Having sat the subject on the steps of the spectacular building where he works I set the flash up directly in front of him. To get the sky and building as dark as I wanted to I had to simply get the flash at the correct distance, without umbrella but with diffuser cap over the reflector.
1.The available light reading at 200 asa to correctly
expose the scene without flash was1/125th at f5.6, so
to get the three stop underexposed background I went
for 1/250th at f11.
2.To get the flash at f11 it was just a case of setting the Lumedyne unit on half power and moving it to the right distance from the subject.
3.The pool of light was wide enough to just catch the wall, giving the slight circle of light on the nearest wall.
4.The LCD screen gave me a good idea of the light balance, but I tried afew exposures around the correct one just in case. The trannie shooter in me still makes me bracket.
Simple. A fast and elegant way of shooting a portrait with real presence. This technique works just as well with brick walls, fire escapes and open countryside so you don't need a Victorian University building to make it work.