Bent Larsens astro photos

Removing the IR cut-off filter on a Canon EOS 1100D

Normal DSLR cameras has a IR filter removing 75% of the light from a H-alpha transition. As 75% of the universe is hydrogen, the H-alpha transition is very important to a astro photografer. By removing the IR cut-off filter a normal cheap DSLR can be used for astro photo.

Starting wiht a standard Canon EOS 1100D, bought on eBay.

Gary Honis has published a very nice and easy strp by step introduction, which I used. Thanks Gary

After removing a lot of screws and plastic, the camera looks like this

Just remember to keep track of the different screws. Again Gary Honis is a huge help. At his site I printed a detailed list of the the screws, and everythin was under controle

After some time I reached the sensor and the IR cut filter

Removing the first filter took some time, but it was possible. The second filter broke quite easily. Luckily this was the filter to be discarded.

After 2 hours the filter was removed, the camera reassembled, and ready to be tested.

NOTHING. The camera didn't work at all

So once more taking the camera apart and checking all cables, and the most difficult flatcable wasen't connected properly.

That is the cable marked H in this photo

Photo by Gary Honis

After an other ½ hour, the camera was againg reassembled, and now everythink works perfectly.

Now I'm just waiting for the clouds to disapere, so I can test the camera properly