Lenses and Lens Design History

Lens design is a complex business. All lenses aim to filter and focus light so that it hits the specified size of the sensor or film strip in the correct place. However, there are a variety of other factors that determine how a camera lens affects the look and quality of the final photo.

Each lens also has its own character as can be seen from the images on this site.

History of Photography Lenses

Photographic lenses have common origins with other types of lenses. The works of the Arabian scholar Alhazen show that the elementary prop­erties of biconvex lenses were known in the 13th century, and convex spectacle lenses were in­ vented before the end of that century.

Newton in 1666 gave the cause of chromatic aberration in such lenses and, believing the prob­lem insoluble. Limits on lens design together with a lack of film sensitivity led to exposure shutter speeds measured in minutes not seconds, necessitating headclamps and white powdered faces.

The early photographic experiments of Thomas Wedgwood, Nicéphore Niépce, Henry Fox Talbot, and Louis Daguerre all used simple single-element convex lenses. These lenses were found lacking. Simple lenses could not focus an image over a large flat film plane (field curvature) and suffered from other optical aberrations.

The very first camera lens, as we would know it today, was invented by the maker of the first camera, Charles Chevalier. In 1840, Chevalier developed the world’s first variable focus lens, specifically for portraiture.This was shortly after Louis Daguerre invented photography in 1839. Chevalier’s lens was an achromatic landscape lens — basically, a lens with two elements that reduce chromatic aberration.

Because the Achromat Landscape lens was quite slow, the French Society for the Encouragement of National Industry offered an international prize in 1840 for a faster one. Joseph Petzval (of modern Slovakia) was a mathematics professor with no optical physics experience, but, with the aid of several human computers of the Austro-Hungarian army, he took up the challenge of producing a lens fast enough for a daguerreotype portrait.

He came up with the Petzval Portrait (modern Austria) in 1840, a four-element lens consisting of a front-cemented achromat and a rear air-spaced achromat that, at f/3.6, was the first wide-aperture portrait lens.

In 1840 Josef Petzval introduced his design for a lens constructed by Voigtlander. This was an incredible aperture for its day, being some 20 times faster than contemporary designs. Petzval used two dissimilar air-spaced achromatic doub­lets, one cemented, the other air-spaced, with some resemblance to a Lister microscope objec­tive.

In the late 1890s, H. D. Taylor departed from Petzval lenses to tackle field curvature and aberrations in an analytical and scientific way. He showed that by splitting an achromatic doublet into two parts and further splitting the positive element into two parts and creating an air-space either side of the central negative element, the variables could be made just suffi­cient to correct the von Seidel aberrations. This, when manufactured by Cooke & Sons, was called the Cooke Triplet and was a further major advance, as well as being of low cost and simple to make. It was the first lens system that allowed elimination of most of the optical distortion or aberration at the outer edge of lenses. The initial aperture of f6.3 for a 50° field has increased to //2.8 with modern glasses.

The Cooke Triplet

The residual zonal SA was reduced by various derivatives produced by the process of compound­ ing and splitting one, two or even all three single elements.

Many now famous, classic designs started as a triplet. Compounding the rear element with the cemented surface curved towards the stop is a particularly effective design and is the basis of the Zeiss Tessar lens, designed by Rudolph in 1902 with f6.3 aperture as a develop­ment of his Protar lens. The Tessar design of aperture 7/3.5 or //2.8 in its modern form became the standard lens for cameras in many formats, cover­ ing a 60° field.

During the 1930s, cameras were becoming more and more common. No longer was the camera a tool used for portraiture or science but also for art so German scientists like Ludwig Bertele started producing the foundations of todays modern lenses.


Zeiss Tessar

Converting both front and rear elements into doublets gives the classic Voigtlander Heliar de­sign of 1902 and later Pentac of f2.9 aperture. Compounding of all three elements was tried, for example by Leitz in 1930 to give an //1.9 Hektor. Splitting the elements, such as in the symmetric­al Aviar of 1920, gave an excellent lens, related to the Celor type. But splitting and com­ pounding gave more scope and allowed very large aperture lenses in the 1920s and 1930s, important in early 35 mm photography.

