847
——, “Photographs from Selected Casts in the Architectural
Museum” in The Architect, vol. 9, June 14, 1873.
LENSES: 1. 1830s–1850s
Technical and equipment
In 1812, William Hyde Wollaston showed that a positive
meniscus lens, used with the concave side facing the
object being viewed, signifi cantly fl attened curvature
of fi eld. Wollaston further fl attened curvature of fi eld
by placing a stop at a distance in front of the lens,
rather than directly in front, which had been the practice
beforehand. This introduced a slight amount of barrel
distortion.
Wollaston’s lens was used by Nicéphore Niépce in his
1820s–1830s experiments with light-sensitive asphal-
tum. Due to the low light sensitivity of the processes,
Niépce was forced to use the lens without a stop. He also
found that the Wollaston lens suffered from chromatic
aberration.
In 1833, Niépce’s successor, Louis Jacques Mandé
Daguerre, switched to an achromatic, positive meniscus
lens constructed by Charles Chevalier. At fi rst Daguerre
reversed the lens, so that the stop faced the sensitized
surface of the plate and convex side of the lens faced
the object being photographed. Using the lens in this
way, he hoped to take advantage of the condensed light
at the center of the image. By 1839, and the public
announcement of the daguerreotype process, he had
returned to using the lens with the concave side of the
lens facing the object being photographed and the stop in
front. This marked an achromatic return to Wollaston’s
original lens arrangement.
The fi rst camera marketed for Daguerre by Alphonse
Giroux contained a similar achromatic, positive menis-
cus element. Because the lens needed to be stopped down
to f/14 to obtain a fl at fi eld, portraits were impracticable
due to the long exposure times involved; however, the
lens was suitable for landscapes, architectural subjects,
and still-lifes. Chevalier was soon overwhelmed by the
demand for lenses, and an achromatic, plano-convex
lens was substituted by his optical rival, Noël-Paymal
Lerebours. Here the fl at side of the lens faced the object
being photographed.
By 1840, the public demand for photographic por-
traiture led opticians to attempt lens designs that could
be used at full aperture. Returning to a duplet telescope
he had designed 1834, in which two achromatic lens
elements were separated by an appreciable distance,
Chevalier modifi ed it to arrive at his Photographe à
verres combinés [Lens Made from Combined Glass].
For many years, this was the only lens capable of pro-
viding a fl at fi eld with whole-plate images when used
at full aperture. It also was the fi rst convertible lens,
meaning that the lens barrel could be taken apart and
the lens elements changed, depending on the subject
being viewed and the format size desired.
Chevalier’s lens was followed in 1840–1841 by an-
other portrait lens, designed by Josef Max Petzval and
marketed by the Voigtländer fi rm of Vienna. This lens
could also be used at full aperture and was eventually
achromatized, although the fi rst 720 examples remained
uncorrected for chromatic aberration. One difference it
had with the Chevalier lens was that it condensed light
at the center of the image. This provided for a shorter
exposure time and centralized focus, combined with a
gradual darkening of the borders of the image. More
analogous to the aesthetic of portrait miniatures, it
became an instant success with Daguerrian portraitists,
and since Petzval had failed to secure the property rights
to the lens, French and English opticians were free to
copy the design and offer competing versions.
Throughout the remainder of the 1840s–1850s,
photographic lenses generally divided into two classes:
landscape lenses and portrait lenses.
Landscape or single lenses were at fi rst identical to
the 1830s achromatic positive meniscus advanced by
Chevalier, with a stop being placed in front of the lens
element at a distance equal to one-fi fth of the lens focal
length. These took in a narrow fi eld of view and were
composed of two types of glass, fl int and crown, with
the softer fl int glass being located in front.
In 1854, J. H. Dallmeyer introduced a landscape lens
that consisted of three meniscus elements cemented
together to form an achromatic, positive meniscus
lens element. This took in a much wider fi eld of view,
coupled with a signifi cant amount of barrel distortion.
The placement of a harder crown glass in front protected
the lens from atmospheric pitting, to which previous
landscape lenses had been subject. In 1857, Grubb modi-
fi ed this to form a two component landscape lens, with
the crown glass in front and the fl int glass behind.
Portrait or double lenses were generally variants
of either the Chevalier or Petzval design. With the ex-
ception of Chevalier’s lens, portrait lenses during the
1840s–1850s took in a very narrow fi eld of view, and
due to problems with curvature of fi eld and astigmatism,
were not suitable for landscapes or architecture.
In 1857, Petzval introduced an improved version of
his portrait lens, based upon an unrealized 1840 design.
This consisted of an achromatic, negative meniscus lens
element in front and an achromatic, positive lens element
in the rear, thus forming an early telephoto lens. The lens
was capable of a fl at fi eld and even illumination, and was
intended for architectural subjects and two-dimensional
copy work. Introduced as the Photographischer Dialyt
[Dialytic Lens], with the stop located in front, it came
to be known as the Orthoscopic lens, with the stop being
later relocated in between the lens elements.LENSES: 1. 1830s–1850s