Grids take a standard flash and make it behave like a spotlight. They're made up of a grid of channels for light to pass through (hence the name) and depending on the length and width of those channels they can radically reduce the area lit by a flash, while giving the light itself a nice falloff. You can use them for lighting small subjects, singling out a part of a whole, adding hairlights, tossing up a quick background... all sorts of things! This instructable will teach you how to convert some black drinking straws, cardboard, and adhesives into a light, durable, and effective grid for the Vivitar 285HV flash.
To build one, you will need:
- Black straws
- Non-corrugated cardboard
- Paper cutter (or scissors, or cutting wheel, etc.)
- Straight edge
- Box knife
- Sandpaper (kinda optional)
- Masking tape
- Tube of silicone (durable and heat resistant!)
- Paper glue
Strobist recently influenced me to obtain two Vivitar 285HV flashes for some manual off-camera lighting. The're great! They're sturdy, easy to use, and last for pop after pop when filed with 2700mAh rechargables. They'd make a great addition to anyone's portable yet flexible lighting kit. Slap some grids on them and they're only that much more versatile!
Here you can see a (mostly) completed grid being lit with another identical grid positioned about three feet away. Nice light, huh? Not bad for less than $10 in materials!
So I know there's another DIY grid instructable here, but their technique is completely different, and mine's fit to the Vivitar 285HV, right? I'm not a total hack! I swear! :)
Step 1: Prepare Your Straws
Black straws make a great material for grids. They're easy to work with, durable, won't add much of a color cast to your flash, and you can get them online for cheaps. A box of 500 was less than $10, and I didn't even look that hard.
Straws also create a super smooth falloff at the edge of a perfectly circular spot of light, with just the right amount of specular highlight in the middle, in my opinion. The picture of the spot below was shot on a crappy textured wall... and it still looks smooth!
Unfortunately, my straws came individually wrapped. So strip off all that paper and compost it or something!
Step 2: Get a Paper Cutter
If you want your grids to look nice, use a paper cutter. That will ensure regular, square cuts. You could also use scissors, or a cutting wheel, or a chopping block & axe... it doesn't really matter that much. I'm just OCD about these things, and want my results to look semi-professional. So a paper cutter it is!
Step 3: Cut 154 Lengths of Straw (And Then a Lot Extra)
Each grid will take exactly 154 lengths of straw, unless your drinking straws are some weird non-standard size. I made 2" and 3/4" grids, so that's what I'll describe here.
The 2" long grid casts about a 1 1/2' spot at 6', the 3/4" long grid's spot is a bit over twice that size at the same distance. I haven't exactly measured. Just to be clear, by length I mean how far the light has to travel to pass through the grid, or the length of the straws that make up the grid!
If you have a friend around, have him do the chopping while you hold the straws, that way you can easily cut a bunch at the same time! Hold the straws on both sides of the blade while your volunteer works it, letting you keep them straight and under control. Watch your fingers, kids!
Voila! Square cuts, fast. You'll pile up the cut straws like crazy at this rate. You may actually want to cut the straws into 1/4 straw and 1/10 straw lengths to be frugal and not waste anything, but I wanted any math I had to do later on to be as simple as possible.
Step 4: Bask in the Glory of your Straws
You cut them all, you deserve a break. Have a Diet Pepsi.
Notice the bag of 2" lengths, and the tray of 3/4" lenghts. It's informative!
Step 5: Prepare Your Cardboard
Find some nice sturdy cardboard. I used the box from a food mill, since it was a bit heavier than the box from a twelve pack or some cereal, and it had a nice smooth finish on the outside.
If you're cutting something up for cardboard, you'll need to make sure you can create a square blank to work from. First, establish one straight edge with a box knife. Then use a square to trim off the adjacent sides, using the edge you just defined as your starting point, keeping the cardboard blank nice and rectangular. Don't bother with the far edge, just make sure not to measure anything using it!
Step 6: Mark the Strips
Now we're going to need some strips of cardboard to fold into the boxes that hold the grids. Fortunately, I've done all the measuring for you!
