Canon Digital Rebel XSi (450D), XS (1000D), T1i (500D) & T2i (550D) Modification Instructions

by Gary Honis


Page 4 - Imaging Chip Disassembly

Removal of IR Cut Filter for Astrophotography

Filter/Imaging Chip Assembly

The following diagram is on Canon's web site and it shows the components of the filter/imaging chip assembly. Use it for reference in the steps below. I have added the label "IR Cut Filter" for the two filter pieces Canon has labeled "Phaser-layer Infrared-absorption glass" and "Low-pass filter 2". This is really just one filter that has two sandwiched layers, so I will use "IR Cut Filter" for these directions along with Canon's other labels.

We are going to remove and replace the "IR Cut Filter" only. The "Low-pass 1" filter will be left in the camera. It is an anti-aliasing filter that Canon is using as a dust cleading surface and is explained on Canon's web site as follows:

"Self Cleaning Sensor Unit - A key element of minimizing dust is preventing it from clinging to the front surface of the imaging sensor. To combat against this, the EOS Rebel XSi features a Canon-designed Self Cleaning Sensor Unit. The low-pass filter at the front of the sensor shakes off dust automatically with ultrasonic vibrations, removing dust from the sensor assembly. The EOS Rebel XSi has a new coating on the front surface of the low-pass filter, to increase its resistance to dust sticking to the sensor."

23. Remove one screw as shown below: ***550D For 550D see step 23A below instead.

23A. ***550D only: Remove the three screws shown below. Be careful; the filter assembly will now be detached from the CMOS imaging sensor:


24. Lift the four corners of the "support material" frame up with a small jewelers driver and pop the metal frame off. Be careful not to scratch the filter.

Michael Pietschnig note: "I was surprised by the springiness of the "support material" frame. It jumped off without warning, luckily landing on the
table and not on the piezo filter. A hint which suggests to hold it down could probably be helpful here."

25. The removed "support material" frame is shown below (on left). Remove two screws as shown from the assembly: ***550D Skip this step for 550D.

Update: You may want to remove Low Pass filter #1 at this point as explained in STEP 28, instead of later to avoid touching it during the next two steps.

26. Now we will separate the filter assembly from the CMOS imaging chip. The black filter assembly is held on to the surface of the imaging chip by a thin strip of double-sided black tape (except for the 550D). This adhesion can be weakened by using an exacto razor knife. I used a flat "Chissel" type razor and patiently pryed between the black plastic frame and the metal base, all around the unit as shown. ***550D For the 550D, there is no need to cut the black filter assembly off the imaging chip. It is not adhesived on. There are three pins that position the frame correctly. Just lift it off, put it in a sealed container and continue at Step 28.

27. Go slow here and be patient. Work the razor blade around the sides of the frame and corners, applying slight prying up pressure. After a few tries, the plastic frame will begin to loosen from the metal frame and you will hear the crackle of the glue of the adhesive tape gasket becoming undone. When the parts separate, be careful not to get the front surface of the CMOS imaging chip dirty. Put the CMOS imaging chip into a sealed container to keep dust-free as you continue to work on the filter assembly.

28. Lift the "Low-pass filter 1" out of the unit; it is not secured. I used a jewelers driver to lift one corner and it came out easily.

29. Remove the original IR Cut Filter (blue glass) from its frame. It is glued in the plastic holder at the four corners. I used a razor knife to loosen the glue in each corner. Then I pryed the glass up at each corner and the glass broke. No problem since this glass will not be used again since it is being replaced with the Baader UV-IR-Cut filter (or clear glass if desired...or nothing at all). There is a thin black tape gasket between the filter glass and the black plastic frame. It lifted up in one corner so I pushed it back into place with the exacto knife.

Photo of 550D filter frame:

Comment by Skyler: Another really handy item was Nitrile gloves. They keep the insides of the camera clean w/o leaving my finger oil marks on components and they were just great when I popped out the glass that you showed in your example. I could push on the filter from the other side with the gloves on - one or two fingers at a time and one side at a time with a gentle prying and pushing motion. Since you have more surface area with your fingers, the chance of the filter breaking is minimized. Could not have done that w/o breaking the filter otherwise.

30. Glue the replacement Baader filter into the plastic frame by using very small drops of silicone glue in each corner. Be sure to use a glue that doesn't outgas as it may affect the optics. Do not use much glue here so that it doesn't run into the field of view. I left the glue dry overnight to be sure it was well cured. Below is the plastic frame with the new Baader filter glued into place.

For the FULL SPECTRUM MOD leave the plastic frame empty. Be sure to transfer the black rubber seal from LPF#1 to the plastic frame if it is still attached to LPF#1.

The dissassembly and filter replacement is now completed. I used a rubber ear syringe blower bulb to remove dust from all optical surfaces. If there is any dust on the Baader replacement filter you can flick it away with a camel hair brush or the end of a microfiber lens cleaning cloth. On the next page, you can continue to follow re-assembly directions that should be easy since you'll be going through the above process in reverse.

CONTINUED Next Page - Imaging Chip Re-Assembly

If you completed the modification and would like to let me know how it went for you, you can contact me at the following email address:

I will add any comments to the modification instructions that might be helpful to others and a link to your site if you wish.


To My Astrophotography & Digital Imaging Home Page

StaCanon DSLR 450D XSi Telescope Eyepiece Astronomy Astrophotography Meade Celestron Televue Eyepieces Telescopes