Re: [ATM] infra-red

[hermit <hermit@outofoptions.org>]

There are folks that specialize in removing IR filters on DSLR's 
according to my son.  If you can't find a web reference, send me an 
email and I'll see if my son has the reference.

Ken Lowther



Dominic-Luc Webb wrote:
> On Sat, 27 Jan 2007, Jarvis Krumbein wrote:
>
>   
>> All CCDs are sensitive to IR.  CCD digital cameras have an IR rejection
>> filter built in to block the IR.
>>
>> Jarvis Krumbein
>>     
>
> Hi Jarvis, others!
>
> As was explained to me, that filter also reduces red in order
> to give more neutral color with respect to blue. The last time
> I found absorbance scan of such a filter, it was not a sharp
> cutoff/bandpass filter. Absorbance smoothly climbed up from
> around 600 nm to a peak around 900 nm.
>
> I am curious about these rejection filters.... can they be removed?
> I have wanted to do IR imaging, and dedicated made-for-purpose
> hi-res IR cameras cost big time. With my common consumer CCD
> camera, I am losing a lot of the signal, albeit I can detect
> near IR, like a 15 mW TV remote IR LED (900 nm???) from about
> 5 meters away (best case scenario). I think without these filters,
> these cameras must make excellent IR cameras for scopes.
>
> That being said, I noticed in the States (Fry's Electronics) there
> are night security cameras being sold with IR LEDs as a light
> source. The ones I saw were B&W CCDs and I would imagine they do
> not have these filters since they are intended to be used in the
> dark, unknown to the person being imaged. Sadly, none of these had
> very high resolution. That was a couple years ago and these cameras
> seemed popular, so perhaps newer are are better.
>
> Dominic-Luc Webb
>
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>   

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