Arpe asked me to post an image of my fuji film canister flash diffuser, so here it is.
This one is just a quick job, so it isn't pretty, but then, it doesn't need to be.
The basic procedure is to use a box cutter or razor blade to cut a rectangle from the bottom of the canister to almost the top. The film canister is about 5 cm in height. The rectangle is about 4 cm long by about 1.5 cm wide, and it should slip right over the built in flash.
These dimensions work for the K100D, you might need to alter the dimensions some if you have a model other than the K100D. Or maybe not.
YMMV. Boxcutters and other sharp implements are dangerous, and should only be used by trained, certified professionals.
Last edited by MPrince; 03-24-2016 at 05:32 AM.