Well, you gotta get creative, Jack! Here are a couple of videos from Filmora that show you two ways to make DIY follow focuses out of household objects, including a magnifying glass and an $8 silicone jar opener.
Film Riot actually shared the jar opener idea back in 2012 — and surely it was floating around before that as well. But check out their video below; not only does host Ryan Connolly talk about this DIY hack, but he also gives you tips on becoming a better focus puller.
Now, I'm not completely sold on the jar opener being a good DIY solution, but only because the end from which you pull seems a little too flimsy to provide the precision you need to pull focus. I've never tried it before, so I may be completely wrong. However, repurposing the magnifying glass is a little slice of genius. Even if these hacks aren't perfect, they're super simple and cheap and can give you at least a little bit more control while you pull focus.
Share your DIY follow focus ideas in the comments below!