Hoping someone can help. I have a really lovely Zeiss Flektogon 20mm but it's developed a looseness/rattle.
You can see (and hear!) from the video that the Aperture Ring and the plastic cover behind it are loose and are free to move backwards and forwards, and the Aprture Ring itself moves loosely and smoothly with no clicking into place.
As you can see, if I squeeze everything together the Aperture Ring goes back to having a nice click and positive feel.
1/2