Portrait Mode: Depth Effects from Stereoscopic to Computational Photography [EN]

Brooke Belisle


The “depth effect” feature of the “portrait” mode available on many smartphone cameras has been
advertised as making it easier to take good photographs, helping the photographer to focus on what’s
important and eliminate distractions from the scene. “Depth effect” features work by relying on the dual, or
now often triple, apertures of contemporary cameraphones. The camera captures multiple exposures from
its multiple apertures, and algorithms compare relationships between pixels across the different ‘takes’ to
map multiple planes of depth. Object-recognition algorithms that have been taught to identify which pixels
of an image are a person’s face, and which other pixels might be ‘part’ of that person, associate the
‘subject’ of the photograph with a particular plane of the image. Image correction algorithms then adjust
the focus of the image to sharpen the plane of the subject and proportionally blur everything else. In
practice this means people show up as what matters, unique individuals against a general backdrop, the
world fading away around them.

In some ways, smartphone camera “depth effects” computationally reinvent 19th century stereoscopic
photography, which, notably, was not especially used for portraiture. People most often show up in
stereographs as figures in the distance (markers for scale) or as part of a theatrical tableau. When a person
is the explicit subject of a view, they are less often “portrayed” than displayed as a specimen, labeled as an
example of an ethnic type. The degree to which stereoscopic photography seemed fit or unfit for
portraiture communicates about the formal and phenomenological conditions of the encounter it seemed
to stage between the one looking, the one looked at, and the world they did or did not seem to share.

In this talk, I explore the relationship between portraiture and “depth effects” by comparing the practices
and possible implications of stereoscopic processes from two very different periods of photography. On
the one hand, the objectifying gaze associated with stereographic images seems to underwrite the
algorithmic processes that rationalize subject-object relationships in computational photography. On the
other hand, however, the way that stereographs stage a dynamic and embodied engagement in order to
even “see the image” as such may point out dimensions of visibility that need to be reasserted within the
shifted terms of algorithmic aesthetics.


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