Hi all,
I confirm what Paul is saying, I have a filter stuck to a Wide Angle Lens adaptor of 77 mm, I have never been able to get them separate, after several months I'm reaching the point of sacrificing the filter to be able to recover the adapter ( more or less same price...).
I'm using the 105mm adapter with an Heliopan 105 slim polarizer in the front. With two filter holders plus the polarizer holder in front of it, around 17~18 mm I start to see the polarizer holder in the scene, also, with the Canon 24 TS-E II, around 9-10 mm shift I start seeing the polarizer filter holder.
Best regards,
David