Sometimes, the simplest solutions are the best ones. This video from Dave Knop a.k.a. Knoptop shows one of such solutions. He uses a simple stretchy keychain to make follow focus, and it seems like this stretchy wristband is a handy knick-knack to have around.
Dave uses a Key Band-It Stretch Wristband, a handy little keychain that costs around $8. You can keep it around your wrist to keep the keys with you, but it’s also a handy DIY follow focus. It’s stretchy enough to fit any lens, and the lens still turns easily and smoothly. The principle is similar to the jar opener follow focus.
When I saw this idea, another item that could work crossed my mind. I’ve noticed that these “telephone cable” hair bands have been pretty popular lately. They’re darn ugly and it seems they’d tangle in my hair, so I’d never use them for my ponytail. But, they look like they could work as follow focus. A pack of 10 is $9, and I guess you can find them in stores individually for under a dollar. They also come as a keychain and cost $2.
[The Follow Focus Keychain – BEST DIY Solution!? | Knoptop]