105 mm lens

Subjects were photographed under standard conditions afforded by the Bench HeadScan (Orion Concept™, Tours, France), using a Nikon™ D300 digital camera fitted with a Nikon™ 105 mm lens (200 ISO sensitivity, 1/60 second exposure time, minimum aperture f/32). For each subject, a set of three photographs was obtained: one front-full face and two others from 45° left and right sides vis à vis the nose axis and all were asked to adopt the most neutral expression during the photographic shootings. Pictures were further blind-coded and used for further zooming/focusing on some facial signs of interest, i.e. apt at being graded by 15 trained experts and dermatologists, using specific scales of severity (see below).
In addition to standard photographic shootings, a magnifying imaging instrument Dermascore^® (Monaderm™, Monaco) was used to image the homogeneity of facial pigmentation (cheeks), under crossed polarized light. This instrument allows to attribute different grades of severity (0–5) of this skin feature.23 ,24 (link)

Volunteers were photographed under standard conditions afforded by the Bench HeadScan (Orion Concept) using a Nikon D300 digital camera fitted with a Nikon 105 mm lens (200 ISO sensitivity, 1/60 second exposure time, minimum aperture f/32). For each subject, a set of three photographs was obtained: one front, full-face and two others from 45° left and right sides from the nose axis.
During photographic shots, all subjects wore a white cotton cap to cover their head hair, to avoid its possible influence (volume and color) during the scoring phases of clinical signs and the assessment of a perceived apparent age from full-face photographs.