Re: Will IR Illuminator work with any CCD Camera?

[I use solid wire <solidwire@xxxxxxxxxxxxxxxxxxxx>]

You are a real piece of work.  I bet your eyes are crosseyed from all
that cut and paste, huh?

To anyone reading this, dismiss this idiot's composition on cameras.
If you want to know which camera to use post on ASA or cctvfourm.com.







On Mon, 8 Jan 2007 01:34:20 +0000 (UTC), don@xxxxxxxxxxxxxx (Don
Klipstein) wrote:

>
>  Cameras that work from IR illumination, with at most very few exceptions
>(I can't name any), work from infrared wavelengths generally in the IR-A
>range, which is .7 to 1.5 micrometers.
>  For that matter, most of such work with illuminators is done with a
>narrower range, since silicon IR photodetectors don't do well with
>wavelengths longer than about 1.2 or so micrometers, and wavelengths a bit
>longer than .7 micrometer (up to .82 easily, maybe .9 or so) are visible
>enough for one to see the light source in the dark.
>
>  As for thermal IR - keep in mind that a 3000 K halogen lamp filament has
>peak close to 1 micrometer and at .4 micrometer (borderline violet-UV)
>output is down to about 7% of peak.  At 300 nm output is close to or a
>little over 1% of peak.
>  Keep in mind that this translates to 300 Kelvin radiation peaking close
>to 10 micrometers, 7% of peak at 4 micrometers, and 1% of peak at or
>hardly below 3 micrometers.  I have a non-contact thermometer and IIRC
>it works from the 7-14 micrometer range according to its documentation.
>
>  Please know that "room temperature thermal IR" is generally absorbed by
>glass, water and most other transparent objects.  A non-contact IR
>thermometer will not see through these objects but read the temperature of
>these objects.
>
>  Further digressing, many materials that absorb 10 micrometer ballpark
>IR, even if transparent in the visible, are transparent at microwave and
>radio frequencies.  IIRC, Hertz managed some determination of an index of
>refraction of some material for radio waves from some kind of spark
>transmiter (presumably of frequency high enough to do this with) before
>Tesla and Marconi, before there was electronics.
>  There are some materials with more limited rages of failing to be
>transparent to medium/long IR wavelengths.  What comes to my mind now are
>some halides (such as potassium chloride - hygroscopic!) and (probably not
>all) non-metallic elements and non-metallic isotropes of elements in the 4
>and 5 column of the periodic table (where 3-8 are the last 6 and 1,2 are
>the first 2), in periods/rows at least 4.  Germanium and silicon come to
>my mind as being mentioned as transparent to "mid-IR"/"far-IR", and
>probably not transparent to all wavelengths in these ranges.
--
"As we know, there are known knowns.
There are things we know we know.
We also know there are known unknowns.
That is to say we know there are some things
We do not know.  But there are also unknown unknowns,
The ones we don't know we don't know."

Feb. 12, 2002, Department of Defense news briefing - (Donald Rumsfeld)