Why use a clear plastic bag? I wouldn't have thought that would do much diffusing - wouldn't a white one be better? Similar things (but purpose-built and harder wearing) can be bought for a few pennies:
http://www.premier-ink.co.uk/photographic/flash-diffusers/universal-soft-flash-diffuser-p-2115.html
Tissue paper will diffuse it better.![]()
Stratman said:Next time you are walking along the street, cast your eyes downwards and pick up some of the many elastic hairbands you see, those that are about an inch or two across. They're just the thing for holding stuff on flashes.