David Krooshof

My First IR Cameras

What converting for IR does

A digital camera is by nature very sensitve for light that is deeper red in color than the human eye can see. For natural (to us) colors, this infrared (IR) needs to be blocked. Therefor there is a filter over the lens, that blocks infrared but passes normal red. It also blocks ultraviolet (UV), which is above blue. If you remove the filter, the camera becomes sensitive to both infrared and ultraviolet, which knock all colors out of place. The secret to good natural colors is a good IR blocking filter. So let's take it out.

Plants reflect way more IR than they reflect green. Without an IR filter, the IR light goes to the sensor via the red pixels, and a bit via the blue pixels too. This overpowers the green so much, that plants turn orange, or even a pale red.

If you'd then block visible colors, and only leave in IR, things get interesting. Living plants, including their flowers, all turn light. Blue skies remain dark, because the blue is blocked, but clouds turn bright. The standard IR eye candy is bright summer days with black skies and bright trees. Light overcast becomes dramatic. Skin looks fuzzy.

Note this is not a heat sensitive camera like a FLIR is.

Selfy in a train dirty window with a complex layered background. You can see the camera in my hand. I'm wearing a surgical mask and a hat.

Converting a camera for IR will likely brake it a bit

I decided to sacrifice my dad's Canon compact camera. It worked nice, but I noticed that something was off in the focus, so I opened it again and then I killed the electronics. With static, I think.

Then a aquaintance, Marleen, gave me a bag with old cameras. There was an Olympus compact camera, which was my next sacrifice. I succeeded, but it can't remember date and time anymore. Also, if you want it to focus to infinity, it is hit and miss. Always do several takes. It seems to do a better job when not zoom out all the way. I think this is induced by the infrared conversion. IR has a longer wave length and chromatic aboration is likely not controlled below visible red, so it needs the sensor to be ever so slightly further away from the lens. Zooming in a tad, allows the autofocus to overcome this.

There is another issue with the camera, that I might have caused or came with the model: When turned off, the camera keeps draining the battery, likely the reason the battery it came with was dead.

This page is about the Olympus, but I can tell you that the Panasonic GF2 that I converted, also got some weird damages: It does not recognize it's native lens anymore (not a problem for me) and it can't tell if the onboard flash is folded in, and fires the flash with every picture. And something is odd with the manual shuttertime too. But Aperture priority works with vintage lenses, so it is good for me.

So before you ask, no I will not convert your camera; chances are I break it beyond usability.

Here's a video I made right after the conversion

You can see what the filters do.

(And I painted the filter holder black, because I saw it's reflection in the images, I failed to mention that in the video)

Video about my first functional IR camera

  • A dog overlooking an open spot in the forest. It's a banded photo, which is typical for me. I call them
  • A dark image. The bottom half is a farmers road on a low dyke, that goes straight to the horizon. Its vantage point is at 2/5ths of the image, from the right, Emphasized by the only tree at the horizon at that point. This is a detail, a small black blip on a black textured horizon line. The road and some bushes form a black square at the bottom left. To the right, the image is dark grey. It is diagonally and horizontally intersected by two water filled ditches. The sky is dark, heavy overcast. To the left there is a rainstorm. But to the right, the sun brightens up a could intensely. It is reflected in the diagonal ditch underneath it.
  • A very dramatic winter sky with bands of clouds radiating out, behind two pine trees. They are even more contrasty than the sky is. They form an arc over a sand road. We can see underneath this arc too. The road bends a bit, but there is something uneasily straight about it. It is a former Nazi anti-tank ditch, now filled with sand, that encircled my town in WW2. In the front is what remains of a cut tree, and to the right side, the image is closed with a bare tree, smaller than the arcing pines. There is a pictorialist atmosphere to it.
  • Another
  • The top half of the photo is a a grey sky, with some clouds in the back that have a silver lining on top. A windmill interrupts this sky. Halfway the photo is a thin black line, these are some trees in the far background and some roof toops, but it is hard too tell. It functions mostly as a division. The bottom half is of a similar grey, but it is textured. It is reeds. The plumes on top are brightly lit and shiny. They look transparent. These plumes intersect the division line. Underneath it, in low contrast but highly detailed, is a cross braid of thousands of 3 meter high reed stems vertically, and 20cm leaves across it, horizontally.
  • A curved tree bend over a sand path. It forms a arc, a ceiling over the photo. Underneath it: My dog patiently waiting for me in the foreground. In the background, a couple is walking into the distance, with lots of motion blur. The horizon is out of focus, and has a nice lack of contrast. The whole scene pictorial.
  • A busy image of my dog at some distance, checking out a rabbit hole in a sandy soil. Top half of the image are bright leaves of a tree. They arc over the image. In the middle, a dark band of trees and soil in the background divide the image. The bottom half is brightly lit, textured sand. Nowhere is not a footprint. In the foreground is a wiggly branch of about 2 meters, with an even more wiggly shadow. The light is so low it peeks underneath this fallen branch. It seems to be parallel to the arcing branch from the crown that forms the top half of the image. My dog is in between these parallel curves. The sun shins on her butt, her snout is in the sand.
  • A close up of a long haired Scottisch cow from a small herd that freely roams the heather. The low sun brightens up the hair on the right side and a wet nostril. The eyes are very dark, as are the inside of the ears. The fluffy ears and the horns make it look happy and inquisitive. To the left: two trees with bright young leaves just coming out. Underneath them, in low contrast, another cow.

