in three areas: coatings, aspheric geometry, and the
creation of compound assemblies. These advances
increased the power and utility of photographic lens-
es, leading to a diverse range of uses that has con-
tinued expanding into the twenty-first century.
Coatings minimize flare and other disruptions
caused by reflections within the lens assembly. The
basic lens is spherical and easily mass produced
because calibrating grinding equipment to a circular
form is relatively simple. Aspherical lenses often
offer superior performance to spherical lenses, but
they require sophisticated design and manufacturing
resources. Finally, photographic cameras require
compound lenses to serve the range of demands
placed by modern users. The item we commonly
denote as a ‘‘lens’’ is, in fact, an assemblage of con-
vex and concave lenses, bonded with cement and
mechanically calibrated to act in concert.
Modern lenses are highly specialized. Photogra-
phy services a range of disciplines: snapshots, jour-
nalism, advertising, prepress production, cinema,
television, photomicroscopy, astronomy, and aerial
surveillance from street level to satellite. Each of
these disciplines and their many subdisciplines
requires a specialized lens apparatus.
The spread of digital computers in the 1970s had
a major impact on lens production. For seven cen-
turies only a handful of organizations had the cap-
ability to produce superior products. Computers
allowed more entrants into the industry, and they
also supported complex manufacturing processes
that were previously difficult or impossible. Com-
bined with advances in materials science, specifically
the development of inexpensive and durable optical-
grade polymers, digital computers have contributed
to the spread of cameras in virtually every context.
Relentless progress has pushed the lens to the
point of invisibility while making its cost negligible.
In such a situation it is impossible to predict which
innovations will take hold, for instance the now
standard practice of including cameras in mobile
phones. While progress will continue in the estab-
lished photographic disciplines, the advent of cheap,
ubiquitous cameras, and their inclusion in a broad-
ening array of devices, will be the most dynamic area
of development in the coming century.
AliHossaini
Seealso:Camera: An Overview; Camera Obscura;
Camera: Pinhole; Depth of FieldFurther Reading
Gernsheim, Helmut, and Alison Gernsheim.The History of
Photography from the Earliest Use of the Camera Obscura
up to 1914. London: Oxford University Press, 1955.
Kemp, Martin.The Science of Art: Optical Themes in Wes-
tern Art from Brunelleschi to Seurat. New Haven, CT:
Yale University Press, 1990.
Ray, Sidney F.The Lens and All Its Jobs. New York: Focal
Press, 1977.
Singer, Charles, ed., et al.A History of Technology, Vol. III.
Oxford University Press: New York, 1958.
Wald, George. ‘‘Eye and Camera.’’ InScientific American
Reader. NY: Simon & Schuster, 1953, 555–68.i A History of Technology, Vol. III.Ed. Charles, Singer et
al. Oxford University Press: New York, 1958.
ii Gersheim 1969, p. 10.
iiiKemp 1990, p. 189.HELMAR LERSKI
Swiss-Polish
Helmar Lerski was among the most original repre-
sentatives of the avant-garde active between World
War I and World War II. He was a very important
link between Pictorialism and what was called
‘‘Neue Sehen’’ or New Vision on the one hand, and
between photography and film, on the other. Born
to Polish immigrants in Strasbourg, then part of
Germany, he came to photography only indirectly.
After receiving an education as a bank clerk in
Zurich, he immigrated to the United States, and
working part-time to make ends meet, eventually
established himself as an actor in German-speaking
theaters. In 1905, he published a book of aphorisms
about free love, a fashionable theme amid the con-
temporary criticisms of bourgeois institutions. This
was his only literary work. He learned photography
with the help of his first wife, Emilie Bertha Ross-
bach, who came from a family of photographers.LERSKI, HELMAR