A commercial teleprompter rig is a piece of glass at forty-five degrees, a hood to keep light off it, and a shelf for a tablet. That is genuinely all it is. The engineering that justifies the price is in rigidity and finish, not in principle — which means a home-built version works, as long as you understand what each part is doing.
This is a practical build guide. It also explains why the text has to be mirrored, because that is the step people skip and then wonder why their footage reads backwards.
How a beam-splitter prompter works
A sheet of partially reflective glass sits at forty-five degrees in front of your lens. Your tablet lies flat below it, screen upward. The glass reflects the tablet toward you, so you see the script floating apparently at the lens. The camera, looking through the same glass from behind, sees only the scene — because the glass is transparent from that side and the tablet is shielded from view.
That is why the illusion works: you read from a surface that appears to be exactly where the lens is, so your eye line is dead-on rather than approximately right. It is a genuinely different result from putting a phone next to the camera.
What you need
- A sheet of glass or acrylic, roughly 20 × 25 cm. A picture-frame glass panel works; so does a cheap acrylic sheet from a hardware shop.
- A tablet or phone for the script.
- Rigid black card or foam board for the hood.
- Gaffer tape, a craft knife, and something to hold the glass at 45° — a small box cut diagonally is the simplest option.
- Optional but transformative: proper beam-splitter glass, which is the one part genuinely worth buying.
On glass: the one part worth paying for
Ordinary glass reflects perhaps eight percent of the light hitting it, so your reflected script will look dim and you will lose contrast in the footage. It works, and it is the right way to test the idea before spending anything.
Real beam-splitter glass is coated to reflect around thirty percent and transmit seventy, which gives you a bright, readable script while letting most of the light through to the sensor. A sheet costs less than most camera accessories and is the difference between a rig you tolerate and one you use. If your test build convinces you, this is the upgrade to make first.
Building it
- Cut a box or frame so one face holds the glass at 45° to the tablet below it. Precision here matters more than materials: a few degrees off and the text sits visibly above or below the lens.
- Set the tablet flat, screen up, directly beneath the glass.
- Position the camera behind the glass, lens as close to the surface as it will go without touching.
- Build a hood of black card around the front of the glass and over the camera. This is not optional — stray light on the glass washes out both your script and your image.
- Line the inside of the hood and any surface the camera can see with matte black card. Anything reflective inside the enclosure shows up as a ghost.
Why you must turn on mirror mode
A mirror reverses left and right. Your script is reflected once by the glass before it reaches your eye, so text displayed normally arrives backwards. Flip it horizontally on the tablet first and the two reversals cancel: what you read is the right way round.
In Teleprompter Online, that is the mirror button, or the M key. Turn it on before you build anything else, because it makes the alignment steps far easier to judge — you can read the text while you work out where the glass should sit.
Getting it aligned
Two adjustments decide whether it reads as professional. First, the glass angle: it should reflect the script so that it appears centred on the lens, not floating above or below it. Adjust by tilting the glass a degree at a time and checking your own eye line on the camera preview.
Second, brightness. Turn the tablet up until the script is comfortably readable and no further. Too bright and the glass throws a visible glow onto your face; too dim and you squint, which the camera records faithfully. Set it in the lighting you will actually shoot in, not in a dark room.
When a rig is not worth it
If you film mostly on a phone at arm's length, a rig is overkill — a second device just under the lens gets you ninety percent of the benefit for none of the effort. Beam splitters earn their place when the camera is further away, because that is when the gap between "next to the lens" and "at the lens" becomes visible.
Build the cardboard version first. An afternoon and no money tells you whether the finished thing belongs in your setup, and if it does, you will know exactly which part to upgrade.