Today is a perfect day for infrared photography. As usual, my preferred lens for IR is the Pentax-M 20mm f4. This lens could be very bad with distortion if not careful, but I find it to be excellent on the APS-C cameras. The signature of this lens is its sharpness, especially on the low density sensors like the Canon 20D. The images captured by this lens has excellent definition. This is one of my favourite K-mount lenses.
All photos below were taken with the Canon 20D IR & Pentax-M 20mm f4.