How to film a phone screen without flicker, lines or glare

First, the line you don’t cross

Most of this guide is about the camera, and it applies whatever is on the phone. One part is about the screen. If it shows money, a balance, a payment or a trade, it is a prop for an audience that knows it is watching a film, a sketch or an advert. The same screen shown to a real person as real is fraud, whichever tool drew it, and our acceptable use policy prohibits it. A prop is for the camera.

Film it, record it or replace it

“How do I film a phone screen” has three answers, and choosing between them saves more time than any setting.

• Film the real screen. Crews call this a practical screen: the phone shows the picture and the camera photographs it, hand and all. The light on the actor’s face is real, the thumb really lands on the glass and the reflections are right. On a large production a playback operator supplies and cues these screens; on a small one it is you. The rest of this guide is about getting it clean.
• Record the screen from inside the phone. Both iPhone and Android have a screen recorder built in. The result is perfectly sharp and suits a full-frame insert. It can’t show a hand, a face or the room.
• Replace the screen in post. Shoot the phone blank or showing tracking markers, and composite the picture later, which crews also call a burn-in. You can change what the screen says after the shoot. It costs tracking and compositing on every shot, and more when fingers cross the screen, because they have to be cut out or keyed.

A working rule: if the actor touches the screen in a close shot, film it for real. If the phone is small in a wide, locked shot and no hand crosses it, replacing it is less work than it sounds. If nobody is in the shot at all, record it.

Lines, dark bands and flicker

Lines or a dark band rolling up or down the phone’s screen, or a screen that pulses, mean the screen and the camera are keeping different time. A screen redraws many times a second, and many phone screens, OLED ones especially, also dim by switching on and off faster than the eye can follow. A camera exposes each frame for a fraction of a second, and most read the picture line by line. When the exposure doesn’t cover a whole number of the screen’s cycles, some rows catch it dimmer than others, and that is the band. Try these in order.

1. Turn the phone’s brightness up, and auto-brightness off. On a screen that dims by pulsing, lower brightness means longer gaps and stronger bands. This fixes more shots than anything else.
2. Hold the screen’s refresh rate still, if the phone lets you. Many recent phones vary it. On an iPhone with a 120 Hz screen, Limit Frame Rate, under Accessibility and then Motion, holds it at 60. Many Android phones have a standard or 60 Hz option in their display settings.
3. Change the shutter speed, not the frame rate. The usual 1/48 or 1/50 at 24 or 25 frames a second often bands. Try 1/60 first; on some screens 1/30 or 1/120 is the one that works. If the camera has a fine shutter adjustment, often called synchro scan or clear scan, step it while watching the band until it stops moving and fades.
4. Filming with a phone? Lock its shutter. A camera app left on automatic picks its own shutter speed and changes it mid-shot. Use a manual mode or an app that lets you set it.
5. Judge it at full size. Record ten seconds and play it back on a proper monitor before you move on.

There is no universal number, because phones differ, and one phone behaves differently at different brightness. The method is what carries over: brighten, steady the refresh rate, step the shutter, look. If a faint band survives all of it, make the screen smaller in the frame or the shot shorter.

Moiré: the ripples and rainbows

Moiré looks like ripples, a wavy grid or bands of colour crawling over the screen. It appears when the fine grid of the screen’s pixels and the grid of the camera’s sensor nearly line up. It depends on distance, angle, lens and focus, which is why it comes and goes as the camera moves.

• Change the distance a little. Move in or out by a few centimetres, or zoom slightly.
• Change the angle. Tilt the phone or the camera a few degrees, so the two grids stop lining up.
• Soften it very slightly. Let the focus fall just in front of the glass, on the thumb for instance. Large figures survive a little softness, and moiré doesn’t.
• Check the recording, not the camera’s small display. A small monitor can show patterns that aren’t in the file, and hide ones that are.

Brightness, exposure and colour

A phone screen is a light, and in a dim room it is far brighter than the face beside it. If it burns out to white, the text is gone and no grade brings it back.

• Bring the room up before you bring the screen down. A little light on the actor’s face lets the phone stay bright, where it bands least.
• Then lower the phone only as far as it stays clean. Check for bands again each time the brightness changes.
• Choose the screen’s colours for the shot. A white screen lights the face and burns out first. A dark screen with light figures holds its detail, and shows every reflection and fingerprint.
• Turn off whatever changes the screen by itself. That means auto-brightness, and the settings that warm the screen at night or match it to the room: Night Shift and True Tone on iPhone, and their Android equivalents. They drift over a shoot day.
• Decide the colour of its light. A phone screen is balanced near daylight, so under warm indoor lamps it reads blue. That cold glow on a face is often the look you want. If it isn’t, light the scene cooler.
• Focus by hand for inserts. Autofocus can hunt on a screen.

