In article 6,
DerbyBorn writes
I have noticed many CCTV cameras have a ring of LEDs around the lens - but
behind a front glass (Saw this on a drone which made me wonder....)
Can the LEDs be of any use given the sort of useful distance that the
camera is expected to focus on? Does having the LEDs behind the front glass
cause scatter off dust and moisture to ruin the image. Are they just a
gimmick?
(a bit like using a flash on a camera at a stadium concert - see Inverse
Square Law of Light)

I think they are a bit ****, I'd much prefer a proper low light camera
rather than one of those fakes. They do still exist but it is near
impossible to find them as the false claims of the LED based ones swamp
the real ones.

It comes down to doing your homework, looking at proper reviews of the
camera sensors themselves and choosing a camera that uses one of the
proper low light ones eg. Sony Super HAD CCD sensors used to be
excellent for sensitivity but may have been surpassed now. I see SONY
EX-View also gets a mention now.

On the scatter back problem, this doesn't happen as you will find there
is a foam grommet surrounding the lens in contact with the glass that
cuts out any internal or external reflections and the LEDs are (just)
far enough away and their beams narrow enough that external reflections
do not occur.

--
fred
it's a ba-na-na . . . .