eBay IR filters

bewsher500

Well-Known Member
just picked up a couple of these from a nice chap in Kelso of all places!
Plan on retrifitting one to a small LED Cree type torch as a additional light source for the NV monocular

has anyone tried these with any success?
at £3 it was worth a punt regardless
 
Link please Bewsh - just remember that a Cree LED will not put out a lot of light in the IR wavelengths - far better with a conventional lightsource.
 
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interesting.

got me digging. not my usual source of technical info but this:
http://en.wikipedia.org/wiki/Light-emitting_diode

would indicate that a "white" LED would be expected to emit the usual range of colour/wavelengths that you would find in white light. including IR.
may not be as high as a filament but should give something.

But when I tested it in the garden just now the LED torch gave next to no light through the filter
my filament Deben Stinger gave a good beam of IR out to the wall at 35yds, no results out past that as I am somewhat restricted in the garden!

just goes to show Wikipedia really is full of sh1t as I thought!
 
interesting.

got me digging. not my usual source of technical info but this:
http://en.wikipedia.org/wiki/Light-emitting_diode

would indicate that a "white" LED would be expected to emit the usual range of colour/wavelengths that you would find in white light. including IR.
may not be as high as a filament but should give something.

But when I tested it in the garden just now the LED torch gave next to no light through the filter
my filament Deben Stinger gave a good beam of IR out to the wall at 35yds, no results out past that as I am somewhat restricted in the garden!

just goes to show Wikipedia really is full of sh1t as I thought!

Without wishing to go into a full-on physics lesson, white light does not contain IR! A standard torch bulb creates heat from the filament which is where the IR comes from (and is a waste of battery power!). An LED is a very efficient means of light production because it produces negligible heat and therefore no IR from a white light LED.
However, LED's can be manufactured which produce only IR which are also very efficient, but invisible to the naked eye.
The type of filters you can buy for standard torches are purely white light blockers which allow the heat from the filament to pass through basically. They are therefore not very efficient either!
Hope that explains the basics?
MS
 
I have a friend doing a lot of work on this, for oil industry NDT work. He has converted my remote control roof mounted lamp by putting a camera that can see IR into the middle of it, and mounting 10 ir leds round it, each with its own wee reflector. I will put up pictures later. It connects to a monitor that is part of my radio / dvd player. When turned on the leds show a small red dot each, just visible, yet will illuminate out to a couple of hundred yards, and rabbits are easy to pick out at this range. Roe and foxes show up like in day time at 150 yards. He tells me that it is very bright, blinding but above the range of our vision, and we are just picking up the very bottom of the wave lengths as dull red lights, and will only shine visibly on your hands from 4 inches.

Going a huge step further he took along a thermal imager today, we went out last night and it was awesome, again plugged into the radios monitor. We stayed out till 10 last night, scanning rabbits and roe, even into the forrest in full darkness. We could see deer moving between the trees in total darkness.It was so good we were back out at 5 this morning, hoping to get into position to catch red deer returning to the forrest. We did not see red deer, it was blowing a gale, but could pick up grouse peaking at us from above the heather, at about 100mtr. We could see a flock of sheep on another hill at 2000mtr, as a series of white dots. Roe at 100 - 200 mtr were easy to see, peaking out of the forrest.

Ok, this is not a shooting tool, but is a spotting one. I have a roof mounted white light lamp, and have a thick IR filter for it. It filters / reduces the light significantly, but still throws a decent light, and the camera really works well with it, it works light a flood light.

We are going to have some fun with this for sure!
 
@ DiverDave - I'd be really interested to see that set up - sounds fab

@MS - I've just taken delivery of the Nightnaster IR and it is as good as the video - I painted the hillside out of the back of the house last evening at c 1000 yards - it will be a really good tool with the right NV....
 
A 'white' light Led is basically a UV LED behind a phosphor screen as you might find in a fluorescent lamp, so IR output would be negligible.
 
