Infrared flare with the 85/f1.2L II USM
The Canon EF 85mm/f1.2L II USM shows pronounced flare in infrared when there is a very bright light source just outside the frame (in this case a 50 watt MR-16 Solux bulb). I haven’t yet tested for this issue in visible light shooting. The full-frame example below used no filter, and the Canon-supplied lens hood was attached: