Intro: Build a Flexible DSLR LED Video Light
LED lighting panels for your DSLR are great, but they can be expensive. So why not build your own? I decided to, with a twist - literally, as my panel is flexible and can conform to various shapes for mounting or to broadcast light in various directions.
The basic materials and tools I used are:
Neoprene - I used an old backpack made of the stuff, so free!
Hardware Cloth - not really cloth - basically a fancy name for chicken wire, available at home center
Flexible LED strips - available on eBay and such, which is where I got mine - about $15 for 300 LED strip (Mostly used on Tron Suit)
Velcro or substitute
Flexible Wire - I used an old ribbon cable salvaged from a computer
Needle and Thread - I used heavy duty thread, but standard should be fine too
Type M port and plug (x2) - For power in and output to light panel, any type of quick connect will work
10K Potentiometer with SPST switch - For dimming/power on control
Drill + bits
Epic music to work to.
Step 1: Part 1 - Light Panel Construction
To build the flexible panel base:
I decided on a 6" x 6" square light panel (somewhat arbitrarily), so I needed about a 12" x 6" section of neoprene to make a sleeve out of.
So I took some scissors to an old neoprene backpack (the neoprene was about 1/8" thick) and cut out the needed piece. I folded it over with the side I wanted inside facing out (this one had a blue inner), and pinned it at one corner to hold it in place. Then I sewed a seamed up one side, tied it off, and sewed up the opposing side. Once the two sides were sewed up, I flipped the whole thing rightside out.
Now time for the inner frame:
Take your snips and cut a 8" x 8" square of wire - getting that from adding 1" to each side of the final dimension. Then cut a 1" x 1" square out of each corner, so the sides can be folded in. With that done, fold each edge in half, then in half again, then finally in to the final 6" x 6" dimension. This folding in gives a thick edge that will help the panel hold its shape when formed.
With the frame formed, next insert it into the neoprene sleeve (which will take some wiggling, as the frame may snag the neoprene). Once the frame is fully inserted, sew up the open end of the sleeve.
Lastly sew back and forth though the entire panel, so that when flexed the stretched neoprene will stick to the frame and not simple stretch straight across the gap.
Step 2: Step 2: Add LEDs
For LEDs I used LED flexible strips, available on eBay and many other places. Mine have built in current limiting resistors, and can be cut every 3 LEDs into smaller sections. The are stated as having a 6500K color temp, and rated for between 12V-30V DC. They also have a 3M adhesive backing, making for easy attachment.
I cut equal length sections (11 total) and removed the adhesive backing, then laid them on the panel base with equal spacing. I flipped it over, the weighed it down overnight to allow the adhesive to bond well.
Once the strips were attached, it was time to wire them together. My first attempt I used magnet wire, but that proved to be too stiff. I decided on using wire from a ribbon cable as in an IDE connector. I stripped off all the plastic covering to use only the actual wire. I made 2 lengths, each roughly 1.5X the length of the panel.
With the wires prepped, I removed all the negative connectors on one side, and the positive on the other. Then I soldered the wire on each end to the first and last connector, then to the middle, then to the connectors left over. I repeated it on the other side as well.
I took another pair of ribbon cables, and split it partly apart, then soldered one end to each side. I then terminated this in a type M power connector to plug into the soon to be control unit. I used a piece of heat shrink tubing to clean up and strengthen the connection.
With all the wiring done, the last step was to sew some strips of black cloth over the exposed connectors and sew the cable to the body of the panel to tidy things up.
Step 3: Step 3: Control Unit
The last part we need is the control unit, which also functions as the base/mount for the light. I used a small plastic project box, available online or from RadioShack or hobby stores.
The first step is to take the hot shoe plate (I used an extra one from my Nikon) which will be used to mount the light onto the camera. Grind down any protrusions so you have a flat work surface, then line up where on the case you want to anchor it. Drill a pilot hole through both, and thread in a small screw. Most likely you'll need to file/grind down the head of the screw so that it is flush with the mount and does not scratch your flash contacts. One side note - if you grind the screw in place, do it in stages, and the heat from grinding will soften and potentially melt the plastic.
With your mount secure, its time to layout the controls and ports. I choose the sides of the box so the know and plugs would not stick towards my face, since I value my eyeballs intact. I used a 10K potentiometer with SPST switch and 2 type M power ports. I drilled the proper size holes for mounting, and then inserted the components and tightened the included mounting hardware. I also removed some mounting holes for PCB boards to allow more room for the 9V batteries. I made sure everything fit again, the started soldering the connections.
First I joined two 9V connectors together in series and heat shrinked the connection. Next I soldered those leads to the ground output of the LED panel connector and one side of the pot's switch. Next I wired the external power input's leads to the same points and the batteries. Then I took the power from the other side of the switch to the center terminal of the pot, and the then output from the proper side (check which one has growing resistance with your direction of rotation) to the positive output of the LED panel connector.
With the wiring done, I connected the batteries, screwed on the lid, and attached some velcro the control unit and the panel, so they could be joined. And then it was time to test it out!
Step 4: Testing and Final Thoughts
I tested the light output using an app on my phone (so numbers should be taken with a grain of salt I'm sure) and got the following:
At 1FT approx 4000 Lux
At 2.5FT approx 450 Lux
At 5FT approx 100 Lux
These numbers were comparable to some LED lights I saw online, so that was nice.
Here's a test video compilation using the light panel:
You can see in the linked video the light output as attached to camera and off camera in a dark room, as well as a compare shot of a bowl of fruit - first without the light then with. I though the color temp worked well, and wasn't overly harsh.
A note on color temp though - I'm aware that since I directly dim the light instead of using PWM to do so, I'm changing the color temp. But since I'm going to almost always use it at full power, and also this was more to prototype the idea of a flexible light, I decided to go simple with just a varying resistance and current.
It is also great since it fits nicely in my camera bag on top of my camera, because it can flex! And it is fairly thing due to using a separable control/power unit.
So, I hope you enjoyed the idea of a flexible LED light panel for your DSLR (or anything really, I use it as a work light sometimes) and can make one of your own!
Keep on building!