How to shoot a headshot with the phone you already have
Ten minutes, a window and a phone. The two things you cannot fix afterwards are focus and light, so this is mostly about getting those right and ignoring the rest.
You do not need a camera. Phone sensors have been good enough for a profile picture for years, and the things that actually ruin headshots are not resolution. They are hard light, a busy background, a bad angle and a lens held too close. All four are free to fix.
Work through this in order. It takes about ten minutes and the first six are just finding the window.
Find the light before you do anything else
Stand facing a window, on an overcast day or in open shade, with the window filling most of what you can see. That is it. That is the lighting setup.
The reason it works is size. A light source that is large relative to your face wraps around it and makes soft edges on shadows. A small source, meaning direct sun or a bare bulb or your phone’s flash, makes hard edges: a sharp shadow under the nose, a bright rim on the cheekbone, deep sockets around the eyes. Soft or hard has nothing to do with brightness and everything to do with how big the source looks from where you are standing.
A few things to avoid, all for the same reason. Overhead office lighting puts the source above you, which digs out the eye sockets. Direct sun is a very small source because it is very far away, so it is hard light. Mixed light, like a window on one side and a warm lamp on the other, gives you two different colours on two halves of your face, and that is genuinely annoying to correct later.
Turn the flash off and leave it off.
Then fix the background
Step forward, away from the wall. Two or three metres of separation between you and whatever is behind you does two useful things: it throws the background slightly out of focus, and it stops light bouncing off the wall onto the back of your head.
Pick something plain and, more importantly, something that is a different brightness from your hair and your top. Dark hair against a dark bookshelf merges into one shape the moment the photo is small. This matters more than the background being attractive.
If you are planning to replace the background anyway, still do this. A cleanly separated subject mattes far better than one pressed against a wall, and fine hair against a busy background is the single hardest case for any segmentation model, ours included.
Use the back camera, and stand further away
Two separate points, both about the lens.
The selfie camera is the worse camera on essentially every phone, and it is also wide, which is the real problem. A wide lens used close up enlarges whatever is nearest it, which is your nose. That is the entire “phone selfies distort faces” effect. It is perspective, not the lens being bad.
So use the rear camera, prop the phone up or hand it to somebody, and get further away. Roughly two metres, then use the 2x or 3x telephoto if your phone has one, or just crop in afterwards. A longer lens from further back flattens the face into the proportions people recognise. This single change does more than any retouching.
Put the phone at your eye height. Below, and you are shooting up someone’s nose and adding a chin. Well above, and you get the slightly pleading look of a held-out arm.
Take thirty, not three
Shoot a burst, change something small, shoot another. Turn your shoulders about thirty degrees away from the camera and bring your face back to it, which is more flattering than square on and reads as less confrontational. Push your chin slightly forward and down, which feels ridiculous and fixes the under-chin.
For the expression, a real smile involves the eyes, and the reliable trick is to not hold one. Relax your face completely between frames, then smile on the shot. Holding a smile for ten seconds is what produces the rictus.
Thirty frames gets you two or three where the eyes are open, the expression is not strange and the focus landed. That hit rate is normal, including for professionals.
Check these four things before you stop
Zoom in on the eyes. If they are not sharp, nothing else matters. Phone autofocus often grabs the nose or the shoulder.
Check for motion blur, especially indoors where the shutter is slower than you think.
Check the whole head is in frame, crown included. Cropping the top of the head off is the one framing mistake that cannot be undone later, because a tool either leaves you with a flat-topped head or invents a skull that is not yours.
Check nothing is blowing out. A completely white patch on the forehead has no detail left to recover.
What you can safely leave for later
Do not worry about the crop, the background if you are replacing it, colour temperature, shine on the forehead, or the overall exposure being slightly off. All of that is adjustable afterwards because the information is still in the file.
Do not bother with beauty filters in the camera app either. They smooth before the file is written, so the texture is gone for good, and anything you do later is working from an already flattened image.
Shoot the plainest, sharpest, best-lit frame you can and finish it afterwards. If you want that done for you, drop the frame you picked into the generator and it will matte the background, relight the face, retouch inside the individual masks and frame it on the eye line, in about four seconds and without the photo leaving your browser. If you want to know what it is aiming at, what a professional headshot actually has to do covers the conventions it frames to.