DIY macro flash tube
This neat little macro tool was originally made from a Pringles can. I decided to make an upgraded version.
The original version for this little light modifier was featured on DIY Photography back in 2011, and was originated by Steve Kushnir on Flickr as far as I can trace it. From there it spread to a number of other photo web sites, and it's been rummaging around on the web since, and still pops up now and then as a novelty. It's a great little gizmo to use with an SLR with a built-in flash, which is usually pretty useless for macro. The lens will get in the way and block out the light from flash because the subject is so close. This tube simply leads it over the lens and down on the subject.
So my version uses drain pipe... OK, not a really big upgrade compared to the Pringles can, but something that can be finished a little more stylish, and not least become a little more durable.
My version is also adjustable, at least a little bit, and can adapt to different lenses. As the last modification to the original design, I have shaped the business end a little differently, making a diffuser part that kind of directs the light a little more towards the subject.
The list of materials is as follows:
Plastic or cardboard tube, about 40-60 millimeters or 1½-2½ inches in diameter and long enough to reach from the flash and a bit over the front of the lens.
Silver cardboard, not too thick.
A white plastic bag for the diffuser.
A gray or silver plastic or a thermal blanket bag for the flash cover (optional).
Rubber bands and maybe a bit of tape.
In the tool department you need a knife or a saw that can attack the tube and maybe a pair of scissors and a bit of sandpaper. That's about it. A pen or marker can also come in handy.
My tube had the option of creating a telescopic section, so I cut two pieces of tube: a straight one and one with a thicker section. I cut the straight part long enough to reach the end of my 85mm macro. By pushing it into the thicker section I can get it to fit a shorter lens like my 40mm macro. If your tube is just straight, measure it long enough to fit the longest lens you intend to use – or just to fit the single lens you might want to use it with. I know that having several macro lenses isn't that common, but I have four and want this gizmo to work with all of them.
Cut the end toward the lens at an angle giving you an “overhang”. 30-45 degrees will work. It isn't critical at all.
You are now going to line the tube. The easiest way of doing this is with some silver covered paper or thin cardboard. A Letter format or A4 sheet will do. Roll it up, shiny side in and stick it inside the tube. It will expand to fill the tube, and you can mark where to cut it on the backside.
Pull out the cardboard and cut it where the mark is. You can now roll it up again and stuff it into the tube again. If you have done this right, the cardboard will expand to fit precisely inside the tube, lining it neatly with a layer of reflective material. Glue or any other means of fastening the reflector shouldn't be necessary. It will sit quite tightly by itself unless you have used very thin paper.
Line it up with the straight rear end of the tube and trim it to fit. Cut at the proper angle in the front using a knife or a pair of scissors. In my telescopic tube the lining can't go all the way through, but it still works and leads the light to the front.
The larger the diffuser the softer the light, and since the tube is quite narrow, it would be good with something a little larger
I simply used a piece of white plastic from a plastic bag. I cut a rough circle and folded it loosely around the tip and secured it to the tube with a rubber band. A piece of white paper arced over front will work too. You might be able to dig out something a little more stylish like the bottom of a white plastic container, some Tupperware thingamajig or three quarters of a large plastic ball. Just make sure that it's sufficiently opaque and neutral in color.
In the flash end you can consider using a piece of plastic too, mainly to avoid light spilling out. For maximum efficiency you should ideally use something silver lined like a piece of a thermal or heat blanket. Thick, white plastic will also work. Black plastic will block light, but also absorb light. Fitting the plastic over the tube is easy, less so over the flash and camera, but again rubber bands can do much, and tape can certainly secure the plastic in a slightly more permanent way.
I decided against this feature on my tube, which sits quite snugly over the flash.
Exposure can usually be handled by the camera. I typically use aperture priority and let the camera decide the flash power. For more control you can go manual and experiment until you get consistent results. I mostly drag the shutter (AKA slow sync) to get a bit of ambient light, but if your subject is really close and blocks the background, this usually isn't necessary. You might actually want the background to go dark, isolating the subject.