IR is great for landscape, with the plants highlighted and dramatic skies.

  • Overlooking a mossy branch of a tree. Sunlight penetrates the moss, making it look bright and a bit translucent. It is the only thing that is bright in this photo. There is a hint if forest in the background.
  • A close up of a dead tree trunk with moss and lichen. People placed stones on this trunk. One is in the center, it is black, inside of bright moss. The moss has a direction to it, it grows sideways to the right.
  • A majestic close up of the face of my dog, brightly lit against a typical IR black sky. The blue eye is also light. She is looking over my shoulder into the distance. The frame cut her nose on the right, and an ear on the left, it is taken that close. The fur is tack sharp and very shiny.

The Olympus camera can focus closely, and focusses well in that range.

  • Shot from a moving train. Late 19th century building, with trees and a lamppost in front. Somehow, one tree has more motion blur than the other. A brightly lit walking person is just cut by the frame. Included here, because the image is odd.
  • Another layered image. It is snowing, and it is shot from the inside of my workplace out. It's hard to tell what is snow and what is dirt on the window. A man with a cap pushes a cargo tricycle, a cyclists just leaves the frame to the right. Above it, the reflection of the camera in my hand. Modern buildings in the background and a huge flair. A selective ray of sunlight hits a traffic sign, and that sign is reflected onto the building across the street too.
  • A dark image. In the center is a huge modern hotel building that dominates the image. There is a textured overcast sky. To the left is a bit of the late 19th century central station, to the right some typical 17th century Amsterdam canal houses. The front of the image is water. There are 5 tourist boats in it, the size of city busses, but low enough to crawl underneath the bridges. Everything is dark grays. But in the modern hotel, the heat isolation of the HR glass does reflect IR very well. We can see a bright sunset mirrored in it. The reflection of the building in the water does not show this sunset, likely because of the viewing angles. The result is slightly distopic.

Some city images

We like the moon!

I like the IR to let out the pictorialist in me. And I wanted a camera with more control over the image.

One day I noticed the camera picked up the moon, before my eyes did. There is a lot more IR coming from the moon than visible light (about two EV more). And I noticed that in infrared, I can photograph the rising full moon with texture in it, while having correct exposure of the foreground in the setting sun too. Normally, the moon blows out all it's texture. You can verify this with your phone. Photographing the mares of the moon is impossible due to the huge contrasts with the sky, or, if the moon just came up, due to the haze of the atmosphere. IR pierces right through such haze (which is one of the reasons the James Webb Space Telescope shoot in IR.)

I made an image of my dog Baloe in these conditions, and it is one of my images that I like best. I wanted to capture such scenes better. It sparked a whole new project. Shooting IR in moonlight.

  • Most of the image is black. The bottom edge are treetops. The moon rising behind these brightly lit pine trees. I kept it low in the frame to keep the sense of rising. The moon is nearly full, only the bottom left is darker. This tells you the moon is rising, too. The sky is dark because there are no clouds, and the blue light is blocked nearly 100% by my IR-pass filter. Both the trees and the moon are textured. A small sensor allows for a hyperfocal distance of 10 meters or so even when zoomed in.
  • Baloe on a mound, sniffing the ground. Exactly frontal light from the setting sun make her a bit flat. But this is what you get at full moon: the sun and the moon are opposing each other, one setting, one rising. I'm ten meters away laying low on the ground, shooting up against the dog, the moon right behind her. But the dog and the moon are textured, but there is slightly fuzzy texture to the image.

Another take of that shoot got some praise of Bad Astronomer Phil Plait.