Distortionless Lenses - Text 1
From a practical perspective, the properties that most clearly defined cinema lenses in the early twentieth century were:
- a lack of distortion across the surface of a recording medium and
- the speed of the lens (meaning the lens could capture images of motion under conditions of “low” light).
These categories became most clearly standardized during the large-scale systematization of cinema’s technological infrastructure in the 1920s.[1] But, prior to this aggressive period of standardization, lenses were infrequently classified or defined as “cinema lenses.” More often than not, lenses that were used for motion pictures were described by companies of as part of a broader continuum of lens-based technologies.
It is wrong to begin the history of cinema lenses in 1920s Hollywood; it is also wrong to define lenses from the late nineteenth and early twentieth century as “prototype” or “primitive” lenses that had not yet reached their cinematic telos. Yet, many of the catalogues and writings surrounding optical history promoted these corporate mythologies.
To help understand lenses in their historical context, this section provides a general overview of a lens quality that was central to discussions around optical design: distortion. Distortion lay at the core of many industrial discussions about lens development and improvement, and the desire for a distortionless image in different recording mediums – from glass plates to flexible emulsion – drove a great deal of optical development.
Distorted Lenses
Prior to 1890, most lenses could be fast or they could be distortionless at a photographic field of view – but rarely both, and certainly not at a mass scale of production. The property of distortion was particularly important to scientists who sought to use instruments as a means of improving knowledge about the world.
There were two kinds of distortion that were particularly consequential for photographic imagery. The first is chromatic aberration, where different colors of light reached a recording medium, like celluloid film or a collodion plate, at different points. Rather than appearing as a rainbow, the difference between where certain light hit a plane would result in fuzzy or haloed images. The second is spherical aberration, where image focus was clear in the image center but increasingly softer at the edges of the film.
