Was wondering! whats a focusable umbrella, do u mean a brolly like the alienbees version?? And yeh Profoto is the shiz, its the one of the hightest strobes as far as i know. If u can afford it, get it and dont look back.
all umbrellas need focused - it's done by sliding the shaft in and out of the mount on the light/stand.
Profoto is good stuff, but must any brand name that's been around 10+ years is good too. You don't need to spend a fortune to get reliable, usable lighting.
