Carl Zeiss (German: [kaʁl ˈtsaɪs]; 11 September 1816 – 3 December 1888) was a German scientist, lens maker, and business owner. In 1846, he started his business, which is still known as Zeiss today. He brought together skilled workers and scientists to change how optical instruments were made. His work with Ernst Abbe helped create new ways to make microscopes. To improve their research, they invited Otto Schott to join, who helped create better types of glass for lenses. The company of Carl Zeiss grew into one of the world's largest and most respected optical companies.
Birth and family
Carl’s father, Johann Gottfried August Zeiss (1785–1849), was born in Rastenberg, where his ancestors had worked as skilled workers for more than 100 years. August moved with his parents to Buttstädt, a small regional capital north of Weimar, where he married Johanna Antoinette Friederike Schmith (1786–1856). Carl Zeiss’s mother was related to Christiane Vulpius, the wife of Johann Wolfgang von Goethe.
August Zeiss later moved to Weimar, the capital of the grand duchy of Sachsen-Weimar-Eisenach, leaving the family business to his brothers. In Weimar, he became a respected decorator who made intricate designs using materials like mother-of-pearl, amber, and ivory. He met Karl Friedrich, the crown prince and later grand duke of Sachsen-Weimar-Eisenach (1783–1853), who was the successor to Carl August. The crown prince wanted to learn ornamental turning and chose August Zeiss as his teacher. Their friendship lasted for 40 years.
When a son was born to the Zeiss family on September 11, 1816, he was the fifth of six surviving children. The newborn was baptized in honor of his godfather, the crown prince, and his father, Carl Friedrich. Of August Zeiss’s siblings, three sisters and two brothers lived to adulthood. Before 1885, the family name was spelled Zeiß.
Education
At that time, higher education was the main way to improve one’s social standing. August Zeiss sent all three of his sons to a preparatory high school called the "Gymnasium" to prepare for university. The two older sons studied subjects like philology and history and later had successful careers in education. One of the sons, Carl, had an inguinal hernia that required him to wear a truss constantly. Because of this, a life focused on sitting and studying seemed difficult for him. Carl attended the Wilhelm Ernst Gymnasium in Weimar but left before finishing. He took a special exam to study specific subjects at the university, mainly the natural sciences.
Carl was interested in technical studies from an early age. He attended lectures at the grand ducal technical school in Weimar and decided to become an apprentice machinist. In 1834, he moved to Jena to work under Friedrich Körner, a skilled machinist and teacher at the University of Jena. Körner was well known for making instruments for Johann Wolfgang von Goethe, a famous scientist and writer. Carl stayed with Körner for four years as an apprentice. During the last two years, he also attended one mathematics or science course each semester at the university, as allowed by his Gymnasium certificate. He completed his apprenticeship in 1838 and left with a recommendation from Körner and a certificate of his studies.
During this time, steam engines and trains were exciting for young engineers. Carl focused on mechanical engineering during his travels from 1838 to 1845. He worked in Stuttgart, Darmstadt, Vienna, and Berlin. While in Darmstadt, he worked for Hektor Rössler, an instrument maker and machinist involved in optical tools and steam power. In Vienna, a major center for heavy machinery, he worked for Rollé und Schwilqué. He also attended Sunday lectures on mechanics at the Polytechnic Institute of Vienna and passed an exam there with high marks. In Berlin, he worked in a machinist’s shop.
Establishment of the workshop for precision machinery and optics. Early years in Jena.
After much thinking, Zeiss chose to return to his original studies with Körner, which focused on building experimental scientific tools. He set up his own business making precise machinery. Zeiss went back to Jena, a well-known city, to work again with Matthias Jacob Schleiden, a botanist who had first sparked his interest in optics and stressed the need for high-quality microscopes. His brother Eduard, who worked as a school director in Jena, kept him updated about changes in the city.
Starting his plan needed patience because of the government rules at the time. First, Zeiss needed a residence permit, which was easiest to get as a student. He enrolled in classes on math and chemistry in November 1845. He also worked as a technician in a private physiology institute, helping professors build tools. Even though Jena already had two instrument workshops, there was still plenty of work. One was run by Körner, and the other by Braunau, who had also studied under Körner.
On May 10, 1846, Zeiss applied to government offices in Weimar for permission to open a workshop in Jena. He argued that the growing need for scientific tools made it important for him to work in the city near university scientists. Despite support from respected professors, the government delayed the request. Zeiss had to take a written test in August and finally received permission in November to build and sell mechanical and optical tools and open a workshop in Jena. After paying a fee and taking an oath before Jena officials, everything was ready.
