Now we see through a glass, darkly...
- Apr 5, 2016
Also, I like to protect my expensive lenses from dust/prints/scratches with the best clear filter you can get, and I prefer B+W XS Pro Nano ones. I also get that type in C-Polarizers if I want one of them. I don't think it's good to put an "ordinary / freebie" filter on a really extraordinary lens, but to each their own.
Some of us don't think it is good to put any kind of unnecessary "protective" filter on an extraordinary lens unless there's an actual environmental reason, such as wind-blown sand or salt-water spray or small bits of hot metal flying around in an industrial environment, that compels one to do so. To each their own. YMMV.