Last month I was shooting a wedding (video) for a couple of good friends (the groom also happens to be my boss). I don't do a lot of this type of work, but it is hardly the sort of thing that I would turn down. I consider myself pretty good at preparing for unexpected situations but this one caught me off guard.
I, of course, had loaded my wagon to the gills with video gear. 3 cameras, firestore, audio gear, light kit, background kit, steadycam, tripods, and more grip then you could shake a stick at. At the last minute I was asked to shoot photos of the rehearsal so I threw my dslr bag in as well.
The thing that I had failed to account for was light. Video requires a heck of a lot less light then a dslr. Under normal circumstances I would have rented a couple of fast primes and an sb-800 or two and been good to go. This was not an option do to the short notice and tight budget in this case. I do carry a couple sb-28s and a set of pocket wizards in my bag. My assistant wasn't to arrive until Saturday morning so off camera seamed out of the question.
Now, what I ended up doing was not quite professional, but it got me through well in the pinch.
The is a company called Lumiquest that makes a bunch of great little mods for speedlights. Most range from about $20 to $30 and they all work really well. I knew that I wanted to use something like this but I had left all of that stuff at home so here is what I did.
1 sheet each: black and white "craft foam" 12"X18"
1 can of spray adhesive (3M 77 or equivalent)
1 pack of the good self adhesive velcro
total cost: $12.44
(ok I bought the big pack of velcro, but you can never have enough of that stuff)
Basically I used the spray adhesive to laminate the foam sheets together, making a reasonably tough but still flexible sheet.
Then I cut the sheet in half and used the velcro to make a "light scoop" and attach it to the flash, similar to the lumiquest modifiers.
The picture below details the light from this mod.
Note that the bottom has a nice even falloff but the top looks a little rough, in practical applications this does not really matter and I was shooting it up into the ceiling a lot anyway.
Hope this helps.