Zeiss opened his workshop on November 17, 1846, using 100 Talers he borrowed from his brother Eduard. His father later repaid the loan. By 1849, the workshop made a profit of 197 Talers from sales totaling 901 Talers. Zeiss worked alone at first, making and repairing many kinds of physical and chemical tools. Simple magnifying lenses were especially popular. He also sold eyeglasses, telescopes, microscopes, drawing tools, thermometers, barometers, balances, glassblowing tools, and other items bought from foreign suppliers in a small shop.
In 1847, Zeiss began making simple microscopes, which quickly became very successful. Compared to competitors like Vincent Chevalier in Paris, Simon Plössl in Vienna, or his mentor Körner, Zeiss’s microscopes were both cheaper and better. His design allowed users to focus by moving the column that held the optics, which was easier for dissecting microscopes.
Business grew so quickly that Zeiss hired an assistant and moved to a larger workshop by early 1847. On July 1, 1847, he took on his first apprentice, 17-year-old August Löber. Löber became a key worker, later sharing profits, and stayed with Zeiss until his death. In 1847, 27 simple microscopes were sold outside the grand duchy. Three difficult years followed, marked by poor harvests, business problems, and a revolution, but by 1850, Zeiss and his microscopes had gained enough reputation to receive an offer from the University of Greifswald in Prussia. The university’s instrument maker had moved, and several faculty members wanted Zeiss to replace him as curator of the physics collection with a salary of 200 Talers. The offer did not happen, however, because a powerful mathematician said the position should not be filled by a “foreigner.” Zeiss remained in Jena.
His sister Pauline managed the household in Jena until he married Bertha Schatter, the daughter of a pastor, on May 29, 1849. Bertha died giving birth to their first son in February 1850. Their son, Roderich, later joined his father in the family business. In May 1853, Zeiss married Ottilie Trinkler, the daughter of a school headmaster. They had one son, Karl Otto (1854–1925), and two daughters, Hedwig (1856–1935) and Sidonie (1861–1920).
Carl Zeiss as an employer
Zeiss managed his workshop with strict rules. Any microscopes made by apprentices that did not meet his high standards of accuracy were destroyed by him personally on the workshop anvil. Workers began their day at 6 AM and worked until 7 PM. They had a 15-minute break in the morning and a one-hour break at noon, resulting in an 11 ¾ hour workday. Even though the rules were strict, the workplace environment was positive. New workers were interviewed at Zeiss’s home over a glass of wine. Employees were often invited to the Zeiss family gardens for drinks and snacks. The workshop also paid for an annual outing to the hills in a hay wagon. By 1856, the longest-serving apprentice, Löber, earned three Talers per week, while other workers earned two and a half Talers.
Zeiss worked hard to improve his knowledge of precision machining and optics, which led to the creation of a large library of books. This library, called the machinist’s library, was available for workers to use for further learning.
As the company grew, the Zeiss health clinic was opened in 1875. This clinic provided free medical care and medication to employees. If a worker could not work, they received full pay for six weeks and half pay for another six weeks. These policies were ahead of similar laws introduced later by Otto von Bismarck in 1883. Employee morale at the Zeiss workshop remained consistently high.
Improvements of the microscope
In 1846, making microscopes was more like a craft and art than a factory process. Each worker built a complete microscope from start to finish, with no help from others. Early microscopes even had the maker’s name written on them. Only parts that took a long time to make, like the stage, were made in advance in small groups. The first changes toward dividing tasks happened in 1857, when Zeiss separated the work on lenses from the work on the metal parts of the microscope stand.
Matthias Jakob Schleiden had supported Zeiss since the company began, often spending time in the workshop. He encouraged Zeiss to focus on microscopes, which were important for studying cells and in high demand. Schleiden was interested because he studied cells himself. Because of this, the first simple microscopes made by Zeiss were improved over time. These microscopes were praised by Leopold Dippel, a respected scientist. The simple microscopes had lenses that could magnify 200 times for 5 Talers or 300 times for 8 Talers. These were the strongest possible for simple microscopes. To achieve higher magnification, compound microscopes were needed. Zeiss needed to expand his products to stay competitive.
Making compound microscopes required research, which Zeiss had planned for. He studied books about microscopes in his free time. He wanted to move away from old methods that used trial and error to match lenses. These old methods involved testing many lenses, changing their positions, and repeating the process until a usable lens was found. This process could not be perfectly repeated, so each lens was slightly different.
