Wednesday, November 14, 2007

Ring Flash Week: Designing the HD Ring Flash

Gettin' tired of the donut logo yet? Have another... We still have a whole 'nother box...

I have been pining for a good DIY ring flash adapter that will do everything I want it to do for a year now. Every time a new design would pop up, I would want to play with it. But ultimately, I knew I would be disappointed if it would not meet my needs. So I just let the idea sit in my head and percolate a little longer.

The result is the Strobist HD Ring Flash Adapter. The "HD" stands for "Home Depot," because that's where all of the parts came from.

(More after the jump.)
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Design objectives, in no particular order:

• Speedlight Based

Sure, I could drop $400 on an ABR800. They are great units, and will do everything I need. But I already own the light output. All paid for. So it seemed kinda wasteful to just go and buy my way out of my problems. So I wanted it to run on speedlights.

Besides, that would mean I could go TTL if I wanted to. (Hey, I do that sometimes...)

• Strong Enough to Use Outside

Almost every DIY setup to date failed on this one. I realized pretty early I would want two speedlights driving it, fired directly at a front diffuser.

• Even Light Around the Ring

Here was the other factor that led to two speedlights. Every one-flash design I have seen balances light even-ness with output efficiency. I needed both. I needed two, symmetrically placed speedlights.

• A Large Ring Source

I like the soft box / ring flash look. Besides, if I want tight and sharp ring light I can always mask it. Not so the reverse with small designs.

• Reasonably Inexpensive

For me, that means $50. Otherwise, what's the point? Just go buy the ABR800.

• Reasonably Rugged

Why bother to design and build it if it would not last? I love some of the folding designs that fit in the camera bags, but they fail on criteria 2, 3 and 4. So I was committed to building something a little more substantial.

• Reasonably Portable

This, I was willing to bend on. In the end, I settle for hand-holdable. I will be putting a 1/4x20 mount on it soon, tho. Monopod and ball head would be a perfect support.

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Design Process

Eventually, I settled on a donut-shaped device which basically housed the camera itself and two lights. I designed it around a specific camera, the D70s, because of it's awesome sync hack. But you could use this reasonably close in full daylight with any camera that synched at, say, a 250th.

Given that the measurements are based on a camera a specific lens, I designed it around a Sigma 50-150/2.8. [Nikon|Canon] I love this little lens -- fast, sharp, light, reasonably priced.

(Any tele/portrait lens you can stick in a 4" piece of PVC should be design-capable, tho.)


The heart of the design is a 4" PVC tube: Cheap, strong, cuttable and readily available. The camera mounts to it via a ghetto bracket made out of aluminum plate strip: 1" x 1/8" x 3'.

Didn't even cut it with a saw, either. Just bent it in a vice and snapped it. Very easy. Also made the bends by holding it in a vise and doing it by hand. No machine shop tools were used in the project. Just a drill, a jigsaw, and a vice. A little sandpaper, too.


The PVC assembly was joined to an outer shell made of concrete footer tube. (Mine was 16" in diameter.) That stuff is tough. If you drill holes in it, it mounts very solidly with nuts, bolts and washers.

To the front was fastened a piece of sanded 1/8" Plexiglass. It was "washer" shaped, and I simply traced the inner and outer circles with a Sharpie and cut it with a jigsaw. I sanded the Plexi to make it frosted (both sides) but that was not enough. I also used a sheet of parchment paper on the inside as an auxiliary diffuser.

Also, it turns out I suck at cutting Plexi, so mine had a few non-fatal cracks and was laminated with clear packing tape. I mounted the Plexi to both tubes using "L" brackets.


Here is a drawing that shows the relationship between the flashes and the unit. You can tell where the efficiency comes from. Those two speedlights are both blasting right into the frosted Plexi/paper sandwich.

With the W/A diffusers on the flash and some foil-backed tape, I got nice, even light at the front.


The flashes are held to the insides by good 'ol ball bungees. Love those things.

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NEXT: How to Build the DIY HD Ring Flash




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20 Comments:

Blogger Jacob said...

Crikey! My first comment got axed by the evil blogspot comment eater. And I couldn't get it back, so now I have to create it from memory.

Glad you acknowledged the re-run of the doughnut, Hobby. Thanks to that fantastic disclaimer, there was no chance of a near-skippness this time!

Excellent ring light start- reminds me of one I built last year of a similar idea - using two strobes, one mounted in the hotshoe, and the other upside down in the tripod mount. Problem was, you still lost light as there were "tubes" to get it to the front of the ring around the lens. It was awkward, so I dumped it without further engineering.

Looking forward to the rest of your ringlight tutorial.. perhaps I'll give it another go.

November 14, 2007 12:20 AM  
Anonymous tarjei99 said...

I assume that an el-cheapo plastic bucket would be acceptable as well?

It is not straight of course, but it might be lighter.

greetings from glorious Norway,

November 14, 2007 1:12 AM  
Anonymous Anonymous said...

Wow I cant wait!!

Alex

November 14, 2007 2:21 AM  
Anonymous Anonymous said...

I'm not sure but it looks pretty heavy. I guess i have to wait one more day...

