2/23/2012

DIY - Infrared Camera Filter

While reading about making the ND filter i saw instructions on making an Infrared filter for your camera. The ND filter used a piece of welding glass to "dim down" the amount of light that enters the camera. With a IR filter you need something that only allows infrared light to enter the camera. I had an old camera that i never use because the lens is kind of scratched, so it was perfect to try this out with.

The infrared wavelength is just longer than is visible to the human eye. In fact visible light is only a small part of the light spectrum.
Infrared Light Table Spectrum
Far infrared is used in thermal imaging cameras. Heat given off by objects is in the far infrared spectrum of light.
Thermal Infrared Camera Heat
The pictures i would be taking would not show this kind of thermal imaging, just the light from the Near Infrared.

Simply put, i wanted to remove the piece of glass that blocks infrared light, then add exposed film which ONLY allows infrared light into the camera.

First, the hard part. Camera's have a tiny piece of glass between the lens and the sensor which blocks infrared light from passing through. I wasn't sure i would be able to remove it but i did. It's the broken pieces of red tinted glass at the bottom right.Build Infrared Camera
And even more surprising is that i was able to put the camera back together the first time and it still worked.
Make Infrared Camera
Now that infrared light can pass to the camera's sensor i needed a way to block the visible light. Online there was a lot of different ways that people said this could be done but the cheapest and easiest way looked to use a piece of film negative and an old floppy disc.

Infrared Film Camera Negative
And i tried part of an old floppy disc.
2HD Floppy Disc
Here are the pieces from the exposed and unexposed processed film.
Exposed 35mm film
I was planning on mounting the film on a PVC filter like i had done before. In hindsight that probably would have been a good idea. So i started to making a fitting out of PVC like before. But then i saw that the best way to do it was to cut the film and glue it in place INSIDE of the camera, right in front of the sensor. So i ended up not using this.
PVC ring
But before i did that i needed to know what is the best material to use. I decided to experiment with all of the ways people suggested to block the visible light. Here were the 3 pieces that i would be testing.infrared filter
The material and the results from the test: (click images to enlarge)

1. Film negative that had been exposed to light
Infrared Test film negative
2. Film negative that had not been exposed to light
Infrared film negative
3. Floppy disc

The floppy disc over the lens made the picture come out so dark that it wasn't usable. I could have left the shutter open for a much longer time, similar to the ND filter, but i decided just not to use it. So i moved on to layering two pieces of material together.

5. Two pieces of film negative that had been exposed to light
Infrared photo test
6. 2 pieces of film negative that had not been exposed to light
Infrared camera film
7. 1 piece of exposed and 1 piece of unexposed film negative
Infrared camera film test
It turned out that the best result was the last one i tested,
1 piece of exposed and 1 piece of unexposed film negative.

I took a couple of pictures in the backyard and liked how they came out. This picture is the original, right out of the camera.
RAW infrared photo dog tree
This is after adjusting the colors in Photoshop.
infrared photo photoshop
Now here's the bad part. When i finally decided what to use i took the camera apart again and glued in the 2 pieces over the sensor.
remove infrared sensor
disassemble infrared camera canon lens
camera infrared glass disassemble canon lens
Then when trying to put the camera back for the 4th time i damaged the small ribbon cable from the lens to the circuit board. You can kind of see the tiny hole in the orange cable.
disassemble canon camera s770is lens
It's a bit of a bummer, not that i would have used this camera a lot but it would have been fun to experiment with.

3 comments:

Anonymous said...

Bad luck. I can recommend using a particularly cheap digicam, a Polaroid PDC 5055. I picked one up at a boot sale for all of £1. It is 5MP, very basic and it works except it never remembers the time/date and asks for it to be set every time - not a problem as one button push skips past that.

Anyway, very very easy to remove the IR cut filter, just pull out the CCD board and unscrew the lens from it. Then use a knife to winkle the filter off. There is no moving zoom so just tape the negatives over the lens and you're off. Actually works as well. The camera has some form of cheap fixed focus that seems to go well with landscapes and the change in light path (with the loss of the IR filter) has minimal impact.

I'm now off to dig out some more old 35mm negatives to optimise my UV-Visible filter.

Oh yes, and stick some negative over the flash to make a IR flash.

Dave Wirth said...

Ya i heard about putting the film over the flash but i never got around to it.

I used the old Casio camera because it had dirt inside of the lens but still basically worked.

And WAS a problem. It only focused well when it was in Macro mode or Landscape mode. It must have been from removing that 1mm thick piece of glass.

Mak Minski said...

I've read much about people doing this, but I have rarely read anyone do this using a UV pass filter. I think you should try that out to get UV only photos. It would be an intriguing post. Unfortunately, it is supposed that cameras see less UV so you'd need much longer exposure. but if one could experiment with various cameras, that would be really something, to compare how much UV the sensors see.