Ok, let me start by saying I'm not nearly as original as I thought I was.
I conceived of this project about a month ago, 'designed' and built it less than a week ago, but only today did I realize how many other people thought the same thing. But that's ok; as my most ambitious DIY photography project to date (meaning it took me about 4 hours of work while catching up on reality shows on my PVR), I'm going to post it anyway!
I'm hoping that this will be useful to some of you out there. The info will be broken into multiple parts which I'll try to post in the next week (linked as I get them done):
- The Introduction, Research, and Design (you are here)
- Real-World Usage
What's My Motivation?
I use my reversed Nikkor 50mm F/2 a lot for macro shots, but getting enough light on the sensor is always a problem. It really clicked for me after the spider shoot though: to get good macros I really needed to use flash.
Of course, I'm a cheap bastard, so buying a commercial ringflash (for $150+) was out of the question. Hell, I'm not even using a real macro lens yet, I'm not ready to shell out that kind of cash. So why not make my own?
My goal was to design and build a macro ring flash for minimal money that would let me shoot bugs, flowers, and animals handheld. Turns out, it cost me nothing, because I already had everything I needed.
My concept was simple: a Sunpak Super 383 Flash on camera with paper/cardboard/foil/whatever I could find to route the light down to a ring around the lens. The Sunpak is so powerful, even if I lost 90% of my light I'd still have enough oomph to light objects inches away from my lens. So I went through a mental design process in my head, jotted some things down last Saturday during proctoring (the sketch page is at right), and started construction that night. The result is the contraption at the top of this entry, without the light leaks (I chose that image because it looks cool and really illustrates how it was built and how it works.
The design is super simple. With the flash facing forward, use a light tube to guide the light forward, then down to the ring around the flash. Use something shiny (like foil-backed tape) to help guide the light and reduce light loss, then spread the light evenly around the ring and place a diffuser in front of that to avoid hotspots. Sizewise, I wanted it to be as small and light as possible while still giving ring width of at least a 1/2 inch.
The advantage of this design is that it slips right on the flash, can be flipped up out of the way if needed (using the tilt motion of the Sunpak), and is light enough to be held by the hot shoe.
The real design difficulty was how to spread the light around the ring evenly and I pondered this many a night before I fell asleep. One requirement was to split the light path to come at the ring from two different directions and avoid a hot spot at the join. In the sketches above you can see I spent some time thinking about it, and I decided on the setup in the upper right with light paths joining the ring tangent to the circle. This prevented the flash from coming out too far but forced enough light down the ring to get even illumination (I hoped).
I also considered double diffusion using a variable width channel down the ring but figured that'd eat too much light and pose nasty construction problems.
And that was the sum total of my design. After making a few sketches, I decided to just build it and see where the problems were; I didn't expect it to work as well as it does right out of the gate. The sad part is I didn't even see that other people had used the same design until just today.
Those Who Came Before
I knew that others had completed single reflector ring flash adapters before, most notably Dennison Bertram (Strobist reference here, legendary picture of model Lenka here) and Jayhan. But, I thought I could bring some originality to the table by placing the modifier on the camera-mounted flash and splitting the light path to get more even illumination.
Turns out I was wrong.
Right before I started this post I looked again at the Strobist: Ring Flash Week: Intro and Resources (for the record, I was planning this project before Hobby posted his design -- gotta love his monster ringflash though). His follow up posts are here, here, here, and here. All are worth the read.
Apparently I got confused by the structure of the introduction post though and I never read the part below the toothy idiot. You know, the part about a Flickr thread soliciting ideas for a ringflash light modifier! To be built by a known company and undercut this commercial flash modifier (which is pretty much what I designed). And the thread includes ibanezrocker's design which is made using similar materials and Jay_in_Frederick's design which has the split light guides.
So apparently I'm not original.
Well, at least I came up with my ideas independently (or who knows, maybe I did read some of these things and then I forgot I had and tried to take the ideas for myself).
Either way, in the next post, I'll explain how to build a light, sturdy macro ring flash adapter for free (well, maybe not free, but I had everything I needed on hand). Last I checked, free is better than anything you have to pay for.
Oh, and to whet your appetite, I'll drop one of my test pictures below. Shouldn't be too hard for you to figure out what the object is. Hint: how do you think I watched the Amazing Race while I was building the thing?