Canon 300mm f/2.8L IS in infrared

Initial testing with a resolution chart suggests that the Canon EF 300mm f/2.8L IS USM might well be the most remarkable lens I’ve ever tested on my Canon EOS 5D-IR infrared camera. Stunning image sharpness wide-open, barely changing as the lens is stopped down, coupled with perfect focus in infrared suggest that this lens is highly corrected for chromatic aberrations. It is rare to see both visible light and infrared light focus perfectly. In fact, I’ve never before seen it with any other Canon EF lens, and I’ve tried about 15 of them. The following image is an actual-pixels crop taken from the extreme corner; it represents as good a result as one can expect from the center of most lenses at f/8:

Canon 5D-IR, autofocus
EF 300mm f/2.8L @ f/2.8
extreme corner