Science question.

SixPapaCharlie

SixPapaCharlie

May the force be with you
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Aug 8, 2013
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First Officer 6PC
How come my smart phone camera can see a visible light coming from my TV (IR) remote but my eyes can't see it? Actually, I know why my eyes can't see it. Why does the camera make it visible to my eyes? If you haven't tried this, aim your tv remote at your smart phone camera and press a button. 20160417_103912-480x853.jpg
 
The spectral range of the camera is different from that of your eyes, but the display device is designed to present data to human eyes so energy is corrected appropriately. The camera rate is more into the red, so IR is emphasized and the other part of the spectrum (UV) is attenuated.

Saw a good example of this years ago, with an early black and white digital video camera and a laser pointer. To the human eye, a laser dot projected onto a surface is a sharply-defined small (but fairly bright) dot. But the video camera had massive blooming, as the red was so intense it saturated the receptors. Also explains why most cats go nuts, their vision is more towards the IR and that little red dot is much more intense.

Ron Wanttaja
 
I remembered a "scandal" years ago.

Early Sony camcorders didn't have IR filters on them and the sensors would see IR. Like many of the "security" cameras ringed with IR LEDs to have "night vision" today.

Apparently many types of apparel are translucent or nearly invisible at IR even though it's not possible to see through them at normal human light source frequencies. Many of the common materials that did this were what ladies swimsuits were made of back then. No idea if this is still an issue. I don't buy many ladies swimsuits. Go figure.

Pervs were buying the cameras and heading to the beach for an afternoon of filming.

Of course Sony's answer was to add an IR filter, which the pervs simply removed. The camera model soon left the market.

Most of the sensors haven't changed since then. I'm sure there's still pervs that remove the IR filters and head to the beach. Or invite the neighbor's over to the hot tub party, and then check their "security" camera footage later after everyone has gone home, hoping for a peek at Mrs Robinson's boobs.

They're probably outside hanging up a better IR light source near the camera, right now. Smile for the camera if your neighbor has a big old thing that looks like an LED array near their "security" camera that's aimed at the pool/hot tub area.

They'll probably tell you it's so they can watch for drowning children or similar. Safety is a popular story amongst anyone lying these days.
 
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denverpilot said:
I remembered a "scandal" years ago.

Early Sony camcorders didn't have IR filters on them and the sensors would see IR. Like many of the "security" cameras ringed with IR LEDs to have "night vision" today.

Apparently many types of apparel are translucent or nearly invisible at IR even though it's not possible to see through them at normal human light source frequencies. Many of the common materials that did this were what ladies swimsuits were made of back then. No idea if this is still an issue. I don't buy many ladies swimsuits. Go figure.

Pervs were buying the cameras and heading to the beach for an afternoon of filming.

Of course Sony's answer was to add an IR filter, which the pervs simply removed. The camera model soon left the market.

Most of the sensors haven't changed since then. I'm sure there's still pervs that remove the IR filters and head to the beach. Or invite the neighbor's over to the hot tub party, and then check their "security" camera footage later after everyone has gone home, hoping for a peek at Mrs Robinson's boobs.

They're probably outside hanging up a better IR light source near the camera, right now. Smile for the camera if your neighbor has a big old thing that looks like an LED array near their "security" camera that's aimed at the pool/hot tub area.

They'll probably tell you it's so they can watch for drowning children or similar. Safety is a popular story amongst anyone lying these days.
Click to expand...
thank you! This is great information. if anyone needs me I will be in the backyard putting security cameras over the pool to keep the kids safe.
 
denverpilot said:
I remembered a "scandal" years ago.

Early Sony camcorders didn't have IR filters on them and the sensors would see IR. Like many of the "security" cameras ringed with IR LEDs to have "night vision" today.

Apparently many types of apparel are translucent or nearly invisible at IR even though it's not possible to see through them at normal human light source frequencies. Many of the common materials that did this were what ladies swimsuits were made of back then. No idea if this is still an issue. I don't buy many ladies swimsuits. Go figure.

Pervs were buying the cameras and heading to the beach for an afternoon of filming.

Of course Sony's answer was to add an IR filter, which the pervs simply removed. The camera model soon left the market.

Most of the sensors haven't changed since then. I'm sure there's still pervs that remove the IR filters and head to the beach. Or invite the neighbor's over to the hot tub party, and then check their "security" camera footage later after everyone has gone home, hoping for a peek at Mrs Robinson's boobs.

They're probably outside hanging up a better IR light source near the camera, right now. Smile for the camera if your neighbor has a big old thing that looks like an LED array near their "security" camera that's aimed at the pool/hot tub area.

They'll probably tell you it's so they can watch for drowning children or similar. Safety is a popular story amongst anyone lying these days.
Click to expand...
It was not early Sony camcorders, it was a specific line with "Nightshot" mode that allowed the user to disable the IR filter. But you've got to somehow filter out most of the visible spectrum too, in order to get the x-ray effect.
 
Lindberg said:
It was not early Sony camcorders, it was a specific line with "Nightshot" mode that allowed the user to disable the IR filter. But you've got to somehow filter out most of the visible spectrum too, in order to get the x-ray effect.
Click to expand...

Ah ok. I never looked up the details. Never had one. I assume a dark ND filter would handle the visible.
 
According to the global warming hoaxers it's not about the science, it's about consensus. If we all agree that your remote and camera are conspiring to make you believe there's a light when there isn't then there must not be a light.
 
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