Where did lenses come from? Video tells the backstory!
posted Thursday, December 17, 2015 at 3:12 PM EDT
John Hess from Filmmaker IQ has made an excellent video detailing the history and science of lenses and glass, and we think it's a "must-see" for our ethusiast gear-heads out there.
The origins of modern camera lenses can actually be traced back to the Nimrud Lens, whose intended purpose remains a mystery, which is from 750-710 BC. In 424 BC, a burning glass (used to magnify light for starting fires) was mentioned in Aristophanes' play, The Clouds. As Hess discusses, our word, lens, actually comes from the Latin word for 'lentil,' "which is shaped like a double convex lens." It wasn't until the Middle Ages when Abu Ali Hasan Ibn Al-Haitham produced the research that led monks to create reading stones, which are pieces of polished glass that can magnify small text. In the 14th century, these advances in optics led to the creation of spectacles.
While being able to start fires and read small text is important, it wasn't until 1609 when the Galilean telescope was invented that glass was used to see very distant objects. Not long after, with some alteration of the glass used in his telescope, Galileo created the world's first microscope.
Hess then goes on to give an overview of how lenses actually work. For much more detail, be sure to watch the video below. For those of you like myself who are less scientifically-inclined, Hess does a great job of explaining how light and lenses work. Basically, curving the surface of glass (or in the case of Hess' video, gel wax) into a convex shape converges light. In fact, the distance from the lens at which light converges after passing through a convex piece of glass is what determines the focal length of your lenses. Hess then discusses, using diagrams and equations, how lenses focus on close and distant objects. By utilizing multiple lenses inside the focal length, including both convex and concave lenses, Hess shows how a zoom lens works. It is really neat to see an example of what is going on inside of your own lenses. Check out the video below to see Hess' detailed history and science of lenses.
So what about lenses specifically for photography? The first lenses used for photography were single element pieces of glass, which came with their own issues: chromatic aberration, spherical aberration, and coma aberration. By utilizing different kinds of glass in different shapes, the aberration issues were reduced. The first relatively fast lens wasn't made until 1840 when Joseph Petzval submitted an (eventually losing) idea to an international French competition that called for portrait lens submissions. The Petzval lens became the dominant portrait lens for nearly a century and actually still sees some use today.
In 1890, the scientifically-designed Zeiss Protar lens was released and was one of the first lenses to reduce all aberrations. Using barium oxide, the invention of Schott glass started a new wave of lens designs. As the number of elements in lenses continued to increase and aberrations decreased, lens makers focused their efforts on making faster lenses. The double Gauss lens was able to capture more light, but it suffered from issues with reflections. It wasn't until 1939 when Zeiss manufactured an artificial anti-reflective coating that the double Gauss lens design took off, and it's still used today in many popular 50mm lens designs.
To see how the massive influx of quality Japanese lenses came to fruition after World War II (and to see how they changed the naming conventions of lenses), be sure to watch the entire video above.
In an upcoming video, Filmmaker IQ will discuss the properties of modern lenses. After watching this comprehensive overview of the history and science of lenses, I can't wait to see it!
(Seen via DIY Photography)