James Clerk Maxwell – the man who changed everything

Today, we commemorate the life and work of James Clerk Maxwell, the Scottish mathematical physicist who died on this day in 1879.

James Clerk Maxwell, 13 June 1831 – 5 November 1879
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While most people will have heard of arguably the two most prominent physicists of all time – Isaac Newton and Albert Einstein – far less are likely to recognise the name of the third person on the list: James Clerk Maxwell. Maxwell, who formulated classical electromagnetic theory, has been hailed as the 19th century scientist whose work had the greatest influence on 20th century physics, and Einstein described it as the “most profound and the most fruitful that physics has experienced since the time of Newton.”

What makes Maxwell’s electromagnetic theory so important is that it is one of the great unifying theories in physics, combining the fields of electricity, magnetism and optics into a single, consistent theory. He showed that electric fields and magnetic fields both travel as waves, and they travel at the speed of light. This led him to postulate that light, electricity and magnetism behave the same, and can be described through the same equations and theories. In his own words, “We can scarcely avoid the conclusion that light consists in the transverse undulations of the same medium which is the cause of electric and magnetic phenomena,” and “The agreement of the results seems to show that light and magnetism are affections of the same substance, and that light is an electromagnetic disturbance propagated through the field according to electromagnetic laws.”

Maxwell’s electromagnetic theory has been reduced down to four fundamental differential equations, known as ‘Maxwell’s Equations’, first presented in his book “A Treatise on Electricity and Magnetism” (1873).

Another contribution by the great man, possibly less grand than his electromagnetic theory, but fundamentally important in its own way, came in the field of colour and optics. His theory of colour vision made a key contribution to colour photography.

Thanks to Maxwell we now understand that a colour image can be split into red, green and blue channels, and that the full colour image can be recreated by combining these channels.
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Maxwell was the first to show that a colour image can be created by photographing the same subject through red, green and blue filters, and then projecting the three resultant images through the same colour filters onto a screen. This showed that the additive primary colours are red, green and blue and not red, yellow and blue, as was previously assumed. It introduced the principle of additive colour synthesis used to this day in colour displays.

So here’s to Scotsman extraordinaire James Clerk Maxwell, one of the greatest minds of modern times and, to paraphrase his biography, ‘the man who changed everything’.

Celebrating the legacy of Carl Zeiss

Today we celebrate one of the great names in optics – it’s the birthday of Carl Zeiss, born on 11 September 1816.

Zeiss studied mathematics, physics and optics, among other subjects, at the University of Jena, before he started experimenting with making lenses. By 1847 he founded Carl Zeiss AG and started manufacturing microscopes full time.

Carl Zeiss built the Zeiss empire through the manufacture of innovative, high quality optics for use in microscopy.
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Zeiss real contribution came from his realisation that, to differentiate himself from other manufacturers in the optics industry, he had to significantly up the ante in terms of quality and innovation. He first teamed up with the physicist Dr Ernst Abbe, who calculated that the optical quality of lenses at the time left much room for improvement, but also found that the optical glass available was not up to his manufacturing requirements. Zeiss then brought on board glass chemist Dr Otto Schott, who established a glassworks at Jena where he produced new, better quality glass that was able to meet and exceed Abbe’s requirements.

While the lenses produced by Zeiss were initially primarily used in the manufacture of microscopes, the glass produced at Jena also opened up possibilities for the creation of much improved photographic lenses, for use in still and video cameras. Zeiss’ early innovations in photographic lenses happened mostly through the contributions of Dr Paul Rudolph, who was responsible for many classic Zeiss lenses around the end of the 19th century including the famous Planar® in 1896. Later famous Zeiss lenses included the Tessar® (1902) and the Sonnar® (1931). In 1935, Alexander Smakula developed an innovative anti-reflective coating for camera lenses, known as the Carl Zeiss T-coating, which opened up totally new possibilities in lens design, and is a key component in modern photographic lens design.

Even though much of the photographic contributions made by the Carl Zeiss AG company only happened after the death of its founder (Carl Zeiss died on 3 December 1888), his name will always be inextricably linked to top quality photographic optics. Zeiss lenses were used extensively in the cameras manufactured by Zeiss Ikon, one of the companies in the Zeiss group, who started producing the classic Contax cameras in the mid-20th century. The Contax rangefinder was the first 35mm camera to pose a serious challenge to the iconic Leica M-series of the time.

Zeiss lenses have been used by many of the great camera brands, including Voigtlander, Hasselblad, Rollei and Sony.

Even in the 21st century, the name Carl Zeiss remains synonymous with quality optics, and brands sporting Zeiss lenses proudly flaunt the fact.
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Aside from microscopy and photography, the optical innovations created by Carl Zeiss and his company have found a use in a wide range of applications, from medical solutions to sports optics to industrial metrology.