Part of the wonderful mystery and allure of photography, for me, is its complex and miraculous marriage of science and art. In a sense, all arts are made possible by science: the sound waves of any instruments as well as the psychology of their perception, and the way that light bounces off paints of different sorts is a matter of science (chemistry and physics). However, even though I also play the guitar and so deeply and greatly love the instrument and the art of music, I cannot think of an art form that is more intimately connected with science than photography. In fact, science, for a photographer, is his/her paintbrush, or his/her finger picks: it is by science that a photographer moulds, shapes, and applies light as a painter strokes paint onto a canvas, or as a musician connects his chords into a melody.

Misconceptions in science, thus, can limit a photographer in his/her style and application of the art. Henry Peach Robinson, around the 1890's, opposed the revolutionary Dr. Peter Henry Emerson, on the science of the human eye. Robinson purported that "healthy human eyes never saw any part of a scene out of focus" (Robert Leggat, http://www.rleggat.com/photohistory/history/emerson.htm, last updated 1999). This was the classical view at the time and widely accepted, except by a few revolutionaries. Emerson, perhaps the foremost of such revolutionaries, sought to dispel Robinson's conception of human vision. Emerson proposed that human eye can only focus on a certain area within its range, and that photography should mimic the reality of human sensation and perception. His ideas were adopted only by a few of his contemporaries, while the rest shunned him, as popular art of any form has always done, at first, with large-scale revolutionaries. However, Emerson published some influential works that simply could not be denied, and eventually science caught up to him and proved him right.

The human eye cannot see everything in focus. The anatomy of the eye is so that the majority of the eyes "detail receptors," or rods, are concentrated in the center of the retina, which is where the inverted image falls on the eye and the light energy is finally transduced into an electrical signal that the brain can understand and interpret. The outer portion of the retina holds a less concentrated number of rods, and thus is not as "clear" as that portion in the center where there are plenty of hungry receptor sites. Therefore, Emerson was quite right in his assertions.

The technique in which one continually and cumulatively blurs the image from a circumference around the center towards the outside of the frame is called vignetting. To achieve this effect in this shot, I employed a spot-in colour filter using my Cokin filter system mounted on my 50mm 1.8 Nikkor lens, as well as an 81b cooling filter. I approached the horse slowly, who did not seem to care at all about my presence, and took this photograph from the appropriate distance. It seems a fantasy to look upon the horse, which seems almost certainly to be missing the horn that would otherwise confirm one is staring at a unicorn.

For information and diagrams on the anatomy of the human eye, its components, their individual functions, and the functions as a group, visit http://www.accessexcellence.org/AE/AEC/CC/vision_background.html.

For more information on vignetting, visit http://photonotes.org/cgi-bin/entry.pl?id=Vignetting.