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Old May 25th, 2006, 04:08 PM   #1
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Infrared LEDs and DV camera

anybody confirm or confute that: it is possible to build nightvision device using IR LEDs(placing them into ringlight for example) and DV camera.

I did a few experiments with single IR LED and Panasonic nv-mx500. Camera
saw turned on IR LED very well. Same time it wasn't visible with naked eye.

Of course IR LED ringlight wouldn't work for very large distances - probably no more than ringlights in visible light specter. But despite that i am interested is there anybody who can say something for sure. Because somebody told me that it's impossible because DV cameras have special filter to get free from IR before CCD, because it's possible source of thermal noise. Believing that i cannot belive my own eyes ... :)
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Old May 25th, 2006, 05:55 PM   #2
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If your camera has nightshot capability, then any IR LED or any other type of infrared light source will work. I made an infrared flashlight to use with my sony camcorder. Its cool how the Infrared is not visible by eye, but is superbright on the camcorder.

My brother just bought a 48 high power IR LED box which is freakin bright. It will light up the room with infrared light. its amazing. Of course, only the camera will see all of this.

so if your question was that other IR leds will work in conjunction with your camcorder, it most definantly will if your camcorder already can record nightshot.

(also, i heard even if a camera doesnt record nightshot, it still picks up some of the infrared range with its sensor already, so its still IR sensitive, i think thats why sensors have the IR filter over it to fix that.)
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Old May 26th, 2006, 12:54 PM   #3
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Will one of you guys post a screencap?


Thx!
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Old May 26th, 2006, 01:52 PM   #4
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an easy test would be to just face a remote controll at the camera and press some buttons to see if it sees it. I tried this with my still camera too. Then I bought a infrared filter for my camera so I could take infrared pictures of stuff outside. pretty cool.
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Old May 26th, 2006, 01:53 PM   #5
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you need to check what kind of IR your led can emmit since there is a wide range of wavelength available and some are a lot better (efficient) to the camera.
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Old May 26th, 2006, 02:19 PM   #6
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Quote:
Originally Posted by Forrest Schultz
Its cool how the Infrared is not visible by eye, but is superbright on the camcorder.
Yeah, exactly!

Quote:
Originally Posted by Forrest Schultz
My brother just bought a 48 high power IR LED box which is freakin bright. It will light up the room with infrared light.
Actually thatswhy i asking.
I made ringlight with ordinary LEDs but i have a plan to change them to IR. Forrest can You tell, how many watts IR-light those high power LEDs emmited?
If You say it will light up the room... it is pretty encouraging...

Quote:
Originally Posted by Bill Porter
Will one of you guys post a screencap?
First i finish my ringlight and then i'll be glad to do that.

Quote:
Originally Posted by Michael Fossenkemper
an easy test would be to just face a remote controll at the camera and press some buttons to see if it sees it.
From that started my experiments.
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Old May 26th, 2006, 03:25 PM   #7
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some googling about subject:
gives basic about electromagnetic spectrum
http://en.wikipedia.org/wiki/Light_spectrum

answers the question that always bothered me:
How can I compare the output of IR LEDs, specified in watts, to visible LEDs, specified in millicandelas?
http://www2.whidbey.net/opto/LEDFAQ/...Pages.html#Q23

Spec of one of many IR LED's, you can find here spectral distribution.
http://www.elfa.se/pdf/75/07522535.pdf

How to build nightvision device:
http://www.badacetechshow.com/nvc.htm
http://www.opticsplanet.com/info/htb_nvd.shtml

interesting thread... especially that post:
Quote:
the cheap ones do but the more expensive cameras have a dichroic filter(heat mirror) which cuts off all IR light. These glasses make excellent camera filters. pop a lens out and tape it over your lens. i was sent a graph with these glasses and showed a cutoff of 700nm going all the way up to 2000nm
http://www.abovetopsecret.com/forum/thread206694/pg1


something about camcorders ability to see IR(given some wavelenghts):
http://www.maxmax.com/aXNiteFAQ.htm
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Old May 26th, 2006, 09:54 PM   #8
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Frank, this is the product we bought.
http://cgi.ebay.com/High-Power-Infra...QQcmdZViewItem

Its not a big box as it might look at first glance. its super compact, but super bright, i dont know the the watts, but when using it, i would say it is about the equilvilant of using a 100 watt light bulb , just in a Infra red version. Its very bright, and on second thought, it really is like a 100 watt light bulb. that thing lit up my garage, and its pretty directional , but when pointed at a wall it can light up the garge, you could even use diffusive sheets or something to spread out the light. either way, its very good for the price.

You can make something like this too, but be sure to purchase the super bright LEds , and not the standard lowpower ones.
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Old May 29th, 2006, 12:29 PM   #9
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quick facts

human eye response spectrum: 380 - 780nm.
most common IR-LEDs have peak at: 850, 880 or 940
typically IR LEDs lightspectrum spreads to 100nm, wich means:
850 spreads between 800 - 900nm
880 between 830 - 930nm
940 between 890 - 990nm

Some camcorders response spectrum can reach to 1000nm.
But even those have better sensibility in closer region to visible light.
So it seems that best IR's would be with 850nm peak. It still invisible for human eye.
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Old May 29th, 2006, 12:35 PM   #10
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jsut like the box i posted above.
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Old May 29th, 2006, 04:30 PM   #11
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this thread is useless without pics, lol

What I'm really curious about is not shooting in the dark, but helping in low-light situations where the footage would have the usual reddish cast to it. I am curious whether or not the use of IR LED's in a low light situation will make the scene appear more bright, or just skew the colors more toward the "night-vision" look?
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Old May 30th, 2006, 09:13 PM   #12
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Bill, i will post some pics. i just have to get off my lazy butt. In terms of using it for cinema, movie-making purposes, night vision basically is the same as lighting a set (except with infrared light instead). But i wouldnt use it for a movie because there is no real color in the picture, its like a black in white with greys and greens. thats all. for ghost work it kicks butt
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Old May 31st, 2006, 12:46 AM   #13
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Hi Forrest,

Right, I am familiar with the night vision look. Let me rephrase what I'm wondering about:

In a moderately low-light situation (indoors, etc.) you can film without any additional light but your footage will have a reddish tinge.

To eliminate this reddish look, I am wondering whether adding a small amount of IR light - just enough - could make the scene appear more bright and do away with some of the red tinge, without giving the ghost/nightvision look.

???
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Old May 31st, 2006, 02:43 AM   #14
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i will do tests according to my last post. With all three kinds of LEDs. Some of those not available from stock of local store. So, Bill, You'll get some theoretical tests first(w single LED) then best is worth to get into ringlight system.

But it seem to take time.
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Old May 31st, 2006, 04:09 AM   #15
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Awesome, thanks! Maybe we'll all learn something useful. It sure would be a nice fix for the typical low-light problems. And it wouldn't blind the subject as much, or be obtrusive.
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