A while back I purchased a Murami 720nm IR filter for my Sony a77v camera. Unfortunately I did not realize that the Sony was not a good candidate for infrared photography because of it’s semi-transparent mirror configuration. So the filter ended up on the shelf along with this “broken” DSLR body I had. Then I got to thinking, I am not using that body anyway, so why not experiment with it. After rooting around on the interwebs for a while I ran across a tutorial on how to take out your hot glass filter and replace it with a clear filter. This allows most any DSLR to film in full spectrum IR.
Let the surgery begin.
Now I am no stranger to modding electronics. I have modchipped XBOX’s, Wii’s, Cell Phones and the like. I have a t-shirt that says, “I VOID WARRANTIES” on it… This DSLR was not being used and had a damaged hot glass filter anyway so what the heck. The first step is to disassemble your camera. This, of course will void your warranty. Dis-assembly can be very tricky as the last thing companies want is the consumer tearing their designs apart. If you are handy with a screw driver then go for it. It also helps to have an eidetic memory. If you don’t, you may want to video your dis-assembly so you know where everything goes when you put it back together. Help with dis-assembly is sometimes found on YouTube as well. Do a little research before you start and save yourself some big headaches. One warning, make sure your camera’s flash capacitor is discharged. You can get a nice 250v shock if you don’t. YouTube to the rescue again, there are plenty of tricks on how to do this. I, of course did not, and did get shocked. (oops) Here, I finally have my camera apart and have pulled the board that has the sensor mounted on it.
The next step is to pry the hot glass off the sensor. A small screw driver or xacto knife does the trick..be careful not to lose a finger or damage the un-protected sensor. I don’t have any shots of me removing the glass as I was a complete nervous wreck as I did so. It’s really not that difficult. You want to make sure that you leave behind the double-sided 3m tape to mount the new filter. This shouldn’t be an issue as it is designed to stay on the sensor in case the glass needs to be replaced. Here is a shot of the glass removed.
Once the glass is removed, place your sensor under plastic case or in a baggy and seal it to prevent dust from entering. You will get dust, but this will cut down on it. We will be cleaning everything before re-assembly. Also set the hot glass aside for a bit as we prep to cut the new filter. If yours breaks from removal, just use transparent tape to hold it together long enough to trace it.
So we need glass for the new filter. I had a few cheaper 72mm filters laying around so I used one of those. On my first attempt (yes, I had to re-do the whole thing) I used an un-coated filter. This was of course a mistake. Use a UV coated filter as this will cut down on internal glare. Use of a cheap filter also means that the glass will probably be thin. The hot glass is a fairly thin piece of glass and we need to match the thickness as close as possible. It does not have to be perfect, but close is good. Remove the glass from the filter frame. These usually unscrew with a good tap from a small screwdriver. Don’t worry about cleaning the glass now. Mask the filter with painters tape as shown here:
Now place the old hot glass filter on the masked filter and trace.
Once traced it should look like this:
Next part is a big step, as we need to cut some glass. I bought my glass cutter at Hobby Lobby for 13.00 and change. It’s a nice heave brass cutter that is easy to use and works incredibly well. By a cheap cutter and you are not going to be happy. Before you go cutting your filter, I suggest that you practice. Cutting glass is easy when you learn the technique. I watched several YouTube videos before I attempted this. You will need some oil to oil the cutter head before you start, I used common vegetable oil.
To cut the filter as accurately as possible I set my ruler an 1/8th of an inch outside the trace line to cut. This allows for the cutter head width which may vary depending on your model of glass cutter.
Once you have done the math, it is time to cut. Place the cutter head 1/16th of an inch from the edge of the glass you are cutting, apply even pressure and draw toward you in one motion to 1/16th of an inch from the edge. Essentially you do not want to run the cutter over either edge of the glass. The cutter should make a nice zipping sound as it is cutting. You will know it when you hear it. If done correctly you should be able to place a penny under the cut and lightly press down on each side to snap the glass with very little pressure. If cut correctly, it will look like this:
If all went well, make the rest of your cuts.
When you are finished cutting your should have a piece that is close to the size of your original hot glass filter.
As you can see, it is close but some sanding will need to be done. To sand the glass you will need medium grit emery cloth on a smooth surface. It takes a bit, but keep at it to get the new glass to match the size of the old. Be careful to sand ONLY the edges. Scratches on the glass face would of course be disastrous at this point.
Once you have completed sanding your new filter should match the size of the old. Get this part right and it’s smooth sailing from here.
Make sure the area is clear of glass dust and carefully peel the painters tape from the new filter. Take your filter to the sink and gently wash it with soap and water. After washing the filter, dry it with a lens cloth. Then ideally, with a methanol cleaner such as eclipse, swab and clean both sides of the filter again. Any lens cleaner will work but I used eclipse as I use it to clean my cameras sensors. To keep oils from contaminating your project you may want to use nitrile or latex gloves while completing the cleaning procedure.
As a final procedure before assembly, I used my lens blower to blow away any dust from the sensor and filter. With all of the dust blown away, carefully seat the new glass on the sensor. The old adhesive will bond nicely to the new glass.
When I disassembled my sensor there was a small frame that stayed in the camera body. This is present as far as I can tell on all DSLR’s. This frame holds the glass in place over the sensor. I believe the adhesive just acts as a dust seal as this frame actually does the holding. Test fit the frame to make sure it rests on the new glass properly. If it does not, you probably did not sand the glass to the right size. Better to know now than later when assembling.
Now that your fit is perfect, drop the frame back into the body, and carefully replace the sensor assembly back in the camera.
Connect all of your ribbon cables and put your camera back together. I would wait to replace all of the screws until after you do a test run. Replace your battery, flash card, and give it a go. If everything works, replace all of your screws and get ready for some fun. If something doesn’t work, don’t panic, disassemble and check all connections. Remember, this is a full spectrum conversion, in order to take infrared shots with this camera you will need a screw on infrared filter for your favorite lens. I use a Marumi 720nm IR filter. It retails for around $69 and can be found on eBay.com or Amazon.com. You may want to experiment with other level IR filters such as a 900nm filter or otherwise. For me, the 720 is working great. The beauty of the full conversion is that the filter is not inside the camera but on the outside so you can experiment.
Here are some shots that I have taken with my newly converted camera. (note: Black and White as well as False Color are easily created with this conversion)
This entry was posted on Monday, May 14th, 2012 at 3:35 am
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Posted in: Tutorials