Recommendations for Circular Polarizer & Variable ND filter

There are a lot of decent circular polarisers out there, but also a lot of iffy VNDs. There's a right way to design a VND and assorted people have gone for a cheaper and less good route, where it's also an uncontrollable C.Pol as well.

A quick test for a VND is hold the whole filter and look at a LCD (not OLED!) screen and with it set to its least blocking setting rotate the whole filter. If the screen goes dark at some point try another one. Don't worry about minor colour changes (as it's a massively more intense test than you'll see in real life).

Note all VNDs will make a darker large X shape on the image if you turn them too dark, however some have hard stops to prevent you getting there and not noticing as you're concentrating on the subject.

I also like VNDs that open quite bright, as you can take "normal" shots without having to remove them in more cases.

Some VNDs will soften the image at long focal lengths, I'm not sure reviewers test for this so maybe do a comparison on any you buy while you can still send it back. Probably not that common.

You may also get a small colour cast, some are good, really cheapy ones less so.

Heliopan make good but expensive and heavy VHDs. B+W are fine for C.Pols if you get their multicoated (MRC and probably slim) ones. Hoya used to make great VNDs but now make lousy ones. I'd be okay with a Hoya C.Pol if it was from one of their better ranges.

I'm not particularly recommending Heliopan for VNDs, as they are expensive, it's just I know they are good. If I get another one I'd probably look at other manufacturers.

Whether you can add a filter in front of a VND is really an issue of how over-size the filter threads on the lens are and whether it is already vignetting a lot. Heliopan do versions with and without front threads.

More detail for the curious:

https://www.dpreview.com/forums/post/64445766

https://www.dpreview.com/forums/post/62857109

https://www.dpreview.com/forums/post/62864515