The mirror and the camera show opposite faces
The face you see every day is your mirror image — left and right swapped. Other people and cameras see the unreversed face. Because every face is slightly asymmetric, flipping it moves small differences, like a higher mouth corner or the side your hair parts on, to the opposite side. The arrangement you are used to is reversed, so the same face suddenly feels "off."
In a 1977 study by Mita and colleagues, participants preferred mirror-image photos of their own faces, while their friends preferred the true, unreversed photos of the same people. The authors explained this with the mere-exposure effect: we like what we see often. A photo looking odd is more likely about unfamiliar orientation than about your face changing.
Shooting up close enlarges the center of the face
Whatever is closer to the camera records larger; whatever is farther records smaller. An arm’s-length selfie is taken from roughly 30cm, so the nose — the most forward part of the face — comes out large while the ears and the sides of the face shrink. Using a mathematical model, Ward and colleagues (2018) estimated that a nose photographed from about 30cm appears around 30% wider than from about 1.5m.
That interpretation has been challenged. In a letter to the same journal, Cooper and colleagues argued that viewing distance and habits, more than distortion in the photo itself, drive the impression. Either way the practical conclusion holds: a single close-up selfie is a poor reference for your actual facial proportions.
Why a slight head turn exaggerates asymmetry
Perspective is strong at close range, so turning your head just a few degrees makes the near cheek look wider and the far cheek narrower. The nose sits farthest forward and shifts most with head direction. Many selfie impressions of "my nose is crooked" or "one side of my face is bigger" come from camera angle.
Shooting from above enlarges the forehead and shrinks the chin; shooting from below does the opposite. The common selfie habit of "slightly above, slightly to the side" is the worst possible setup for a comparison photo.
Lenses and the edges of the frame
Front-facing phone cameras often use wide-angle lenses. Wide lenses stretch whatever sits near the edges of the frame, so if your face is off-center, that side can record wider. Simply keeping your face in the middle of the frame reduces this.
Some camera apps flip the image on save or apply face retouching automatically. For comparison photos, turn beauty and retouch features off and keep the same settings every time.
Expressions naturally move unevenly
It is common for one mouth corner to rise higher or one eye to close more when you smile. Most selfies are taken mid-expression, so they show more asymmetry than a relaxed face. To compare facial balance, use a relaxed, neutral expression as your baseline.
How ALYGN handles this
ALYGN’s camera preview is mirrored like the mirror you know, but the photo used for analysis is the unreversed original. "Left" and "right" in your results refer to your own face, not the screen. The camera also blocks shots when your head turns too far from frontal and corrects small remaining tilt before calculating.
Distance, lighting, and expression are still up to you. That is why comparing repeated records taken under the same conditions means far more than any single score.
A practical way to compare with selfies
If you can, prop the phone up a meter or more away and use the timer. If you must shoot at arm’s length, keep the same distance each time, hold the camera at eye level, and center your face. Same place, same time of day, same lighting, neutral face — under those conditions a selfie becomes useful comparison data.
Detailed lighting and angle setup is covered in "How to Photograph Yourself for an Accurate Self-Check."
Frequently asked questions
Q. Which is my real face — the mirror or the photo? — Both are the same face. Others see the photo orientation; you are used to the mirror orientation. Finding photos unfamiliar is a normal reaction.
Q. Should I turn on selfie mirroring? — For photos you want to look good in, it is personal preference. For comparisons, the key is to pick one and stick with it; mixing them records left-right differences in opposite directions.
Q. Photos taken on the same day give different scores. — Distance, head angle, and expression vary slightly between shots. Look at the trend across weeks of same-condition records rather than day-to-day differences.
