Nice testing. I think we are coming to some agreement that in reasonable conditions the SX50 is a useful piece of kit to have available and really can take on a 5D/100-400L. I am going to throw it my bag whenever I travel or leave in the car. The whole camera costs about the same as a 2xTC III and weighs less than twice.
5D IV, 5DS R, 7D II, EOS-M, Powershot G3 X, 400mm DO II, 300/2.8 II, 1.4xTC III, 2xTC III, EF 1.8 STM, EF 70-200/4 IS, EF 24-105, 15-85, 100-400 II, Sigma 10-20, Sigma 150-600mm C, EOS-M 18-55, f/2 22, 11-22