1. Life
Carl Zeiss's life journey was marked by a strong foundation in craftsmanship and a continuous pursuit of knowledge, which laid the groundwork for his future innovations in optics.
1.1. Birth and Family
Carl Zeiss was born on September 11, 1816, in Weimar, the capital of the Grand Duchy of Saxe-Weimar-Eisenach. He was the fifth of six surviving children born to Johann Gottfried August Zeiss (1785-1849) and Johanna Antoinette Friederike Schmith (1786-1856). His father, August Zeiss, was a respected ornamental turner who crafted intricate lathe-turned works from materials like mother of pearl, amber, and ivory. August Zeiss had moved to Weimar from Buttstädt, where his forefathers had been artisans for over a century. He developed a close friendship with Crown Prince, and later Grand Duke, Karl Friedrich of Sachsen-Weimar-Eisenach, who became his ornamental turning student for 40 years. Carl was baptized in honor of his godfather, the crown prince, and his father, the archduke, receiving the name Carl Friedrich. Before 1885, the family name was spelled Zeiß.
1.2. Education and Training
Recognizing education as a path to social mobility, August Zeiss sent all three of his sons to the "Gymnasium," a university preparatory high school. While his two elder brothers pursued careers in philology and history, Carl's path was influenced by an inguinal hernia that required him to wear a truss, making a desk-bound scholarly life seem unsuitable. Carl attended the Wilhelm Ernst Gymnasium in Weimar but left early after passing a special exam that allowed him to study specific subjects at the university, primarily the natural sciences. He showed an early interest in technical studies, even attending lectures at the grand ducal technical school in Weimar, ultimately deciding to pursue an apprenticeship as a master machinist.
1.3. Early Career and Apprenticeship
In Easter of 1834, Carl Zeiss moved to Jena to begin a four-year apprenticeship under Friedrich Körner (1778-1847), the "Hofmechanikus" (court-appointed precision machinist) and private docent at the University of Jena. Körner was renowned for making and repairing instruments for the famous polymath Johann Wolfgang von Goethe. During his last two years as an apprentice, Zeiss also enrolled as a student at the university, attending one mathematics or science lecture course per semester, a right afforded by his gymnasium certificate. He completed his apprenticeship in 1838 and embarked on his journeyman years with strong recommendations from Körner and his university certificate.
From 1838 to 1845, Zeiss traveled extensively for professional development, working in various cities including Stuttgart, Darmstadt, Vienna, and Berlin. During this period, he focused on mechanical engineering, a field strongly influenced by the rise of steam engines and locomotives. He worked for Hektor Rössler, an instrument maker in Darmstadt involved in both optical/scientific instrument production and steam power. In Vienna, a hub for heavy machinery, he worked for Rollé und Schwilqué and attended Sunday lectures on popular mechanics at the Polytechnic Institute of Vienna, where he passed an exam with distinction. His travels concluded with work in a machinist's shop in Berlin.
2. Establishment of the Workshop and Early Business
Upon returning to Jena, Carl Zeiss embarked on his entrepreneurial journey, establishing a workshop that would become the foundation of his renowned optical enterprise.
2.1. Workshop Establishment and Early Operations
After careful consideration, Zeiss decided to return to Jena to establish himself as an independent maker of precision machinery, focusing on experimental scientific apparatus. He was particularly influenced by the botanist Matthias Jakob Schleiden, who had stimulated his initial interest in optics and emphasized the critical need for high-quality microscopes. His brother Eduard, who directed the local public school in Jena, also kept him informed about developments in the city.
The process of establishing his workshop required considerable patience due to the bureaucracy of the time. Zeiss first secured a residence permit by matriculating as a student in November 1845, attending lectures on mathematics and chemistry. He also worked as a technician for several professors at the private physiological institute, building various apparatuses. Despite the presence of two other instrument workshops in Jena (Körner's and Braunau's), there was ample demand for his skills.
On May 10, 1846, Zeiss formally applied to the government offices in Weimar for a concession to establish a machinist's atelier in Jena. He justified his request by citing the increasing demand for scientific apparatus and the importance of close association with university scientists. Despite recommendations from respected professors, the government proceeded slowly, requiring Zeiss to pass a written exam in August. Finally, in November 1846, he received his "concession for the construction and sale of mechanical and optical apparatus as well as the establishment of an atelier for precision machinery in Jena." After paying a fee and swearing an oath, everything was ready.
