On 1/27/19 12:03 AM, Jeff Liebermann wrote:
On Sat, 26 Jan 2019 15:05:10 -0800, John Robertson
wrote:
Another detector for a hidden camera lens is the reflective LED method.
You wear a headdress of LEDs facing outwards just above your eyes and if
you see bright point reflections then you may have found your hidden
camera (lens)...

This was explored in the book by Cory Doctorow "Little Brother"
https://boingboing.net/2008/05/09/ho...ct-hidden.html
John :-#)#

Nice idea. My initial guess(tm) was that the anti-reflective coating
on the camera lens would umm... not reflect anything:

It's the retroreflection from the surface of the image sensor that you
see, like a cat's eye in the dark. If the sensor is at the focus of the
lens, the reflection goes straight back to the light source.

Cheers

Phil Hobbs

--
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC / Hobbs ElectroOptics
Optics, Electro-optics, Photonics, Analog Electronics
Briarcliff Manor NY 10510

http://electrooptical.net
http://hobbs-eo.com