So I currently have a 580exii and 430 exii and am currently using a gary fong diffuser on each. I'm looking to improve the softness of the light by starting to experiment with a softbox. The one I'm looking at is:
Some of the reviews mention it only being good for one person. I'd like to be able to use it with groups as well. Will this not work for that due to the angle of light transmission? Thanks.
Please don't take this the wrong way (I know everyone takes things personally on the internet), but it sounds as if you need to understand a little more about light before you start buying more gear. Check this link out for some softbox basics
. I only caution you on your purchase because of my own experience; I've bought tons of gear only to learn later that it wasn't what I needed. Buy once - buy right.
"Softness" is created by increasing the size of the light source relative to your subject. This is why bare speedlites, no matter how close they are positioned to your subjects, produce hard shadows. This is why the sun, a tiny spot in the sky, creates really unflattering light when it is at high angles... the shadows just kill portraits.
So, by increasing the size of the light source relative to your subject, you create a softer light that can "wrap" around body features. This fills in shadows, and creates gradients from light areas to dark areas, which is that "soft" look everyone comes to know from a softbox. This is why people are saying your 24" softbox may only be good for one person. At that size you can only place it so far from your subject before it becomes a point source. With that dimension you wouldn't get much use out of it beyond a key light for headshots, or maybe a gridded rim/effect light in a full body shot.
As I mentioned, a softbox will end up being a point-source if it's far enough away from your subject. This is why those on-flash softboxes really don't have a significant effect for shooting event candids. Going from a 2"x3" bare flash, to a 6"x10" soft box, is still a point source when you're 10'-12' from your subject!
Now, come full circle to your question about lighting groups of people. I wouldn't worry about softboxes and instead simply worry about trying to light them evenly. Large reflective, or even shoot through umbrellas, are good for this kind of work. Don't get me wrong, you can make softboxes work with groups, but like keithfullermusic pointed out, yer gonna need a few of them.
I do a lot of event work for DU, and two Alien Bee B800s with 42" shoot-thru umbrellas do the trick every time... 2012 August Hood Presentation-41
by Daniels at University of Denver
, on Flickr