Zeiss was more of a skilled metalworker than an expert in lenses. This made him less limited by old methods and more open to new ideas. He decided to use math to design lenses, even though experts thought it was impossible. Earlier, Joseph von Fraunhofer had used math to make telescope lenses in 1819, and Josef Petzval had done the same for camera lenses in 1840. Zeiss studied math books but failed to learn the theory. He then asked Friedrich Wilhelm Barfuss, a math professor, for help. Barfuss had worked on Zeiss’s simple microscopes before. Their collaboration continued until Barfuss died, but it did not solve the problem of making compound microscopes.
Zeiss’s first compound microscopes were listed in his 1858 price list. These microscopes had a short body tube with a field lens and two eyepieces. They could be attached to the stand and used with double lenses from stands 1 through 5 to achieve higher magnification. A 120-power lens from a simple microscope could be used to make 300- or 600-power magnification.
Despite Schleiden’s support, these early compound microscopes were not a long-term solution. A similar design, called a Brücke’s Loupe, remained available for years. However, the original lenses were not as good as lenses made for compound microscopes. By 1861, Zeiss had created five new compound microscopes. The most expensive, costing 55 Talers, had a horseshoe-shaped stand, a popular design by Georg Oberhaeuser. Zeiss added a curved plate under the stage and a mirror that could move forward and sideways to create better lighting. Each microscope was made to order, allowing customers to choose lenses, eyepieces, and lighting.
The lenses for these new compound microscopes were still made using trial and error, but they were praised by Leopold Dippel. Dippel tested the best lenses, A, C, D, and F, and said they were as good as lenses from other makers. The D lens was compared favorably to lenses from Belthle and Hartnack, and the F lens was said to be nearly as good as expensive lenses from Hartnack. However, Zeiss knew his lenses could not match the quality of Hartnack’s water immersion lenses, which were still better. This was a problem because scientists needed the best possible tools for their work.
Collaboration with Ernst Abbe
To solve his problem, Zeiss returned to his original plans to design his objectives based on a calculated theoretical basis. He looked again for a partner and this time chose Ernst Abbe (1840–1905), an assistant professor at the university. The official partnership between Zeiss, who was 50 years old, and Abbe, who was 26 years old, began in July 1866. Their goal was to create a water immersion objective with the same level of detail as those made by Emil Hartnack.
A key step in making optics more efficiently was updating the workshop methods. This change faced some resistance from Löber and other workers who preferred traditional ways. The plan was to measure every property of each lens before building an objective, so the optical system could be made accurately. For example, the D objective had five lenses. Each lens was made of glass with a specific index of refraction, exact curvatures, a specific focal length, and precise spacing between parts. Löber had already studied one requirement by using glass reference gauges to compare lens surface curvatures through Newton’s rings. Fraunhofer had used the same method earlier, but it had been kept secret. Abbe built new tools to measure focal lengths and refractive indices. By 1869, the changes were clear. The microscopes looked similar to before, but more were produced with the same workers. Prices dropped by 25%.
Abbe then focused on calculating the designs for the objectives. Zeiss supported him fully, including helping from the most skilled worker in the workshop, August Löber. Despite this support, many challenges remained. It was not until 1872 that the work was completed. Abbe redesigned the existing A through F objectives for systematic production and added four new, larger aperture objectives labeled AA through DD. Most importantly, he created three water immersion objectives with resolution and image quality equal to those made by Hartnack, Gundlach, or other competitors. In catalog number 19, titled Microscopes and Microscopical Accessories, it was announced that, "The microscope systems presented here are all constructed based on the recent theoretical calculations of Professor Ernst Abbe of Jena." These microscopes were no longer outperformed by competitors. This was also shown in prices. In 1871, the best microscope cost 127 Taler, but by 1872, the top model cost 387 Taler. Despite the higher prices, business stayed strong, and the new objective system received praise at a conference of scientists and doctors in Leipzig.
Zeiss thanked Abbe for his work by offering him a generous profit-sharing agreement in the workshops and made him a partner in 1875. As a condition of this partnership, Abbe was required not to take on more responsibilities at the university. The optical calculations were considered the property of the company and could not be published, which went against Abbe’s original plans.
