I went for a walk today, in a park and in a paddock. I shot mostly infrared with the 18mm ZM Distagon and 35mm C-Biogon. the Distagon isn’t recommended for IR, but not because of a hotspot, rather because of the strange internal reflections evident in all shots taken with it, you can see it in the corners of the image with the darkest sky. That shot is actually the last shot I took, shortly after taking it I saw a 2m long snake slithering past and decided to get outta there.