I have the 12586 lens hood for the 50mm f1.4 pre-asph lens. The unit unscrews to accept filters (I assume). What series size filters do I need and how are they held in place? I understand that I need to use a special slim 43mm filter if I want to hood to fit, but I'd rather just use drop in filters if that is possible. Why else would the hood unscrew into two parts otherwise?
Thanks
LarryK