If someone began recording you in a café, you would probably expect to spot a phone being held up in front of you.
That assumption is becoming less reliable, however, as AI-powered smart glasses allow people to capture video while appearing to wear an ordinary pair of Ray-Bans.
The privacy concerns surrounding the technology came into sharp focus this week after actor Bill Nighy was reportedly filmed without his knowledge by a YouTube prankster using Ray-Ban Meta smart glasses.
A source close to the Love Actually star described the incident as “very unpleasant and disrespectful”.
But how can you identify camera-equipped smart glasses — and, more importantly, work out whether the wearer is actually recording?
Technology experts say there are several details that could provide a clue.
Experts have identified several signs that may reveal when someone is wearing smart glasses. Pictured: Meta CEO Mark Zuckerberg wearing Meta Ray-Ban Display glasses
Look for the camera lenses
Will Greenwald, a consumer electronics writer for PCMag, says the most obvious sign may be easier to miss than people expect.
Camera-enabled designs, including Meta’s Ray-Ban models, generally have miniature lenses built into the front corners of the frames.
The lens often looks like a tiny black circle positioned near the outside edge of the frame, close to the hinge.
From a distance, it may be mistaken for a screw, rivet or decorative feature. Once its purpose is known, though, the small circular camera can be relatively easy to recognise.
“The technology inside is so small and discreet that they look and feel almost exactly like regular glasses,” Mr Greenwald said.
“There is a giveaway, though, and once you learn how to spot it, you’ll wonder how you didn’t see it before.”
Smart glasses often have thicker arms to house their internal components, along with small camera lenses positioned in the frame corners. Pictured: The Duchess of Edinburgh trying on Ray-Ban Meta glasses
Check how thick the arms are
The frames must contain a range of components, including a battery, speakers, antennas and processors, which can make them bulkier than conventional eyewear.
Smart-glasses buying guides and specialists suggest looking for unusually thick temples, visible seams, speaker openings or groups of tiny holes along the arms.
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Whereas standard spectacles usually have slim, simple arms, smart glasses often require extra space to conceal their electronic hardware.
Listen for voice commands
Another feature that can make these devices difficult to detect is hands-free activation.
On some models, recording can begin with a spoken command such as “Hey Meta, take a video”, removing the need for the wearer to take out a smartphone or press an obvious button.
Experts also recommend noticing brief audio prompts, sudden pauses or someone appearing to speak quietly to themselves. Frequent taps on the frame may be another sign that the wearer is controlling or using the glasses.
At first glance the camera can look like a decorative rivet or screw rather than a camera lens. But once you know where to look, the small circular lenses can be surprisingly easy to spot. Pictured: Meta Ray-Ban Display AI glasses
Watch where they are looking
Because the camera generally points wherever the wearer is facing, body language can offer clues.
Technology commentators say people filming with smart glasses may make deliberate head turns, hold their gaze on particular subjects, or tilt their head slightly to frame a shot.
If someone seems unusually focused on a particular person or repeatedly turns their head to keep them in view, they may be capturing footage.
‘Behaviour matters – watch for repeated temple taps, short voice prompts, and ‘pause-to-read’ patterns,’ Even Realities, a company that manufactures AI smart glasses, said.
Look for the indicator light
The most reliable sign that recording is taking place is a small LED indicator light.
Meta’s Ray-Ban glasses include a white LED on the front of the frame that illuminates when the camera is taking photos or recording video.
‘Look for the small white LED on the outer right-hand side of the frame, next to the camera. Meta calls it the Capture LED. It lights when the camera is active,’ experts at Tech Buzz said.
However, they warned the light can be easy to miss in bright daylight or at a distance.
A spokeswoman for Meta said: ‘People use our AI glasses because they’re genuinely helpful in everyday moments like listening to music, getting live translation while traveling, or making a call hands-free.
‘They were built to be noticed, which is why every pair with a camera has a bright light on the front that blinks when you take a photo or video.
‘It cannot be turned off and the camera is disabled if someone covers or tampers with it. We will keep strengthening our protections as our glasses become even more capable.’
