Infrared on digital?

[ksmattfish]

A softbox is a fabric or plastic "box" that goes over a flash head; one side is transluscent. This diffuses the light, and makes the light source larger. They can be huge in studio, but you can also buy smaller models that will go on an on-camera flash. They usuall use velcro to attach to the flash. Here's a link to one brand and model, there are plenty of other brands too.

http://www.lumiquest.com/lq951.htm

Proper exposure is going to be a combination of flash power, aperture, and distance to subject. Who knows how much IR your flash is putting out, and the DIY filter isn't perfect either. You'll want to make sure the flash is firing at full blast, and then bracket. It's hard to take notes when doing this, so I always use the same bracket order, so when I look at the negs at home I know it goes f/2.8, f/4, f/5.6, f/8, f/11.