Remote Control Check

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Duff wrote:

Differing sensitivity ranges -- the camera CCD can "see" the IR and images it onto the display into the visible spectrum. The "raw" IR isn't in the portion of the spectrum visible directly.
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If you wanted an explanation, you should have asked for one. Otherwise, we'll assume the answer is as obvious to you as it is to us.
Why you can't see anything: Those wavelengths of light are called "infrared" because they are longer wavelength (lower energy) than visible red. They are used for remote controls *because* they are not visible to us, yet easily generated and detected by silicon devices.
Why your camera sees it: The camera uses a silicon-based detector, either CCD or CMOS. Silicon is quite sensitive to near-IR, which is one thing that makes near-IR a good choice for remote control communications. So the camera sensor naturally sees the IR, unless the camera incorporates a really effective IR filter to remove those wavelengths before they reach the sensor.
In fact, most digital cameras *do* have an IR filter, because IR is seen as white light by the sensor (it passes through the RGB filters) which reduces saturation and shifts colours. So there is an IR-blocking filter which is effective enough at reducing the effect of IR naturally present in scenes illuminated by the sun or incandescent lamps. But it's not effective enough to *completely* block the very bright IR produced by the LED in the remote control.
BTW, there are video cameras built for security/surveillance that deliberately have high IR sensitivity so the camera plus a few IR LEDs make a "see in complete darkness" camera.
    Dave
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Duff posted for all of us...

eye.
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Tekkie - I approve this advertisement/statement/utterance.

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And then you sister looks at my snake eye.
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