A mirror selfie and a rear camera photo can show the same smile and still look like two different faces, because one of them is reversed. That single fact - the flip - explains most of the shock people describe when they see a saved photo of themselves. Nothing about your teeth changed between the two images. What changed is which side every small asymmetry appears on, and your brain has spent a lifetime learning only one of those two versions.
Key takeaways
- A reversed image is geometrically identical to the original, so no proportion, angle or size actually changes when a photo is flipped.
- The Institute of Physics states that a mirror does not swap left and right, it swaps front for back, and the left-right description is our interpretation.
- On the phones we can check, the live selfie preview is mirrored, and whether the saved file keeps that mirroring depends on a setting.
- Apple calls the setting Mirror Front Camera and Google calls it Save selfie as previewed, and neither company publishes a default in its help page.
- Zajonc's mere exposure work and Suchow and colleagues in 2024 explain why the familiar version feels more like you, though the evidence is not uniform.
- Lens focal length and camera distance are a completely separate effect from the flip, and the two are constantly conflated.
Where this article sits alongside our others
We have written about most of the neighbouring questions already, so this page sticks to the flip itself. If you are looking for something else, here is the map.
- Why teeth look different in the mirror covers the bathroom mirror specifically: lighting, distance, angle and what a mirror can and cannot show you about your own teeth.
- Why teeth look different in photos covers photography in general, including exposure, flash and why a camera flattens a three-dimensional smile.
- Why teeth look different on video calls covers webcams, compression, screen position and the particular strangeness of watching yourself talk.
- Ring light colour temperature and tooth shade covers lighting colour and how it changes the apparent shade of teeth.
What is left, and what this article is about, is lateral inversion: the reversal itself, the difference between the live preview and the saved file, and why an asymmetry you have never noticed becomes obvious the moment it is mirrored.
First, a correction about mirrors
Almost every consumer page says a mirror flips you left to right. The Institute of Physics, in its IOPSpark teaching material on lateral inversion, says that is a misdescription. A mirror swaps front for back, not left for right. In its own words, right and left are not actually reversed in the image; it is just our interpretation of the image. The useful way to put it is that a mirror shows you a reversed view whose handedness is opposite to what a camera records. Everything else in this article follows from that.
The important consequence is that a reversal changes nothing measurable. If your incisal plane is canted by a degree or two, it is canted by the same amount in both versions. If one gum margin sits slightly higher, it sits by the same slightly. The flip only changes which side you see it on.
The live preview versus the saved file
This is the most actionable part of the page, and most people have never checked it.
Apple's support page on taking a selfie says that to capture the shot as you see it in the front-facing frame, rather than reversing it, you turn on Mirror Front Camera in Settings, then Camera. Two things follow from that wording. The live preview on screen is mirrored. And with the setting off, iOS reverses the preview before saving, so the file you end up with is the non-mirrored view. Apple does not state a default in words, and it does not list which devices the setting applies to.
Google's Pixel Camera help page says you can save selfies as mirrored or non-mirrored photos, and that if you save a selfie as previewed it will not appear reversed after you take it. The path is Camera, then the down arrow, then Settings, then Save selfie as previewed. Google does not publish which way it ships either.
For other brands, the honest answer is that we cannot tell you. Third-party write-ups and forum threads disagree with each other, defaults have changed between software versions, and manufacturers do not document them. Third-party camera apps such as social media apps are a separate code path again, and none of them publish their behaviour. Whether the setting applies to front-camera video is also not stated by either Apple or Google.
So the practical step is to check your own phone rather than trust a general claim. Take one selfie, then look at the saved file and see whether the text on your shirt reads correctly. If it does, the file is mirrored. If it is backwards, it is not.
Why the reversed version feels more like you
Zajonc published "Attitudinal Effects of Mere Exposure" in the Journal of Personality and Social Psychology in 1968, showing that mere repeated exposure to a stimulus is enough to improve attitudes toward it, across polygons, drawings, photographs, nonsense words and ideographs. You have seen your mirrored face many thousands of times and the true-orientation version far less often. Familiarity does the rest.
Mita, Dermer and Knight tested exactly this in 1977 in a paper titled "Reversed facial images and the mere-exposure hypothesis", published in the same journal. Thirty-three female undergraduates were photographed, and each print was produced as both a true image and a mirror image. The subjects preferred their mirror image. Their close friends preferred the true image. That double dissociation is the cleanest demonstration of the effect, and it is worth noting that most pages citing this study get the title wrong.
Suchow, McDowell, Huang and Haberman revisited it in "A reflection on faces seen under mirror reversal", published in Perception in 2024. Non-reversed images of one's own face were perceived as more unlike oneself and less pleasant than reversed images, and the pattern disappeared for close friends, for whom the non-reversed image is the familiar one. The authors also note that their first experiment was fully replicated seven years later. They attribute the effect to a strong but malleable visual self-representation that is activated when an unfamiliar perspective exposes facial asymmetries.