An example of this is The Zeiss Sonnar design which still widely used. Its particular features are very thick elements, making it a heavy lens, but it is a compact design, not a telephoto, its rear nodal point being well forward in the lens. Correc­tion capabilities are excellent. Its early f/1.5 version was preferred to other designs as its six surfaces gave low flare in the days before lens coatings.

Sonnar

The Gauss type of achromatic doublet lens is a solution giving a less preferred, air-spaced configuration the double Gauss designs covering a 60° field; this was due to Rodenstock and Busch. Early designs included the Ross Homocentric and Meyer Aristostigmat. The outstanding feature was (and is) the flat field at moderate apertures and good correction even with old glass types. The design was dormant until the 1920s when Hollywood demanded a large-aperture, high- quality lens to use.

A further boost to large-aperture anastigmat designs was the advent of the Leica camera in 1925. Derivatives were produced by processes of compounding and splitting to use air gaps. All retaining the highly curved surfaces concave to the stop. Notable early designs were the Zeiss Biotar f1.5 and similar apertures by Leitz and Voigtlander.

Biotar

The design is still very viable, forming the basis for most large-aperture standard lenses, where six and seven elements are still required for f/2 and //1.4 respectively. High-index modern glasses are of great assistance.

Krasnogorski Mekhanicheskii Zavod (KMZ) was an optical company based out of Krasnogorsk, Russia, a western suburb of Moscow who would take over primary optics production for the Soviet Union during World War II. Prior to the war, the source of most of the Soviet Union’s optical and camera technology was from the FED factory (named after Felix E. Dzerzhinsky) in Kharkov, Ukraine.

Although the FED factory saw success, their location was vulnerable to attack from German forces at the beginning of the war. Anticipating this, the Soviet Union moved most of the FED machinery and staff to the KMZ plant deeper into the Soviet Union, making it much less likely to be attacked.

At the end of World War II, the Russians occupied East Germany. They left with the Biotar formula and many of the toolset. In 1945, KMZ would begin making photographic lenses based off designs from Zeiss-Ikon obtained by the red army during the war.

But it was not just the Russians who benefited after the war from the German lens designs. Some gGerman companies had been using cheap labour in Japan to make some of their lens elements. But during the war, the Japanese economy was also devastated. Afterward, during the U.S. occupation of Japan, billions of dollars were poured into the nation’s economy. With close to half of the country’s factories destroyed — and a large population of soldiers entering a workforce that did not have the jobs to support them — the Japanese turned themselves into a technological powerhouse and photographic equipment was high up on the list. The modern era of photographic lenses was born. Companies like Nikon, Olympus, Minolta started. Canon was an off-shoot of Nikon. And so, the Japanese came to dominate the camera as well as the lens market.

The photographic lens is still being developing to produce better imagery, based upon the traditional configurations. Evolution of the photographic lens builds upon this development ,but also use computerised ray tracing and design optimisation programs; optical glasses of various properties such as low-weight, high-index and low- dispersion; and other optical materials such as fluorite, aspheric surfaces, floating elements and multi-coating techniques.

Modern Canon RF Lens

Summary

Images here have been taken with a range of vintage (embracing imperfection) and modern (embracing technological perfections) lenses on mirrorless cameras.

We all know that the three primary variables in image making are aperture, shutter speed, and ISO.

But there is also:

• The photographic tools used
• The available subject matter
• Creativity

Part of creativity is to have a very open mind about these variables. In recent years emphasis has been placed upon the tools and pixel counting at the expense of creativity. Yes I have much of the latest photography technology but often creativity is assisted by the restrictions of the media used, not its sophistication. The imperfections lead to creativity. This section is only provided as a general introduction to the lenses used for the images on this site.

Hover over the menu item for example "images" in the top corner and then scroll and click on the lens of personal interest. Enjoy.



For more information read sections on Optical Design, Glass, Chromatic Errors, Perspective, Flare and Vignetting.