[Jerry] recently got a shiny new DSLR camera and was looking to do something with the old Pentax DSLR it replaced. Having performed a few point and shoot IR conversions in the past, he was pretty confident he could tackle this conversion without too much trouble.
He located the service manual for the camera and got busy taking it apart. He had to desolder the main board to get to the CCD block, where the sensor, IR cut filter, and the shake reduction motors are all located. The IR cut filter was pried off without too much trouble as it is only secured with a clip and an adhesive foam gasket.
Once things were disassembled, the real work began. He had a little trouble cutting the IR filter he purchased, so it took a little bit of elbow grease to get things exactly the way he wanted. Once he got the filter in place, he carefully re-mounted the sensor block to ensure that it was set at the proper height.
Once things were fully reassembled, he tried taking a few test shots, but found that there were some focus issues due to the IR filter being thicker than the original IR cut filter. A few manual tweaks in the camera’s debug menu and he was in business.
Be sure to check out his photo stream to take a look at some of the pictures he snapped with his new IR camera.
Heh. I still have my CVS camcorder IR conversion. Incidentally, sharpie marker is invisible to IR, so it’s easy to make a visible-light filter.
I don’t notice much difference in the after pictures. What is the benefit from allowing extra IR to the sensor? Given that the grass is white and the asphalt black, I would expect the asphalt to be warmer, and black to indicate that. But then, the power lines have a white corona to them, so white means hotter? Very confusing.
@Joe
You are thinking of “heat vision”. That is where the far-IR spectrum is amplified in order to detect hot and cold surfaces. This mod blocks out all human visible light and only allows the background IR in. This is the world that is invisible to your eyes.
It’s not thermography, or long-wave IR, joe, if it was you’d need to cool the thing with a peltier I expect, this is near ifra-red and another wavelength.
“Near infrared: from 0.7 to 1.0 micrometers (from the approximate end of the response of the human eye to that of silicon).”
It’s still interesting to see the different look of things and you can use it as night vision with an IR light.
The results are very dependent on the IR-passthough filter used though and it’s odd that he’d install it in the camera instead of simply using one on the lens and then have options to select one by what he wants to shoot.
You just cant use a IR pass filter on a DSLR. They have very effective IR Cut filters that eliminate almost all of the IR to the sensor. Second issue with IR on a dSLR is focus. Putting a IR Pass filter on the lens kills the auto focus since the sensor is after the lens. On the Pentax K10D there is no live view, so focus would require you to take a shot, manually adjust, take another, and keep fine tuning. By installing the filter directly on the sensor auto focus is retained, though must be adjusted due to the focal shift due to the thicker filter and the longer wavelength.
As for using other filters, I used a 750nm filter on the camera. If I am using a tripod I can focus and then out on a filter with a higher cutoff and it still should be in focus.
Heat sensitive cameras use special, very expensive, sensors. Standard silicon will not work, even if cooled. Cooling will reduce noise levels.
i have done this a gizzlion times for friends … personally i have a 720nm D7000 and a 950nm D90
after some post processign the images dont look half bad http://www.deviantart.com/download/198039815/ir_day_by_biozz-d39wohz.jpg
http://www.deviantart.com/download/190765248/ir_lake_2_by_biozz-d35kreo.jpg
in post after i get the white balance and levels right i swap the red adn blue channels giving the deep red from the little bit of regular light that enters the 720nm look blue and turn the sky blue than i take any red tint on the ground in to a hue shifter and remove it (photoshop CS4)
but as you can see in the last one leaving a little red does not really hurt the photo
I’m kind of surprised a low pass filter wasn’t used to replace the hot mirror. Since the camera is an SLR if an actual low pass filter is used (like most infrared photography is done with) on the end of the lens the photographer won’t be able to see through the lens. Hind sight is 20/20 I guess? As for the what and why comments, this only covers near infrared which is what your television remote uses to talk to the television or what garage door sensors use to know if something is blocking the door. This is different from far infrared radiation or “heat” seeing infrared if you will. As to the why, it provides a surreal look to photographs in the right circumstances. Like these… also taken with a modified camera.
http://whenpicsfly.com/wordpress/wp-content/uploads/2008/04/chasm.jpg
http://whenpicsfly.com/wordpress/wp-content/uploads/2008/04/half_tank.jpg
By low pass filter do you mean an IR Passing filter? If so, thats what I did, mount the filter to the sensor as seen in this photo:
http://www.flickr.com/photos/67292116@N00/5639306265/in/set-72157626377651582
@Joe – with IR B&W photography you tend to get white foliage and (if a deep red filter is also used) very dark skies. This looks dramatic.
