i am no photography buff, but, my hobby project "night vision rifle scope" has me reading on stuff...
I know from photography sites and similar, that "ir" focuses differently than visible light. That actually for photography, the different colors of visible each focus slightly differently, and that some lenses cause "chromatic" abberations.
multiple lenses and special lenses/coatings correct for this...
a demonstration with a security cam, running in low ambient light, with a fairly strong IR light video... showed how you can have to re-focus some "zoom" lenses, as how it focuses ambient (visible) light, is a different "focus" from the strong IR light source.
basically, i gathered that different wvelengths of light, bend (refract) a different percentage from their original path, going thru the same lens. It makes sense that IR focuses behind/in front of the film/sensor... when i think of it as another "color".
in a PRACTICAL sense, this seems to be just a focus adjustment... i was wondering if there are any bizarre focusing things a NEWB like me would be expected to know about IR light coming from a laser diode...
i mean, if i can focus VISIBLE light a certain way thru a certain lens... are we just talking a slight focal length change to do the same thing with IR source of light? I'm not talking collimated/focused laser light... i'm thinking more along the lines of using it more like a flashlight for my application.
i realize laser output is different from incandescent and ambient light... but, i have been using a LED EMITTER flashlight to rough out the illuminator, and that is a fairly narrow bandwidth of output... am i stupid in not knowing that, for instance, that 800-850nm laser illumination needs special lenses and coatings that the almighty grinds and polishes and coats? or, can i just count on a few mm's of focal point difference?
I mean, remember i am not trying to focus and collimate the output... if 5 or 10 percent f the light is refracted off, or shifts wavelength or something, or reflects, it doesnt really concern me.
I just wanna make sure a "regular" optical lens isnt going to be like a BRICK WALL or anything...
I know from photography sites and similar, that "ir" focuses differently than visible light. That actually for photography, the different colors of visible each focus slightly differently, and that some lenses cause "chromatic" abberations.
multiple lenses and special lenses/coatings correct for this...
a demonstration with a security cam, running in low ambient light, with a fairly strong IR light video... showed how you can have to re-focus some "zoom" lenses, as how it focuses ambient (visible) light, is a different "focus" from the strong IR light source.
basically, i gathered that different wvelengths of light, bend (refract) a different percentage from their original path, going thru the same lens. It makes sense that IR focuses behind/in front of the film/sensor... when i think of it as another "color".
in a PRACTICAL sense, this seems to be just a focus adjustment... i was wondering if there are any bizarre focusing things a NEWB like me would be expected to know about IR light coming from a laser diode...
i mean, if i can focus VISIBLE light a certain way thru a certain lens... are we just talking a slight focal length change to do the same thing with IR source of light? I'm not talking collimated/focused laser light... i'm thinking more along the lines of using it more like a flashlight for my application.
i realize laser output is different from incandescent and ambient light... but, i have been using a LED EMITTER flashlight to rough out the illuminator, and that is a fairly narrow bandwidth of output... am i stupid in not knowing that, for instance, that 800-850nm laser illumination needs special lenses and coatings that the almighty grinds and polishes and coats? or, can i just count on a few mm's of focal point difference?
I mean, remember i am not trying to focus and collimate the output... if 5 or 10 percent f the light is refracted off, or shifts wavelength or something, or reflects, it doesnt really concern me.
I just wanna make sure a "regular" optical lens isnt going to be like a BRICK WALL or anything...