Expansion of the workshop into a major concern
On October 14, 1876, the company completed its 3,000th microscope. At that time, the company had 60 employees. That same year, Carl Zeiss’s son, Roderich, joined the company. He took on responsibilities related to business and management and became a partner in 1879. Roderich also helped design equipment used for taking microscopic photographs. Carl Zeiss continued to work at the company daily. In 1880, the University of Jena awarded Carl an honorary doctorate. This honor was recommended by Prof. Ernst Häckel, a long-time collaborator who was a zoologist.
Ernst Abbe encouraged the company to update its methods and grow larger. However, Carl Zeiss was more cautious because of past difficulties. Despite this, by the 1880s, the company began moving toward larger-scale operations.
By 1883, the company was experiencing strong business success. It published its 26th catalog as a hardcover book with pictures and 80 pages. The book was printed in 5,000 copies. Carl Zeiss, who was careful with money, required retailers to share the cost of three or four silver groschen per copy. The company’s London retailer, Baker, often ordered 40 or more lenses at a time. The company also started opening offices in different countries.
Optical glass
After solving the problem of creating objectives based on calculations from theory, one challenge remained: making suitable optical glass. At that time, optical glass was imported from England, France, or Switzerland, but it was not of high quality, could not be depended on to be available, had limited choices in optical features, and was not delivered quickly. The optical features of the glass varied between batches, and the available glass was not ideal for the features needed to improve microscope objectives.
Abbe and Zeiss believed that the quality of microscope objectives could be improved if glasses with specific features were available. However, such glasses did not exist. Zeiss supported Abbe’s theoretical work by using workshop resources to test his ideas with liquid-filled lens triplets in 1873, called polyop objectives. Liquid lens triplets were not a new idea; David Brewster described them in 1837. These lenses allowed access to optical features not found in glass, but they were too expensive and not practical for commercial use. These experiments proved that Abbe’s predictions were correct. Better optical corrections were possible. The 1872 series of objectives, including water immersion lenses, were as good as any made at the time. For the first time, these objectives were better than any produced elsewhere. This result showed the need to develop new types of glass.
Abbe discussed the problem of expanding glass features with major producers, but no progress was made. He continued searching for solutions. When chemist and glass technician Otto Schott contacted Abbe to ask for help analyzing new glass compositions, Zeiss and Abbe supported him. Schott was skilled at making small batches of high-quality experimental glass. He agreed to move to Jena to expand his work. After showing many successful experiments, Zeiss used his influence to get financial support from the Prussian government. Within two years of starting a glassworks in Jena, Zeiss, Abbe, and Schott could offer many well-characterized optical glasses with consistent composition and produced in large quantities. The company still operates today as Schott AG.
In the same publications announcing Schott’s glass products, Zeiss introduced a new set of objectives based on Abbe’s work. These apochromatic objectives were corrected to a higher standard than any existing lenses. They marked the success of a collaboration that lasted nearly two decades.
Later years and death
In December 1885, Carl Zeiss had a mild stroke but recovered completely. In 1886, the Grand Duke honored him by making him a member of the Order of the White Falcon for his 70th birthday. That same year, special lenses called apochromatic objectives became available. These lenses completed a long-term plan to create microscope lenses based on scientific theory, a plan Zeiss started and Abbe finished. These lenses produced images of higher quality than ever before. Russian doctors were so impressed by the lenses that they made Zeiss an honorary member of their group.
Zeiss attended a celebration on September 24, 1886, to mark the completion of the 10,000th microscope. All employees and their spouses were invited, and the event was a large and memorable party in Jena. Later, Zeiss’s health worsened. After several strokes in late 1888, he died on December 3, 1888. He is buried in Jena.
When reviewing Carl Zeiss’s contributions, it is clear that while he improved the mechanics of microscopes, he did not personally create major new inventions. His most important contributions were his strict focus on precision in his work and in the work of his employees, and his early collaboration with scientists who helped guide the design of microscopes.
Zeiss’s greatest contribution was his continued effort to create microscope lenses based on scientific theory, even after his own attempts and those of others failed. Although Abbe completed the task, Zeiss played a key role by inspiring Abbe’s interest in optics and providing Abbe with all the support needed for the project. High-quality lenses required skilled workers trained to achieve extreme precision, a goal Zeiss always prioritized.
Zeiss also helped transform a small workshop into a major company. This change allowed the mass production of microscopes with high precision. Ernst Abbe led the expansion, but Zeiss had the final decision and supported the effort fully. Other workshops that ignored scientific calculations and failed to grow as businesses eventually declined.
Ernst Abbe honored Carl Zeiss in speeches and established the Carl Zeiss Foundation, which continues to exist today.