f/1.8 - 22
This is one of the best performing lens I have seen for infrared. Good performing native FE auto-focus lenses are rare, so to have one that is this sharp across the frame that is also amazing for infrared is extremely special. When you combine this with the fact that mirrorless cameras/lenses have no focus offset issues no matter what wavelength you're shooting it makes the IR experience with this lens simply amazing! This has been my 'Go-To' lens for two trips to Switzerland.
The high contrast examples below demonstrate why I require such good infrared performance from my lenses (and thus why I do these tests). Trying to correct a hotspot on these examples would be impossible as it would destroy the delicate contrast.
If you have an IR or full spectrum converted Sony A7 or A9 this is, hands down, THE lens to get.