The lens, the eye and perception
A useful ability when framing up a shot is having the experience to predict how a particular subject or view will translate into a twodimensional recorded image. A beginner without this skill may have to wander around the subject looking through the viewﬁnder at various set-ups, and with various choices of lens angle and camera distance, in order to see how these variables aﬀect the shot. Cameramen and directors often have the developed visual ability to mentally predict the eﬀect of mass, line and size relationships and how they will impact on the shot for any speciﬁc lens angle and camera position chosen. Viewpoint can be decided before a camera is taken out of its case. This is often called having a photographic eye and in one sense it is learning to see like a lens. How do we learn to see like a camera and why is it necessary? Composing a shot involves the translation of a three-dimensional
subject into a two-dimensional image. The eye and the lens are both used in this activity but the two imaging devices diﬀer in their interpretation. The lens of the eye focuses a two-dimensional image onto the retina
of the eye and somehow the mind interprets the image. That ‘somehow’ is known as perception and has a signiﬁcant inﬂuence on how an individual understands what he or she is looking at. There is always a subjective element in any individual’s interpretation of their senses. The lens of a camera focuses an image onto a recording medium but
it is not an objective scientiﬁc instrument precisely translating the ﬁeldof-view of the lens into an image. The conversion of the original subject into an image viewed on a screen is conditioned by what is chosen from a number of variables associated with the conversion at the moment of recording, and its later method of two-dimensional presentation. The variables include:
* the lens – fno, focal length, camera height, camera distance, etc.; * the recording medium characteristics – ﬁlm, tape and method of
processing; * detail and resolution of lens and recording/transmission medium; * colour rendition; * lighting conditions; * ﬁlters; * the image size when viewed; * viewing conditions; * the subjective inﬂuence of context; * cultural inﬂuences.