Science Can Help You Fix Your Terrible Selfies

You've probably heard the phrase "the camera adds 10 pounds." You might be surprised to learn it's kind of true.

Obviously, the camera can't make you physically heavier. But in the accompanying video, we experimented with zoom and distance to show how lenses of different focal lengths can change the way you look. By moving the camera a little bit farther away on each shot while changing the focal length by zooming in, we were able to stretch the subject's face - as if someone was pulling their nose.

To understand how this startling effect works, first you need to understand a little bit about lenses. Camera lenses bend and focus light rays so that they converge at a single focus point on a sensor. A lens' focal length is the distance from the centre of the lens to the focus point, when the lens is focused at infinity - which means that distant objects are in focus.

The camera lens that you attach to your DSLR camera is composed of a series of internal lenses designed to focus light that bounces off a subject into a clear image on a camera sensor. Shorter focal length lenses provide a larger field of view and lower magnification than longer focal length lenses, which magnify and narrow the field of view. Optical zoom lenses allow a photographer to change the focal length of the camera lens without removing and replacing the lens. In a zoom lens, multiple lenses move within the housing to adjust the focal length.

The effect is especially apparent in a famous film effect called a "dolly zoom" or a "Hitchcock zoom," so named because director Alfred Hitchcock pioneered the technique in the movie "Vertigo."

To create a dolly zoom, the camera zooms in at the same time as it moves back and away from the subject, all while keeping the subject the same size in the frame. By changing the focal length (or zooming) and moving the camera, you can add in more background or take it away. The effect is unsettling, the visual equivalent of feeling your stomach drop.

This effect also occurs when you take a selfie. Cellphone cameras have the equivalent of a very short focal length lens, around 28 to 30 millimetres. Holding such a short focal length lens at 12 inches away from your face can increase the size of your nose by up to 30 percent.

Camera lenses give photographers the artistic freedom to represent a subject in different ways; sometimes a photographer wants the most realistic or accurate depiction and sometimes they may prefer something a little larger than life. However, larger than life is not usually what we want to see when we take photos of ourselves.

Luckily, there's an easy fix. To take a more flattering selfie, or at least more realistic one, simply take the photo from farther away by using a selfie stick or getting a friend to take it for you.

© The Washington Post 2018