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Viewing infrared rays

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Hi guys,
while browsing through this site,i came across some amazing thing.i read that by using the camera having lcd screen,we can see whether ir led is glowing or not.i tried this with mobile camera and i was amazed to see ir led glowing.i want to know whether any mobile camera will work(i mean any mobile)
 
Pretty much all digital cameras are particularly sensitive to infrared, and have a filter to balance it out some. Unlikely to find one that doesn't these days.
 
Remember when Sony got into trouble for having a camera that could see IR though clothing?
Then an IR filter was added.
 
Long as you're here, guru, answer a question: in the Old Days, (mid last century) they used a term micro-micro farad, which I suspect we'd call a nanofarad today. Was there any other classification used then, or was mike-mike the least in common use?
 
Hi guys,
i want to know whether any mobile camera will work(i mean any mobile)

The key is the LCD screen. Some digital cameras having only a clear window viewfinder will obviously not work. You have to be able to see what the lens sees.
 
Long as you're here, guru, answer a question: in the Old Days, (mid last century) they used a term micro-micro farad, which I suspect we'd call a nanofarad today. Was there any other classification used then, or was mike-mike the least in common use?
No.
A nano-farad is one-thousandth of a millionth of a farad. A micro-micro farad is a pico-farad.
 
audioguru, pretty much all video cameras and obviously all digital cameras today are based on CMOS or CCD image sensors which are sensative to near IR to some degree, you'll see a remote control light up on every single digital camera in existence filtered or not. The IR cut filters simply aren't that steep of a cutoff, they're primarily there to keep things like trees and the sky from looking over exposed as they reflect quiet a bit of near IR light. With a filter visible light almost completely bleeds out any IR received so it doesn't affect the image noticeably. However if you go to a high end camera store you may be able to purchase yourself a visible light filter, which cuts off most of visible light and will allow you to take IR photo's if you have manual exposure control on the camera, because of all the attenuation from both the IR cut and visible light filters you're only getting a tiny fraction of what's there.

It is possible to remove the IR Cut filter from some digital cameras, it's really on a case by case basis, but the filter would have to be replaced with a piece of glass of nearly the same dimensions. I also believe the IR cut filters aren't actually in the glass itself it's a coating, so cleaning with acid may remove it.
 
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Thanks, AG. Piddling with those wee numbers is probably the most difficult part of learning this hobby. Have a hard time keeping my nanos separated from my µµF's.
 
Don't forget your femto,s attos, zeptos, or yoctos AllVol =)
 
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Long as you're here, guru, answer a question: in the Old Days, (mid last century) they used a term micro-micro farad, which I suspect we'd call a nanofarad today. Was there any other classification used then, or was mike-mike the least in common use?

They used milli-microsecond instead of nanosecond. You'll find this in the Radiation Lab books.
 
They used milli-microsecond instead of nanosecond. You'll find this in the Radiation Lab books.

Thanks! I was reading "Radio - Television and Basic Electronics" by R. L. Oldfield, 1957. He only mentioned micro and micro-micro. I wondered about the rest.
 
Did the terminology not exist back then, or where they intentionally trying to be obtuse?
 
Remember when Sony got into trouble for having a camera that could see IR though clothing?
Then an IR filter was added.
Really? Silicon detectors are sensitive up to about 1.1 microns. Wouldn't any IR that can pass through clothing be much longer wavelengths?

Or was this not a silicon detector camera?
 
Depends on the dies and fabric type of the cloth Redbelly. It's not so much that the rays can penetrate the cloth, moreso it's the cloth more transparent to near IR than it is to visible light. The whole thing was overblown in the first place, all it let you see was an outline under optimal conditions.
 
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