Figure 1 – Susse Frére camera in the collection of the Westlicht Photography Museum in Vienna, Austria. From the Wikipedia, image by Liudmila & Nelson and put into the public domain without restrictions.

Today I’d like to pick up on the story of the earliest cameras’s. The great french physicist François Arago revealed publicly the details of the daguerreotype process on August 19, 1839. Daguerre was a business man determined, much like technology entrepreneurs of today, to make a public success of his process. Two months earlier he had signed contracts with two manufacturers, Alphonse Giroux and Maison Susse Frères.  Both of the manufacturers were granted exclusive rights to sell the modified  camera obscura designed by Daguerre.  Today only one Susse Frères daguerreotype camera, made in 1839, remains, or at least is known to remain, and is on display in the camera museum of the WestLicht auction house in Vienna, Austria. It is shown in Figure 1. The cameras made by the Alphonse Giroux et Compagnie, are almost identical.

The brass-mounted lens was produced by optician Charles Chevalier. It contains an 81 mm diameter meniscus achromatic doublet, (concave surface facing the front) and has a 382 mm focal length. In front of the lens is a  fixed 27 mm diameter aperture and a manual picoting brass shutter.  As a result the lens is approximately f/14.

The Giroux camera sold for 400 francs and the Susse Frères cameras for 350 francs. What does this translate to? There is a delightful link that describes the cost of things in Daumier’s time. It tells us that in 1838 the monthly salary of an unskilled laborer was 30 francs. Today we are told that is about $3,200. So we can estimate these early camera’s to have cost the equivalent of something on the order of $40,000!

Figure 1 – Viking aspheric Visby Lens (11th to 12th century). From the Wikimedia Commons originally posted to Flickr.com, by Jonund and is licensed under the Creative Commons Attribution-Share Alike 2.0 Generic license.

Yesterday, I discussed the mystery of Layard’s Nimrud Stone and sided with the British Museum’s view that it was a decorative object rather than either a magnifying glass or a burning stone.  It should be noted that the view that it was possibly a functional lens was voiced by none other than the great Victorian physicist Sir David Brewster (1781-1868).  Even if the British Museum is correct and the Nimrud stone never served as a functional lens, the question remains whether there were functional lenses in the ancient world or asked differently, when was the lens invented?

The answer is “absolutely,” as this quote from Aristophanes’ “The Clouds” proves.

STREPSIADES I have found a very clever way to annul that conviction; you will admit that much yourself.

SOCRATES  What is it?

STREPSIADES Have you ever seen a beautiful, transparent stone at the druggists’,with which you may kindle fire?

SOCRATES You mean a crystal lens.

STREPSIADES That’s right. Well, now if I placed myself with this stone in the sun and a long way off from the clerk, while he was writing out the conviction, I could make all the wax, upon which the words were written, melt.

SOCRATES Well thought out, by the Graces!

Now “The Clouds” was first performed in 423 BCE; so the fifth century BCE, which is not really all that far from the Nimrud Stone wthat dates back to the seventh century BCE. And you can see by Aristophanes’ words that it is a pretty common place object in his day.  Of course, you are skeptical of the name lens. Why call it a lens? The word lens comes from Lens culinaris the Latin name of the lentil, because a double-convex lens is lentil-shaped. The lentil plant also gives its name to a geometric figure. So Aristophanes is our earliest written record of lenses.

Some have argued that lenses were well-known to the ancient world.The writings of Pliny the Elder (23–79) show that burning-glasses were used by the Romans and also mentions how the emperor Nero (37-58) used a concave emerald as a corrective lens to help him watch gladiatorial games.

As we move into the eleventh and twelfth centuries ACE the use of lenses becomes well documented. Figure 1 is an example of a quartz lens excavated in the Viking harbor town of Fröjel, Gotland, Sweden 1999. These “Visby lenses” appear to have been produced turning on pole lathes. The lens of Figure 1 is encased in a beautiful silver mount, which may have been created later. These 11th to 12th century objects have imaging quality comparable to aspheric leneses produced in the 1950s.

