Like the CPL405, the newer - all polymer - CPL460, for the 800 PF, does not let you remove the CPL to screw in a different filter.
Nikon's internal CPL's have always been pricey, with different models of a very similar system of a geared rotating mechanism. They include the G type 52mm, and E type 40.6mm. Just to complicate things, the 800 f5.6E still uses the older 52mm design of rotating CPL (of the G type era).
Unlike the older F-Mount exotic telephotos, the clip-in cover that fills the filter slot of the 800 PF has no clear internal filter, which is integral to the optical formula of the respective F-mount exotics.
However, you can flip up the hinged frame cover to screw in a filter - labelled as ø 46mm (just visible below). This hinged cover clips into place.... a less obvious feature of the well designed 800 f6.3S PF that I've not seen mentioned in reviews etc of this lens.
However, Nikon states their 46mm NC is
compatible with the 400 f2.8S TC, and this OEM internal holder seems to be the only way to use filters.
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