Friday

Make a cheap, crushable DIY flash diffuser

Ever since I first started playing with craft foam to make my DIY snoot for my SB-800 flashes, I've been mulling the possibilities of using this stuff for other kinds of light modifiers and gobos. Now, using a 12x18" sheet of white craft foam I've been able to make a couple of nice big diffusers for my speedlights that fold down to almost nothing and can be stuffed in to any spare space in my camera bag.



You can make one of these for your flash in less then ten minutes, and it they cost less than $2 apiece.

To make this handy little diffuser/redirector, I first cut the sheet of craft foam in half so that I had two 9" by 12" pieces. Turns out that 9" is just about the diameter of my SB-800 head with just enough overlap to tack on a piece of industrial Velcro to hold it together. At this point, I've basically got a large tube fitting over the unit — doesn't all this just sound so dirty??? — that is acting like a snoot. But a snoot is not what I want.


So about halfway up the length of the foam I fold it down, which causes the whole piece to buckle and form a big scoop. Of course, it doesn't hold this shape on its own, so I cut a vertical diagonal slit about 2 inches long on each side at the point where I make the fold, and then attached a small set of Velcro fasteners to the points where I want it to hold the foam in place once it's folded.

And to give me a bit more light spread, I cut away a section of the sides just above where the flash head fastens to the foam, about 2-3" up and maybe an inch or two in. You can see this in the diagram. This completes the "scoop" look of the diffuser and helps throw a little more light forward right from where it comes out of the flash head. Round off the corners for aesthetics, and you're done.


So you might be thinking to yourself, why is this any different from a plain old bounce card? With a bounce card you are primarily throwing light toward the ceiling to fill the room with most light falling, essentially, downward once it bounces of the ceiling, and your bouncecard is there to throw maybe 10-20% of it forward. Well, here my objective is not to bounce light off the ceiling, but to throw as much of it forward as possible in a way that is softer than just using direct flash. So I end up with a very directional variety of light that comes from a reasonably large source and is fairly soft. Think of it as being like a mini beauty dish.

It's also better than using the diffusion dome attachment that comes with the flash, because you're not throwing light around to the sides or behind the flash. Those of you with eagle eyes and a desire to nitpick will notice that I do get a little bit of light coming through the foam, so it's not reflecting as much light forward as it could and it also is lighting up some of the space behind the flash. But that's mostly because for this first attempt at fine artisanal craftmanship I used a fairly thin piece of foam. They (I'm talking "Big Foam" here, or FOPEC) make two or three different thicknesses of foam, and next time I'll probably go for the medium grade rather than the thinnest stuff. Hell, this only came about because my wife dragged me to Michaels for her needlepoint supplies and I found myself killing time in the kids crafts aisle.

(NOTE: Since making this first prototype I've gotten my hands on the thicker foam, which is 3mm thick according to the label, and it virtually eliminates any light loss out the back. )

This light looks great for tabletop shots, like my little Danish dude holding the star. But any flash attachment like this loses its benefits the further away you get it from your subject. So if I was shooting a portrait with this and had my flash, say, five feet away, it's not going to look too much different than if I was using a point-source (like direct flash.) But I often use several flashes on a shoot, and if I put two or three of these arrayed five feet or so from the subject, suddenly I've got me some nice lookin' light. And as I said in my DIY snoot post, the beauty of this material is that it's super--lightweight (I don't think this diffuser even weighs two ounces) and it folds up or wads up and can be tucked in to your pocket without any permanent harm. You might end up with it being a little bit wrinkly, but we all get that way as we get older.

This foam comes in several colors, so I guess if you wanted you could use orange or red or green or whatever to create some colorful effects. But it seems easier to just gel your flashes rather than carry around a bunch of foam, and you probably lose some reflectivity from the other colors. You can get this stuff at your local Joann or Michaels store, and you can probably find it at any sort of craft store and maybe even places that sell toys because it's designed mostly for kids. But it holds up nicely: it's easy to cut, holds its shape pretty well, you can easily attach fasteners like Velcro or snaps to it and I like it because I'm not allowed to have pointy scissors.



So far I've only made these for the SB-800. But a few days ago I finally bought an SB-900 and it's a much larger unit. But given how cheap the foam is, I'm willing to experiment on making a bigger diffuser. In fact I'm kinda wondering how big a piece I can get away with, so that I could end up having a huge diffuser with more than a square foot or so of surface area to spread the light around. Given how very lightweight this foam is, it just might be easy to do.

The photos in this post were all shot on a tabletop in my basement against a white paper seamless background using a Fuji S5 and SB-800 flashes set on manual triggered by RadioPopper PX units.

1 comment:

Josh said...

Tom, I dont know if you still experiment with these but I have done the same thing in the past..

2 other things that could be done to improve this type of diffuser is to use a cross stitch board .5" smaller than the layout of your foam sheet's edges inbetween black and white sheets of foam.. the black back will eliminate leakage and the plastic mesh will stiffen the unit..

Good luck!

Josh