Just bought a fascinating antique Minolta CPL from a nice gentleman. 72mm thread, but the filter size is 77mm - works almost like a permanent step-up ring. To prevent any vignetting from happening at all. Turning on the CPL is nice and tight, unlike the Hoya equivalent. Glass seems excellent. Only problem is that I have no lens cap to fit it.
I actually prefer the CPL to turn easily, so I can quickly run it through 360deg to see at which angle gives the greatest effect. Maybe its just me :dunno: