| Sometimes there is a flange on the filter ring that is 'rolled over' to hold the glass in place. Hoya sometimes uses a spring wire that retains the lens. And sometimes the screw-in retaining ring doesn't have any notches in it and looks like part of the main filter ring - you either need to make a friction tool to remove it or drill a pair of holes to allow use of a spanner wrench.
You don't say if you want to save the glass, the ring or both. |