DSLR Pop-up flash diffuser

Step 1: Measure your flash and cut the canister

Well, this step is simple... pop up the flash on your DSLR and measure the depth of it's base. You need this to know how wide to make the cut on the film canister.

Then grab your canister, a box cutter or X-Acto knife and cut a slit down the side of the canister. Make sure that slit is barely wider than your flashes stalk.