My cactus decided to blossom which was a good opportunity to try different kinds of flash photography. All pictures are taken with a Nikon D70s, a Nikkor AF-S 18-70mm 3.5-4.5 G ED DX lens and a Vivitar 285hv off-camera flash.
The first picture is taken with a diffuser (sto-fen omni-bounce):
The second picture is taken without the diffuser (see how the shadows are sharper):
The last picture is shot with a diy grid spot and the flash head zoomed out (see http://strobist.blogspot.com/2006/10/free-and-so-easy-diy-grid-spots-for.htmlfor how to make one). This both focuses the light and sharpens the edge of the shadows even more: