I'm new to filters. I am considering buying a circular polarising filter. I would probably want to use it most on my Nikkor AF-S 24-70 f3.5-4.5 VR, which has a 72mm thread and by Nikkor 20mm f2.8 AF-D, which has a 62mm thread.
I was thinking I would therefore buy a 72mm filter and a 72 to 62 step down ring.
Is there any reason not to do this? (e.g. vignetting? the 20mm is already quite bad for that)
I am unlikely to buy any more lenses in the future that I would want to use this filter on.
Thanks in advance.