Zeiss officially opened his workshop on November 17, 1846, with an initial capital investment of 100 Taler, borrowed from his brother Eduard and later repaid by his father. Initially, Zeiss worked alone, constructing and repairing various physical and chemical apparatus. There was high demand for loupes cut from mirror blanks. He also sold eyeglasses, telescopes, microscopes, drawing instruments, thermometers, barometers, balances, and glassblowing accessories purchased from foreign suppliers in a small shop. By 1849, the workshop had earned a profit of 197 Taler on sales of 901 Taler.
2.2. Early Products and Business Growth
In 1847, Zeiss began manufacturing simple microscopes, which quickly achieved significant commercial success. These microscopes proved to be not only more affordable but also superior to those produced by competitors like Vincent Chevalier of Paris, Simon Plössl of Vienna, or even his former mentor Körner. A key improvement was Zeiss's method of focusing by moving the column carrying the optics, rather than the object stage, which was more convenient for dissecting microscopes.
The business thrived, allowing Zeiss to hire an assistant and move to a larger workshop by early 1847. On July 1, 1847, he took on his first apprentice, 17-year-old August Löber (1830-1912), who would become one of the most important workers in the Zeiss workshops, eventually becoming a profit-sharing partner and remaining with the company until his death. In 1847, a total of 27 simple microscopes were delivered to customers beyond the borders of the grand duchy. The following three years (1847-1850) were challenging, marked by poor harvests, business crises, and revolution, but by 1850, Zeiss and his microscopes had established a strong reputation. He received an attractive offer from the University of Greifswald in Prussia to fill a vacancy as curator of the physics cabinet with a salary of 200 Taler, but the offer fell through due to a mathematician's objection to a "foreigner" filling the position, keeping Zeiss in Jena.
On May 29, 1849, Carl Zeiss married Bertha Schatter (1827-1850), a pastor's daughter, with his sister Pauline having previously managed his household. Bertha died the following February while giving birth to their first son, Roderich, who survived and later joined his father in the family firm. In May 1853, Zeiss married Ottilie Trinkler, a headmaster's daughter, with whom he had another son, Karl Otto (1854-1925), and two daughters, Hedwig (1856-1935) and Sidonie (1861-1920).
3. Microscope Technology Development
Initially, microscope production in 1846 was more a handcraft than a manufacturing enterprise, with each worker producing an instrument from start to finish. Early examples were even signed by the maker. Only time-consuming assemblies, like the stage, were prepared in series. The first steps towards a more efficient division of labor were taken in 1857 when Zeiss separated the optics, managed by Löber, from the metalwork of the stand.
Matthias Jakob Schleiden, a botanist and interested patron, frequently spent hours at the workshops and advised Zeiss to focus on microscopes, which were crucial for the rapidly advancing science of cellular anatomy and in high demand due to Schleiden's own field of study. As a result, the simple microscopes produced were constantly improved and received favorable reviews from influential microscopist and botanist Leopold Dippel. The optics for these simple microscopes included a triplet with 200-fold magnification, priced at 5 Taler, and another with 300-fold magnification, for 8 Taler. These pushed the limits of simple microscopes, but greater magnification would require compound microscopes. Zeiss recognized the need to expand his offerings to remain competitive.
Production of compound microscopes necessitated extensive research. Zeiss, a self-taught scholar in his spare time, delved into all available literature on microscope theory. His primary goal was to move beyond the prevailing empirical methods of microscope production, which relied on trial-and-error matching of lens sets to create high-magnification compound lenses. This empirical approach involved examining dozens of lenses, repeatedly exchanging and altering elements and spacings until a usable lens was obtained, making exact reproduction difficult.
Being more a fine machinist than a traditional optician, Zeiss was less constrained by conventional methods and more open to innovation. He decided to pursue the design of microscope optics through theoretical calculation, a feat considered impossible by many experts at the time. Despite this skepticism, Joseph von Fraunhofer had already produced telescope objectives by calculation in 1819, and Joseph Petzval had done the same for camera objectives in 1840. Zeiss attempted to acquire the necessary theory through his evening studies but, failing to do so, turned to Friedrich Wilhelm Barfuss, a Jena mathematics professor who had previously worked with Körner and successfully on Zeiss's simple microscope triplets. This collaboration continued until Barfuss's death but did not yield progress on the compound microscope problem.
