for the same image using a color correcting filter and Auto
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
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
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***.
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
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.
note is from Rui Alvaro who completed the modification: "
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."
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."
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
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
in the United States can place orders for Jerry's Books on CD-ROM
Domestic orders for "A Beginner's
Guide To DSLR Astrophotography".
Domestic orders for "A Guide to Astrophotography
with DSLR Cameras".
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".