Subscriber Discussion

Has Anyone Tried Using Smoked Domes With Integrated IR?

TC
Trisha (Chris' wife) Dearing
Jun 06, 2015
IPVMU Certified

Smoked domes with IIR, wtf?

On the one hand it seems kind of idiotic:

Clear glass and polycarbonate already bi-directionally reduce transmission of IR, a smoked dome would therefore be expected to absorb/reflect a good deal more IR.

On the other:

if you need to use a smoked dome you are already at a low-light disadvantage, so even of half the IR gets thru (and is returned) that would be an improvement.

Additionally, let's face it, a lot of the IIR domes out there are eyesores, and would be more aesthetically pleasing with one on.

Yet, searching on the web I find very few models and fewer mentions of this combination, which leads me to believe I'm missing something.  

Has anybody tried it?

 

U
Undisclosed #1
Jun 06, 2015

in an elevator

(1)
TC
Trisha (Chris' wife) Dearing
Jun 06, 2015
IPVMU Certified

We have an inside joke of the week winner!

BG
Bob Germain
Jun 07, 2015

We (Hikvision) warn of potential internal reflections if using a smoked bubble with IR so it is recommended to disable the IR if using a smoked bubble.

TC
Trisha (Chris' wife) Dearing
Jun 07, 2015
IPVMU Certified

Thanks, Bob! That makes sense that there might be some additional reflection due to the smoked dome, how much more I wasn't aware.

btw, does this Hik, the DS-2CD3Q10FD-IW, really have IR? Where does it come from?

TC
Trisha (Chris' wife) Dearing
Jun 22, 2015
IPVMU Certified

One thing to keep in mind that may not be intuitive is that just because the dome tint looks dark, that is only proof that it is absorbing/reflecting visible light.

Indeed, many photographic filters are designed to block all visible and let pass IR. They, obviously, look dark. Maybe too expensive to implement in CCTV, I don't know. Then again maybe since IIR domes have come to popularity only recently, this combination has not been correctly engineered by many mfrs to enable good performance.

Take look at this FLIResque example:

Notice how the clear glasses are opaque to IR and the opaque garbage bag is translucent to IR.

Of course the thickness of the materials is paramount here as well, but does illustrate the point that opaqueness is spectrum specific.

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