What are the good softboxes for a small flash like a Canon Speedlite 430EX, for example?
Lastolite make an ezybox which is pretty "good" but it really depends on how you term "good". Do you want:
- Small when collapsed
- Durable and long-lasting
- Big (bigger the light source, the softer the light)
Have you also considered just using a shoot-through unbrella?
I love my EzyBox 60x60cm for use with speedlights.
The packed size is smaller(!) than the 43x43cm Ezybox, and it is way more versatile than my Lumiquest III thingies.
LumiQuest Softbox makes the best on flash softbox. I use this for all indoor/outdoor (dawn/dusk )shots and on the go shots. (Wedding, Baby, and Engagment) It attaches with Velcro on the end of the flash. Full tilt and rotate are not impacted.
I've experimented with a lot of these devices and agree that the EzyBox is probably the best, but honestly I find that a flash bounced off the ceiling or wall with the little white card thing pulled up (or a business card taped on) is really the best bet for most scenarios. Check out my blog for a book review of On-Camera Flash to see some amazing stuff, and I've done many of those types of shots with less sophisticated flash attachments than Neil uses.
I also have interviewed some of the top photographers in the world on my blog and I find that many don't even bother with mods beyond the card trick I mention above. It's only the prosumers that obsess over flash modifiers