Glare, reflections and fingerprints

The glass is a mirror, and a dark screen is a better mirror than a bright one.

• Find what it reflects. A window, a soft light, the operator’s pale shirt. Move it, switch it off, or block it with something black.
• Or tilt the phone. A few degrees is usually enough to make it reflect a dark part of the room.
• Be careful with a polarising filter. It can cut reflections, but phone screens give off polarised light, so on many phones the filter also dims the screen, or blacks it out, at some rotations. Turn it slowly while watching the monitor, and check again if the phone turns sideways.
• Clean the glass before every setup. Use a dry microfibre cloth. Fingerprints show most on a dark screen under a hard light. A scratched or bubbled screen protector should come off.

Stop the phone behaving like a phone

• Auto-lock off. Set Auto-Lock to Never on an iPhone, or the screen timeout to its longest on Android, and put it back afterwards.
• Do Not Disturb on. A real message sliding down ruins the take, and can put something private on camera. Airplane mode is surer still, if what is on the screen works without a connection.
• Low Power Mode off. It can dim the screen and shorten the auto-lock.
• Rotation locked, so the picture doesn’t flip when the actor tilts the phone.
• Charged, and on a cable between setups. A screen at full brightness drains a battery quickly.
• Rehearse the thumb. An actor who knows where each tap goes reads as someone who uses the app every day.

Continuity between takes

• The status bar is in the shot. The clock, the battery and the signal sit at the top of the screen, and a scene filmed over three hours shows three hours. Set the clock by hand for the scene, frame the bar out, or keep the takes close together.
• Photograph the screen at each setup. Which tab, how far it is scrolled, what the numbers say. It is the cheapest continuity note there is.
• Keep one brightness per scene. Note the level. A brighter phone in the reverse angle shows.
• Undo what the last take did. A sent message, a typed number, a balance that moved.
• Give the audience one thing to read. They get a second or two. Shoot the insert separately, with the camera locked off and the phone resting on something.

What to put on the screen

The camera work is half of it. The other half is a screen that can be shown, shown again, and shown from the other angle next week. A real app is the obvious choice and often the wrong one. A real banking or trading app shows your name, your balance and parts of your account details to everyone who watches. Its numbers will be different on the day of a reshoot, and they are rarely the figure the script needs.

A prop app answers all three. Pozer makes working prop apps for the screens where the story is money: a payment app, a trading app, a crypto wallet and exchange, a prediction market and four dashboards. Each is an original design with no real company’s name, logo or artwork. You type the figures, publish the app to a link and add it to the phone’s home screen, where it opens fullscreen from its own icon. Building it, installing it and filming it are free.

Three things about it matter to the advice above.

• The actor can play it. On the payment app, Pay ends in a receipt; on the trading app, Buy fills an order. The owner’s Edit button hides in the installed app and returns when two fingers are held on the screen, and Reset to published values in its sheet undoes the last take.
• You choose light or dark. Every app has a Background colour field. On the payment app the text turns light when you pick a dark one, as in the pair above.
• It is a web app. It needs a connection to open, so use Do Not Disturb, not airplane mode. The three crypto apps can follow live prices, refreshed about once a minute; switch Live prices off and the figures you typed hold still.

Free apps carry SIMULATED · POZER.COM in fine print on screen, and Pro at US$12.99/mo removes it. Pozer has no text threads, call screens or social feeds. The guide to a prop phone app for film says which screen fits which script beat, and what to use for the ones it doesn’t cover.

The short version

1. Decide whether to film the screen, record it or replace it.
2. Brightness up. Auto-brightness, Night Shift and True Tone off.
3. Auto-lock off, Do Not Disturb on, rotation locked, Low Power Mode off.
4. Clean the glass and deal with the reflection.
5. Bands: steady the refresh rate, then step the shutter, starting at 1/60.
6. Moiré: move, tilt, or soften slightly.
7. Light the face up towards the screen, and expose so the screen keeps its text.
8. Photograph the screen, note the brightness, reset between takes.
9. Play a clip back at full size before you move on.