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I modded an old Canon EOS 1000D camera, hoping to add IR 'night vision' to it but during testing I noticed that it doesn't capture the IR illumination at all despite the room being lit by two powerful IR LED arrays.

The mod procedure is described here: http://dslrmodifications.com/rebelmod450d4.html In there they instruct to add a clear glass piece in place of the IR filter but I din't as I don't have such glass available, so I left the "low pass filter 1" in place without any other glass or filter. But I dont see how not adding a clear glass could affect the result like this.

I have an old webcam that I removed an IR filter from too and it can capture the IR light illumination in complete darkness as expected.

What am I missing here? I thought removing the IR filter would work the same way as it did for the webcam.

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  • It is just a wild guess, but did you try if you shine the IR light through the unmounted lens into your webcam, that the IR light passes the lens? Just to make sure it is not the lens you used, that filters out the IR light in any way. – Kai Mattern Apr 9 at 9:17
  • A low pass filter filters out infrared light. – Eric S Apr 10 at 12:52
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... I left the "low pass filter 1" in place...

Try removing both the low-pass filter and hot mirror. Some Canon cameras do not appear to be as sensitive to IR as other cameras. There is likely an element on the sensor stack, other than the IR Cut Filter, that blocks a significant amount of IR. Based on a diagram in the modification guide you reference, a potential culprit is the low-pass filter.

sensor assembly

See also:

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    I took the camera apart again and removed the low pass filter 1, leaving a clear light path from the lens to the sensor and now it picks up IR illumination as expected! Though leaving the sensor directly exposed like that worries me a bit, I will try to add a clear glass piece if I find one sometime. – nyaol9 Apr 9 at 10:22
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    I believe a clear glass cover of the correct thickness is necessary for DSLRs to focus properly. I'm not sure this is true for mirrorless cameras which focus using the imaging chip. – BobT Apr 9 at 14:38
  • @nyaol9 The sensor should be fine since it's normally protected by the shutter, mirror, and lens. Adding an uncoated piece of glass may introduce unwanted reflections. But without it, focus with the AF sensor will no longer be accurate. Focus with Live View should still work, but some lenses may no longer focus to infinity. – xiota Apr 9 at 17:32
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    @BobT Removing the filters from the light path shouldn't affect focus accuracy of mirrorless cameras. However, lenses may lose infinity focus. – xiota Apr 9 at 17:36

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