Frontiere della visualità: la stenoscopia

The pinhole camera is a device made up of three essential elements to take a photographic shot: a hollow volume hermetically impermeable to light (the camera body), a small hole (the lens) and a photosensitive support (the film). These three elements reproduce an optical-projective scheme similar to human vision (pupil, bulb and retina) and linear perspective. After years of oblivion, just when digital has almost definitively supplanted analog photography, stenoscopy has developed again; this is confirmed by the growing number of enthusiasts and the numerous initiatives dedicated to it. Shooting an image with a pinhole camera requires a series of operations (choice of framing, positioning of the device, evaluation of exposure times, composition of the image through targets) which can be summarized in the ancient expression ‘desired view’, which has always been associated with Renaissance perspective; a search for the image expressed through that patient construction that the ease of use of digital devices leads to neglect. For this reason, stenoscopy can be considered a frontier of visual experimentation, in which the final image derives from a series of weighted and closely interdependent choices, even if the outcome is never completely predictable. This article summarizes a visual research path carried out using a pinhole camera with a lens (hole) of 0.3 mm in diameter and a focal length of 45 mm. The camera takes medium format film; the camera body has removable partitions inside, which allow you to obtain negatives of 45 x 60 mm (portrait), 60 x 60 mm (square) and 90 x 60 mm (landscape). In addition to the sensitivity of the film and the lighting of the scene, shutter speeds depend on the aperture ratio. The vertical angle of view of the framed space occurs through a triangular target placed on one side of the camera, while the horizontal angle through three targets (depending on whether the camera has been set for portrait, square or landscape format) placed on the top cover. Here we present three different projects referring to as many fields of application: documentation of the architectural heritage, studies on the static and dynamic elements of the urban scene, multiple shots. The three projects represented the starting point for the development of as many didactic experiences, carried out with the students of an Architectural Drawing course at the Mediterranea University of Reggio Calabria. The perfect correspondence between stenoscopy and perspective makes the pinhole camera an ideal device for teaching, also valuable from the point of view of learning projective mechanisms; moreover, thanks to the control of all the phases of image definition (including the construction of the camera), the course proved to be able to excite the participants in the study of photographic technique.