November 14, 2007 4:06 AM  
Anonymous Jeremy Center said...

dude. i speak strobist, but your diagrams are a bit, ummm... how do i say this politely... they suck. and you know the routine. we want to see some `pix. Or at least I do and that´s good enough reason alone.

November 14, 2007 6:02 AM  
Anonymous Jeffrey Friedl said...

Here's an idea that might allow more of the Speedlights' original power to get out. Rather than rely on the light-robbing parchment paper, line the back and insides of the unit with tin foil, and aim the flashes backward. My no-real-experience guess is that you'll lose less power and gain more diffuseness this way than with the parchment paper.

Also, does it at all help to "channel" the light forward by putting the sanded Plexiglas a bit back from the opening, so that at least a bit of the stray light sent off in odd directions is reflected back toward the subject?

November 14, 2007 7:46 AM  
Blogger sgazzetti said...

I love the technical drawings. The soul of efficiency.

November 14, 2007 8:21 AM  
Blogger silence said...

Wouldn't it be easier to buy some xenon (readily available from industrial gas suppliers) and use sealing wax to seal it in a flexible plastic tube, and then attach it to the electronics from an existing flash?

You'd have issues with the gas leaking out if you did enough zaps at full power to heat the wax, but it would probably run just fine under all other conditions.

November 14, 2007 10:09 AM  
Anonymous mkayi said...

>Besides, that would mean I could go
>TTL if I wanted to. (Hey, I do that
>sometimes...)

ARGH! Is this like Tarrantino being the first to stop doing Tarrantino movies back in the nineties?! I trusted you...


^^

November 14, 2007 10:47 AM  
Blogger Drime said...

oooh! SB800s!!

November 14, 2007 10:49 AM  
Blogger scubajunkie said...

I'll ditto the suggestion to mount the flashs backwards. I had the same thought. But doing so with the flashes on the inside of the, um, thing, puts two black bricks on each side blocking light. So, you could mount brackets to hold the speedlights on the outside and cut flashhead sized holes large enough to angle the strobe through pointing toward the back wall of the ring flash. And the entire inside would be lined with foil (except for the plexiglass front, of course). Not only does this make more efficient use of light, but by putting the SB800s on the outside, this allows for use of Nikon's Wireless CLS (please, don't hurt me) for those of us that don't own and don't want to shell out the bucks for Nikon's TTL cables.

November 14, 2007 12:46 PM  
Blogger Danno said...

This is a great idea. Even if you don't reverse the flashes, I'd still recommend trying to line the dull & non-reflective innards with tinfoil, or some aluminum tape (if you can find it cheap).

November 14, 2007 3:41 PM  
Blogger Holly said...

Can I see an actual photo of this beast? I'm having enough trouble trying to wrap my head around this anyway... I am a farmgirl, but these building projects sometimes trip me up. Thanks!!

November 14, 2007 4:31 PM  
Blogger Bill Stormont said...

About the Doughnut Logo: how about taking a bite out of it each time you post? Side-lit, of course, and off-camera. Eventually it would disappear, replaced by an apple fritter, cream puff, or other pastry of your choosing.

November 14, 2007 5:29 PM  
Blogger Pinecreekboy said...

May I see the bagel and SB26 again and again? I'm tired of looking at Lenka.

November 14, 2007 6:01 PM  
Anonymous Anonymous said...

Im about to make the PVC ringlight shown on the kithen floor... Looks fantastic. I figured Id poe around and see if I could find anyhting weve missed before undertaking this project though and I think I may have
Has anyone seen this? Terrific mounting solution.... somewhat pricey but may help in designing a DIY model.
Look : http://www.ephotozine.com/article/Flash-gets-ringed-in

Jason Joseph
www.JasonJosephStudio.com

November 15, 2007 12:00 AM  
Anonymous Anonymous said...

Im about to make the PVC ringlight shown on the kithen floor... Looks fantastic. I figured Id poe around and see if I could find anyhting weve missed before undertaking this project though and I think I may have
Has anyone seen this? Terrific mounting solution.... somewhat pricey but may help in designing a DIY model.
Look : http://www.ephotozine.com/article/Flash-gets-ringed-in

Jason Joseph
www.JasonJosephStudio.com

November 15, 2007 12:07 AM  
Blogger biplaza said...

Mmmmh... found it!
This happens when you talk before googleing...

Inflatable
RingFlash


Anyone has more info on this?

November 15, 2007 7:56 AM  
Blogger biplaza said...

My previous comment lacks the former one, which must have been devoured by some "blogspot seek&kill comments robot" or so. I was suggesting to make an inflatable ring adapter ala Gadget Infinity inflatable diffusers. Seems that this ELECTRA model already exists (see link in previous comment).

Anybody has tried this one?

TY

November 15, 2007 9:30 AM  
Anonymous Al said...

Hi - great page. Just gettting into off-camera flash and will be back for more. Here is my plan (including step-by step DIY) for a fibre-optic macro ring flash that cost $5 to build. Very easy to build - just need scissors. Surprisingly rugged and crush-proof - can go into the gadget bag along with the lens. Go to www.fring.we.bs (My web-designing is awful - be patient as it loads.) Not claiming any of these ideas are terribly orignial - (didn't realize just how many people were building their own ring flashes until someone directed me to this blog.)
Enjoy!

August 12, 2008 12:01 PM  

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