Have an RB67, and stopped at a thrift store that was selling 7, assorted 77mm Tiffen filters, for $28. What a steal, and I'm very happy with that.. all in good shape, but I'm having trouble with the narrow Tiff circular Polarizer. Getting it on is easy, but getting it off, as the base with the thread is only about 3/32 wide, is difficult, making it very hard to grip, to take it off a 90mm lens. Had to use a small screw driver tip, twice, to 'grab' the notches, to start it off... not liking that solution very well.. Any suggestions? Those with the same filter, must have the same difficulty, what have you done to rectify this?