Without wishing to go into a full-on physics lesson, white light does not contain IR! A standard torch bulb creates heat from the filament which is where the IR comes from (and is a waste of battery power!). An LED is a very efficient means of light production because it produces negligible heat and therefore no IR from a white light LED.
However, LED's can be manufactured which produce only IR which are also very efficient, but invisible to the naked eye.
The type of filters you can buy for standard torches are purely white light blockers which allow the heat from the filament to pass through basically. They are therefore not very efficient either!
Hope that explains the basics?
MS


So... We should feel heat from a IR LED then?
 
white light is generally referred to as light containing the full spectrum visible and invisible. Including Infra Red and Ultra Violet
midday sun, incandescent lights, fluorescent lights etc all produce "white light" albeit some are missing elements of the spectrum

it is true radiant heat is Infra Red, but not all IR is heat so the measure of effciency through heat production doesnt always follow


OC0811004_WhiteLight.jpg
 
So... We should feel heat from a IR LED then?

No, the IR used by night vision devices is 'near IR' which is only just out side our visible spectrum which is why some illuminators and filters have a dull visible glow to them. Near IR therefore behaves in a similar fashion and is mainly reflected. (Substances only heat up if the radiated waves are absorbed). True 'heat' radiation tends to be towards the middle of the IR range. (But I suspect you already knew that!?;))
The night vision devices we generally use are 'image intesifiers' which do nothing more tham amplify ambient light.
Thermal imaging is something completey different, but lets not go there as it is expensive!
MS:)
 
I am out with the kit again tonight, so will pop up some pictures of the IR set up, the thermal image set up and some screen shots. We are building another set up for attaching it all to the landys roof at the moment, as it is of course alloy. I am working all day and the others are having fun setting up the kit.

They came round with the thermal imager today and it is awesome, just touch a tree for 3 seconds and the heat is visible for 30 seconds and more. I can see it being great for tracking animals and seeing where they congregate.

We are still in the early stages of it all, and just ordered a second screen for the landy, so we can work both at the same time, instead of swapping between them.

What we are finding best in the few sessions we have had since buying it is it saves so much time, the Thermal imager shows us when there is nothing there. So a quick scan of a field or sparce forest is showing when there is nothing there. If we see anythiung we can look properlay at it with the IR and id it. We are not using it for shooting yet, as we only have an ir set up for the rim fires, but it will be deadly for foxes, and for showing us where our deer are. I can see it being ideal for checking an area in complete darkness for the deer, then allowing us to get into position for a first light shot.

They are a work in progress but initial results are awesome. One other pal has a nitesite on his 243, for the foxes. It is good, and probably really good value, but not in the same league as the set up we are working with.
 
This is the toy, up on the top of the landy. It is a simple remote control lamp with the reflector removed and a light sensative camera fitted with an adjustable lamp and 10 ir led's/

IMG-20120930-00060.jpg


This is it turned on, the camera on my phone is seeing the IR as red, my eyes could not really see it. All i could see was a really dull glow.


IMG-20120930-00061.jpg


A hill ride, in total darkness, again our eyes could only see a black hillside, though the full moon did show some features. It works better in total darkness with no moon. To give you an idea what outside looked like, the screen is in front of the windscreen, so the background is what we could actually see outside the windows.


IMG-20120930-00071.jpg


Thermal imaging a sheep, total darkness. The imager is awesome, a quick scan reveals whatever is in the field. we are quickly finding it shows us what is there and when a field or the his is empty. We clearly saw one roe with our eyes earlier, but the IR and the TI revealed there were actually two!


Aberdeenshire-20120930-00086.jpg

IMG-20120930-00071.jpg


The sheep could not see my son, sneaking up on them! I am sure some will find this useful!

Aberdeenshire-20120930-00088.jpg


Thermal image of a bunny, at about 60 yards


Aberdeenshire-20120930-00081.jpg

The kit is awesome, we are really enjoying using it. We are seeing loads of wildlife, deer foxes and badgers, in places we have never seen them before.

The landy now has a split charging system and two batteries and alternators to power it all, but it is so worth it!

Dave
 
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+1 for the dereerlight 800 with IR rop in, its not the cheapest option but very good with outstanding throw
 
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