Re: IR Illuminators

["Robert L Bass" <no-sales-spam@bassburglaralarms>]

> I have several day/night cameras, some really cheap,
> one is somewhat expensive.  They work great.  But I
> also have some very expensive high end cameras,
> such as the Sensormatic Speeddome Ultra VII, and
> the Axis 213 which are not day/night, at least not
> automatic day/night.  These are the ones I need the
> extra illumination for.  What would I need illumination
> for on cams that already have day/night?

Day/Night usually means (among other things) that the
camera is equipped with a IR filter that disengages during
the night.  The IR filter's purpose is to prevent IR light
which is abundant in daylight from overloading the imaging
sensor.  Without IR filtering the image would be washed
out by all that IR light because the sensor sees it almost
as well as it does visible spectrum light.  At night, however,
there is very little natural IR light or visible light.  By
removing IR filtering at night the camera can see objects
(they look black and white) which would not be viewable
due to the lack of visible light if you provide auxiliary IR
illumination.

IR illuminators are like visible light sources as far as the
camera is concerned.  The more IR light the easier it is
for the camera to see when there's little or no visible light
available.  The problem with non-day/night cameras with
IR filters is they get no visible light at night AND their
fixed filters block IR.

> I bought an IR illuminator on ebay thinking that I could
> use it with the Speeddome Ultra VII inside my house so
> that my daughter could not sneak back to her room
> after being out half the night, but I can't see squat
> because it's so dark.  It has 48 LEDs, but doesn't
> illuminate worth a damn with that camera.  I tell the
> seller, he says "you need low lux camera to take
> advantage". That's like giving Dolly Parton a boob job
> if you ask me.

Heh, heh, heh...  An apt comparison.  :^)

The seller is not giving you an adequate explanation,
possibly because he doesn't really understand it himself.
How far is the illuminator from the subject (in this case
your daughter)?  It's possible the IR light isn't bright
enough.  It's also possible (though I'm not certain without
looking at the spec sheet) that the camera is not set for
day/night operation.  If that is the case, a filter might
be blocking the IR.  I'm not expert on that camera so I
can't say for sure.

--

Regards,
Robert L Bass

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