Camera Labs

First some pics as the mod was in progress...


I thought this was a Canon


The brains behind the operation


The view from behind the shutter.


Sensor module with no filter in place.


And... the IR pass filter in place, held by double sided tape to the module, and black electrical insulation tape around the edges.

And the results?

Following are taken with in camera auto white balance set to a shot of the sky. PP is auto colour balance in photoshop, resize and sharpen.


Outdoor view - seems to be good considering this is heavily overcast and raining.


Indoors, part of my kitchen. Interesting amount of blue going on. This happens mostly on blue or green coloured objects. Yellows and reds come out white.


The left over parts of the filter - may be dark in visible light, but looks transparent here.


Final comments - severe dust problems! I just re-cleaned the outer surface of the filter to see if that helps but haven't retested yet. If it's on the sensor side of the filter, or even the sensor itself, it's staying there as it takes a long time to open it up.

Remaining on my to do list is to check the AF accuracy, and adjust it as necessary.

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Canon DSLRs: 7D, 5D2, 1D, 600D, 450D full spectrum, 300D IR mod
Lenses: EF 35/2, 50/1.8, 85/1.8, 135/2+SF, 28-80 V, 70-300L, 100-400L, TS-E 24/3.5L, MP-E 65, EF-S 15-85 IS
3rd party: Zeiss 2/50 makro, Samyang 8mm fisheye, Sigma 150 macro, 120-300 f/2.8 OS, Celestron 1325/13
Tinies: Sony HX9V.

Cleaned outer surface of filter - dust remains Maybe I'll have to take it apart again after all. Will do it at work as it's a lot cleaner there than at home

I tried it with the 400mm wide open. This happened:







I'm really happy with the performance - this is on a wet and rainy overcast day! I can't wait to see what happens with some sunlight.

Camera jpeg with custom WB, PP: auto colour balanced and noise reduced. Bit of highlight recovery on 2nd.

The focus seems to be pretty close to ideal. Doing the battery test (put 3 batteries in a line, with the end ones slightly forward/backwards of middle one, and AF on middle). Even with the 50mm f/1.8 and 150mm f/2.8, the focus seems to vary slightly from being spot on to a small back focus. I'm not going to bother tweaking it at this point since I'm not planning on doing extremely shallow DoF on it.

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Canon DSLRs: 7D, 5D2, 1D, 600D, 450D full spectrum, 300D IR mod
Lenses: EF 35/2, 50/1.8, 85/1.8, 135/2+SF, 28-80 V, 70-300L, 100-400L, TS-E 24/3.5L, MP-E 65, EF-S 15-85 IS
3rd party: Zeiss 2/50 makro, Samyang 8mm fisheye, Sigma 150 macro, 120-300 f/2.8 OS, Celestron 1325/13
Tinies: Sony HX9V.

A question I had for a long time was what is the actual spectral response now that the filter had been altered? Tonight I got the first cut of the answer.

I set up a test after quite a lot of fiddling. First part is to get a light source that covers well into IR. I used a high power torch for this, as I know the bulb runs hot so should be throwing out from visible well into the IR range. Ok, now how do I get the spectrum so that I can pick off individual wavelengths? I impulse bought a diffraction grating in the past, and a prism. The prism I found incredibly hard to use, with the grating a lot easier. So I used two boxes lined up to produce a narrow-ish beam of light from the torch, and put the grating on the other side of it. All I needed behind that was something white. This happened:


Image resize only. Taken by 7D, to show what it looks like normally.


Image resize only. This is the output from my modified 300D set to "sunny" white balance. The setting isn't too critical, but just to give an indication of what the output looks like without more extreme correction. If you look to the left of the join between the two target boxes, you can see a patch that is brighter.


Level adjusted. This is with my custom white balance setting. Interesting that the IR patch now looks like a spectrum too, but remember this is false colour. The colours are arranged opposite to the visible portion earlier, with the redder output closer to visible red, with more blue as you enter longer wavelengths.

As mentioned before, I find some man made items (plastics, inks) to come out very blue with the custom white balance. Those objects are usually blue or black in visible light.

_________________
Canon DSLRs: 7D, 5D2, 1D, 600D, 450D full spectrum, 300D IR mod
Lenses: EF 35/2, 50/1.8, 85/1.8, 135/2+SF, 28-80 V, 70-300L, 100-400L, TS-E 24/3.5L, MP-E 65, EF-S 15-85 IS
3rd party: Zeiss 2/50 makro, Samyang 8mm fisheye, Sigma 150 macro, 120-300 f/2.8 OS, Celestron 1325/13
Tinies: Sony HX9V.

The reverse spectrum is really cool! Nice shots popo! And an interesting experiment for sure!

- Bjorn -

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Street and documentary photographer | Google+ | Twitter | Tumblr

Leica M9-P (my article on Camera Labs) | Leica D-Lux 5 | 50mm Summilux

Very nice pictures.
So you do this for any practical reason or just for the style of the photos and messing around with things?

Btw, whats with the light blue on the tape and milk bottles?
And the rose is very nice, how it almost completley looses the feal of depth is preaty interesting

Why? I'm curious about the look of the world lit just outside our normal perception.

The blue I'm not sure about. Either it is real blue pushing through the various filters, or those items reflect particular IR at the wavelength the blue detectors pick up. I suspect it is the latter but couldn't prove it right now.

_________________
Canon DSLRs: 7D, 5D2, 1D, 600D, 450D full spectrum, 300D IR mod
Lenses: EF 35/2, 50/1.8, 85/1.8, 135/2+SF, 28-80 V, 70-300L, 100-400L, TS-E 24/3.5L, MP-E 65, EF-S 15-85 IS
3rd party: Zeiss 2/50 makro, Samyang 8mm fisheye, Sigma 150 macro, 120-300 f/2.8 OS, Celestron 1325/13
Tinies: Sony HX9V.

Yeah, just that IR imidiatly sprung images of assains and stuff to mind xD

Yeah its preaty interesting, it makes the world look... Kinda feals like a surreal version of black and white photos.