De Runz and colleagues reported in the Journal of Plastic, Reconstructive and Aesthetic Surgery in 2016 that plastic surgery patients preferred mirror-reversed photographs of themselves, more so among facial aesthetic surgery patients. That study is available here at abstract level only, so treat the direction of the effect as supported and the specific proportion as second-hand.
The evidence is not one-sided, and that matters
It would be easy to stop there. The literature does not.
Al-Bitar, Hamdan, Shqaidef, Garagiola and Naini published a study in Maxillofacial Plastic and Reconstructive Surgery in 2023 in which dental students judged their own photographs. The result splits by image type. Most preferred the true image of a third-party volunteer. Most preferred their own original, true frontal photograph, both at rest and smiling. But most preferred the mirror image of their own selfie, at rest and smiling. That is the most dentally relevant paper on this question and it complicates the simple story considerably.
Wen and Kawabata, in "Why am I not photogenic? Differences in face memory for the self and others", published in i-Perception in 2014, found that participants selected images of themselves with magnified eyes and shrunken mouths as their real face, while choosing classmates' unmodified real faces. In their third experiment, mirror reversal did not change what participants selected. That is a genuine limit on the flip explanation.
So the fair summary is this. Reversal changes how familiar a face feels, and familiarity changes how much you like it, but it is not the whole story and it does not behave identically in every study or with every kind of photograph.
Why an asymmetry you never notice becomes obvious when reversed
Faces are not symmetrical, and smiles are less symmetrical still. A study on perception thresholds of dental and gingival asymmetries using eye tracking, published in the American Journal of Orthodontics and Dentofacial Orthopedics with 195 participants across three groups, measured how large a discrepancy has to be before people notice it. For the gum border of a central incisor, the threshold was 1 mm for orthodontists and dentists and 1.5 mm for laypeople. For the gum border of a lateral incisor, it was 1 mm for professionals and 2 mm for laypeople. For a lateral incisor crown-width discrepancy, it was 2 mm for orthodontists, 3 mm for dentists and 4 mm for laypeople. Dental asymmetries drew more visual attention than gum ones, and thresholds were smaller closer to the midline.
Those are detection thresholds under direct comparison. Now consider what a mirror does. It gives you a lifetime of habituation to one handedness only. Sub-threshold differences - a slight midline cant, a slight tilt of the incisal plane, uneven gum zeniths, a one-sided lip lift, unequal buccal corridors - sit quietly below conscious notice because they are part of the template you learned. Reverse the image and the template no longer matches. Nothing got worse. The comparison got harder. Suchow and colleagues describe exactly this mechanism when they refer to an unfamiliar perspective exposing facial asymmetries.
If a particular feature is bothering you, we cover two of them in detail: the smile midline and why a smile looks off centre, and facial asymmetry and why a smile looks crooked.
Focal length and distance are a different problem entirely
This deserves its own heading because almost every page on this topic mashes it together with the flip. They are independent, they are separately testable, and only one of them changes geometry.
Ward, Ward, Fried and Paskhover published "Nasal Distortion in Short-Distance Photographs: The Selfie Effect" in JAMA Facial Plastic Surgery in 2018. It is important to be precise about what that paper is: a mathematical and geometric model, not a measurement study on patients. Faces were modelled as parallel planes using average anthropometric data. Holding bizygomatic breadth constant, the model calculated that perceived nasal size increases by about 30 per cent in males and 29 per cent in females at 12 inches compared with an orthographic projection from infinite distance. At five feet, the model found essentially no difference in perceived size. So a geometric model published in JAMA Facial Plastic Surgery calculated that effect. It did not measure it in real photographs of real people, and it is about the nose.
There is no published figure for how much camera distance changes the perceived width of teeth or a smile. None exists. Do not let anyone extrapolate the nasal number onto your smile.
Trebicky, Fialova, Kleisner and Havlicek approached it differently in PLoS ONE in 2016. They photographed 45 subjects at 50, 85 and 105 mm and had 369 raters compare them. Photographs taken at 50 mm were rated significantly less attractive, less dominant and less feminine or masculine than those taken at longer focal lengths, and shorter focal lengths produced a smaller facial width-to-height ratio. Geometric morphometrics confirmed that focal length significantly altered the depicted shape of the face. Derakhshan, Gadkaree and colleagues, in The Laryngoscope in 2024, compared smartphones and a full-frame DSLR across six distances and seven focal lengths and concluded that vertical distortion of the midface occurs at selfie distances on both.
Front cameras are wide-angle by design. Apple publishes the iPhone front TrueDepth camera as a 23 mm-equivalent f/2.2 lens on recent generations. Combine that with an arm's-length working distance and you have the geometric opposite of the 85 to 105 mm portrait range that Trebicky's raters preferred. Dental photography convention specifies 90 to 105 mm macro lenses for clinical facial and intra-oral work for exactly this reason: a longer lens forces a longer working distance and limits perspective distortion.