Zeiss's first compound microscopes appeared in his 5th price list in 1858. These were described as a "Small body tube, consisting of a field lens and two oculars with an adaptor to attach the tube to the stand and doublet objectives of stands 1 through 5 to allow use of the doublets as objectives to obtain two stronger magnifications after the fashion of the compound microscope. The 120 power doublet of the simple microscope yields in this fashion 300 and 600 fold magnification." While approved by Schleiden, these improvised compound microscopes were not a long-term solution. By the publication of his 7th price list in August 1861, five different versions of newly developed compound microscopes were offered. The largest, costing 55 Taler, featured a horseshoe foot stand, popularized by Parisian microscope maker Georg Oberhaeuser. Zeiss introduced a domed aperture plate and a movable mirror under the object stage, allowing for oblique illumination. Each microscope suite was custom-produced, allowing customers to choose their preferred optical components.
The objectives for these new compound microscopes were still empirically designed but immediately received approval from Leopold Dippel. Dippel highly praised their optical quality, particularly objectives A, C, D, and F. The D objective compared very favorably with similar power objectives from Belthle and Hartnack (Oberhaeuser's successor), and the F objective was deemed almost as good as Hartnack's more expensive water immersion objectives. However, "almost as good" was a commercial disadvantage when selling to leading researchers, and Zeiss knew his strongest objectives could not match Hartnack's water immersion objectives. All attempts to empirically design a satisfactory water immersion objective had failed.
4. Collaboration with Ernst Abbe
To overcome the limitations of empirical design, Zeiss returned to his original plan of designing objectives based on theoretical calculations. He renewed his search for a collaborator and chose Ernst Abbe (1840-1905), a private docent (associate professor) at the university. Their official collaboration began in July 1866, with the ambitious goal of creating a water immersion objective with resolution equal to those of Emil Hartnack.
A crucial first step in the rational production of optics was the modernization of workshop methods. This faced some resistance from long-term employees like Löber, who preferred traditional techniques. The new approach involved precisely measuring every individual property of each lens element-such as refractive index, exact curvatures, focal length, and spacings-before constructing an objective, to allow for precise reproduction of the optical system. Löber had already explored using glass reference gauges to compare lens surface curvatures based on Newton's rings, a technique independently discovered by Joseph von Fraunhofer but kept as a trade secret. Abbe further developed this by constructing a series of new measuring apparatus for focal lengths and refractive indices. By 1869, these efforts yielded clear results: while the microscopes' appearance remained largely unchanged, the rationalization of the workflow allowed for more microscopes to be produced with the same personnel, leading to a 25% reduction in prices.
With the workshop modernized, Abbe proceeded with the core task of calculating theoretical objective designs. Zeiss provided him with extensive support from the workshop, including the assistance of August Löber. Despite this, the work was challenging, and it was not until 1872 that it was completed. Abbe recalculated the existing A through F objectives for systematic production and introduced four new, larger aperture objectives (AA through DD). Most importantly, he developed three water immersion objectives whose resolution and image quality equaled or surpassed anything available from competitors like Hartnack or Gundlach. Catalog number 19, "Microscopes and Microscopical Accessories," proudly announced that "The microscope systems presented here are all constructed on the basis on the recent theoretical calculations of Professor Ernst Abbe of Jena." For the first time, Zeiss's objectives were unsurpassed by any competitor. This superior quality was reflected in the prices; the best microscope, which cost 127 Taler in 1871, was priced at 387 Taler in 1872. Despite the higher cost, business remained brisk, and the new objective system received high praise at a conference of natural scientists and physicians in Leipzig.
In recognition of Abbe's monumental contributions, Zeiss offered him a generous profit-sharing arrangement in the workshops and made him a partner in 1875. A condition of Abbe's financial participation was that he would not expand his responsibilities at the university further. The optical calculations were specifically regarded as the firm's property and were not to be published, which initially contradicted Abbe's own plans.
