Flash umbrellas

Just wondering whether an AF200T (my off-camera flash, with an AF240Z on the camera and a simple optical trigger for the off camera unit) would be powerful enough to make an umbrella useful? I have seen a few umbrella/bracket kits on ebay for about £12 and I'm tempted to buy one and have a play with off-camera bounced flash, as I have a spare tripod to mount it on.

I would guess that you need a decent amount of light output in the first place to make the reflected light from the umbrella useful?

Shoot through is more effective since you can please them close to the subject so your flash distance is shorter.
guide number = distance x f-number after all.

http://strobist.blogspot.com/2008/03/rethinking-umbrella.html

silver umbrellas work well with low powered flashes, but shoot through is better...

Thanks chaps - I think the one I was looking at is the shoot-through sort. I'll probably order one and see what happens.