Cheap infrared photography

2011-07-13

Infrared panorama

After a few unsuccesful attempts to modify an old camera for infrared photography, I modified one of the two cheap cameras ($40 USD) that I’ve got some time ago. Those cameras are cheap and tiny, usually came embedded inside pens or keychains.

Due to their size it is quite common to modify or attach those cameras to a variety of places; think, for example, to attach the camera to ballons for aerial video, radio controlled planes, helicopters or other vehicules, or seal it inside an empty bottle for underwater photography, just to mention some random uses that came to mind.

It was on a RC forum thread where I first read about removing the infrared filter in those cameras, along with a lot of useful information.

Microcamera disassembledMicrocamera IR filter detached

The infrared filter is a thin circular element located on the rear of the lens. It was needed to carefully remove the glue around lens thread, but the overall process of removing the filter was much easier than expected, specially in comparison with any other camera I’ve tried before. Colors are distorted without its infrared filter, but in return it recieves more light, sensitivity improves, and it can be used as a “night vision” camera.

Once assembled and refocused, the first test was quite simple: let’s see the infrared light of a remote controller. The modified camera captures the light, while it is invisible to the other (as our eyes).

Infrared remote seen by 2 cameras

Next step was to block the entire visible spectrum, in order to capture infrared exclusively; that is, the inverse effect than the one performed by camera’s internal infrared block filter. I’ve used a filter designed for infrared photography, a piece of glass that looks black and completely opaque to our eyes, but not to the modified camera which can see through it.

Visible light filter seen by 2 cameras

The quality of the pictures straight from the camera is far from great. I’ve done the following:

Infrared panorama before color modification

The original has a red or pink tone because the filter allows some deep red to pass through it. A deeper infrared filter should produce black and white images and only purely invisible light would be recorded, supposing that camera’s automatic white balance won’t become crazy, this is something I want to test later.

A common effect for infrared photography is to switch red and blue channels (if the filter allows some red to pass), or just modify color channels and give a fake set of new colors to the image.

Infrared panorama

Infrared photos tend to look surrealistic. We normally can’t see the infrared light reflected by things, hence the strange appearance. Sky becomes dark (blue is easily removed by the filter), clouds are bright and prominent; green trees and grass reflect a lot of infrared light and become very bright, while dry plants remain darker.

Filed under: Hardware, Photography

Comments

  1. Comment by Dr. Zen

    2011-07-26 @ 17:20

    Nicely documented! Here via your post on rcgroups.

    I’ve similarly modified my #11 as well, and shot using an IR-pass filter just as you have. I’m using an inexpensive (but good) filter I found on amazon.com, a Zykkor 850 nm IR filter. I’m guessing you’re using a lower wavelength filter (720 nm?) than mine, because my videos are a blue color – no reds at all. I thought 850 nm would be the most versatile filter for this camera, and it appears to be the case.

    A question: Do you know if it is possible at all to grind down a replacement disc of the IR filter so it can fit inside the camera lens assembly? Are you just manually shooting holding the filter by hand in front?

  2. Comment by Roberto

    2011-07-26 @ 23:23

    It is a 760 nm filter, thanks for your feedback about the 850 nm, I think I’ll get one of them. The amount of red passing through the 760 nm is too high.

    About the question, you guessed it, I’m just holding the filter :)

    It may be possible to build, by several methods, a handmade filter easy to cut to the right size. I remember I’ve read somewhere about stacking gel filters, or taking a virgin negative film used in traditional analog photography and develop it (so it will become black and block all visible light). I was considering those options for a while, but finally took the easy path. I don’t know how well they will work. I guess it will be near to impossible to get the desired wavelength with them, though.

  3. Comment by Dr. Zen

    2011-07-27 @ 04:30

    Thanks for the response. Great minds think alike :) I considered the gel filters too, but after reading that they are very delicate and susceptible to humidity and dust, I chose optical glass instead.

  4. Comment by Dr. Zen

    2011-07-28 @ 18:49

    Just wanted to add here, that this modification might not be possible anymore.

    My original IR modified #11 died, and the replacement I received now has the lens assembly glued in with some kind of super industrial adhesive. I tried acetone, needlenose pliers… nothing worked. The lens assembly cannot be unscrewed to access the IR block glass.

  5. Comment by Roberto

    2011-07-28 @ 19:46

    I’m afraid my mind is very far from being great, it just has an obscure perversion that makes it enjoy itself when fooling other minds to let them think how great is it :P

    About the glue in your newer camera… I had to use acetone and pliers too, but it was not very difficult so probably they have changed the kind of glue or put it in the inner side of the thread. Once again, manufacturers trying to limit what can people do, very sad.

RSS feed for comments on this post.

Sorry, comments are closed at this time.

Alone in the Light


Copyright

Creative Commons License
Unless otherwise stated, articles and their accompanying pictures are licensed under a Creative Commons Attribution 3.0 Spain License.

Roberto Gordo Saez

roberto@zenvoid.org

Categories

Latest posts

Links