Behind the Scenes: Stroboscopic Dancer

Ever since I saw Joe McNally capture the sequence of a dance in a single long exposure several months ago, I have been aching to try the technique myself.

The advanced technique Joe used is called stroboscopic flash, or repeating flash in some other camera systems, and involves using an off-camera flash to light the subject multiple instances over a specified amount of time. This allows the camera to capture movement of an object across the frame in a single exposure.

“Movement? Minifigs don’t move!”, I hear you say.
“Why don’t you just take multiple exposures with the minifig in different poses and blend them in Photoshop?,” you exhort.
“This is overkill!,” you complain.
“There’s an app for that,” I hear you scoff.

Yes, but my journey and joy in photography is about experimenting with new techniques and challenging myself, not doing what I already know or having software automate it for me.

So last night, with my husband away on business and my 7-year-old at a sleepover nearby, I animated a minifig and strobed her to make her freeze. And it was awesome. And perhaps alarmed the neighbors.

The minifig

Inspired by Joe McNally’s photo, I went with a dancer as well. To create my dancer, I dipped into my LEGO minifig storage cabinet and fished out the tutu from Elephant Costume Girl, some plain white legs, and the torso from the Pop Star.

I wanted her to have a peaceful expression, like she was in her own world just dancing for herself, so I used the reverse side of the head from the mom in the Outdoor Adventures People Pack and gave her Neville Longbottom’s hair with headphones.

Dancer minifig with Crazy Arms

As I played around with dance poses, pulling out arms and twisting hands, I remembered the yellow Crazy Arms I bought many moons ago but never took out of the baggie. Now, if any, would be the perfect time to try them out.

The Crazy Arms come in straight, bent and “javelin”, which is kind of like an overhand throw. I didn’t have the “javelin” arm in yellow so I went with the other two to form this kind of “shall we dance?” pose. I bought them as a pair for $4.00 since you can’t buy them individually or in any another combination.

The Crazy Arms don’t pop into the LEGO torso as simply as the official arms do. Instead, you insert brackets in through the bottom of the torso and then connect the arms through the torso arm holes. The brackets provide effective clutch but they are also two more small pieces that are rather easy to lose. Once you pull out the Crazy Arms, the brackets drop right out.

Obviously, it would be great to have it so that the Crazy Arms fit into the sockets just like official LEGO arms but it seems to be a manufacturing challenge to all but LEGO.

Still, if you’re not the purist kind of minifig photographer, these Crazy Arms are crazy useful in getting cool poses.

The setup

Animating a minifig and making it glide across the frame requires some gear, and I thank my GAS-afflicted self for capriciously buying that rotating time-lapse tripod head a few months ago! It wasn’t too much of a price to pay at $30, but still, a largely unnecessary purchase.

Motorized panoramic time lapse tripod head

I set this to spin 360 degrees in the fastest time it could do it: 10 seconds. That’s way more time than I needed for this exposure, which I calculated to be 2 seconds (more on that later), so I knew that I would only be able to get the minifig in partial rotation for this shot.

To attach the minifig to to the motorized time-lapse tripod head, I used a LEGO tripod plate that I made last week. It’s a regular Arca-Swiss tripod plate that I sanded down and epoxy-glued a few black LEGO plates to.

The screw of the Arca-Swiss tripod plate sticks out a little through the top, preventing me from simply putting another LEGO plate over the whole thing. I can’t get the screw out so I had to add a couple of layers just to get a flat surface for the dancer which I’m not sure I needed for this shot, in retrospect. I thought I wanted her dead center to create a tight spin but maybe it could’ve worked better if I put her slightly off-center. Anyway, that’s for another day.

Stacked LEGO plates on modified Arca-Swiss tripod plate

I should mention that I used an Arca-Swiss plate for this because I have Arca-Swiss clamps on nearly all of my support gear. It just makes it easier to switch things out.

With the Arca-Swiss clamp on the motorized time-lapse head, and the LEGO-ized Arca-Swiss tripod plate seated into the clamp, all that was left to do was screw in that assembly into the dolly to fashion a moving platform for the dancer. The time-lapse head is motorized so I just needed to turn it on and then manually push the dolly across the table left to right to create the illusion of a dancer spinning across the floor in the photo.

Complete kit for moving the dancer

The final piece of the setup is the flash. I set a small flash on Multi mode to flash 4 times at 2 Hz. This would give me a shutter speed of 2 seconds (number of flashes/frequency=shutter speed) which is a good amount of time to push the dolly so that it travels a couple of inches across the camera frame.

Here’s a good primer on how to use the stroboscopic feature on your flash:

The flash was bare and I had it positioned quite close to the minifig, just out of frame camera right, so that it would be relatively soft light even though it didn’t have any modifiers. I set the flash to its lowest intensity so that it would have an easier time recycling.

My Sony a6500 with a Minolta 100mm 2.8 macro lens was on a tripod, as with all the long exposure shots I do. I had the aperture dialed in to something like f8-11 to get more of the minifig in focus as she twirled and the ISO at its native 100.

The shoot

With the room lights on, I positioned the minifig so that it occupied the leftmost part of the frame and then slowly moved the dolly to the right so I could see more or less how much space to travel in the 2 seconds that the shutter would be open in order to fill the frame. At this point, I should have used some painter’s tape to physically mark the end points on the table but I was too excited to get on with the shooting.

I manually focused on the minifig and then I turned off the lights.

At first, I used the timer in my camera and would begin moving the dolly across as soon as the first flash went off, but then realized 10 shots later that I could just simultaneously hit the shutter on the camera and move the dolly with my other hand since it was within arm’s reach anyway.

Depending on how quickly I moved the dolly, I could get more spaced out poses or tighter, more overlapped poses.

It was quite a bit of trial and error with dolly speed and distance: sometimes I literally went too far and would find that I had cut off a whole arm. Or sometimes my timing was off and I would have an entire sequence of just the minifig’s back to the camera.

Conclusion

I really enjoyed shooting with stroboscopic mode on my flash and will definitely give it another go. Re-watching Joe McNally’s video, I might try manually popping a second light at the end of the sequence and experimenting with mixing in some continuous light to capture some ghosting between poses.

Probably won’t be shooting another dancer, but who might it be? Hmmm…

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Margus
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I like very much that You experiment with different techniques to make Intresting Lego minifigures pictures. And I like You share with Us (Your home page readers and Instagram fallovers) how You did they pictures. Your behind the scenes descriptions are very Intresting and easylly understandable. That means You explain very good every aspect. I like read how much fun it is for You to make they pictures.You enjoy taking different pictures and make for Your self Small word photography more Intresting and find more new motivation. Discovering new things and share they with Us. You make very Awesome work… Read more »

armybratbricks
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armybratbricks

Awesome! I am always interested in BTS of creative Lego pictures, so it was great to read this!