Aspheric lenses are lenses that correct by shape for spherical aberration. That is a pretty sophisticated and some complicated mathematics is required to derive the required shape. But herein lies another marvelous paradox. The Viking craftsmen didn’t have knowledge of the mathematics needed, instead they worked by trial and error. Indeed, we may ask whether more than one craftsman actually possessed this knowledge. In any event it is a beautiful example of so-called “secret knowledge.” Perhaps most intriguing is the fact, a reverse on the paradox, that today when an optical engineer wants to design a complicated lens, (s)he uses Monte Carlo-based software. These programs are the modern day equivalent of trial and error.

Plus ça change, plus c’est la même chose.

Figure 1 – The Nimrud or Layard’s lens in the British Museum. What was its purpose? Image from the Wikipedia and uploaded by user Geni under Creative Commons Attribution-Share Alike license https://commons.wikimedia.org/wiki/File:Nimrud_lens_British_Museum.jpg.

It is an interesting point that the critical “invention” of photography was the development of the photochemical process. That is, because of the development of the camera obscura many centuries earlier, the “camera” itself was developed before the process. Indeed, it may be solidly argued that the concept that you could create a miniaturized or demagnified image of what you were looking at was a well-established fact as was the fact that light can react with materials, such as the bleaching of book binding exposed to too much sun. Neither of these rise as obvious, but rather each had to be discovered and refined through observation and experimentation.

This said, it has to be the case that while it was invented and developed much earlier than the photographic process, the camera too did not spring forth fully born from the brow of Zeus. Over the next few weeks, I’d like to explore some of the history of the camera. It seems a good point to begin with the mystery of the Nimrud or Layard’s lens. This object is shown in Figure 1 and is a mystery fit for Sherlock Holmes, and while it has an answer, we will never know it for sure. What is it?

The name of Austen Henry Layard (1817 – 1894) is one that raises the hairs on the necks of antiquaries. He was an archaeologist and cuneiformist, best known for his excavation of ancient Assyrian ruins at Nimrud and of Niniveh. Significantly, in 1851 at Niniveh he uncovered the library of Ashurbanipal. We should note that the Assyrian king Shalmaneser I (1274 BCE–1245 BCE) built Nimrud and that it remained occupied until 610 BCE.

Layard’s Nimrud lens, is a 3000-year-old piece of rock crystal or quartz, which was excavated by Layard in the Assyrian palace of Nimrud, in modern-day Iraq. Obviously, it looks very much like a magnifying glass. But the mystery of what it was used for remains unanswered. Was it indeed a magnifying glass? Was it perhaps a burning-glass used to start fires? Or was it merely decorative?

The lens is currently on display at the British Museum in London. It is slightly oval and appears to have been roughly ground. It has a diameter of ~ 38 mm and a thickness of ~ 23 mm with a focal length of about 12 cm (so ~ f/3.0)  and is approximately equivalent to a 3 X magnifier. It is very imperfect as a focusing or imaging device and as a result the British Museum believes that the lens was merely decorative. They point out that there is no evidence that the lens was used either as a lens for magnification or as a burning glass.

There you have a straight-forward scientific mystery complete with a likely, albeit disappointing, solution. However, there are those that subscribe to the view that the ancients were more intelligent than we or, at least, than we give them credit for. This is a curious phenomenon, and you have to wonder whether it reflects a keen observation of current events leading to the view that we are an incredibly stupid species and must have been smarter once. In any event, conjecture has run simply from the suggestion that Layard’s lens was used to aid in fine detail writing or decoration to the fanciful belief that the ancient Assyrian’s invented the telescope – two and a half millennia before Galileo. The fact that the god Saturn was often depicted surrounded by rings of serpents has been taken as evidence of this view. For us, it would appear unlikely that Layard’s lens is an ancestor of the modern camera lens. But the mystery remains. We must look elsewhere for the camera lens’ origin.