From my own equipment it would have to be the 300f2.8IS from any I would go for the 500f4IS.
I will own both one day.
To be serious.. Someone wanting to get into portaits then I would have to go for the EF 85mm F1.2 Mark II L
I would say something like a 400MM - 600mm 2.8 tbh, especially in light of the work I am ebbing towards.![]()