Focus rings let you manually adjust the focus of your images—video too, on select DSLRs—but they aren't particularly smooth. A DIY focus knob gives you finer control over the range of focus.
Photo by lonelysandwhich.
Although most focus rings are mechanically smooth and not deficient in anyway, the limitation is the size of your hand. It's not easy to hold the camera and smoothly turn the focus ring more than a half turn or so. By adding a DIY focus knob you can increase the range of focus you can cover with a single movement. How does it work? Check out the two videos below, the first demonstrates the view from the camera and the second shows how the actual device is constructed.
The build is simple, inexpensive, and produces great results. The only caution we would offer is to make sure not to over tighten your hose clamp and damage the focus ring—hose clamps tighten more quickly and with a stronger grip than you'd initially anticipate!
Have a clever camera hack of your own to share? Let's hear about it in the comments.
Hardware Store Follow Focus [Hack A Day]