5. Optical Glass Development
After successfully producing objectives based on theoretical calculations, a significant challenge remained: the availability of suitable optical glass. At the time, optical glass was primarily obtained from England, France, or Switzerland, and its quality, reliable availability, selection of optical properties, and prompt delivery left much to be desired. The optical properties were inconsistent between batches, and, crucially, the available glasses were not ideal for achieving the best corrections in microscope objectives as calculated by Abbe.
Abbe and Zeiss were convinced that the optical qualities of microscope objectives could be further improved if glasses with specific, desired properties could be obtained. Unfortunately, such glasses did not exist. Zeiss once again supported Abbe's theoretical work by providing workshop resources. By 1873, they were producing experimental objectives using liquids in lens triplets, known as polyop objectives, to test Abbe's theories. While liquid lens triplets were not a new idea (described by David Brewster in his 1837 "Treatise on the Microscope"), they allowed access to optical properties not achievable with existing glasses. Although these experiments were expensive and not commercially viable, they proved Abbe's prediction that superior optical corrections were indeed possible. The 1872 series of objectives by Abbe and Zeiss, including the water immersion objectives, were already as good as any made at the time, and for the first time, these objectives were better than anything made anywhere. This result provided a compelling argument for the development of new types of optical glass.
Abbe discussed the problem of expanding the range of properties of optical glasses with major producers but without success. He continued to search for a solution. Zeiss and Abbe responded enthusiastically when Otto Schott, a chemist and glass technician, contacted Abbe seeking help in characterizing new chemical compositions in glasses. Schott possessed unique skills in producing small batches of high-quality experimental glass compositions. He was persuaded to move to Jena and expand his experiments. After demonstrating dozens of successful experiments, Zeiss leveraged his credibility and connections to secure financial support from the Prussian government for their efforts. Within two years of establishing a glassworks in Jena, Zeiss, Abbe, and Schott were able to offer dozens of well-characterized optical glasses with repeatable compositions and on a large scale. This firm still operates today as Schott AG.
Concurrently with the announcement of the Schott glassworks' product line, Zeiss introduced a new set of objectives, based on Abbe's work, corrected to a higher standard than any existing lenses. These apochromatic objectives represented the culmination of almost two decades of collaborative effort, achieving previously unknown image quality.
6. Development of Photographic Lenses
The company's commitment to optical innovation extended beyond microscopes. In 1886, Carl Zeiss welcomed Paul Rudolph, a talented mathematician, to the company. Rudolph's expertise marked the beginning of Carl Zeiss's strategic expansion into the production of high-quality lenses for cameras, a response to the rapid technological advancements in photography. This move diversified the company's product offerings and cemented its reputation in the broader field of optics.
7. Carl Zeiss as an Employer
Carl Zeiss managed his workshop with a strict, yet progressive, paternalistic approach. He maintained exceptionally high standards of precision; any microscopes produced by apprentices that failed to meet his exacting criteria were personally destroyed by Zeiss on the workshop anvil. The working hours were long, from 6 AM to 7 PM, with a 15-minute mid-morning break and an hour-long midday break, resulting in an 11.75-hour workday.
Despite these strict rules, the working environment in the shop was notably positive. New recruits were extensively interviewed by Zeiss in his home over a glass of wine, fostering a personal connection. Workers were often invited to the gardens of the Zeiss home for wine and refreshments, and the workshop even covered the cost of a yearly outing to the hills in a hay wagon. His longest-serving apprentice, August Löber, earned 3 Taler per week by 1856, while other workers earned 2.5 Taler.
Zeiss's dedication to improving his employees' knowledge was evident in the substantial library of books he accumulated on precision machining and optics. This collection became the machinist's library, freely available for the further education of any worker. As the firm expanded, Zeiss established a health clinic by 1875, which guaranteed employees free treatment by a clinic doctor and free access to medication. If a worker was unable to work due to illness, wages were paid for six weeks, followed by another six weeks at half wages. These forward-thinking policies predated Otto von Bismarck's state welfare laws, which were introduced in 1883, demonstrating Zeiss's commitment to employee welfare and contributing to consistently high worker morale.
