Question about lens selection for IR led

Happytobehere

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May 30, 2016
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I'm putting together an IR light source for use with camera for night vision capability. I'm using 2 of these 100 watt leds https://www.ebay.com/itm/100W-Infra...296201?hash=item3cfaf37209:g:hy0AAOSwZd1Vac0P
I've found this dual led heat sink with lens and fan https://www.ebay.com/itm/60-degree-...809115?hash=item3adb26149b:g:nLoAAOSw3v5Yr5ko . My question is in the drop down section to select the lens on the heat sink it list 57mm or 44mm as a choice for the lens. I'm confused about this selection. Will either lens 57mm or 44 mm fit on my 100 watt leds ? If both will fit what difference would there be between the 2 lens sizes ? Also anyone know if 850 nm light would pass through the lens easily ? Also I've noticed a line cut in the heat sink block that passes under where the leds will mount, would this still carry away the heat evenly from the leds even where the line is cut ?
Sorry for the long and dunce questions but I'm new at this and working on a very limited budget and trying to build because I can't afford already assembled.
Thanks a ton for any and all help on this subject.
 
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