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Digicam IR conversion [NEW: Conversion complete with pix]

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Dr. Shark

Sun Apr 23 2006, 08:59AM

Registered Member #75 Joined: Thu Feb 09 2006, 09:30AM
Location: Montana, USA
Posts: 711

There is a lot of talk about IR in the chatting board at the moment, so I thought I'd start a thread about this here, so people who have experience with this can share with people who dont. I am somewhere in between.
I have got an old Coolpix 2500 (you can pick up this or a similar model for about 50 bucks on eBay), and it is fairly easy to take it apart an remove the hot-mirror (this is the IR blocking element in front of the CCD). However, you need to replace this with a piece of glass of pretty much exactly the same thickness, so the optical distance from the CCD to the lens stays the same. Otherwise you will be able to focus beyond infinity, not focus further than 5cm, or something like that. One way to do this is to stack up a couple of layers of microscope slides, they are about 1mm, so you will usually need three layers. Easy.
The part where I didn't get on was the actual IR-transmitting filter, seems like you have to spend at least 30â‚¬ for one from a camera shop, and I found that a bit much for this experiment. This is where you come in, post your experience!

Sorry I don't have any pics of the dissection because my cam was sort of out of order when I did this

mikeselectricstuff

Sun Apr 23 2006, 09:13AM

Registered Member #311 Joined: Sun Mar 12 2006, 08:28PM
Location:
Posts: 253

You should be able to find IR filters a lot cheaper than that. I'm told that exposed, developed negative (or was it unexposed slides?) film works well.
I got some 4x4" sheets of IR transparent/vis opaque plastic from the front of some old lightbeam-break detectors. Older IR TV remote receivers (before these got integrated into single devices, they were typically a metal-canned receiver module which sometimes had an IR filter on the front) might also be worth a look
I'm sure there are some other sources of suitable plastics out there.
Edmund do some IR filters at not-stupid prices :

although these don;t look as opaque as the usual jet-black stuff.

c4r0

Sun Apr 23 2006, 11:18AM

Registered Member #151 Joined: Sun Feb 12 2006, 02:53PM
Location: Poland
Posts: 153

mikeselectricstuff wrote ...

I'm told that exposed, developed negative (or was it unexposed slides?) film works well.

The IR photos that I posted in 'Post your cool pic here!' thread was taken using this type of filter. My brother made it using 3 layers of full exposed and developed negative, and as you can see there it works very well

HV Enthusiast

Sun Apr 23 2006, 01:10PM

Registered Member #15 Joined: Thu Feb 02 2006, 01:11PM
Location:
Posts: 3068

If you are going to modify your camera for IR, you might as well do it right. For best performance, you will need a R72 or RM90 type IR filter - the R72 is less expensive. If you contact the guy at Life Pixel Infrared, he may have a replacement hot mirror for you made from the R72 material. They are about $95.00 USD, but well worth it especially if they are cut to the correct size.

Simon

Sun Apr 23 2006, 11:43PM

Registered Member #32 Joined: Sat Feb 04 2006, 08:58AM
Location: Australia
Posts: 549

For amateur work, you can also make an IR filter from the magnetic stuff inside floppy-disks, or steal one from an old VCR (or something else with an IR remote).

Michael W.

Mon Apr 24 2006, 12:54AM

Registered Member #50 Joined: Thu Feb 09 2006, 04:07AM
Location: Vernon, B.C, Canada
Posts: 324

I haven't found the floppy medium to work....All it does is make things brownish red.....

Dr. Shark

Mon Apr 24 2006, 07:33AM

Registered Member #75 Joined: Thu Feb 09 2006, 09:30AM
Location: Montana, USA
Posts: 711

EastVoltResearch wrote ...

If you are going to modify your camera for IR, you might as well do it right. For best performance, you will need a R72 or RM90 type IR filter - the R72 is less expensive. If you contact the guy at Life Pixel Infrared, he may have a replacement hot mirror for you made from the R72 material. They are about $95.00 USD, but well worth it especially if they are cut to the correct size.

Dan definitely has a point here: If one goes though all the trouble of modifying a cam for permanent and IR-only operation, it would be nice to get something with a clear wavelength cut-off at around 700nm and highly transparent from 700 to at least 1400nm, and not something of questionable optical qualitiy like a floppy disk. Since it is going to be mounted directly in front of the sensor, every minor flaw will show up.

So, anybody else got conversions to show off?

Sulaiman

Mon Apr 24 2006, 09:26AM

Registered Member #162 Joined: Mon Feb 13 2006, 10:25AM
Location: United Kingdom
Posts: 3140

My camcorder (HC1E) has 'nightshot' and 'super nightshot'
with or without ir led illumination.
I bought a proper ir filter and made an extra multi-ir led light!

After all that I'm quite dissapointed with the results
- No 'predator' vision
- just monochrome with some things (grass etc.) being brighter than usual.

So unless you have a USE for ir (typ >=900 nm)
I wouldn't bother.

Have a look at ir photographs on the net - easier/cheaper/wide-range.

Anyone know how to convert to "thermal imaging"?

P.S. uv flourescsnce is a little more interresting.

P.P.S. "NIGHTSHOT" is just the inbuilt ir filter being physically moved out of the light path.

Penguin7471

Mon Apr 24 2006, 12:01PM

Registered Member #71 Joined: Thu Feb 09 2006, 08:23AM
Location:
Posts: 63

You can pick up a Hoya R72 filter on eBay for a pretty decent price.

There is no way to simply modify a CCD to make it sensitive to FIR (thermal). You'd have to buy a FLIRcam or whatchacallit.

I want to remove the IR filter in my Konica Minolta Z10, but since I also use the cam for normal photography, I'm reluctant to do so.

Bjørn

Mon Apr 24 2006, 01:30PM

Registered Member #27 Joined: Fri Feb 03 2006, 02:20AM
Location: Hyperborea
Posts: 2058

Anyone know how to convert to "thermal imaging"?

A CCD chip is sensitive to heat and on some modern cameras you can annoyingly register heat from the chips inside the camera on long exposure times. You would need something like a metal mirror to form the image and a very good filter. Since the chip conducts heat fairly well the image would smear as heat conducts to different parts of the chip.

$95.00 USD, but well worth it especially if they are cut to the correct size.

For some people that would mean being without food for 3 months and not an option in any way. For them unexposed slide film is an excellent free substitute.

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