A beam-splitter teleprompter is a sheet of half-mirrored glass at 45 degrees in front of your lens: you see your script reflected in the glass, and the camera shoots straight through it, so reading and eye contact become the same act. Setting one up alone takes about twenty minutes the first time and under two once you know the order — glass, mount, mirror mode, light, then a quick read check from where you'll actually stand.
This guide covers the whole rig for one person with no crew: what the glass does to your light, how to mount a phone or small camera, the mirroring trap, lighting your face when the prompter itself is a light source, and the software half that most hardware guides skip.
What a beam-splitter actually does
The glass in a prompter hood is coated so that it reflects some light and transmits the rest. Your screen lies flat below the hood, facing up; its image bounces off the glass towards you; the camera behind the glass sees through it to your face.
The part nobody mentions in the product photos: that split is expensive. Depending on the coating, the glass passes roughly a third to a half of the light in each direction. Your camera loses up to a stop through the glass, and — more importantly for reading — the script you see is dimmer and lower-contrast than the same screen viewed directly.
Two consequences follow from that maths, and they shape everything else in this guide. First, whatever looks comfortably readable on the bare screen will be harder to read through glass, so set text and contrast for the rig, not the desk. Second, subtle visual cues die in the mirror. Anything your prompter software signals with a gentle tonal shift — a faint highlight, a slightly dimmed line — needs to be bold enough to survive losing half its light.
Choosing glass and a mount
You do not need broadcast kit. For a solo setup there are three sensible rungs:
A smartphone prompter hood (roughly £30–£100) clamps your phone below a small glass panel, with the camera — often a second phone — mounted behind. Fine for arm's-length to about two metres. Check the stated glass size against your phone: a 6.7-inch phone in landscape wants the larger hoods.
A tablet-and-camera rig (£100–£250) takes an iPad or large phone as the screen and a mirrorless or compact camera behind. The bigger screen is the point — at two to three metres, screen area buys you font size, and font size buys you a natural eye line.
Purpose-built units with an integrated screen sit above that. Worth it if you shoot daily; overkill for a first rig.
Whichever rung: look for 70/30 glass (70% transmission) described as "beam splitter" rather than ordinary mirror glass, a hood that actually blocks room light from hitting the back of the glass, and a mount that lets you set the whole assembly at your seated or standing eye level. The most common first-rig mistake is a prompter at chest height — you end up looking down on camera, which reads as reading.
If you're weighing this rig against simply propping a phone next to the lens, the trade is eye line: with the script beside the lens, the further back the camera, the less visible your glances. The beam-splitter removes the glance entirely, which is why it wins for anything closer than about three metres. We've written more about eye line and distance in how to read a teleprompter without sounding wooden.
Mirroring: the whole surface flips
The glass reverses everything horizontally. Your prompter software must have a proper mirror mode that flips the display so the reflection reads correctly — reading mirrored text is possible for about a sentence and miserable thereafter.
The subtler point is that everything on the screen flips, not just the words. A control in the bottom-right of the screen appears bottom-left in the glass. A progress bar that fills left-to-right appears to fill right-to-left. So when you're evaluating prompter software for a rig, look at what happens to the interface in mirror mode, not just the script: anything that depends on left meaning left will lie to you mid-take. Good rig-aware software treats mirroring as a first-class mode; TellyPrompter, for instance, is designed so that no cue depends on left/right meaning, precisely because mirrored rigs are normal use rather than an edge case.
While you're in the settings: if your phone is locked to portrait, look for a rotation control in the software itself, since some rigs want the screen turned 90 degrees.
Lighting yourself when the screen is pointed at your face
A prompter is a light source aimed directly at the presenter. In a dim room it becomes your key light — an unflattering, screen-coloured one that also reflects in glasses.
The fix is not a darker screen; you need that brightness to survive the glass. The fix is more light elsewhere, so the prompter stops being the brightest thing in your face:
- Key light first. One soft light at roughly 45 degrees, brighter than the prompter's glow on your face, and the screen's contribution disappears into it.
- Dark interface, light text. A mostly-dark prompter screen throws far less light and reflects far less in glasses and in the glass itself. Near-black backgrounds are standard in prompter software for exactly this reason.
- Glasses wearers: raise the key light and tilt it down, and angle the prompter hood a degree or two off square if you can. Most lens reflections are the screen; a dark background removes most of the problem at source.
- Check the hood for leaks. Room light striking the back of the glass washes out the script. If your text looks milky, shade the back of the hood before touching any brightness setting.
The software half: scroll speed should be the read
Here is where most rig guides stop, and it's half the rig.
A conventional prompter app asks you for a scroll speed — a words-per-minute number — before you've said a word, and then plays the script at that speed while you perform to it. On a beam-splitter this is worse than it is on a propped phone, because the whole point of the glass is unbroken eye contact: there's nowhere to glance for a controls check, and your hands are usually in frame. If the scroll runs ahead of you, the recovery options are to chase it or to stop the take.
The alternative is software that listens. TellyPrompter follows your voice: as you read, a highlight tracks the word you're actually saying, through pauses, ad-libs, skipped lines and backtracking, so the pace of the scroll is set by the read rather than by a guess you made before it. On a rig this matters twice over — you can't reach the phone to correct a bad speed guess, and you can't afford the eye movement of hunting for your line. Speech recognition runs on the device and the audio is never uploaded.
It runs in the browser, works with mirror mode and rotation, and the text and contrast settings are built for reading at one to three metres through glass. One honest limit: voice-following depends on the browser's speech recognition, so quality varies by platform and language, and Firefox doesn't implement the API at all — there, the constant and sound-level modes still work.
The two-minute setup checklist
Run this from your performing position, not from beside the rig:
- Height — glass at eye level, lens behind it at eye level. You should be looking dead ahead.
- Mirror mode on, and confirm the script reads correctly in the glass.
- Font size — step back to your mark. Read a line. If you lean or squint, go bigger. Bigger than feels necessary is usually right.
- Contrast — light text on a near-black background; check nothing important is carried by a subtle tonal difference, because the glass just ate half of it.
- Key light on, brighter on your face than the screen's glow. Check glasses for reflections.
- Hood check — no room light washing the back of the glass.
- One read aloud — half the script, at performance volume, watching the highlight or the scroll. If it keeps your place, sit down and take the take.
The rig's job is to disappear. When the glass is clean, the text is big, the mirror is set and the scroll is following you rather than the other way round, what's left is you, talking to the lens — which is the whole point of bolting a mirror to a camera in the first place.