You really can get soft light, with a little help from The Pop-Up Flash Bounce. ---(I like the comparison pics but the product name makes me think of some sort of stripper move -pop-up-flash-bounce-) is it just me?
Trace your lens (or an existing filter) onto thin cardboard. For every filter you want to make cut 2 cardboard circles. Cut the same size holes in the middle of the circles so you have 2 rings of cardboard and place the filter you want