Anamorphic

Anamorphic Chop Shop – Splitting Diopters

June 5, 2016

Since I watched “The Hateful Eight” and noticed a split field shot, meaning, a close up filter that only covers half of the lens, I wanted to get myself a set of these. With no help from eBay, I ended up making my own, and here’s how you can do yours!

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Tito Ferradans here for an extremely hardcore tutorial on how to make your own split field diopters. In case you don’t know what split fields are, they are diopters that cover only half the lens. By doing so you can have things in focus on the foreground and background at the same time. I started to obsess about these after watching “The Hateful Eight”, which features a split field shot, and started to hunt them on eBay with no luck. All I could find were small sized ones and I needed at least 72mm to fit my anamorphics. It takes some practice to get used to the technique, so the sooner you get yours done, the sooner you can start practicing.

What are we gonna need here? Diopters (mine are 72mm, but you can get whichever size you like), a few circular polarizers, a black sharpie marker, many clamps, LOTS of sandpaper (or sanding stones), wire, a transformer (mine is 24V, 50W), nichrome wire (thicker than gauge 34, for your own good), a ceramic connector, lens wrench, gloves, mask, protection goggles, pliers, exacto knife, a ruler a bucket of water and a water sprayer.

Electricity is a key part in this tutorial, so play SUPER SAFE. I had a ton of help from my friend Bruno Nicko, who’s starting his own channel with a series of DIY videos (his first project is revamping a dead electric scooter). Many things can go wrong with electricity, so I asked Bruno to explain the details regarding resistance, current, voltage and everything else so you have a rough idea if you’re gonna burn your house down. Always wear protective gear and be extra careful with all the steps in this tutorial.

Let’s get started with an easy step: remove the diopter from its original filter frame. These rings are super cheap and you won’t be using them anymore, so don’t worry if the locking ring breaks in the process.

Now, the electrical rig. Connect the transformer to the wires and the wires to the ceramic box (this thing is meant to resist great heat and contain electricity). Now make your nichrome loop – my wire was too thin (gauge 34) so we had to make it thicker, since the heat was melting it right off the bat. Connect the loop to the ceramic box too. The nichrome wire works as a resistance and heats up as electricity passes through. I highly recommend using an extension with its own fuse instead of connecting this contraption directly to a wall outlet.


Step away from this for a second, fill your spray bottle with water and put it in the fridge.

With your diopter, ruler and exacto knife, head outside. It’s time to score the edges of the diopter to hold the wire in place. Use a piece of cloth as a base so the glass doesn’t get scratched and there’s some tolerance for the pressure you’re applying. Don’t put too much pressure or you’ll break the lens, but if you do it too lightly you won’t carve the line you need. WEAR MASK, GLOVES AND GOGGLES for this. Glass dust is a mean thing.

Back to the wiring, rig up everything to hold the lens in place. Don’t hold it with your hands for cutting: the wire goes over 800°C and the glass heats up as well, so you don’t wanna hold that. We used a bunch of clamps to hold the ceramic box and another two (attached to a tripod as a flexible arm) to hold the lens in place. The two popsicle sticks make sure the clamp isn’t scratching the glass. The sticks also handle the heat. Fit the nichrome wire on both sides of the lens using the cuts in the glass. The wire should run right through the middle of the diopter. We used the convex side so the lens itself helps in keeping the wire stretched. You want it to be as stretched as possible, applying some counter-pressure to the glass.

This is the hard part, it’s also when magic happens right before your eyes. Turn on the transformer and wait for the wire to heat up, give it a good minute. Turn it off, spray the glass with cold water. Heat it up again, spray it with cold water. It takes time. My transformer was at the very edge of dying while we did this. You’ll be motivated to continue since you’re able to see the cracks forming through the glass. The center is the thickest part, and it’s a pain, but eventually it’ll give in. As a reference, the entire process took about four hours for me, but we were still figuring things out along the way.


This will get you two halves of a circle and an edge that tries to cut you just by looking at it. Once more with your mask, gloves and goggles, head outside. Grab the sandpaper and the bucket of water. Using a coarse sandpaper (or sanding sponge, in my case), submerge the glass and sand the edge away. Don’t do it flat, always sand the glass at an angle to smooth it out. This step takes a reasonable amount of time. When the edge is straight, switch to a thinner grade sandpaper for finishing it up. Now you have a friendly edge that won’t chop your fingers off, the problem is that the white of it will introduce a terrible glow across the frame. Using the black sharpie marker, paint it the best you can. Since you sanded it down, the ink will stick for good.



The last step is to get the glass and mount it onto the circular polarizer ring, so you can rotate it as you please once you put it in front of your lens. On the bright side, each set of diopters gives you TWO sets of split fields so you can keep the leftovers as backup gear.

Last minute advice, if you’re thinking of trying a different method than the wire, I did that for my first diopter. I tried the flaming thread method, then a glass cutter, both failed. We ended up hammering a ruler to the line down the middle of the glass. It cracked unevenly, of course, and I had to sand down 1/8th of an inch on the good half of the diopter. It doesn’t look like much but it took me three and a half hours to dust it and the resulting split still could use some more polishing to get straighter.

As mentioned before, I had tons of help from Bruno Nicko for this tutorial, so you should definitely check out his channel for more extreme DIY projects. Let me know if you got the guts to try this out and how the process goes! I’ll get back to work here because Vancouver is sunny for a change and I gotta shoot as much as I can to keep you all busy! Subscribe to the channel and check my blog for more tutorials and anamorphic stuff! See you soon.

In case you wanna see some more split field in Hollywood, here’s a supercut! Music is a bit off, but the technique is well represented and you can see which ones are split diopters and which ones are done in post!

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