Focal length affects the perception of faces and bodies

Perception of our bodies and faces by others as attractive or unattractive influences our everyday lives. The vast majority of research in social perception uses photographs of faces and bodies, but the methodology for capturing these photos has not yet been unified and can greatly influence the results of these studies. However, it is not yet clear how camera and scene settings can affect social perception of people pictured. An important factor affecting the resulting photo is the focal length used, as shorter focal lengths create a so-called barrel distortion. That’s why we decided to conduct a methodological study and test how different focal lengths affect the perception of male and female faces and bodies in photographs.

In total, 45 people attended our study (22 women and 23 men). From each participant, 3 face photographs and 3 body photographs were taken under standardized shooting conditions and with the same camera settings (Nikon D90, Nikkor 18-135mm, F = 8; 1 / 100s) differing only in focal length. We used focal lengths equivalent to full-format lengths of 50 mm (fairly often used focal length, which is supposed to represent the focal length of the human eye), 85 mm and 105 mm (focal lengths recommended by professional photographers for taking photographs of people). The evaluators were then assigned to sort the three pictures of each woman with different focal lengths according to their femininity and attractiveness, photographs of men according to their masculinity and dominance (eg 1 – the least attractive, 2 – moderately attractive, 3 – the most attractive). Each characteristic was rated by 30 women and 30 men, with a total of 240 evaluators.

The results showed that photographs of women’s faces taken at a focal length of 50 mm were rated as the least feminine and the least attractive. For female body images, no effect, depending on the focal length, occurred. Photos of male faces and bodies were affected by focal length as follows: photographs taken at a focal length of 50 mm were rated the least masculine and least dominant; on the other hand, those taken at a focal length of 105 mm as the most masculine and dominant.

Our study points to the fact that the methodology of taking photographs may affect the results of individual studies; at least it may increase the risk of a second type of error (ie, false negative results – the effect of the ceiling or floor). According to our results, focal length affects the perception of female and male faces and male bodies. This effect is probably caused by varying degrees of distortion of proportions and shapes caused by different focal lengths. For this reason, it is important that the same focal length is maintained at least in the individual studies, and that the camera and scene settings are maintained.

Consensual configurations and composites of female and male images for the 50 mm, 85 mm and 105 mm focal lengths.

For more information please contact Vít Třebický (vit.trebicky@natur.cuni.cz) or Jitka Fialová (jitka.fialova@fhs.cuni.cz).