To calculate the width of a strip, just add 5/8" to whatever length you cut your straws, which is exactly enough to fit snugly on the (awesome) beveled head of the 285HV. Mark this width at each end of the blank, then connect those marks to draw a nice square line indicating where to cut later on.
For a 3/4" grid, you'll need a 1 3/8" wide strip.
For a 2" grid, you'll need a 2 5/8" wide strip.
Step 7: Mark the Folds
Now mark the edges of the strip to indicate where each side of the box will fold, using a square to connect the marks. Squares make it so easy, because you only rely on the marks as a guide, not to square your line. The edge of your blank is playing that role as it pushes against the inside of the square. It's the right tool for the job.
Each side should each be this long:
Side 1: 3 1/4"
Side 2: 2 3/16"
Side 3: 3 1/4"
Side 4: 2 3/16" minus one cardboard thickness
So, mark the strip at 3 1/4, 5 7/16, 8 11/16, ~10 7/8, and ~11 3/8 inches.
Once you have all of the folds drawn, go back over them a bunch of times with the pen using a LOT of pressure, to score them and make the carboard easier to fold. Also notice that I'm marking all my boxes at once, reducing the need to measure stuff. Lazy... or efficient?
Step 8: Cut and Fold
Cut the strip along any uncut sides with a box knife, then carefully fold the box into shape, using the scored lines to help start the correct bend. Don't use a ruler, use your fingers! It's easier to keep the bend straight and in place.
Step 9: Some Prep Work
If the cardboard you're using is glossy like mine, sand the outside of the tab and the inside of the first 1/2" of side 1. Glue will stick to it better!
Tape the sanded area on the inside of the strip to keep adhesive off of it while you work, so it will be fresh for gluing later. Use masking tape.
Step 10: Start Building the Grid
Now for the fun part. Grab the silicone and start squeezing. For a 3/4" grid lay a bead 3/8" from the side you'd like to be the front, and for a 2" grid lay two beads at 1/2" and 1 1/2" from the front. Unfortunately I didn't really have any pictures that show me laying a bead of silicone on a 285HV grid, so I've had to substitute some shots from the construction of a grid for the 580EX II. So much for continuity!
Once you're done, start placing straws, lining them up with the front and pushing them down into the silicone one after the other. Each row should be 14 straws. Start at the back and work forward, leaving a half-straw gap at the near end. You don't have to be super accurate about lining them up, silicone stays gooey for a while and we'll fix them later on. Just get close.
Step 11: Keep at It
After each row of straws, run another bead (or two) of silicone and stack a new row on top, honeycomb style. That means every other row should be shifted a half-straw width, alternating back to front, each straw nestled into the two below it.
Step 12: Keep Things Stable
As you continue to build your grid, make sure to lightly tamp the straws down into place and shore up the sides a bit to keep it square and stable. It should not feel wobbly or squishy.
Step 13: Final Glue
Once you've reached 11 rows, run a bead or two of silicone around the entire outside of the grid, depending on the length of the straws.
Remove the masking tape protecting side 1, and apply a thin coat of paper glue to the outside of the tab and its mate. Let the glue sit a bit to get tacky, then press the tab into the opposite side of the strip, squishing the completed box into the silicone surrounding the grid.
Step 14: Finishing Up
Hold the glued parts together until they set a little, then carefully tape the corner to keep it snug while it dries. Now that you have both hands free, lay the grid flat on a piece of paper and push the straws to the front to even them out. You did work fast enough to keep the silicone gooey, right?
Neaten up any crooked straws with a toothpick/pen/poker and give the sides of the box a little squeeze to set everything in place.
Step 15: You're Done! (Maybe)
And there you go! A fresh grid. All you really need to do now is wait for the glue to dry and the silicone to cure! I slapped mine on a flash after just two hours clamped between two boards (for ultimate squareness) and suffered no ill effects!
I have some further suggestions though:
- Run gaffer's/foil tape over the corners and fold it over the back edge to radically improve the grid's durability, for very little extra weight. I used foil tape, but I don't have any pictures yet. Oh well!
- Paint it a nice color.
- Label it with the spot size it throws at a few distances, as a guide.