Special steps for 600D Modification continued




Filter/Imaging Chip Assembly

The following diagram is on Canon's web site and it shows the components a Canon DSLR 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. (For a Full Spectrum modification, both filters are removed and the Astronomik MC Clear Glass is placed in the position of Low-pass filter #1). Low-pass filter #1 provides the automatic dust cleaning feature of the camera 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."

16. Remove the four screws shown below. Be careful; the filter assembly will now be detached from the CMOS imaging sensor:

17. 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."

18. Grasp the small ribbon cable where it meets the filter frame and lift the "Low-pass filter 1" out of the unit. Place it in a sealed container.

19. Now we will separate the filter assembly from the CMOS imaging chip. There are three pins that position the frame correctly. Use a small flat head driver to pry up one corner of the filter assembly and lift it off.

20. 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 and using nitrile gloves pushed it out of the frame. There is a thin black gasket around the perimeter of the frame that can be reused if it remains in place. If it lifts off with the filter glass, no problem; it can be removed and left off.

Tip 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.

21. 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 only, 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.

Filter/Imaging Chip Re-assembly

Here is the diagram again showing the components of the filter/imaging chip assembly. Use it for reference in the steps below.

22. Install two screws on right side as shown below:

23. Place Low-pass filter 1 into the Baader replacement glass assembly completed in Step 30. Make sure for the next steps that all optical surfaces are clear of dust using a blowers bulb, camel hair brush or a microfiber lens cleaning cloth.

For the FULL SPECTRUM MOD instead of re-installing the Low-pass filter 1, install the Astronomik MC clear class. It is a little thicker than the original Low-pass filter 1, but the metal frame in the next step can still be used to secure it in place. As an option, you can transfer the black gasket from Low-pass filter 1 and place it on the the Astronomik MC clear glass in the same position, but some may prefer to leave the gasket off.

24. Place the "support material" metal frame over the above assembly and push down on all four corners until it snaps into place. Note the orientation of the metal frame. Be careful not to scratch the filter. Install two screws as shown below in support material frame.

25. The filter/CMOS assembly is now completed and ready to be placed back into the camera body.

Continue to the next page to see how this is done.

CONTINUED Next Page - Camera Re-assembly



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