CLICK HERE for the same image using a color correcting filter and Auto White Balance.
On December 5, 2004 I successfully completed a modification of the Canon Digital Rebel to remove its IR Cut filter. The procedure I used was based on information on the web provided by Terry Lovejoy, Mathew Chang and Tam Kam-Fai. Removal of the filter allows for a great increase in sensitivity to the color red and the H-Alpha wavelength important for some deep sky imaging. I followed Terry's mini-procedure posted on his web site as a guide. I took photos of the replacement clear window glass, camera disassembly and reassembly and provide detailed directions below.
Opening the camera will void your Canon warranty and you may ruin your camera. Proceed at your own risk; I am not responsible for any damage to your camera. I am an electrical engineer and have done other imager modifications including building a peltier cooled webam and also the Steve Chambers long exposure modification (SC-1) to the Philips Vesta Webcam. The scariest part of the Rebel modification are the many ribbon (flat) cable connections involved and removal of the IR cut filter from its holder above the CMOS imaging chip.
I decided to replace the Canon IR cut filter with a clear glass window from Edmunds Scientific Optics. (Part No. 32741). The window is coated on both sides and is close to the same thickness of the Canon filter; a .3mm difference. With the addition of a .1mm spacer, the focus of the modified camera is returned to that of the original and the camera's Auto Focus works. For astro imaging I will be using a 48mm Baader UV-IR Rejection Filter. The filter can be easily added to the two inch imaging accessories that I use for the camera, including with my 20 inch Starmaster. An "X-nite CC1" color correcting camera lens filter is used for normal daytime photography. A "Hoya R72" infrared camera lens filter is used for daytime infrared photography.
Tool List - Bottom to Top in picture above: Metal Ruler (95 cents Walmart), toothpicks, 25W fine tipped soldering iron (Walmart), magnifying glass, #000 size philips screwdriver (#Craftsman #45726), flat head jewelers screwdriver, tweezers, pliers with shrink tubing on tips, solder, solder-wick (Radio Shack), cotton photographer's glove, glue, tungsten carbide scribe pen - General #70088 (Lowes - $5).
Not shown in photo: microfiber lens cleaning cloth.
The Edmunds glass window is 84mm by 48mm and is 3mm thick.
The Canon Digital Rebel IR cut filter is 27mm by 19.6mm and is 2.7mm thick***.
(***Based on feedback from those that have done the modification in Europe, some cameras sold there have an original IR cut filter size of 27mm by 19.6mm as shown here, while some others are 28mm by22mm in size. It was thought that the size of the filter depended upon the country where purchased, but both sizes have been found in the same country. The size of the filter by all modifiers of USA cameras has been 27mm by 19.6mm. I would advise that for European cameras, the camera be disassembled first to Step No. 28 in order to determine the filter size before cutting a clear glass replacement.)
For the cutting procedure I used a tungsten carbide scribe. A diamond tipped glass cutter could also be used. I don't recommend using a wheel glass cutter for such a thin piece of glass. I also used a microfiber lens cleaning cloth, photographer's cotton gloves for handling the glass, a small book for making the break and a metal ruler to use for the edge. The glass is large enough to make seven windows. The glass is blue in the photo since it comes with a blue protective covering on both sides that peels off. I cut the glass with the covering off. First cut was for a piece 20mm wide:
I used a microfiber cloth to protect the glass and scribed a line using the metal ruler. I used medium pressure for the scribe. It is important to make only ONE pass when cutting with the scribe; multiple passes may cause the glass to not break along the scribed line. Also be careful to apply continuous pressure when scribing, the scribed line needs to begin at the edge of the glass and continue to the opposite edge without skipping.
I placed the edge of a small book under the ruler and glass to make the break. The side of the glass with the scribed line was faced upward. Another small book was placed over the 20mm section protected by another microfiber cloth. The glass was somewhat hard to break. For the next glass cuts I used harder pressure for the scribe and the glass was easier to break. The protective blue cover was still on the glass for these two photos but it was taken off for the scribe and break.
Now the 20mm strip of glass is cut into three almost equal sections of 27mm. The breaks were pretty clean. I inspected the three pieces and selected the best to be used in the camera.
This note is from Rui Alvaro who completed the modification: " …..the only difference I made from your procedure is that for cutting the glass I used a normal glass cutter since I found it a bit hard to make a deep enough scratch on the glass with a scribe to cut it. I left the plastic protection on top of the glass and cut it. Later I used a carburundum stone to make the necessary adjustments to the sides."
This note is from Denis Slattery who completed the modification: "I found that a small diamond-surfaced file was a (relatively) quick way to grind the piece to size, then finished with the wet-or-dry paper."
General note: One modifier reported keeping the protective blue film on the glass to protect the glass while cutting instead of removing the film and using microfiber cloth as I did.
So you now have a modified DSLR for astro imaging. If you are a beginner to DSLR astrophotography, your next best step is to learn all you can about using your modified DSLR. When I complete camera modifications for owners, I get many questions afterward about how to use the camera, including: How to get precise focus? Which exposure settings to use? How to calibrate, align and stack exposures? How to adjust white balance? How to process images?
I am happy to advise and welcome all questions, but the best advice I can give is to order "A Beginner's Guide To DSLR Astrophotography". The book on CD-ROM is authored by Jerry Lodriguss, a professional photographer, amateur astronomer and astrophotographer. Based on his over 25 years of astrophotography experience, he makes it an easy learning process to capture and process astro images. Jerry also has a more advanced book on CD-ROM available: "A Guide to Astrophotography with DSLR Cameras". Consider arming yourself with both these books on CD-ROM, read them at your leisure and maximize your potential for capturing and creating the most spectacular DSLR astro images your modified camera can provide.
Those located in the United States can place orders for Jerry's Books on CD-ROM here:
Domestic orders for "A Beginner's Guide To DSLR Astrophotography".
Domestic orders for "A Guide to Astrophotography with DSLR Cameras".
Those located outside of the United States can place orders for Jerry's Books on CD-ROM here:
Foreign orders for "A Beginner's Guide To DSLR Astrophotography".
Foreign orders for "A Guide to Astrophotography with DSLR Cameras".