The View Up Here

Random scribblings about kites, photography, machining, and anything else

Converting the Canon A2200 to Infrared

Posted by Tom Benedict on 06/06/2014

I finally broke down and did it: I converted my Canon A2200 to infrared.

I’d actually planned to this when I bought the camera. It was the whole point! But then when it finally arrived I played with it, took some pictures with it, and started to like it as a visible light camera. It was the camera I used the first day of WWKW 2014, and it was the camera I built my helmet cam around. I’d just about come to the point of admitting I was never going to convert the thing.

Then I saw the dust. When I zoomed all the way in (the way I use it on the helmet cam) I got a big dust smudge in the upper left corner. Bad enough that I had dust inside the thing. The dust was up where I would have sky in the frame regardless of whether I was doing ground photography or KAP! It had to go.

I used Ned Horning’s procedure on Public Lab to get me to the optics. Sure enough there was a big blob of dust on the inside of the IR blocking filter. I removed it, started to put the camera back together, and paused… I already had the camera apart. The IR blocking filter was right there. Put it back together sans dust? Or wait a day and put an infrared longpass filter in instead?

Normally a decision of that magnitude would’ve required a lot of soul-searching on my part. I really had fallen in love with the thing. Converting it ran the risk of permanently destroying the camera. If I cracked the camera’s IR blocking filter, there would be no going back. Should I? Or should I take the safer road?

Out of curiosity I hit Ebay and saw another A2200 going for $16. Oh heck yes! I clicked “Buy” and scrounged up a color negative film leader to use as a filter for my disassembled A2200.

The conversion went relatively smoothly. There were three tough spots I ran into: The first was getting the case off. Canon doesn’t make their compact cameras in a way that’s easy to disassemble. The second was removing the three screws that hold the detector onto the optics assembly. They’re painted over with varnish, which has to be cracked off. Only problem is that cracking the varnish off makes a gazillion little dust particles that need to stick to your optics! (THAT’S WHAT GOT ME INTO THIS IN THE FIRST PLACE! GRRRR!) Cleaning them up took time, but it was time well spent. The third trouble spot was finding a piece of film leader that didn’t have scratches on it. When the A2200 lens is zoomed all the way in it’s a fairly high f-ratio beam. This makes dust and scratches stand out like nuts. I went through a couple of film chips before I found a keeper.

Once the conversion was done I had to take it outside to test. I was going to our summit facility the next day so I grabbed my camera and took it with me. I had partly cloudy sunny skies to play with. Perfect!

Infrared Panorama of 10m Ridge

Ned Horning and Chris Fastie from Public Lab had warned me that white balance with a NIR converted camera was critical. So I white balanced mine off the tops of some nearby clouds: nature’s white cards. Then I walked to the other side of the building and made this panorama. I’m really pleased with how it turned out. It’s not the best test subject for a newly converted camera, but it worked. The air at 4000m of altitude has very little water vapor so it’s quite dark in the IR. There’s no vegetation up there, but the South Kohala Coast, visible just to the right of the rightmost telescope, is nice and glowy. Success!

During subsequent testing I found the upper and lower left corners to be a little soft. At first I worried that the optical thickness of the original IR blocking filter and my IR longpass filter were different enough to cause problems. The original filter is 0.32mm thick. Film, as it turns out, is almost the same thickness. Then I thought to check some of the visible light images I’d made with the camera prior to conversion. Sure enough the camera has soft corners on that side. Considering the heritage of the camera and the state it was in when I first received it, I expect it had been dropped several times in the past. I’m guessing the optics barrel is slightly out of position. I don’t think it had anything to do with the conversion.

The next step is to put this in the air. If the weather is favorable this weekend I’m planning to get out for some near-IR KAP. And when my second A2200 arrives I’m planning to build a two-camera mount for my KAP rig so I can do four-color photography. But that’s for another post.

– Tom

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2 Responses to “Converting the Canon A2200 to Infrared”

  1. Nick said

    How did you get the case off? I am running into the same problem with mine but, I have almost stripped one of the screws trying to get it off before giving up.

    • Tom Benedict said

      I more or less followed the procedure on the PublicLabs site. But after all the screws are removed when the procedure says to pry the case off… yeah, mine didn’t want to pry off. I snapped off one of the tabs. But when I put it back together it seemed to go back ok without it, so I called it good. It helped to have one of those miniature sets of screwdrivers to stick under the seams as the case came apart to keep it from locking back together. (This may be why I snapped one of the tabs, though!)

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