Replacing the IR-block filter of a Canon EOS 550D

Preparations.

• Remove the lens, battery, battery hatch, strap, eye cup and any other accessories.
• Quickly clean the outside of the camera body with a brush or damp cloth.
• Print out the form for all screws and attach a strip of double sided tape (or cut a strip out and use duct tape from the back side). You can stick all screws on the tape with their heads to keep track and not lose them.
• Have a neat and clean table top.

Stuff you need:

• The camera (Canon EOS 550D)
• Paper sheet with sticky tape to collect the screws. » Print Form (pdf)
• Screwdrivers: crosshead (Philips) #00, small Flat (~2mm), Torx T6.
• Scalpel, or exacto knife. To cut the low-pass filter from its frame. A small breaktip knife may also work but is less convenient.
• Vernier Calliper, with depth probe.
• Lint free lens tissue, Cleaning fluid (eclipse), sensor swabs.
• A rocket air blower or some canned air.
• A replacement filter (cutting your own filter) if needed and some fine glue, preferably silicone glue (I used standard superglue (thin 2seconds glue) which work"s fine, but only when the fit is tight as is has little filling capacity), no modern 1sec glue, as it may cause a white haze deposition on the filter.

Dissassamble the camera

Remove the back panel of the camera (8 screws) Four screws at the bottom: (1)+(4) long, (2)+(3) short. Two screws at the right side (5) long, (6) short. Three screws at the left sid: (7) long, (8)+(9) short, on the connections panel The panel and its cover comes of easily after removing (8)+(9). Set these aside safely. The back panel now should come off easily. The first bit is the hardest, some convincing might be necessary, use a flat head screwdriver and carefully wiggle the seams apart. Now lift of the back panel carefully and slide out the one ribbon cable (A) from it’s socket.

Remove the first set of the ribbon cables from their sockets. It is easiest to take out the first set of ribbon cables before taking the camera further apart. There are four types of connections:

• (B): plug type. Loosen the plug by prying gently using a screwdriver and then pull out the plug using tweezers.
• (C), (D), (F), and (H): slide type. Some of these are quite difficult, the ones with a little hole can be pulled out using a toothpick, the other are just gently pulled using flat tweezers.
• (E), (G), and (I): hinge type. These are locked in place with the brown hinged part, pry this up with a toothpick and once it is loose, the cable should come out very easy.
• (J): pop-off type. Pull this plug up using your fingernail, maybe wiggle a bit and it should pop off quite easy.

Remove the front (5 screws) and top (5 screws) cover To get to some remaining plugs and screws of the circuit board (and the sensor) we have to remove the top cover. To get to this, we need to remove the front cover.
Remove the two short screws (10) + (11) next to the viewfinder and also the diopter adjustment wheel (12). Remove the two screws on top, next to the strap attachment loops: left (13) short, and right (14) long. The bottom has three screws, all long. One in the center below the lens mount (15), and two near the battery hatch (16) + (17). Now remove the two screws on the front of the camera, just above the lens mount (18) + (19) both long. The Front cover can be taken off easily, you just have to lift it over the tripod socket (use a small flat screwdriver to push the socket aside). The top cover will stay attached to the camera, so lift it gently to access the remaining connectors. Be very carefull: you will see the flash capacitor, this may have very high residual voltage!

Disconnect the remaining cables from the circuit board: (K) + (L): hinged type.
(M): plug type. Sits on the top side of the circuit board, white with black cables.
(N): Sits next to plug M, this looks like a fiberoptics cable when it is loose, but don’t forget to reinsert it in its socket when putting the camera back together again.
(O): pop off type. The main connector of the sensor
With all cables disconnected you can lift of the top, but it remains attached with some cables you don’t need to remove. Just let it sit on top of the camera. Take out the circuit board ( 5 screws) Now we can take out the circuit board, it is attached with 5 screws, 3 short : (20) + (21) + (22), and two longer (23) + (24). Having removed the screws, lift the circuit board out and set it aside.

Remove the sensor (2 big head screws, 3 spring loaded screws) Finally we have reached the sensor. First remove the two big headed screws on the grounding straps: 25) is hidden below a brown piece of plastic tape, and (26) at the bottom side of the sensor. The sensor is seated using three spring loaded screws with torx heads (T6). The screws can be used to adjust the position of the sensor wich affects the focus of the camera. Therefore you need to remember their position, either by measiring the length of the little black pin that sticks trough the mount, or by counting the number of turns when taking the screw out (best do both). Take out the screws (27), (28), and (29) all same size. And carefully lift out the sensor.

Remove the filters (3 screws) Set the camera aside, and focus on the sensor and filters only. The sensor has two filters which are both to be removed for IR photography, because the both block IR. As a replacement you can install either a permanent IR-pass filter, or a clear glass and use filters in front (or at the back) of your lens. For Astrophotography you can just remove the second filter with no replacement, and reinstall the first Anti-Aliasing filter with dust shaker.
The first (AA and dust) filter is retained by a silver clip. Two short screws (30) + (31) need to be removed, after which the filter can be unclipped at its corners using a small flat screwdriver. The second filter (the real IR-block) is glued in a plastic holder. It has one screw left (32) and can then be lifted of the sensor. Be very carefull with the sensor itself, keep it absolutely dustfree! You might consider to store it in a closable plastic box while your replacing the filters. To remove the IR-block filter from its frame, cut the glue gasket all around the filter. The glass is very thin, using small force will already break it. Once the filter is out, clean the frame. If you use a replacement filter, insert it in the frame and apply a very small drop of glue in each corner. Leave the glue to cure: take yourself a coffee or beer (in the kitchen, don’t spill on your clean camera worktop!), you deserved it now.

If the glue is cured, clean very well (absolutely no dust may remain, especially on the back side as you will have to take the camera apart again to clean it) and reinstall the filter on the sensor and attach the silver spring clip.

Put your camera back together in reverse order, remember:

• Exact positioning of the sensor using the spring-loaded torx head screws.
• If needed: correction of the sensor position because of differences in filter thickness. » Correcting focal plane
• Carefully attach all (14) Cables connected to the circuit board.
• Secure the top and front covers.
• Reattach the back panel ribbon cable (I found this a pain in the ass).
• Before installing all screws on the back cover, run a quick check of the camera functioning. Do all screens, buttons, shutter, sensor, etc. work? If not, recheck all ribbon cables first before you panic.

No problems? Reinstall all remaining cover screws and Congratulations!

This gallery contains all the pictures used in this tutorial, to be viewed fullscreen and downloaded if needed. Remember, all these are **copyrighted!** you may use them for your own modding purposes, but not distribute or publish them without my permission.