Anyone who had been working on Canon FD 24mm f2.8 will understand what I mean by design disaster when talking about the lens. Forget about all the other quirks, the biggest issue this lens has is the bushing sliders that deteriorate over time causing loose focusing and moving rear element.
Canon decided to use brass bushing sliders covered with a plastic layer. The plastic deteriorate over time leaving the bushing bare brass cores. Beside the issue with plastic pieces getting to helicoid threads, the lens suffered from bad loose focusing and the rear assembly moving badly. When I shook the lens, I can hear the rear assembly knocking back and forth crazily inside.
I had been looking for a solution for the problem for quite a bit and was thinking about a few things ranging from making new bushings to covering the brass bushing cores with some materials. Nothing seemed to be a good solution to my feeling. I just came to an idea last night that electrolytic capacitors might be good for the job. It was not a trivial task like it seems. I needed to file both the inside and the outside of the tiny tube to have 3.96mm external diameter and 3.65mm internal diameter. There are four of them. Luckily, the project was completed successfully and the lens work smoothly with zero play.
