Distortionless Lenses - Text 2
Early optical design was an art of finding ways to counterbalance different kinds of distortion. For example, a lens might control for chromatic aberration, but maintain a very soft focus around the edges of a plate (making it effective for portraits, but not landscape shots). Or, a landscape lens might control for both chromatic and spherical aberration, but require a significantly extended period of exposure to capture an image on a recording medium.
Distortionless Lenses
With the exception of the original Zeiss Anastigmat (which will be discussed in a later section), an anastigmatic lens is not a technical lens design that defines a particular arrangement of optical elements. Anastigmatic is a “class” of lenses that simultaneously corrected chromatic aberration and spherical aberration. Prior to anastigmatic lens designs, most lenses could correct for chromatic aberration or spherical aberration – but rarely both. Photography had been practiced for decades prior to Zeiss’ mass production of the anastigmats in the 1890s. The significance of the anastigmatic lenses, at least in regards to early cinema, was that these lenses worked very well at the speeds required to record images on flexible film stocks while correcting both forms of distortion.
To record images on flexible celluloid film stock, practitioners needed fast lenses that could capture distortionless images at quick exposure speeds – a practical feat that anastigmats were particularly suited to in comparison to other lens designs. As McKay suggests in the 1927 Handbook of Motion Picture Photography:
The lens used with the motion camera may be any photographic lens, but in practical work, the choice is limited to a great extent. The motion picture lens must be an anastigmat. The anastigmat is the only lens which will give the critical definition all over the frame which will stand the 288 times linear enlargement which is not uncommon.[2]
A historical view suggests that anastigmatic lenses were far from the defining factor that led to the emergence of cinema, particularly when considering the wide range of screen practice traditions and visual culture that compose the broader cultural and technological ecosystem of early cinema. Yet, the pursuit of distortionless lenses was central to the way that opticians, advertisers, and trade press writers both imagined and engineered the development of lenses in the late nineteenth and early twentieth century. The pursuit of this ideal is one that continues to shape how motion pictures and visual documentation are part of a broader imagination of technologically mediated vision.
As the capture of motion pictures rose in the early twentieth century, lenses would eventually come to be designed for cinematic practice. But lenses suited to cinematic practice were not initially designed with cinema in mind. Rather, the history of optics was strongly influenced by the history of microscopy.
