Question for M.Zuiko 45mm f/1.8 owners
Ok, that's helpful. I guess I won't be buying the bayonet-mount hood, then.
As for the closeup filter, I have the Kenko auto extension tubes for my macro needs, but a whole set of NDs that are 58mm and fit my other lenses. Perhaps a 3rd party metal hood on a step-up ring is the answer.
Thanks for everyone's input!