Many years ago a got a prewar Cooke and Perkins shade for the Elmar 50mm f/3.5 that offers control of the f/stop of the lens.
This week I've found the lens cap that belongs to it! This cap slips into
this shade, right from the front. Exact fit.
When I look at the lens cap very closely, I see traces of wear on the outside, not on the inside. That gives me the certainty that the lens cap belongs to the Cooke and Perkins lens hood. Unbelievable. The Cooke and Perkins lens hood is in itself quite rare.
Finally back together again! After so many years.