Rather than start a new thread on my just acquired MC Tele Rokkor PF 100mm f/2.5, I thought it would be best to just post here. Hope OP doesn't mind.
Anyways, the pic of my son below is from the first few shots (5th I believe) with the lens on my A7Rii.
@ f/2.5 1/200s ISO400 in manual mode. Nissin Di700A at 1/32 output with Air Commander at camera right through a translucent brolly. Background -0.7 stops.
Selective sharpening and serious zits removed in PS.