for apochromatic correction in 35mm format. Reviews from serious photographers tend to run out of adjectives fairly quickly. People who shoot with these lenses often describe an almost unsettling sharpness, as if something fundamental about what a photograph can look like has shifted.

What stands out when you read interviews with Karbe is the combination of rigor and humility. He consistently frames his own work as standing on the shoulders of the designers who came before — Berek, Mandler, and the long Wetzlar tradition — while pushing tolerances and correction levels that simply weren’t achievable in earlier eras. He’s described Leica’s approach as maintaining manufacturing tolerances incompatible with mass production: not a boast, but an honest description of the trade-off they’ve chosen to make.

The Through-Line: Part Two

Look at this list and two things jump out immediately.

First: Zeiss/Jena, Rochester, and Japan have produced a wildly disproportionate share of the people and ideas that define this field. Rudolph, Abbe, Bertele, and Gullstrand’s collaborator von Rohr all connect to the Zeiss ecosystem. Kingslake, Bentley, and Olson all connect to Rochester. Although I am extremely biased, Wakimoto, Yamaji, and Matsui represent a Japanese tradition that was running in parallel the whole time — and whose contributions to the semiconductor world may ultimately be the most consequential of all.

Second: every generation has had people who didn’t just design lenses — they wrote it down. Petzval had his mathematics (though sadly his work on the Petzval lens was later lost). Kingslake had his books. Smith had his shelf of references. Yamaji wrote the theory of zoom lenses. Matsui wrote the theory of aberrations in Japanese, and then had it translated so more people could use it. Gross wrote the handbook that covers all aspects of lens design. Bentley and Olson have their field guide. The field advances because people take the time to make knowledge transmissible.

Which, come to think of it, is not a bad reason to write a blog.

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Part Three: My Personal Eras in Lens Design

We’ve spanned millenia from Euclid and Ibn al-Haytham to Einstein and Kingslake. After writing about two eras in length, I had an idea. If I may be so bold: I have personal eras too, and I’d like to briefly tell you about them.

I’m going to skip the “toddler era” and the “mullet era.” You’re welcome. I promise to keep it optics-focused.

1. Innocent Photographer Era

My first interest in photography started with a film camera. My grandfather bought my mom a camera when I was born. By the time I was in high school, it was collecting dust — I took it out, loaded some film, and started shooting. It was a Pentax ME, autoexposure, with the standard kit 50mm f/1.4. Nothing special, but it was all I needed.

My first digital camera was a Sony Cybershot U10. I loved that camera. Limited battery, crummy lens, tiny sensor, but I took it everywhere. I didn’t think much about anything back then — I didn’t know anything about lenses, aberrations, or image quality. In a sense, I may have had a lot more fun back then.

2. Physics Grad Student Era

I did my MSc and PhD in physics. My MSc was in the electromagnetic response of semiconductors; my PhD was the photonic response of semiconductors. I learned how to tune lasers, set up mirror configurations, operate a CCD camera, and maintain a cryostat below 4 Kelvin. A lot of lessons, a lot of critical thinking — and the foundation for everything that came after.

3. Lens Designer Era

I started lens designing after graduating with my PhD, joining a small company that made plastic lenses. Since the company went from design to production entirely in-house, a fair amount of our products were designed on-site. I was one of six to eight lens designers who not only designed lenses on a PC, but organized metrology, prototyping, and mass production.

A short list of what I designed: telecommunication lenses, HMD prisms, headlamps, viewfinders, diffractive optics, laser beam printer scanner lenses, microlens diffusers, and MWIR optics. Zoom lenses weren’t something we typically designed — plastic lenses are mostly compact for imaging optics — but I designed telescopes, eyepieces, microscope objectives, zoom lenses, and various camera lenses for fun. Imaging lenses in Zemax; illumination systems in LightTools.

4. Pencil of Rays Era

I remember exactly what prompted me to start Pencil of Rays. I came across a website on organic chemistry, where the author helped med students with their MCAT. I thought: that is a niche of a niche — but the content was gripping and tailored precisely to the audience. I also loved my optics textbooks, but felt there was a disconnect between the content and what the books really wanted to do, which was to teach the world about optics.

Thus Pencil of Rays was born. On launch, I got 40 hits. Over 20 of them were mine, since I was checking if the pages worked. I posted links to Reddit and Quora, and slowly the ball got rolling.

Somewhere along the way, I developed a following — and built correspondences and friendships that span continents.

5. Software Era

I joined Zemax, then Ansys, and now Synopsys. My job has evolved over the years, but it is firmly in optics. I get to interact with the cutting edge of optics across a vast range of topics. Although I still maintain the website, my day-to-day has changed from manufacturing plastic lenses to developing solutions with the software.

Hopefully I have another era or two left in the tank.

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A Challenge for You

So, I have a challenge for you. Think about your own set of eras. What do they represent? Any pivot points? Where are the tentpoles?

I know there are a lot of students in my audience, and your eras are yet to come. But suffice to say: you are laying the foundation for it all, today.

I’d love to hear about your eras. Hit me an email — or leave a comment below — and let me know.

Happy lens designing.

—Kats