A light tent is a three dimensional enclosure constructed from a lightweight frame over which a translucent white fabric or diffusion material is stretched, creating a hollow tent like structure into which small to medium sized objects can be placed for photography. By surrounding the subject on all sides with a continuous, seamless surface of diffusing material, the light tent transforms any light sources positioned outside it into a large, soft, and virtually shadowless illumination that wraps evenly around the subject from multiple directions simultaneously, eliminating the harsh specular reflections and hotspots that make highly reflective subjects notoriously difficult to photograph successfully under direct or undiffused lighting.
The fundamental optical principle behind the light tent is the same as that governing any large diffused light source - the larger the light source relative to the subject, the softer and more wrapping the quality of illumination it produces, with shadows that are more gradual in transition and reduced in intensity. By effectively making the entire surrounding environment into a single continuous diffused light source, the light tent takes this principle to its logical conclusion, creating an illumination environment in which reflective surfaces on the subject reflect only the uniform white interior of the tent rather than the distracting and unpredictable reflections of the camera, the photographer, the studio surroundings, or the light sources themselves.
Light tents are particularly valued in product, commercial, and still life photography, where highly polished, chromed, lacquered, or otherwise reflective subjects such as jewellery, glassware, silverware, electronic products, automotive parts, and similar items must be photographed with clean, controlled reflections and accurate colour rendition. The even, shadowless illumination produced within a light tent allows the true form, surface quality, and colour of such objects to be recorded faithfully and attractively without the visual distractions that uncontrolled reflections would introduce.
Light tents are available commercially in a range of sizes from small desktop versions suitable for jewellery and small product photography through to larger structures capable of accommodating bigger objects. They can also be constructed inexpensively from basic materials including wire frames, white fabric, tracing paper, or purpose made diffusion material. The camera is typically positioned outside the tent shooting through a small opening or a translucent panel in the front face, and two or more light sources are placed outside the tent on either side and above to provide even, balanced illumination through the diffusing walls. A plain white, black, or coloured background card or sweep is placed inside the tent beneath the subject to provide a clean, uncluttered background for the finished image.