The other advantage is with architectural photography, where the ‘light’ is just beneath the skin of the building.
Thanks for the explications Bob, Whatnot and abobymouse. I asked since I’ve only ever worked with thermal infrared cameras, and with those glass does not even work, so I was curious why this hack was even functional with a visible light camera. Now I understand.
@macona
It’s true that DSLRs have IR blockers in place to block non-visible light from the sensor. But they are not perfect.
You can use eg a Hoya R72 IR filter on most DSLRs, but you need to do long exposures. (On my old Canon 20D I need 20-30s.)
You can’t focus with the filter on, but if you use a tripod (which you need anyways for exposures that long) you simply focus before putting the filter on.
@Biozz
D7000 really?
You are in an enviable position to be able to muck with such new models.
Likely voiding any warranty however.
Also your image seemed not in sharp focus compared with macona’s.
@macona
I think there is a “low pass” filter plate in all digital cameras used to reduce the moire effect, and that’s being confused with the visible light blocking filter (which is also “low pass” I guess).
@macona: what I have learned from your mod is that lifeforms really don’t like to absorb much infrared at your wavelength except we animals through our pupils. I wonder if that’s always been the case, I mean, would the plants of 600ma look just as white in this camera? go find a fern.
Well the ‘you can’t see if the IR-pass is in front since it’s a SLR’ makes sense, but the auto-focus should be the same though, with the same issues.
Or in fact it might be better if the focus doesn’t use the main sensor as some do I understand? I guess it depends on what method is used by the manufacturer.
And clearly I didn’t suggest to NOT remove the internal filter, I was merely wondering why it was replaced, and that was because it’s SLR, and yeah that was stupid of me (but I’m not swimming in money so I don’t have 20 DSLRs lying around that I always think DSLR when thinking camera).
Incidentally, an interesting thing I discovered when I removed the IR filer in a webcam was that my lasermouse’s laser was quite bright IR but also that it stays quite tight all across the room, I never saw that on any youtube or IR discussion and it’s funny that apparently nobody ever noticed.
@rickroll, yes there is a low pass AA filter in cameras as well, they are usually integral with the IR cut filter.
@dan, A lot of things show up totally different in IR than visable light. For example the pic with the girl with glasses. She is wearing opaque sunglasses and a solid black sweater and jacket, Yet the glasses are transparent, the sweater is white, and the threads in the jacket showed up white. Also check out this other gallery from when I took a class on studio lighting last year:
http://www.flickr.com/photos/67292116@N00/sets/72157623590544340/
@whatnot, There is a possibility that the auto focus might work. I just dont know how sensitive to IR they are. I suppose I could throw on another external filter and see what happens. My guess is it might focus, but it will be highly unreliable. That’s one of the advantages of doing an IR mod on a dSLR with live view, the camera used contrast detection which will work either way.
Oh and one more small thing, I know some people did actually convert webcams to use with telescopes to do IR astronomy with long exposures and then actually did cool the thing down to reduce noise.
So even with near-IR it can help it seems.
google has abundant links on the subject.
And when they did a breakdown of the kinnect they also found a small powered thing behind the IR camera which they guessed was a small peltier element to cool it.
I quote a british website:
“..Peltier cooling is to reduce the temperature of the CCD chip itself, usually to 20-30 degrees Celsius below ambient. This effectively eliminates thermal electrons due to the ambient conditions and allows long exposures to result mainly from photon generated electrons, rather than thermally generated electrons. Nonetheless, good results can be obtained with long exposures from totally uncooled cameras”
@rickroll
im a photographer i have more cameras than i know what to do with
and those 2 pics were taken in winter with the sun far behind so the exposures were long causing blur … i hope when sumer hits for me to get the exposure back down to 2 stops over instead of 7-10 stops over
i use a D7000 a D300s and a D3x for regular photography so i decided to get a second D7000 for the R72 … it was not until an R95 glass filter crossed my desk that i dusted off the old D90 and cut and placed
i think it was worth the cost but my girlfriend was not to happy ^^;