How to Build a Grid Spot

I love to build stuff. It’s one of the many reasons I love photography. Every lighting situation is an opportunity to make a new gadget. So it stands to reason that after following Strobist for a while I’d find a kinship with them in the building of light modification devices for flash. And perhaps the most cool is the grid spot.

Thanks to Strobist, I was able to find a source of black Coraplast in manageable quantities. In case you didn’t know, Coraplast is basically corrugated cardboard constructed out of plastic, available in colors. You’ve most likely seen it as those silkscreen screen-printed campaign signs posted on folks’ front lawns. The hollow core forms narrow tubes through which light can pass in a narrow beam. You cut it into narrow strips perpendicular to these tubes, and laminate them into a flat panel, like this:

The greater the thickness, the narrower the overall beam, constructed of many smaller beams. One-inch is a good starting point. Grid spots, or grids as they are also known, essentially do the same thing as a snoot, but offer more control and are more compact. The challenge was to design mine in such a way that it can fit all the flashes I don’t have yet. And with the help of a friend who loaned me his Vivitar 285HV (probably the largest scenario) and Nikon SB-600 (probably the hardest to fit due to the projection on the top) I came up with the design above. The outer panel on the left is made 3/4" longer than the rest to form a tab which you can use to rubber-band it to the flash. I did’t want to attach it with something that wraps around the back of the flash, as there seemed to be too many variables to overcome, such as the size of the flash, and the angle of bounce, if it’s to be used. I’ve notched the corners so that the tab is slightly narrower than the flash head to make for a more secure fit.

The Vivitar 285HV not only has a large flash head, but its bezel is also very narrow. So, if I could make it fit this flash, it should be able to fit anyting else. And it does.

Coraplast Grid on Vivitar 285HV

Coraplast Grid on Nikon SB-600

The projection at the top of the SB-600 may at first present a mounting challenge, but in reality it creates an advantage; you could make slight adjustments to the vertical tilt if necessary by using the projection as a pivot point. Here the angle has been adjusted ever-so-slightly upward.

Detail: Using the Wide Angle Adapter projection as a pivot point. 

Of course, being a designer, the raw edges of the coraplast on the sides drove me crazy. So, I simply wrapped a 1-1/8" band of self-adhesive black craft foam around the whole thing. The extra width provide a slight rim around the front and back sides to give it a finished look and hide imperfections.

Not only does it fit these flashes, but also the D90’s on-board flash via the Janco flash diffuser bracket. You just insert the bracket into the appropriate holes. It fits perfectly.

Grid mounted directly on D90 using a Janco Flash Diffuser bracket.

For me, this was the icing on the cake. It gives me a level of control from the camera’s flash I would never have expected. A quick test shot reveals some dramatic lighting effects:

Taken at a distance of about five feet, with the grid mounted directly to the D90.

So now that I know a single design can meet the requirements of all my proposed flash purchases, I just have to duplicate it in multiple thicknesses for different beam spreads. I’m thinking a half-inch, one-inch, and two-inch version. Perhaps a four-inch version for pinpoint lighting. Perhaps experimental designs (what if every other row was blocked off, or random cells plugged?)

What’s next, a light diffuser made from Tupperware?

Hmmm...