Infrared
How to spot night-vision cameras with your phone’s camera
Night-vision cameras light the room with infrared LEDs that your eyes can’t see, but many phone cameras can. Test your phone first: point a TV remote at the camera, press a button and look for a flashing light on screen. If you see it, darken the room and scan slowly for small purple, white or pinkish dots, often in a ring or a pair around a lens.
Quick steps
- Test your phone with a TV remote. Point a TV remote at your phone camera, press a button and watch the screen for a flash. Try both the front and rear camera.
- Darken the room. Close the curtains and switch off every light, including the bathroom.
- Scan slowly through the camera. Using the camera that showed the remote best, sweep each wall and object at bed height and above.
- Look for dot patterns. Note faint purple, white or pink dots that you cannot see with your eyes, especially in rings or pairs.
- Check each hit with light. Turn the lights back on and inspect the spot with a flashlight and zoom for a lens.
Can a phone camera see infrared?
Phone camera sensors respond to near-infrared light, the same band most night-vision LEDs use. Manufacturers add a filter to block it because it spoils colors in daylight photos. How much gets through varies by model and between cameras on the same phone. On many phones the front camera shows infrared better than the main rear camera.
The TV remote test
A TV remote uses an infrared LED, which makes it a free test source. Point it at your phone camera from about a foot away, press and hold any button, and watch the screen. A flickering purple or white light means that camera passes infrared. No flash means switch cameras and try again. If neither camera shows it, your phone won’t help with this particular check, and the flashlight sweep matters more.
How to scan a room for infrared lights
Make the room as dark as you can, turn the screen brightness up and move slowly. Night-vision cameras usually ring the lens with four to twelve LEDs, so a cluster of faint dots in a circle is the pattern to notice. A single dot is often a standby light on a TV, an air conditioner or a smoke detector, which is ordinary. Note it, then check the object with the lights back on.
What an infrared check can’t tell you
A camera only shows up this way while its infrared LEDs are on. Daylight cameras have none, and many night-vision cameras turn theirs off when the room is lit. LEDs at 940 nm are much dimmer to phone cameras than the more common 850 nm ones, which can glow faint red even to the eye. Remotes, security sensors and the face-scanning projectors on other phones emit infrared too.
Infrared camera detectors compared with your phone
Handheld camera finders sold for travel are usually a ring of red LEDs around a filtered viewer. They work by catching lens reflections, the same principle as the flashlight sweep. You can do the same thing with your phone’s flashlight and a red-tinted camera view, which Room Privacy includes in its Lens check.
Questions
Why do I see purple light on my phone camera?
Your camera is picking up near-infrared light that your eyes can’t see. Phones show it as purple or white because the sensor’s color channels respond unevenly to it.
Can an iPhone see infrared?
Often through the front camera, less often through the rear cameras, which filter infrared more strongly. It varies by model, so use the TV remote test on both before you rely on either.
