G'day Bill,



27 Nov 96 15:41, Bill Grimsley wrote to Dieter Mirbach:



 DM>> I believe a standard video camera can detect IR, and sees it

 DM>> as a point of light, or whatever.



 BG> Rod seems to think so as well, but I'm not convinced (then again, nor



Alas, it is true - The CCD (and tube) cameras are sensitive to IR.

However most (if not all) of them have a filter in front of the pickup

to block it out.

Even without this filter they are generally not sensitive enough to be

useful though... they will only just bearly show the IR radiation

emitted from typical IR remote control when pointed directly at the

lens from a few inches (sometimes feet) away.



 BG> am I in a position to prove it either way).  However, given that

 BG> almost all video cameras now use an IR beam for their auto-focus

 BG> detectors,



Not so....  IR beams for AF haven't been used in most camcorders for

several years now..  They generally use a dedicated CCD pickup these

days and monitor & adjust the focus for the best frequency response

from it  (well, that's the simple description). Such cameras actually

focus the _image_, unlike the older IR system which basically measured

the distance from the object being filmed and adjusted the lens

position according to this distance.



Cheers,

Rod



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