The ring should not be fastened too tightly against the Zoom or Focus Ring. Otherwise, the mechanism is possibly stiff. Sits the ring is not tight enough, he slips through. Possible solution: Den or the lens rings with Lasso tape, etc. thus wrapping the Fokkusierring softer rests. A professional solution is not. Suitable as a last resort. Be careful when screwing in the Focus lever: plastic fine thread!