8. Company Expansion and Growth
The workshop's transformation into a major industrial enterprise was a gradual but significant process. On October 14, 1876, the completion of the 3,000th microscope was celebrated, by which time the staff had grown to 60 employees. That same year, Zeiss's son, Roderich, joined the firm, taking on commercial and administrative duties and becoming a partner in 1879. Roderich also made important contributions to the design of microphotographic apparatus. Carl Zeiss himself remained actively involved in the firm on a daily basis. In recognition of his contributions, Carl was awarded an honorary doctorate by the faculty of the University of Jena in 1880, at the recommendation of the zoologist Professor Ernst Haeckel, a long-term collaborator.
While Ernst Abbe encouraged the modernization and enlargement of the firm, Zeiss remained somewhat more conservative, influenced by the many setbacks he had experienced throughout his career. Nevertheless, by the 1880s, the transition to large-scale operations was well underway. By 1883, the firm enjoyed solid business success. It published its Catalog No. 26 as an illustrated and bound 80-page volume, with an edition of 5,000 copies. The always thrifty Zeiss required retailers to share the cost of three or four silver groschen per copy. The firm's retailer in London, Baker, frequently ordered 40 or more objectives at a time, indicating strong international demand. The company also began opening field offices both within Germany and abroad, further expanding its reach.
Following Carl Zeiss's death, Ernst Abbe took the lead in reorganizing the company. In 1889, Abbe established the Carl Zeiss Foundation, which became the sole owner of the Carl Zeiss company and the Schott Glassworks. This unique foundation model ensured the company's long-term stability and its commitment to scientific research and social welfare, continuing to operate to this day.
9. Later Years and Death
In December 1885, Carl Zeiss suffered a mild stroke, from which he made a full recovery. In 1886, the same year the groundbreaking apochromatic objectives were introduced to the market, the Grand Duke enrolled him in the Order of the White Falcon for his 70th birthday. These apochromatic objectives represented the final realization of the grand design for the theoretical design of objectives, a vision inspired and made possible by Zeiss and brought to fruition by Abbe. They delivered previously unknown image quality, so much so that the members of the congress of Russian physicians were inspired to make Zeiss an honorary member.
Zeiss was able to attend the celebration on September 24, 1886, marking the completion of the 10,000th microscope, an event to which all employees and their spouses were invited. It was a lavish party that was remembered in Jena for decades. Carl Zeiss's health rapidly declined after this, and following several strokes in the final quarter of 1888, he died on December 3, 1888. He is buried in Jena.
10. Legacy and Impact
Carl Zeiss's enduring contributions to the fields of optics and scientific instrumentation are profound, fundamentally reshaping the production of optical instruments. While he did not personally introduce groundbreaking innovations in the mechanics of the microscope, his critical contributions lay in his unwavering insistence on the greatest precision in his own work and in the products of his employees. He also maintained close contacts with scientists from the very beginning, gaining valuable insights that guided the design of his microscopes.
Zeiss's greatest legacy stems from his steadfast pursuit of the idea to produce microscope objectives based on theoretical calculations, even when his own initial efforts and those of Barfuss had failed. Although the final theoretical task was accomplished by Ernst Abbe, Zeiss is credited with awakening Abbe's interest in optics and providing every conceivable personal, material, and financial support for this enormous undertaking. The production of objectives based on theoretical design was only possible with highly skilled artisans trained to work with the highest possible precision, an emphasis Zeiss had always championed.
A final, significant accomplishment was his guidance in the internal reorganization and transformation of his workshop from a small atelier into a major industrial enterprise. This transformation enabled the mass production of microscopes with the highest precision. Although Ernst Abbe was the driving force behind much of this expansion, Zeiss had the final say and provided his full support. Competing workshops that did not embrace the calculation of optical systems and the transition to large-scale operations were ultimately unable to compete and failed.
Ernst Abbe recognized and honored Carl Zeiss's contributions in several major speeches. Most notably, Abbe created a lasting memorial through the foundation of the Carl Zeiss Foundation (Carl-Zeiss-StiftungGerman), which still endures today. This foundation ensures the continued success and ethical operation of the Carl Zeiss company, which has achieved a worldwide reputation for manufacturing optical equipment for all types of devices, including high-quality lenses for cameras after their invention. The FC Carl Zeiss Jena football club is also named after him.