Have you seen some of the homebrew Follow Focus Ring solutions for the Canon 7D? (Homebrew#1 and Homebrew#2) I was going to Home Depot to try to build my own, but I stopped on the way to the kitchen. You see, those solutions reminded me of a jar opener I had in the drawer. Take a look.
This jar opener is several years old. It is made out of rubber and is flexible enough to fit a variety of jars. With its gripping teeth, open-ended design, it is perfect as a Do-It-Yourself Follow Focus Ring. It is flexible enough to fit around my Canon 15-55mm EFS lens and even my Canon 70-200mm f/2.8 IS L. And, it works! I used it in my latest video Sample of Shoulder Mount Stabilizer. The stills above were from the intro where I used my DIY Follow Focus Ring.
My main concern about the homebrew solutions is clamping something to these expensive lenses. Do you really want to chance bolting a steel plumbing clamp to your lens?
A Follow Focus Ring allows you to manually adjust the lens focus smoothly on the fly. A camera lens is already designed to do that, so a Follow Focus Ring just needs to make it easier. The $1000+ solutions from Redrock Micro and Zacuto do it by adding gears and a dial knob. But, all you really need is a handle on the lens to make adjusting the focus easier. That’s where the jar opener comes in.
I was hoping to point you to a place where you could purchase this jar opener, but it is harder to find than I thought. Ace Hardware carried the jar opener in red during the Summer 2009, but is now a clearance item. I went to Bed Bath & Beyond as found this one.
It works for a small lens, but it can get you thinking. It needs to be a jar opener with a flexible open ended design which can accommodate large jars of various sizes. So, before you spend $1000+ on a Redrock Micro or Zacuto rig, stop in the kitchen and see what you find.