Focus puller for lenses with 8cm diameter

You can use this simple focus puller to create smooth focus pulls between objects without having to watch out for the sharpness all the time.

Just focus on one object, push one blocker at the position and then focus on the other object and block the position with the other blocker. Then start recording and move the focus ring from one blocker to the other. Done.

You need:
-small rubber band

Succesfully tested on:
Canon EF 50mm f/1.8 STM
Canon EF-S 18-55mm STM
Canon EF-S 55-250mm STM