Can it infrared? - Leica M11

Friday, 3 February 2023 10:53

Some time last yeah, I experimented with my infrared filter on the M11 for about 5min, concluded that it looked like turd, and left it at that. Then someone on Leica Forum posted some compelling images taken with an infrared filter and it tickled my curiosity again. 

Simply, it works, but it needs assistance in the form of a custom colour profile. I created one for Adobe Camera RAW using Adobe’s DNG Profile Editor where I had to adjust the white balance in a rather heavy handed way. There are occasional interpolation artefacts towards the edges of the frame, which look a little like steps or a raster pattern at times. These seemed worse without the custom colour profile, but I’m not sure what their route cause is. Maybe it has to do with the easy over exposure of the red channel. Here is a crop of how the artefacts look and no it’s not luminance or chroma noise.

I suspect that the M11 has stronger infrared sensitivity than other DSLR’s or Mirrorless cameras, since a design objective for digital M cameras is to keep the cover glass thin as possible, which probably makes the efficacy of infrared filtering lower than ideal. Infrared contamination in regular colour photography isn’t very nice, but there is barely any visible contamination on the M11. 

The image below was taken at f/2, ISO 64 at 1.5sec with a 715nm filter. I’m curious to try a 780nm or 850nm filter which should hopefully create nice monochrome results.

To showcase a more evident wood effect, below is a shot from the back garden. The exposure was 2sec f/2.8 ISO 64, with a 715nm filter. Not a great exposure compared to a full spectrum camera, but very usable for the occasional infrared photo. Bare in mind that Leica can’t make a digital M camera that doesn’t leak light from the mount (nor a modern film camera that doesn’t scratch  film) so one will have to accessorise the lens with a hair scrunchy around the mount in order to take long exposures. 

Just for reference, the image below has the same exposure as the one above, however I’ve fitted a Leica UV/IR filter to the front of the lens just to show how much infrared contributes to the exposure.