I was looking for something small and light that would make a good flash modifier, and soften the light. After getting a couple of payouts from DT, I decided to purchase Lumiquest's new softbox III for $40. It is lightweight, folds flat, and fits in my camera bag (a little smaller than a piece of standard letter sized paper).
Attaching it: I already owned a couple of speedstraps
, so attaching it to my flash (Canon 580EX) was simple. It has four velcro tabs that secure it to the flash. Velcro being velcro it isn't totally secure, but I haven't had it fall off or otherwise disrupt shooting. You could easily secure it better with an elastic on the outside of the tabs, or some other cinching strap.
Use: A large softbox this is not. While it does increase the apparent size of the flash, it is only effective for relatively short distances. For small items, product shots, or a daylight fill flash this is an excellent tool. Above is my first shot submitted using this light as the primary source. I also see using this closeup for kids or people...
Of note is that the softbox III has pretty even light distribution. I find that taken a photo of the front of the box shows pretty even light distribution when the flash is manually set to wide angle. I have used it with both a cord and a ST-E2. In both cases you get the benefit of ETTL exposure, so I haven't bothered to figure out the lighting loss in stops.
While there are a ton of links to make your own similar device, Lumiquest has captured those of us who would rather not spend a bunch of time eating cereal and cutting boxes :)
As you can see in the photo, it has pretty nice light falloff as well. You get few harsh shadows (assuming it is within a few feet), but it doesn't light the whole room like a sto-fen.
Unlike a bunch of other modifiers that promise lots but don't make much difference, I find this lends itself to some specific purposes - and does a good job of them. Mounted to your flash on your camera from 10 feet away you won't notice any difference except a loss of light...