So: the flip changes which side things appear on. Distance and focal length change how big near features look relative to far ones. Those are two different sentences about two different phenomena, and blending them is why so much of what you read on this subject does not quite make sense.
| Factor | What it changes in the image | What it does not change | How to test it yourself |
|---|---|---|---|
| Left-right reversal (mirror versus saved file) | Which side every asymmetry appears on, including midline cant, a higher gum line and a one-sided lip lift | Any actual proportion, size or angle; the image is geometrically identical | Flip the photo in your phone's editor and look at the same photo both ways |
| Camera distance | Perceived size of whatever is closest to the lens relative to the rest of the face | Which side features sit on | Take one photo at arm's length and one from about 1.5 m with the rear camera, same pose |
| Lens field of view (front cameras are wide) | How strongly the near-far size difference is exaggerated | Left-right orientation | Compare the front camera with the rear camera from the same distance |
| Head tilt and pose | Apparent cant of the incisal plane and the lip line | Underlying tooth position | Photograph with the head level against a horizontal reference line |
| Lighting direction | Which side of the smile reads as shadowed or fuller | Tooth shape or position | Face an even light source, or shoot outdoors in open shade |
| Expression (a smile is rarely symmetric) | How much of each side's teeth and gum shows | Resting tooth position | Compare a relaxed-lips photo with a full-smile photo |
| Crop and aspect ratio | Where the eye reads the midline as sitting | The face itself | Re-crop centred on the facial midline rather than on the frame |
| Screen, print or app | Colour, contrast, and whether an app re-mirrors on export | The underlying geometry | Open the same file in two different apps and compare |
A method you can actually run
If you want to know what is real and what is the capture, compare like with like. Use the rear camera. Ask someone else to take the photo, or use a timer and a stable surface. Stand about 1.5 m away rather than at arm's length. Keep your head level against a horizontal line in the room. Use even light with no strong side shadow. Take one photo with lips relaxed and one with a full smile. Then open the same file and flip it, and look at both versions.
Two things usually happen. The distortion you were blaming on your teeth turns out to have been distance. And the asymmetry that looked severe in one orientation looks ordinary in the other, because it was always the same size.
One caveat worth keeping. Neither version is the truth. Both are two-dimensional captures of a three-dimensional face. Other people see you in motion, at varying distances, under changing light, and never as a single frozen frame. A still photograph, flipped or not, is not the ground truth about how you look.
Frequently asked questions
Is the mirror or the camera showing what I really look like?
Both and neither. The mirror shows a reversed view and the rear camera shows the orientation other people see, but both are flat representations of a moving three-dimensional face. The geometry is identical in the two versions, so neither is more accurate about the size or angle of anything.
Why does my face look uneven in the inverted filter but normal in the mirror?
Because you have spent your whole life comparing your face to one orientation. Reversing it removes that familiar template, and asymmetries that sat below your detection threshold become visible. Research on asymmetry perception has found thresholds of roughly 1 to 4 mm depending on the feature and on whether the observer is a clinician.
Does the iPhone flip your selfie when it saves it?
Apple's support page says that turning on Mirror Front Camera captures the shot as you see it in the preview rather than reversing it, which means that with the setting off the saved image is the non-mirrored view. Apple does not state a default, so check the setting on your own device rather than assuming.
How do I stop my selfies from being mirrored?
On iPhone, look in Settings, then Camera, for Mirror Front Camera. On a Pixel, open the camera, tap the down arrow, then Settings, and look for Save selfie as previewed. Other brands vary and do not document their defaults, so the reliable test is to photograph some text and see whether it reads correctly.
Is my smile actually crooked, or is it just the photo?
A flipped image cannot make a smile crooked, because reversal does not change any angle. Head tilt, crop and lighting can all make a level smile look canted, and camera distance changes apparent proportions. A dental assessment with the head positioned against a reference line is the only way to answer that properly.
Why do I look worse in photos than in the mirror?
Partly familiarity, which Zajonc described as mere exposure and Mita and colleagues demonstrated with reversed faces, and partly capture conditions such as focal length, distance, lighting and a frozen expression. The evidence for the familiarity explanation is directionally supportive but not uniform, since Wen and Kawabata found mirror reversal made no difference in their study.
Which photo should a dentist look at to assess a smile?
A standardised one. Clinical facial photography convention uses a 90 to 105 mm macro lens at a controlled working distance with the head in natural head position, which is a long way from an arm's-length selfie on a 23 mm-equivalent front camera. That is why a practice will usually take its own photographs rather than work from the ones on your phone.
If you would like a proper look
The team at Lumi Dental in Melrose Park takes standardised photographs as part of a cosmetic assessment, which removes most of the variables described above and gives you something consistent to look at. You can book a complimentary cosmetic consultation to talk it through, and our current offers page lists what else is available. We are open Monday to Saturday.
This article is general information only and is not a substitute for an examination and individual advice from a registered dental practitioner. Nothing here suggests that an asymmetry visible in a photograph indicates a clinical problem, and individual suitability for any treatment varies.
